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This study investigated the successful synthesis and characterization of nonisocyanate polyurethanes (NIPUs) based on polylactide. The NIPUs were synthesized by a condensation reaction of oligomers with hard segments (HSs) and synthesized carbamate-modified polylactic acid containing flexible segments (FSs). The oligomers with HSs were prepared from phenolsulfonic acid (PSA) or a mixture of PSA and hydroxynaphthalenesulfonic acid (HNSA), urea and formaldehyde. The mixing of oligomeric compounds with different amounts of formaldehyde was carried out at room temperature. Obtained NIPU samples with different hard segment content were tested for their mechanical and thermal properties. The tensile strength (TS) of all NIPU samples increased with an increasing amount of HSs, attaining the maximum value at an HS:FS ratio of 1:3. Samples prepared from PSA and HNSA showed higher tensile strength (TS) without significant change in elongation at break compared to the samples based only on PSA. Thermogravimetric analysis data indicated an absence of weight loss for all samples below 100 °C, which can be considered a safe temperature for using NIPU materials. Maximum degradation temperatures reached up to 385 °C. Fourier transform infrared spectroscopy results confirmed the existence of expected specific groups as well as the chemical structure of the prepared polyurethanes. DSC analysis showed the existence of two characteristic phase transitions attributed to the melting and crystallization of hard segments in the NIPU samples.

Blends of poly(lactic acid) (PLA) with poly(propylene carbonate) (PPC) are currently in the phase of intensive study due to their promising properties and environmentally friendly features. Intensive study and further commercialization of PPC-based polymers or their blends, as usual, will soon face the problem of their waste occurring in the environment, including soil. For this reason, it is worth comprehensively studying the degradation rate of these polymers over a long period of time in soil and, for comparison, in phosphate buffer to understand the difference in this process and evaluate the potential application of such materials toward agrochemical and agricultural purposes. The degradation rate of the samples was generally accompanied by weight loss and a decrease in molecular weight, which was facilitated by the presence of PPC. The incubation of the samples in the aqueous media yielded greater surface erosions compared to the degradation in soil, which was attributed to the leaching of the low molecular degradation species out of the foils. The phytotoxicity study confirmed the no toxic impact of the PPC on tested plants, indicating it as a “green” material, which is crucial information for further, more comprehensive study of this polymer toward any type of sustainable application.

This study aims to synthesize sustainable polylactide (PLA) materials, specifically polyester-urethanes based on PLAs with various molecular weights, to enhance thermal shape stability through crosslinking and enable reprocessing due to the presence of a new type of dynamic/reversible covalent bonds in the polymer structure. PLA-based networks containing dynamic bonds were prepared by coupling (using hexamethylene diisocyanate) PLA star polymers bearing four terminal -OH groups with a low molecular weight diol containing groups that undergo reversible dissociation upon heating. The PLAs prepolymers of two molecular weights (Mn = 3700 and 7800 g/mol) were synthesized via cationic polymerization of D,L-lactide to obtain the networks of different crosslinking densities. The low molecular weight diol, containing a tetraphenylethane moiety (TPE) with an easy dissociating bond, was synthesized from 4-hydroxybenzophenone. Networks without reversible bonds, containing 1,1′-bi-2-naphthol (binol) instead of TPE units, were also prepared as a reference. All networks were analyzed by Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis and were subjected to tensile tests. The tensile strength of all networks was in the range of 22–45 MPa. The elongations at break of networks differed based on the type of used low molecular weight diol, with values in the range of 28–67% for TPE-containing networks, in comparison with 10% for reference samples. Rheological studies of these materials were performed at a higher temperature (150 °C) to clearly demonstrate the behavioral differences between networks with and without “reversible” bonds. Only the networks with TPE groups were able to recover their previous strength after strain deformation at 150 °C in four subsequent cycles. Moreover, it was shown that networks with reversible groups were repairable and 3D printable at temperatures as low as 150 °C, while those containing non-reve

Composite materials based on PLA have been studied in depth for many applications, including food packaging. This manuscript describes extensive research conducted on a biodegradable polymer (PLA), inorganic filler (CaCO3), and polyester-based plasticizer (PEP, based on a copolymer of low-molecular-weight PLA and PEG) prepared under semi-industrial conditions, as applicable for the packaging of hot food. The properties of the composite were achieved by post-processing annealing, notably its thermal stability, thereby permitting contact of the material with hot food. The manner of processing was deemed suitable for deployment at an industrial scale, moreover, the thermal stability of the final product endured, evidencing its applicability for such packaging. Change in the morphology of the structure of the composite material depended on the composition and annealing process, as detailed herein. The effect of the post-production thermal annealing on the molecular weight of samples was studied using the gel permeation chromatography. The thermal properties of the composites were investigated by differential scanning calorimetry, dynamic mechanical analysis, and thermogravimetric analysis. The crystallinity was assessed using X-ray diffraction technique, while mechanical behavior was tested in relation to the given tensile properties, shape stability at high temperature, and permeability by the transmission rates of gas/water vapor.

An optimization study utilizing response surface methodology (RSM) and central composite design (CCD) was conducted to investigate batch foaming processes using supercritical CO2 as the physical blowing agent for neat polylactide (PLA) and polylactide/polyurethane (PLA/PU) blend foams. This study investigates the effect of single processing parameters on the properties of neat PLA foams. We demonstrate a complex interplay between foaming conditions and resulting foam properties, driven by competing effects of cell collapse and nucleation under varying temperatures, pressure, and time. Notably, thicker cell walls and higher sphericity, achieved through optimized foaming conditions, significantly enhance the foam’s compressive modulus and resistance to localized collapse. These findings underscore the critical role of processing parameters in tailoring the mechanical properties of PLA foams for diverse applications. Significant interactions between foaming process parameters were identified, impacting the properties of neat PLA foams. Foam density and average cell size exhibited an inverse relationship with foaming temperature and time. Initially, increases in both parameters decreased foam density and increased average cell size, attributed to enhanced gas dissolution at higher temperatures and longer durations, promoting rapid cell growth. Subsequent rises in these factors slightly increased foam density, possibly due to instability of foam structure and excessive gas diffusion. Compressive modulus was influenced by temperature and time, achieving the highest modulus at 50% strain under shorter foaming times and lower temperatures, facilitating rapid PLA solidification and smaller crystallite growth. Cell density decreased with rising temperature and pressure, likely from increased CO2 dissolution fostering more cell nuclei and reduced cell merging. Optimal lightweight PLA foams were obtained at 180°C, 165 bar, and 2.3 hours. Moreover, chemically recycled PLA, synth

The structural, thermal, and mechanical properties of unreinforced and reinforced polylactic acid (PLA) were investigated. The PLA was a biopolymer that was reinforced with four fillers (i.e., graphene oxide (GO) and silver (Ag); vermiculite (VMT) and silver (Ag); and two organically modified vermiculites). The processing technique for the production of the composite materials were carefully planned. The PLA nanocomposites were investigated by examining their morphological aspects, changes in PLA phases and transitions and, most importantly, the effect on certain final properties. X-ray diffraction and differential scanning calorimetry (DSC) analysis indicated that the sample was completely amorphous. Thermogravimetric analysis (TGA) results indicated that the presence of reinforcing particles in the PLA matrix did not affect the thermal degradation of these composites. Furthermore, the local mechanical properties were investigated using the microindentation method to evaluate the effect of different nanofillers. Scanning electron microscopy (SEM) and a VHX-500 optical digital microscope (Keyence International, Mechelen, Belgium) were also used to examine the surface morphology of the PLA polymer composites. These results can help to select suitable fillers to enhance the PLA performance of biopolymers.

In the study, an investigation was made into the hydrolytic degradation behavior of the microporous polylactide (PLA) in the initial stage in three biological buffer solutions with various pH-simulating body fluids in comparison with pure PLA. Studies also include the analysis of selected mechanical properties and physical structures. A microporous PLA was obtained by melt extrusion using a chemical blowing agent. The rate of Mw decrease induced by hydrolysis over 35 days of microporous PLA was roughly comparable to the pure material. The rate of depolymerization was slightly accelerated at an acid pH due to acid-catalyzed hydrolysis at the end of the observed period. The mechanical analysis showed the influence of various pH on the obtained results.

This work presents, for the first time, a detailed report on how the nucleation and crystallization of polylactide (PLLA) are affected by biobased aliphatic polyesters plasticizers. Three biobased polyesters were synthesized via solvent-free two-stage melt polycondensation of adipic acid (AdA) with three different biobased aliphatic diols and used as plasticizers for poly (L-lactic acid) (PLLA). The molecular structure of the synthesized polyesters was proved using H-1 NMR, C-13 NMR and Fourier transform infrared (FTIR) spectroscopy. PLLA/AdA-based blends containing 10 wt% of the polyester plasticizers were studied by tensile tests, dynamic mechanical analysis (DMA), wide-angle x-ray scattering (WAXS), differential scanning calorimetry (DSC) and polarized light optical microscopy (PLOM). Adding the plasticizers to PLLA decreased T-g by up to 11 degrees C and significantly increased the elongation at break by about 8 times compared with neat PLLA. The addition of 10 wt% of any AdA-based plasticizer to PLLA increases the nucleation rate from the glassy state by around 50-110 % depending on the plasticizer. The overall crystallization rate from the glassy state was 2-3 times faster for the plasticized PLLAs than neat PLLA. These results are a consequence of the lower energy barrier for both nucleation and growth processes. The incorporation of AdA-based linear polyesters had an incremental impact on the crystal growth rate (or secondary nucleation) of PLLA spherulites from the melt and glassy states. In conclusion, the AdA-based aliphatic polyesters allowed to enhance PLLA crystallization rates and showed interesting potential for the formulation of fully biobased PLLA blends.

As plastic pollution in aquatic environments keeps happening it has become more and more important to learn more about nanoparticles. Bio-based and biologically degradable plastics, such as polylactic acid (PLA), are gaining popularity and it is therefore important to determine whether they break down into nanoplastics or not. Should this be the case, it is of interest to characterize their size, morphology, surface charge, chemical composition, and determine if they are toxic to aquatic organisms. The approach was to break down five different consumer PLA plastic products in Milli-Q water with an immersion blender. These products were a soup cup lid, coffee cup lid, plastic cup, plastic bag and 3D printer filament. The soup cup lid and coffee cup lid were also exposed to UV-C to see if that made any difference when characterizing them. Manufactured PLA nanoparticles were also purchased and studied. They were then characterized by using tools such as NTA, DLS, FTIR and TEM. To determine the toxicity of the particles, the zooplankton Daphnia magna was exposed to them. The results showed that nanoplastics were formed, with an average size 145 - 230 nm in diameter depending on the product. The particles seemed to have different shapes, there were particles with sharp edges, and particles with round edges. The surface charge differed between the different products, all values indicated they should be unstable in Milli-Q water. However, when the stability was studied with the NTA, they seemed stable. The chemical composition of the soup cup lid, plastic cup and 3D printer filament matched that of pure PLA, while the coffee cup lid and the plastic bag seemed to be made of polystyrene and polyester, terephtalic acid (PET), respectively. The toxicity was tested with the soup cup lid, the UV-C treated soup lid, the plastic bag and the manufactured nanoparticles in a short-term test where the plankton were not fed. They showed no sign of being toxic. On the contrary, the plan, Nanoplaster: Hur ser de ut och är de farliga för vattenlevande organismer? I detta projekt har polylaktid (PLA) brytits ner mekaniskt, för att undersöka om nanoplaster bildas och bestämma vilken storlek de blir. Dessa har sedan använts för att undersöka om de är toxiska för planktonet Daphnia magna. Även fabrikstillverkade PLA-nanopartiklar användes i experimenten. Vi har alla hört talas om plastöarna i haven, och sett videon på en sköldpadda med ett sugrör i näsan. För att minska den stora påverkan plast har på miljön har biologiskt nedbrytbar plast, som PLA, blivit mer populära att använda. En nanopartikel på storleken 100 nm är 400 gånger mindre än bredden på ditt hårstrå. På denna lilla skala kan de ha helt andra egenskaper än partiklar i mikrostorlek, som mikroplaster, och därför är nanopartiklarna otroligt viktiga att studera. Fem konsumentprodukter av PLA bröts i detta projekt ned med en stavmixer för att simulera mekanisk nedbrytning i naturen. Av detta bildades nanoplaster i storlekarna 145-230 nm, och i mikroskop kunde man se att några av partiklarna hade vassa kanter medan andra var mer rundade. När den kemiska sammansättningen av produkterna analyserades var soppskålslocket, plastmuggen och 3D-printer filamenten identiska med ren PLA, medan plastpåsarna liknade polyester, och kaffemuggslocken liknade polystyren. Efter nedbrytning tappade partiklarnas sammansättning likhet med sina respektive hela produkter, men blev istället lika varandra. Toxixciteten hos D. magna testades med partiklar av sopplock, UV-exponerat sopplock, plastpåse och tillverkade PLA-nanopartiklar. I testen hade planktonen ingen mat i vattnet. De tillverkade nanopartiklarna var de enda som påvisade toxicitet. Med nebrutna PLA-partiklar i vattnet levde planktonen längre än kontrollplanktonen, som inte hade någonting alls i vattnet. En gissning till varför detta hände är att bakterier kunde föröka sig på plastpartiklarna tillräckligt mycket för att planktonen skulle kunna livnära sig på

This work presents, for the first time, a detailed report on how the nucleation and crystallization of polylactide (PLLA) are affected by biobased aliphatic polyesters plasticizers. Three biobased polyesters were synthesized via solvent-free two-stage melt polycondensation of adipic acid (AdA) with three different biobased aliphatic diols and used as plasticizers for poly (L-lactic acid) (PLLA). The molecular structure of the synthesized polyesters was proved using 1H NMR, 13C NMR and Fourier transform infrared (FTIR) spectroscopy. PLLA/AdA-based blends containing 10 wt% of the polyester plasticizers were studied by tensile tests, dynamic mechanical analysis (DMA), wide-angle x-ray scattering (WAXS), differential scanning calorimetry (DSC) and polarized light optical microscopy (PLOM). Adding the plasticizers to PLLA decreased Tg by up to 11 °C and significantly increased the elongation at break by about 8 times compared with neat PLLA. The addition of 10 wt% of any AdA-based plasticizer to PLLA increases the nucleation rate from the glassy state by around 50-110 % depending on the plasticizer. The overall crystallization rate from the glassy state was 2-3 times faster for the plasticized PLLAs than neat PLLA. These results are a consequence of the lower energy barrier for both nucleation and growth processes. The incorporation of AdA-based linear polyesters had an incremental impact on the crystal growth rate (or secondary nucleation) of PLLA spherulites from the melt and glassy states. In conclusion, the AdA-based aliphatic polyesters allowed to enhance PLLA crystallization rates and showed interesting potential for the formulation of fully biobased PLLA blends., QC 20230925

The Cosmetic packaging industry is on the rise and through consumer demand, cosmetic companies are increasing their focus on sustainability and accountability. This has left many companies in need of a deeper understanding regarding the environmental impact of their current packaging solutions as well as how to improve their footprint in the future. This thesis addresses these points by providing a life cycle assessment (LCA) of five chosen materials; polypropylene, high-density polyethylene, polylactide, polyhydroxyalkanoates, and aluminium. Due to the differences in physical properties and production methods, the plastics will be modelled as an airless dispenser and the aluminium as a tube with screw cap. Stand-alone environmental footprints as well as comparative results are provided with a discussion and analysis of sensitive parameters (weight, recycled content, recycling rate). The report has found that for the defined base case of 0\% recycled content and current Swedish recycling statistics, polypropylene is the best option. Further, the thesis shows how even smaller changes in the sensitive parameters drastically alter the environmental impact of the materials, emphasizing the importance of always including these parameters into packaging material discussions. This conclusion is of significance due to the lack of nuance that many companies experience when making sustainability decisions. Finally, the report has also provided a framework for working with LCA's in the form of a methodology and a model in the LCA software, OpenLCA. The report is done in collaboration with the Danish skincare company, NØIE., Through consumer demand, cosmetic companies are increasing their focus on sustainability and accountability for their products and packaging. This has left many companies in need of a deeper understanding of how their packaging and product affect the environment. The danish skincare company NØIE is one of these companies and has addressed the need to know how their current packaging for face cream is affecting the environment. Additionally, NØIE is looking to gain information about other materials that can be used and how they stack up beside their current packaging. To meet this need, this thesis employs a methodology called life cycle assessment. In practice, this means looking at the life cycles of the chosen materials from the production of their raw materials to their final waste management processes. The materials chosen can be divided into three categories. Fossil plastics (plastics that are based on oil and natural gas) included in this category are the polymers polypropylene and polyethylene. Bioplastics (plastics that are based on biomass such as corn or sugarcane) included in this category are Polylactide and polyhydroxyalkanoates. The third category is metals, and included is aluminium. Because of differences in how the materials can be processed and their physical properties, they have been divided into two different packaging designs when modelled. The fossil and biobased plastic are modelled as an airless dispenser which is the design currently used by the company, and the aluminium is modelled as a tube with screw cap. The main results from the thesis are firstly that the currently used material of polypropylene shows the least overall impact on the environment compared to the other materials when modelled with 0\% recycled content and recycling rates according to Swedish recycling statistics. Secondly, it can be seen that this result changes depending on the values of three tested variables; weight, recycled content, and recycling rate. These result

This work presents, for the first time, a detailed report on how the nucleation and crystallization of polylactide (PLLA) are affected by biobased aliphatic polyesters plasticizers. Three biobased polyesters were synthesized via solvent-free two-stage melt polycondensation of adipic acid (AdA) with three different biobased aliphatic diols and used as plasticizers for poly (L-lactic acid) (PLLA). The molecular structure of the synthesized polyesters was proved using H-1 NMR, C-13 NMR and Fourier transform infrared (FTIR) spectroscopy. PLLA/AdA-based blends containing 10 wt% of the polyester plasticizers were studied by tensile tests, dynamic mechanical analysis (DMA), wide-angle x-ray scattering (WAXS), differential scanning calorimetry (DSC) and polarized light optical microscopy (PLOM). Adding the plasticizers to PLLA decreased T-g by up to 11 degrees C and significantly increased the elongation at break by about 8 times compared with neat PLLA. The addition of 10 wt% of any AdA-based plasticizer to PLLA increases the nucleation rate from the glassy state by around 50-110 % depending on the plasticizer. The overall crystallization rate from the glassy state was 2-3 times faster for the plasticized PLLAs than neat PLLA. These results are a consequence of the lower energy barrier for both nucleation and growth processes. The incorporation of AdA-based linear polyesters had an incremental impact on the crystal growth rate (or secondary nucleation) of PLLA spherulites from the melt and glassy states. In conclusion, the AdA-based aliphatic polyesters allowed to enhance PLLA crystallization rates and showed interesting potential for the formulation of fully biobased PLLA blends.

As plastic pollution in aquatic environments keeps happening it has become more and more important to learn more about nanoparticles. Bio-based and biologically degradable plastics, such as polylactic acid (PLA), are gaining popularity and it is therefore important to determine whether they break down into nanoplastics or not. Should this be the case, it is of interest to characterize their size, morphology, surface charge, chemical composition, and determine if they are toxic to aquatic organisms. The approach was to break down five different consumer PLA plastic products in Milli-Q water with an immersion blender. These products were a soup cup lid, coffee cup lid, plastic cup, plastic bag and 3D printer filament. The soup cup lid and coffee cup lid were also exposed to UV-C to see if that made any difference when characterizing them. Manufactured PLA nanoparticles were also purchased and studied. They were then characterized by using tools such as NTA, DLS, FTIR and TEM. To determine the toxicity of the particles, the zooplankton Daphnia magna was exposed to them. The results showed that nanoplastics were formed, with an average size 145 - 230 nm in diameter depending on the product. The particles seemed to have different shapes, there were particles with sharp edges, and particles with round edges. The surface charge differed between the different products, all values indicated they should be unstable in Milli-Q water. However, when the stability was studied with the NTA, they seemed stable. The chemical composition of the soup cup lid, plastic cup and 3D printer filament matched that of pure PLA, while the coffee cup lid and the plastic bag seemed to be made of polystyrene and polyester, terephtalic acid (PET), respectively. The toxicity was tested with the soup cup lid, the UV-C treated soup lid, the plastic bag and the manufactured nanoparticles in a short-term test where the plankton were not fed. They showed no sign of being toxic. On the contrary, the plan, Nanoplaster: Hur ser de ut och är de farliga för vattenlevande organismer? I detta projekt har polylaktid (PLA) brytits ner mekaniskt, för att undersöka om nanoplaster bildas och bestämma vilken storlek de blir. Dessa har sedan använts för att undersöka om de är toxiska för planktonet Daphnia magna. Även fabrikstillverkade PLA-nanopartiklar användes i experimenten. Vi har alla hört talas om plastöarna i haven, och sett videon på en sköldpadda med ett sugrör i näsan. För att minska den stora påverkan plast har på miljön har biologiskt nedbrytbar plast, som PLA, blivit mer populära att använda. En nanopartikel på storleken 100 nm är 400 gånger mindre än bredden på ditt hårstrå. På denna lilla skala kan de ha helt andra egenskaper än partiklar i mikrostorlek, som mikroplaster, och därför är nanopartiklarna otroligt viktiga att studera. Fem konsumentprodukter av PLA bröts i detta projekt ned med en stavmixer för att simulera mekanisk nedbrytning i naturen. Av detta bildades nanoplaster i storlekarna 145-230 nm, och i mikroskop kunde man se att några av partiklarna hade vassa kanter medan andra var mer rundade. När den kemiska sammansättningen av produkterna analyserades var soppskålslocket, plastmuggen och 3D-printer filamenten identiska med ren PLA, medan plastpåsarna liknade polyester, och kaffemuggslocken liknade polystyren. Efter nedbrytning tappade partiklarnas sammansättning likhet med sina respektive hela produkter, men blev istället lika varandra. Toxixciteten hos D. magna testades med partiklar av sopplock, UV-exponerat sopplock, plastpåse och tillverkade PLA-nanopartiklar. I testen hade planktonen ingen mat i vattnet. De tillverkade nanopartiklarna var de enda som påvisade toxicitet. Med nebrutna PLA-partiklar i vattnet levde planktonen längre än kontrollplanktonen, som inte hade någonting alls i vattnet. En gissning till varför detta hände är att bakterier kunde föröka sig på plastpartiklarna tillräckligt mycket för att planktonen skulle kunna livnära sig på

Nanocomposites comprising bio-based polymers have become relevant in fields such as food packaging and biomedical applications. Polylactide (PLA) is a chiral and aliphatic polyester that can attain a wide range of tacticities which enables to tailor of the final material properties. However, PLA exhibits hydrophobic characteristics requiring the enhancement of its bioactivity by the generation of composites with hydrophilic materials as an approach to generate multifunctional material. Collagen is a natural and hydrophilic biopolymer that is partially hydrolyzed to obtain a material exhibiting higher solubility in aqueous solutions, namely gelatin, thus improving collagen usability. Herein, a series of free-standing films comprising different concentrations of commercial PLA and gelatin obtained from waste fisheries were produced to afford biocompatible coatings with promising biomedical applications. The multiscale structural characterization performed from the molecular scale (FTIR) to the nano-scale (SAXS/WAXS) level has been correlated with the thermal behaviour (DSC) and degradation (TGA) of the bionanocomposites generated to understand the processing conditions on the final material

The preparation, characterization, and controlled release of hydroxyapatite (HAp) nanoparticles loaded with streptomycin (STR) was studied. These nanoparticles are highly appropriate for the treatment of bacterial infections and are also promising for the treatment of cancer cells. The analyses involved scanning electron microscopy, dynamic light scattering (DLS) and Z-potential measurements, as well as infrared spectroscopy and X-ray diffraction. Both amorphous (ACP) and crystalline (cHAp) hydroxyapatite nanoparticles were considered since they differ in their release behavior (faster and slower for amorphous and crystalline particles, respectively). The encapsulated nanoparticles were finally incorporated into biodegradable and biocompatible polylactide (PLA) scaffolds. The STR load was carried out following different pathways during the synthesis/precipitation of the nanoparticles (i.e., nucleation steps) and also by simple adsorption once the nanoparticles were formed. The loaded nanoparticles were biocompatible according to the study of the cytotoxicity of extracts using different cell lines. FTIR microspectroscopy was also employed to evaluate the cytotoxic effect on cancer cell lines of nanoparticles internalized by endocytosis. The results were promising when amorphous nanoparticles were employed. The nanoparticles loaded with STR increased their size and changed their superficial negative charge to positive. The nanoparticles’ crystallinity decreased, with the consequence that their crystal sizes reduced, when STR was incorporated into their structure. STR maintained its antibacterial activity, although it was reduced during the adsorption into the nanoparticles formed. The STR release was faster from the amorphous ACP nanoparticles and slower from the crystalline cHAp nanoparticles. However, in both cases, the STR release was slower when incorporated in calcium and phosphate during the synthesis. The biocompatibility of these nanoparticles was assayed by t, Peer Reviewed, Postprint (published version)

As plastic pollution in aquatic environments keeps happening it has become more and more important to learn more about nanoparticles. Bio-based and biologically degradable plastics, such as polylactic acid (PLA), are gaining popularity and it is therefore important to determine whether they break down into nanoplastics or not. Should this be the case, it is of interest to characterize their size, morphology, surface charge, chemical composition, and determine if they are toxic to aquatic organisms. The approach was to break down five different consumer PLA plastic products in Milli-Q water with an immersion blender. These products were a soup cup lid, coffee cup lid, plastic cup, plastic bag and 3D printer filament. The soup cup lid and coffee cup lid were also exposed to UV-C to see if that made any difference when characterizing them. Manufactured PLA nanoparticles were also purchased and studied. They were then characterized by using tools such as NTA, DLS, FTIR and TEM. To determine the toxicity of the particles, the zooplankton Daphnia magna was exposed to them. The results showed that nanoplastics were formed, with an average size 145 - 230 nm in diameter depending on the product. The particles seemed to have different shapes, there were particles with sharp edges, and particles with round edges. The surface charge differed between the different products, all values indicated they should be unstable in Milli-Q water. However, when the stability was studied with the NTA, they seemed stable. The chemical composition of the soup cup lid, plastic cup and 3D printer filament matched that of pure PLA, while the coffee cup lid and the plastic bag seemed to be made of polystyrene and polyester, terephtalic acid (PET), respectively. The toxicity was tested with the soup cup lid, the UV-C treated soup lid, the plastic bag and the manufactured nanoparticles in a short-term test where the plankton were not fed. They showed no sign of being toxic. On the contrary, the plan, Nanoplaster: Hur ser de ut och är de farliga för vattenlevande organismer? I detta projekt har polylaktid (PLA) brytits ner mekaniskt, för att undersöka om nanoplaster bildas och bestämma vilken storlek de blir. Dessa har sedan använts för att undersöka om de är toxiska för planktonet Daphnia magna. Även fabrikstillverkade PLA-nanopartiklar användes i experimenten. Vi har alla hört talas om plastöarna i haven, och sett videon på en sköldpadda med ett sugrör i näsan. För att minska den stora påverkan plast har på miljön har biologiskt nedbrytbar plast, som PLA, blivit mer populära att använda. En nanopartikel på storleken 100 nm är 400 gånger mindre än bredden på ditt hårstrå. På denna lilla skala kan de ha helt andra egenskaper än partiklar i mikrostorlek, som mikroplaster, och därför är nanopartiklarna otroligt viktiga att studera. Fem konsumentprodukter av PLA bröts i detta projekt ned med en stavmixer för att simulera mekanisk nedbrytning i naturen. Av detta bildades nanoplaster i storlekarna 145-230 nm, och i mikroskop kunde man se att några av partiklarna hade vassa kanter medan andra var mer rundade. När den kemiska sammansättningen av produkterna analyserades var soppskålslocket, plastmuggen och 3D-printer filamenten identiska med ren PLA, medan plastpåsarna liknade polyester, och kaffemuggslocken liknade polystyren. Efter nedbrytning tappade partiklarnas sammansättning likhet med sina respektive hela produkter, men blev istället lika varandra. Toxixciteten hos D. magna testades med partiklar av sopplock, UV-exponerat sopplock, plastpåse och tillverkade PLA-nanopartiklar. I testen hade planktonen ingen mat i vattnet. De tillverkade nanopartiklarna var de enda som påvisade toxicitet. Med nebrutna PLA-partiklar i vattnet levde planktonen längre än kontrollplanktonen, som inte hade någonting alls i vattnet. En gissning till varför detta hände är att bakterier kunde föröka sig på plastpartiklarna tillräckligt mycket för att planktonen skulle kunna livnära sig på

A series of bionanocomposites composed of shark gelatin hydrogels and PLA nanoparticles featuring different nanostructures were designed to generate multifunctional drug delivery systems with tailored release rates required for personalized treatment approaches. The global conception of the systems was considered from the desired customization of the drug release while featuring the viscoelastic properties needed for their ease of storage and posterior local administration as well as their biocompatibility and cell growth capability for the successful administration at the biomolecular level. The hydrogel matrix offers the support to develop a direct thermal method to convert the typical kinetic trapped nanostructures afforded by the formulation method whilst avoiding the detrimental nanoparticle agglomeration that diminishes their therapeutic effect. The nanoparticles generated were successfully formulated with two different antitumoral compounds (doxorubicin and dasatinib) possessing different structures to prove the loading versatility of the drug delivery system. The bionanocomposites were characterized by several techniques (SEM, DLS, RAMAN, DSC, SAXS/WAXS and rheology) as well as their reversible sol–gel transition upon thermal treatment that occurs during the drug delivery system preparation and the thermal annealing step. In addition, the local applicability of the drug delivery system was assessed by the so-called “syringe test” to validate both the storage capability and its flow properties at simulated physiological conditions. Finally, the drug release profiles of the doxorubicin from both the PLA nanoparticles or the bionanocomposites were analyzed and correlated to the nanostructure of the drug delivery system

This work deals with the preparation and characterization of antimicrobial polymeric composite materials based on polylactide, which is currently widely investigated to produce temporary implants. Polylactide was blended with antimicrobial fillers: silver, hexadecylpyridinium or hexadecyltrimethylammonium bromides anchored on vermiculite or graphene oxide matrices in an amount of 1% wt. The prepared samples were characterized by conventional methods, further they were exposed to degradation tests in physiological saline conditions and characterized for their antimicrobial properties using common pathogen microorganisms. It has been proven that the prepared polylactide composites change their antimicrobial effects after being in physiological saline of pH 7 and 9 for 0-6 months. The weight of the composites changed by about 10%, and antimicrobial properties were growing over time. The effectiveness of the composites was confirmed for 6 months at minimum. Therefore, they are suitable for the preparation of temporary stents, catheters or implants suitable for fracture fixation.

The structural, thermal, and mechanical properties of unreinforced and reinforced polylactic acid (PLA) were investigated. The PLA was a biopolymer that was reinforced with four fillers (i.e., graphene oxide (GO) and silver (Ag); vermiculite (VMT) and silver (Ag); and two organically modified vermiculites). The processing technique for the production of the composite materials were carefully planned. The PLA nanocomposites were investigated by examining their morphological aspects, changes in PLA phases and transitions and, most importantly, the effect on certain final properties. X-ray diffraction and differential scanning calorimetry (DSC) analysis indicated that the sample was completely amorphous. Thermogravimetric analysis (TGA) results indicated that the presence of reinforcing particles in the PLA matrix did not affect the thermal degradation of these composites. Furthermore, the local mechanical properties were investigated using the microindentation method to evaluate the effect of different nanofillers. Scanning electron microscopy (SEM) and a VHX-500 optical digital microscope (Keyence International, Mechelen, Belgium) were also used to examine the surface morphology of the PLA polymer composites. These results can help to select suitable fillers to enhance the PLA performance of biopolymers.

In the study, an investigation was made into the hydrolytic degradation behavior of the microporous polylactide (PLA) in the initial stage in three biological buffer solutions with various pH-simulating body fluids in comparison with pure PLA. Studies also include the analysis of selected mechanical properties and physical structures. A microporous PLA was obtained by melt extrusion using a chemical blowing agent. The rate of Mw decrease induced by hydrolysis over 35 days of microporous PLA was roughly comparable to the pure material. The rate of depolymerization was slightly accelerated at an acid pH due to acid-catalyzed hydrolysis at the end of the observed period. The mechanical analysis showed the influence of various pH on the obtained results.

This study explores the feasibility of modifying the surface liquid spraying method to prepare porous bioscaffolds intended for wound dressing applications. For this purpose, gentamicin sulfate was loaded into polylactide-polyvinyl alcohol bioscaffolds as a highly soluble (hygroscopic) model drug for in vitro release study. Moreover, the influence of inorganic salts including NaCl (10 g/L) and KMnO4 (0.4 mg/L), and post-thermal treatment (T) (80◦ C for 2 min) on the properties of the bioscaffolds were studied. The bioscaffolds were characterized by scanning electron microscopy, Fourier Transform infrared spectroscopy, and differential scanning calorimetry. In addition, other properties including porosity, swelling degree, water vapor transmission rate, entrapment efficiency, and the release of gentamicin sulfate were investigated. Results showed that high concentrations of NaCl (10 g/L) in the aqueous phase led to an increase of around 68% in the initial burst release due to the increase in porosity. In fact, porosity increased from 68.1 ± 1.2 to 94.1 ± 1.5. Moreover, the thermal treatment of the Polylactide-polyvinyl alcohol/NaCl (PLA-PVA/NaCl) bioscaffolds above glass transition temperature (Tg ) reduced the initial burst release by approximately 11% and prolonged the release of the drug. These results suggest that thermal treatment of polymer above Tg can be an efficient approach for a sustained release. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Lactide copolymers were developed to increase the utility of biodegradable polymers. Using redox switchable ring-opening polymerization, we synthesized a series of zirconium compounds to be used as precatalysts. We studied their geometry change behaviors in polymerization, and one compound, (salfen)Zr(OiPr)2 (salfen = N,N′-bis(2,4-di-tert-butylphenoxy)-1,1′-ferrocenediimine), was selected and then tested as a precatalyst for redox switchable ring-opening polymerization. Copolymers from LA (lactide) and CHO (cyclohexene oxide) were prepared as a proof of concept, and conditions were optimized for the redox switchable copolymerization method. LA-LO (limonene oxide) copolymers were then prepared and their solid state self-assembly properties were studied. Finally, LA-CHDO (cyclohexadiene oxide) copolymers were prepared and post-functionalized to enhance the mechanical properties.

[EN] This research work reports the potential of maleinized linseed oil (MLO) as biobased compatibilizer in polylactide (PLA) and a thermoplastic elastomer, namely, polystyrene¿b¿(ethylene¿ran¿butylene)¿b¿styrene (SEBS) blends (PLA/SEBS), with improved impact strength for the packaging industry. The effects of MLO are compared with a conventional polystyrene¿b¿poly(ethylene¿ran¿butylene)¿b¿polystyrene¿graft¿maleic anhydride terpolymer (SEBS¿g¿MA) since it is widely used in these blends. Uncompatibilized and compatibilized PLA/SEBS blends can be manufactured by extrusion and then shaped into standard samples for further characterization by mechanical, thermal, morphological, dynamical¿mechanical, wetting and colour standard tests. The obtained results indicate that the uncompatibilized PLA/SEBS blend containing 20 wt.% SEBS gives improved toughness (4.8 kJ/m2) compared to neat PLA (1.3 kJ/m2). Nevertheless, the same blend compatibilized with MLO leads to an increase in impact strength up to 6.1 kJ/m2, thus giving evidence of the potential of MLO to compete with other petroleum¿ derived compatibilizers to obtain tough PLA formulations. MLO also provides increased ductile properties, since neat PLA is a brittle polymer with an elongation at break of 7.4%, while its blend with 20 wt.% SEBS and MLO as compatibilizer offers an elongation at break of 50.2%, much higher than that provided by typical SEBS¿g¿MA compatibilizer (10.1%). MLO provides a slight decrease (about 3 °C lower) in the glass transition temperature (Tg) of the PLA¿rich phase, thus showing some plasticization effects. Although MLO addition leads to some yellowing due to its intrinsic yellow colour, this can contribute to serving as a UV light barrier with interesting applications in the packaging industry. Therefore, MLO represents a cost¿effective and sustainable solution to the use of conventional petroleum¿derived compatibilizers.

This study investigated the effect of natural antioxidants inherent to beetroot (Beta vulgaris var. Vulgaris) on the ageing of environmentally friendly plastics. Certain properties were examined in this context, comprising thermal, mechanical, and morphological properties. A visual evaluation of relevant changes in the given polymers (polylactide and polycaprolactone) was conducted during an ageing test in a UV chamber (45◦C, 70% humidity) for 720 h. The films were prepared by a casting process, in which samples with the extract of beetroot were additionally incorporated in a common filler (bentonite), this serving as a carrier for the extract. The results showed the effect of the incorporated antioxidant, which was added to stabilize the biodegradable films. Its efficiency during the ageing test in the polymers tended to exceed or be comparable to that of the reference sample. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

[EN] This research work reports the potential of maleinized linseed oil (MLO) as biobased compatibilizer in polylactide (PLA) and a thermoplastic elastomer, namely, polystyrene¿b¿(ethylene¿ran¿butylene)¿b¿styrene (SEBS) blends (PLA/SEBS), with improved impact strength for the packaging industry. The effects of MLO are compared with a conventional polystyrene¿b¿poly(ethylene¿ran¿butylene)¿b¿polystyrene¿graft¿maleic anhydride terpolymer (SEBS¿g¿MA) since it is widely used in these blends. Uncompatibilized and compatibilized PLA/SEBS blends can be manufactured by extrusion and then shaped into standard samples for further characterization by mechanical, thermal, morphological, dynamical¿mechanical, wetting and colour standard tests. The obtained results indicate that the uncompatibilized PLA/SEBS blend containing 20 wt.% SEBS gives improved toughness (4.8 kJ/m2) compared to neat PLA (1.3 kJ/m2). Nevertheless, the same blend compatibilized with MLO leads to an increase in impact strength up to 6.1 kJ/m2, thus giving evidence of the potential of MLO to compete with other petroleum¿ derived compatibilizers to obtain tough PLA formulations. MLO also provides increased ductile properties, since neat PLA is a brittle polymer with an elongation at break of 7.4%, while its blend with 20 wt.% SEBS and MLO as compatibilizer offers an elongation at break of 50.2%, much higher than that provided by typical SEBS¿g¿MA compatibilizer (10.1%). MLO provides a slight decrease (about 3 °C lower) in the glass transition temperature (Tg) of the PLA¿rich phase, thus showing some plasticization effects. Although MLO addition leads to some yellowing due to its intrinsic yellow colour, this can contribute to serving as a UV light barrier with interesting applications in the packaging industry. Therefore, MLO represents a cost¿effective and sustainable solution to the use of conventional petroleum¿derived compatibilizers.

[EN]In the present work, crystallization of a soluble nucleator N, N′, N″-tricyclohexyl-1,3,5-benzenetricarboxylamide (TMC-328) in a poly(l-lactic acid) (PLLA) matrix has been studied at different temperatures. Based on the change in solubility with temperature, different levels of supersaturation of TMC-328 in a PLLA matrix can be obtained. This nucleator presents a fibrous structure produced via self-assembling and develops into an interconnected network when the temperature is lowered. The TMC-328 crystal nuclei density is quantified via optical microscopy, using the average distance of the adjacent fibrillar structure, which shows a steady decrease with the decrease in temperature. The crystallization rates of TMC-328 were assessed through rheological measurements of network formation. Both fibrils’ density and crystallization kinetics display a power law dependence on supersaturation. For the first time, the solid–melt interfacial energy, the size of the critical nucleus, and the number of molecules making up the critical nucleus of the nucleator TMC-328 in the PLLA matrix have been determined by adopting the classical nucleation theory. The subsequent crystallization of PLLA induced by this nucleator was investigated as a function of the fibrils’ spatial density. The crystallization rate of PLLA is enhanced with the increase in the TMC-328 fibrils’ density because of the availability of a larger nucleating surface. The self-assembled fibril of TMC-328 can serve as shish to form a hybrid shish-kebab structure after the crystallization of PLLA, regardless of the number of nucleation sites.

One of the methods of making traditional polymers more environmentally friendly is to modify them with natural materials or their biodegradable, synthetic equivalents. It was assumed that blends with polylactide (PLA), polysaccharides: chitosan (Ch) and starch (St) of branched polyurethane (PUR) based on synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) would degrade faster in the processes of hydrolysis and oxidation than pure PUR. For the sake of simplicity in the publication, all three modifiers: commercial PLA, Ch created by chemical modification of chitin and St are called bioadditives. The samples were incubated in a hydrolytic and oxidizing environment for 36 weeks and 11 weeks, respectively. The degradation process was assessed by observation of the chemical structure as well as the change in the mass of the samples, their molecular weight, surface morphology and thermal properties. It was found that the PUR samples with the highest amount of R,S-PHB and the lowest amount of polycaprolactone triol (PCLtriol) were degraded the most. Moreover, blending with St had the greatest impact on the susceptibility to degradation of PUR. However, the rate of weight loss of the samples was low, and after 36 weeks of incubation in the hydrolytic solution, it did not exceed 7% by weight. The weight loss of Ch and PLA blends was even smaller. However, a significant reduction in molecular weight, changes in morphology and changes in thermal properties indicated that the degradation of the samples should occur quickly after this time. Therefore, when using these polyurethanes and their blends, it should be taken into account that they should decompose slowly in their initial life. In summary, this process can be modified by changing the amount of R,S-PHB, the degree of cross-linking, and the type and amount of second blend component added (bioadditives).

[EN] This work reports on the development of polylactide (PLA) and polycarbonate (PC) blends with different compatibilizers with enhanced toughness. Since both polymers are immiscible, two types of compatibilizers are tested: petrochemical-based copolymers Xibond 160 and Xibond 920 with maleic anhydride and epoxy groups, respectively, and natural-based compatibilizers with the same functionalities, namely maleinized linseed oil (MLO) and, epoxidized linseed oil (ELO). Mechanical, thermal, and morphological characterization shows better properties for the PLA/PC (80/20 wt%) blends with chemically modified natural oils (ELO and MLO). The addition of 5 phr (parts per hundred resin) of MLO gives the maximum values for impact strength and elongation at break. Moreover, the glass transition temperature (Tg) slightly decreases with the addition of natural compatibilizers, thus showing some plasticization effect. Petroleum-derived compatibilizers give interesting results regarding tensile strength and stiffness without plasticization. PLA/PC blends show higher thermal stability than neat PLA, regardless of the compatibilizer used, since PC is much more thermally stable than PLA. The obtained results indicate that both petroleum-based and natural-derived compatibilizers positively contribute to enhance the properties of the binary PLA/PC blends. Nevertheless, the results with MLO suggest this is an interesting biobased solution to provide increased toughness to PLA/PC blends.

[EN] This research work reports the potential of maleinized linseed oil (MLO) as biobased compatibilizer in polylactide (PLA) and a thermoplastic elastomer, namely, polystyrene¿b¿(ethylene¿ran¿butylene)¿b¿styrene (SEBS) blends (PLA/SEBS), with improved impact strength for the packaging industry. The effects of MLO are compared with a conventional polystyrene¿b¿poly(ethylene¿ran¿butylene)¿b¿polystyrene¿graft¿maleic anhydride terpolymer (SEBS¿g¿MA) since it is widely used in these blends. Uncompatibilized and compatibilized PLA/SEBS blends can be manufactured by extrusion and then shaped into standard samples for further characterization by mechanical, thermal, morphological, dynamical¿mechanical, wetting and colour standard tests. The obtained results indicate that the uncompatibilized PLA/SEBS blend containing 20 wt.% SEBS gives improved toughness (4.8 kJ/m2) compared to neat PLA (1.3 kJ/m2). Nevertheless, the same blend compatibilized with MLO leads to an increase in impact strength up to 6.1 kJ/m2, thus giving evidence of the potential of MLO to compete with other petroleum¿ derived compatibilizers to obtain tough PLA formulations. MLO also provides increased ductile properties, since neat PLA is a brittle polymer with an elongation at break of 7.4%, while its blend with 20 wt.% SEBS and MLO as compatibilizer offers an elongation at break of 50.2%, much higher than that provided by typical SEBS¿g¿MA compatibilizer (10.1%). MLO provides a slight decrease (about 3 °C lower) in the glass transition temperature (Tg) of the PLA¿rich phase, thus showing some plasticization effects. Although MLO addition leads to some yellowing due to its intrinsic yellow colour, this can contribute to serving as a UV light barrier with interesting applications in the packaging industry. Therefore, MLO represents a cost¿effective and sustainable solution to the use of conventional petroleum¿derived compatibilizers.

[EN] This work reports on the development of polylactide (PLA) and polycarbonate (PC) blends with different compatibilizers with enhanced toughness. Since both polymers are immiscible, two types of compatibilizers are tested: petrochemical-based copolymers Xibond 160 and Xibond 920 with maleic anhydride and epoxy groups, respectively, and natural-based compatibilizers with the same functionalities, namely maleinized linseed oil (MLO) and, epoxidized linseed oil (ELO). Mechanical, thermal, and morphological characterization shows better properties for the PLA/PC (80/20 wt%) blends with chemically modified natural oils (ELO and MLO). The addition of 5 phr (parts per hundred resin) of MLO gives the maximum values for impact strength and elongation at break. Moreover, the glass transition temperature (Tg) slightly decreases with the addition of natural compatibilizers, thus showing some plasticization effect. Petroleum-derived compatibilizers give interesting results regarding tensile strength and stiffness without plasticization. PLA/PC blends show higher thermal stability than neat PLA, regardless of the compatibilizer used, since PC is much more thermally stable than PLA. The obtained results indicate that both petroleum-based and natural-derived compatibilizers positively contribute to enhance the properties of the binary PLA/PC blends. Nevertheless, the results with MLO suggest this is an interesting biobased solution to provide increased toughness to PLA/PC blends.

Lactide-valerolactone copolymers have potential application in the packaging sector. Different copolymers were synthesized, and the kinetics of the copolymerization reactions and the microstructure of the copolymers were analysed. Lactide showed higher reactivity than valerolactone which leads to composition drift through the reaction. Thermal, mechanical and barrier properties of the selected copolymers were studied. Overall, the incorporation of valerolactone results in copolymers with higher ductility than poly(lactide) with intermediate water and oxygen permeability which makes these materials appropriate candidates for use in the packaging sector.

[EN] This work reports on the development of polylactide (PLA) and polycarbonate (PC) blends with different compatibilizers with enhanced toughness. Since both polymers are immiscible, two types of compatibilizers are tested: petrochemical-based copolymers Xibond 160 and Xibond 920 with maleic anhydride and epoxy groups, respectively, and natural-based compatibilizers with the same functionalities, namely maleinized linseed oil (MLO) and, epoxidized linseed oil (ELO). Mechanical, thermal, and morphological characterization shows better properties for the PLA/PC (80/20 wt%) blends with chemically modified natural oils (ELO and MLO). The addition of 5 phr (parts per hundred resin) of MLO gives the maximum values for impact strength and elongation at break. Moreover, the glass transition temperature (Tg) slightly decreases with the addition of natural compatibilizers, thus showing some plasticization effect. Petroleum-derived compatibilizers give interesting results regarding tensile strength and stiffness without plasticization. PLA/PC blends show higher thermal stability than neat PLA, regardless of the compatibilizer used, since PC is much more thermally stable than PLA. The obtained results indicate that both petroleum-based and natural-derived compatibilizers positively contribute to enhance the properties of the binary PLA/PC blends. Nevertheless, the results with MLO suggest this is an interesting biobased solution to provide increased toughness to PLA/PC blends.

Producción Científica, The kinetics of crystallization of Polylactic Acid (PLA) in the presence of CO2 pressures from 1.5 to 4 MPa, has been studied by measuring the optical absorbance evolution of the material with time. To perform this study, an own-designed pressure vessel provided with windows has been used. The non-destructive approach presented in this paper allows for obtaining very accurate crystallinity data as a function of time for a wide range of pressures. Besides, this new approach allows measuring with spatial resolution, i.e., obtaining the crystallization kinetics' evolution in different areas of the samples, which helps to analyze in detail the crystallization mechanisms by using the Avrami approach. The results obtained have allowed observing an unexpected peak in the absorbance curve connected with the physical phenomena taking place during the CO2 uptake and the associated crystallization of PLA., Junta de Castilla y León (grant VA202P20), Ministerio de Ciencia e Innovación (grants RTI2018-098749-B-I00 and RTI2018-097367-A-I00)

Reinforced plastic composites are a class of that are both strong and light. They typically consist of a strong fiber surrounded by a softer matrix. The performance of the material as a whole is strongly dependent on the properties of the fibers. Although the performance of reinforced composites is excellent, they are not easily reused after they fail. Reinforced composites can be recycled via different routes: recovery of the fibers or mechanical recycling of the complete composite. The second route is generally favorable, but the material properties decrease as the fibers are damaged in the process. This research was focused on the development of composite materials where the reinforcing fibers are formed while the materials is molded into a product. Upon recycling, the material is molten and remolded allowing the fibers to be formed again. Therefore, the developed composites are not only strong and light but also more sustainable.

Eumelanin as a natural pigment present several key functional properties that can protect human skin from ultraviolet (UV) light. Photoprotection ability that can absorb most of the UV light as a result of aromatic compounds in its structures has drawn vast interest to harness its excellent properties for various applications. Major drawbacks shown by organic molecules as UV absorber that limits their application includes their short lifespan. Encapsulation of the compound by various shell materials has been extensively studied to further optimize and extend its shielding efficiency from UV radiation. Polylactide (PLA)-based copolymers are widely used in encapsulation of various active compounds, due to their biocompatibility and biodegradability, promoting the sustained release of the active compounds. In this study, stereocomplex PLA (sc-PLA) formed by blending of poly(D-lactide-caprolactone-D-lactide), P(DLAb-CL-b-DLA), triblock copolymer with linear poly(L-lactide), PLLA, was employed in the encapsulation of eumelanin. An oil in water emulsion (O/W) approach followed by solvent evaporation was performed in encapsulation process. Effect of eumelanin distribution in PLA’s enantiomers and ultrasonication on physicochemical properties, encapsulation efficiency, and release behavior of nano/microparticles was evaluated. The potential application of the resulting particles for sunscreen was also examined by measuring the UV absorbance and in vitro sun protection factor (SPF) of sunscreen containing particles in the UVA-UVB region. FTIR spectra of the particles show characteristic peaks of sc-PLA with the changes in the intensity of significant peaks that correspond to eumelanin, denoting the success of the encapsulation process. Morphological image analysis reveals that the resulting particles have spherical shaped with the particle size that can be controlled by applying ultrasonication. Distribution of eumelanin in copolymer and ultrasonication process promote the g

[EN]In the present work, crystallization of a soluble nucleator N, N′, N″-tricyclohexyl-1,3,5-benzenetricarboxylamide (TMC-328) in a poly(l-lactic acid) (PLLA) matrix has been studied at different temperatures. Based on the change in solubility with temperature, different levels of supersaturation of TMC-328 in a PLLA matrix can be obtained. This nucleator presents a fibrous structure produced via self-assembling and develops into an interconnected network when the temperature is lowered. The TMC-328 crystal nuclei density is quantified via optical microscopy, using the average distance of the adjacent fibrillar structure, which shows a steady decrease with the decrease in temperature. The crystallization rates of TMC-328 were assessed through rheological measurements of network formation. Both fibrils’ density and crystallization kinetics display a power law dependence on supersaturation. For the first time, the solid–melt interfacial energy, the size of the critical nucleus, and the number of molecules making up the critical nucleus of the nucleator TMC-328 in the PLLA matrix have been determined by adopting the classical nucleation theory. The subsequent crystallization of PLLA induced by this nucleator was investigated as a function of the fibrils’ spatial density. The crystallization rate of PLLA is enhanced with the increase in the TMC-328 fibrils’ density because of the availability of a larger nucleating surface. The self-assembled fibril of TMC-328 can serve as shish to form a hybrid shish-kebab structure after the crystallization of PLLA, regardless of the number of nucleation sites.

One of the methods of making traditional polymers more environmentally friendly is to modify them with natural materials or their biodegradable, synthetic equivalents. It was assumed that blends with polylactide (PLA), polysaccharides: chitosan (Ch) and starch (St) of branched polyurethane (PUR) based on synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) would degrade faster in the processes of hydrolysis and oxidation than pure PUR. For the sake of simplicity in the publication, all three modifiers: commercial PLA, Ch created by chemical modification of chitin and St are called bioadditives. The samples were incubated in a hydrolytic and oxidizing environment for 36 weeks and 11 weeks, respectively. The degradation process was assessed by observation of the chemical structure as well as the change in the mass of the samples, their molecular weight, surface morphology and thermal properties. It was found that the PUR samples with the highest amount of R,S-PHB and the lowest amount of polycaprolactone triol (PCLtriol) were degraded the most. Moreover, blending with St had the greatest impact on the susceptibility to degradation of PUR. However, the rate of weight loss of the samples was low, and after 36 weeks of incubation in the hydrolytic solution, it did not exceed 7% by weight. The weight loss of Ch and PLA blends was even smaller. However, a significant reduction in molecular weight, changes in morphology and changes in thermal properties indicated that the degradation of the samples should occur quickly after this time. Therefore, when using these polyurethanes and their blends, it should be taken into account that they should decompose slowly in their initial life. In summary, this process can be modified by changing the amount of R,S-PHB, the degree of cross-linking, and the type and amount of second blend component added (bioadditives).

Lactide-valerolactone copolymers have potential application in the packaging sector. Different copolymers were synthesized, and the kinetics of the copolymerization reactions and the microstructure of the copolymers were analysed. Lactide showed higher reactivity than valerolactone which leads to composition drift through the reaction. Thermal, mechanical and barrier properties of the selected copolymers were studied. Overall, the incorporation of valerolactone results in copolymers with higher ductility than poly(lactide) with intermediate water and oxygen permeability which makes these materials appropriate candidates for use in the packaging sector.

The utilization of renewable resources is a challenging and an importantaspect towards development of sustainable plastic products. Therefore,commercial biomass conversion to produce biobased chemicals isnecessary to replace current fossil-based chemicals. In this thesis, a libraryof plasticizers was designed utilizing the biobased platform chemical,levulinic acid (LeA), as the building-block. In combination with othercurrent or future biobased constituents, LeA esters and their derivativesserved as a versatile plasticizer library for the biobased and biodegradablethermoplastic polylactide (PLA).The successful syntheses of thirteen plasticizers were confirmed, includingnine monomeric plasticizers employing a classic Fischer-esterification andfour oligomeric plasticizers by means of polycondensation, or a two-stepprocedure with ring-opening polymerization (ROP) of L-lactide, followedby Fischer-esterification with LeA. Utilizing nuclear magnetic resonance(NMR) spectroscopy, as the primary method, the reaction process wasmonitored and the structures of the designed plasticizers were determined.The structural characterization was further supported by electrosprayionization mass spectrometry (ESI-MS). From a plasticizer designperspective, the structure of the plasticizer molecules in combination withthe polymer matrix determines the plasticizer performance. The designedplasticizers with linear and flexible cores, ethylene glycol (EG) or 1,4-butanediol, demonstrated great potential, lowering the glass transitiontemperature (Tg) of PLA from 59 °C to 15 °C and 16 °C respectively andincreasing the strain at break of PLA from 5% to 546% and 227%respectively at 20 wt% addition. The introduction of branching (utilizingglycerol as a core) or cyclic and rigid cores (isohexide and 1,2-cyclohexanediol) lowered the plasticization efficiency. A cis-/trans stereoisomerism of the rigid cores could, to some extent, tune theplasticizing effect and the thermal stability of the plasticizer, Att använda förnybara resurser för utveckling av hållbara plastprodukterär en utmaning. Därför behöver de kommersiella teknikerna föromvandling av biomassa generera biobaserade kemikalier, som kan ersättanuvarande fossilbaserade kemikalier, utvecklas. I denna avhandling har ettbibliotek av mjukningsmedel med den biobaserade plattformskemikalienlevulinsyra (LeA), som en central byggsten, designats. I kombination medandra befintliga eller framtida biobaserade byggstenar fungerar estrarna avLeA och deras derivat som en mångsidig plattform av mjukningsmedel förbiobaserad och biologiskt nedbrytbar termoplastisk polylaktid (PLA).Totalt syntetiserades tretton LeA-baserade mjukningsmedel, vilketinkluderar nio monomera mjukningsmedel syntetiserade genom enklassisk Fischer-förestringsmetod och fyra oligomera mjukningsmedelsom framställdes genom polykondensation eller ett tvåstegsförfarande medringöppningspolymerisation (ROP) av L-laktid följt av Fischer-förestringmed LeA. Genom kärnmagnetisk resonans (NMR)-spektroskopi, somprimär karakteriseringsmetod, följdes reaktionsprocessen och strukturernaverifierades hos de designade mjukningsmedlen. Strukturerna bekräftadesytterligare med elektrosprayjonisering masspektrometri (ESI-MS). Ur ettdesignperspektiv bestämmer kombinationen av mjukningsmedlens ochpolymermatrisens struktur materialens prestanda.Mjukningsmedel med linjära och flexibla centra, etylenglykol (EG) eller1,4-butandiol, visade stor potential som mjukningsmedel genom att sänkaglasövergångstemperaturen (Tg) för PLA från 59 °C till 15 °C och 16 °Coch öka töjningen vid brott av PLA från 5% till 546% och 227% vid tillsatsav 20 vikts%. Ett förgrenat centrum (glycerol) eller cykliska och styvacentra (isohexid och 1,2-cyklohexandiol) minskademjukningseffektiviteten. Cis-/trans-stereoisomerismen hos styva centrakunde till viss del justera mjukningseffekten och mjukningsmedlenstermiska stabilitet. När ketoner av LeA omvandlades till ketaler med EGsom reagens, ökade mjukningsmed, QC 2021-08-30

Lactide copolymers were developed to increase the utility of biodegradable polymers. Using redox switchable ring-opening polymerization, we synthesized a series of zirconium compounds to be used as precatalysts. We studied their geometry change behaviors in polymerization, and one compound, (salfen)Zr(OiPr)2 (salfen = N,N′-bis(2,4-di-tert-butylphenoxy)-1,1′-ferrocenediimine), was selected and then tested as a precatalyst for redox switchable ring-opening polymerization. Copolymers from LA (lactide) and CHO (cyclohexene oxide) were prepared as a proof of concept, and conditions were optimized for the redox switchable copolymerization method. LA-LO (limonene oxide) copolymers were then prepared and their solid state self-assembly properties were studied. Finally, LA-CHDO (cyclohexadiene oxide) copolymers were prepared and post-functionalized to enhance the mechanical properties.

Producción Científica, The kinetics of crystallization of Polylactic Acid (PLA) in the presence of CO2 pressures from 1.5 to 4 MPa, has been studied by measuring the optical absorbance evolution of the material with time. To perform this study, an own-designed pressure vessel provided with windows has been used. The non-destructive approach presented in this paper allows for obtaining very accurate crystallinity data as a function of time for a wide range of pressures. Besides, this new approach allows measuring with spatial resolution, i.e., obtaining the crystallization kinetics' evolution in different areas of the samples, which helps to analyze in detail the crystallization mechanisms by using the Avrami approach. The results obtained have allowed observing an unexpected peak in the absorbance curve connected with the physical phenomena taking place during the CO2 uptake and the associated crystallization of PLA., Junta de Castilla y León (grant VA202P20), Ministerio de Ciencia e Innovación (grants RTI2018-098749-B-I00 and RTI2018-097367-A-I00)

Eumelanin as a natural pigment present several key functional properties that can protect human skin from ultraviolet (UV) light. Photoprotection ability that can absorb most of the UV light as a result of aromatic compounds in its structures has drawn vast interest to harness its excellent properties for various applications. Major drawbacks shown by organic molecules as UV absorber that limits their application includes their short lifespan. Encapsulation of the compound by various shell materials has been extensively studied to further optimize and extend its shielding efficiency from UV radiation. Polylactide (PLA)-based copolymers are widely used in encapsulation of various active compounds, due to their biocompatibility and biodegradability, promoting the sustained release of the active compounds. In this study, stereocomplex PLA (sc-PLA) formed by blending of poly(D-lactide-caprolactone-D-lactide), P(DLAb-CL-b-DLA), triblock copolymer with linear poly(L-lactide), PLLA, was employed in the encapsulation of eumelanin. An oil in water emulsion (O/W) approach followed by solvent evaporation was performed in encapsulation process. Effect of eumelanin distribution in PLA’s enantiomers and ultrasonication on physicochemical properties, encapsulation efficiency, and release behavior of nano/microparticles was evaluated. The potential application of the resulting particles for sunscreen was also examined by measuring the UV absorbance and in vitro sun protection factor (SPF) of sunscreen containing particles in the UVA-UVB region. FTIR spectra of the particles show characteristic peaks of sc-PLA with the changes in the intensity of significant peaks that correspond to eumelanin, denoting the success of the encapsulation process. Morphological image analysis reveals that the resulting particles have spherical shaped with the particle size that can be controlled by applying ultrasonication. Distribution of eumelanin in copolymer and ultrasonication process promote the g

The utilization of renewable resources is a challenging and an importantaspect towards development of sustainable plastic products. Therefore,commercial biomass conversion to produce biobased chemicals isnecessary to replace current fossil-based chemicals. In this thesis, a libraryof plasticizers was designed utilizing the biobased platform chemical,levulinic acid (LeA), as the building-block. In combination with othercurrent or future biobased constituents, LeA esters and their derivativesserved as a versatile plasticizer library for the biobased and biodegradablethermoplastic polylactide (PLA).The successful syntheses of thirteen plasticizers were confirmed, includingnine monomeric plasticizers employing a classic Fischer-esterification andfour oligomeric plasticizers by means of polycondensation, or a two-stepprocedure with ring-opening polymerization (ROP) of L-lactide, followedby Fischer-esterification with LeA. Utilizing nuclear magnetic resonance(NMR) spectroscopy, as the primary method, the reaction process wasmonitored and the structures of the designed plasticizers were determined.The structural characterization was further supported by electrosprayionization mass spectrometry (ESI-MS). From a plasticizer designperspective, the structure of the plasticizer molecules in combination withthe polymer matrix determines the plasticizer performance. The designedplasticizers with linear and flexible cores, ethylene glycol (EG) or 1,4-butanediol, demonstrated great potential, lowering the glass transitiontemperature (Tg) of PLA from 59 °C to 15 °C and 16 °C respectively andincreasing the strain at break of PLA from 5% to 546% and 227%respectively at 20 wt% addition. The introduction of branching (utilizingglycerol as a core) or cyclic and rigid cores (isohexide and 1,2-cyclohexanediol) lowered the plasticization efficiency. A cis-/trans stereoisomerism of the rigid cores could, to some extent, tune theplasticizing effect and the thermal stability of the plasticizer, Att använda förnybara resurser för utveckling av hållbara plastprodukterär en utmaning. Därför behöver de kommersiella teknikerna föromvandling av biomassa generera biobaserade kemikalier, som kan ersättanuvarande fossilbaserade kemikalier, utvecklas. I denna avhandling har ettbibliotek av mjukningsmedel med den biobaserade plattformskemikalienlevulinsyra (LeA), som en central byggsten, designats. I kombination medandra befintliga eller framtida biobaserade byggstenar fungerar estrarna avLeA och deras derivat som en mångsidig plattform av mjukningsmedel förbiobaserad och biologiskt nedbrytbar termoplastisk polylaktid (PLA).Totalt syntetiserades tretton LeA-baserade mjukningsmedel, vilketinkluderar nio monomera mjukningsmedel syntetiserade genom enklassisk Fischer-förestringsmetod och fyra oligomera mjukningsmedelsom framställdes genom polykondensation eller ett tvåstegsförfarande medringöppningspolymerisation (ROP) av L-laktid följt av Fischer-förestringmed LeA. Genom kärnmagnetisk resonans (NMR)-spektroskopi, somprimär karakteriseringsmetod, följdes reaktionsprocessen och strukturernaverifierades hos de designade mjukningsmedlen. Strukturerna bekräftadesytterligare med elektrosprayjonisering masspektrometri (ESI-MS). Ur ettdesignperspektiv bestämmer kombinationen av mjukningsmedlens ochpolymermatrisens struktur materialens prestanda.Mjukningsmedel med linjära och flexibla centra, etylenglykol (EG) eller1,4-butandiol, visade stor potential som mjukningsmedel genom att sänkaglasövergångstemperaturen (Tg) för PLA från 59 °C till 15 °C och 16 °Coch öka töjningen vid brott av PLA från 5% till 546% och 227% vid tillsatsav 20 vikts%. Ett förgrenat centrum (glycerol) eller cykliska och styvacentra (isohexid och 1,2-cyklohexandiol) minskademjukningseffektiviteten. Cis-/trans-stereoisomerismen hos styva centrakunde till viss del justera mjukningseffekten och mjukningsmedlenstermiska stabilitet. När ketoner av LeA omvandlades till ketaler med EGsom reagens, ökade mjukningsmed, QC 2021-08-30

Despite technological feasibility and industrial scalability in toughening polylactide (PLA) by direct blending, avoiding the sacrifice of mechanical strength or full renewability remains a challenge. Here, low-molecular-weight poly(ethylene 2,5-furandicarboxylate)-block-polylactide (PEF-b-PLA) was synthesized to yield a fully biobased copolymer with expected partial miscibility with PLA. The ability of PEF-b-PLA to toughen PLA at 10 wt % (PLA10) and 20 wt % (PLA20) loadings was then evaluated. To understand the achieved properties, the formation of a nanostructured dispersion phase due to favorable interfacial adhesion arising from the miscibility of the PLA block with the PLA matrix was investigated. The morphological features, together with comparable strength inherited from the PEF blocks, afforded an unusual combination of toughness and strength for the PLA blends. Compared to the poor tensile toughness of a pure PLA film (1.77 MJ/m(3)), a striking increase of 839 and 912% was achieved for PLA10 and PLA20, respectively. More importantly, both pure PLA and the blends were characterized by comparable yield strength (similar to 30 MPa). This was accompanied by excellent UV-shielding imparted by the functional groups on the PEF blocks, which would improve the prospects of realizing PLA-based functional packing materials. The proposed design of copolymers, with good industrial feasibility, should be useful to guide the toughening approaches for PLA and probably other degradable polyester blends by profound morphology control., QC 20220525

Producción Científica, The kinetics of crystallization of Polylactic Acid (PLA) in the presence of CO2 pressures from 1.5 to 4 MPa, has been studied by measuring the optical absorbance evolution of the material with time. To perform this study, an own-designed pressure vessel provided with windows has been used. The non-destructive approach presented in this paper allows for obtaining very accurate crystallinity data as a function of time for a wide range of pressures. Besides, this new approach allows measuring with spatial resolution, i.e., obtaining the crystallization kinetics' evolution in different areas of the samples, which helps to analyze in detail the crystallization mechanisms by using the Avrami approach. The results obtained have allowed observing an unexpected peak in the absorbance curve connected with the physical phenomena taking place during the CO2 uptake and the associated crystallization of PLA., Junta de Castilla y León (grant VA202P20), Ministerio de Ciencia e Innovación (grants RTI2018-098749-B-I00 and RTI2018-097367-A-I00)

Eumelanin as a natural pigment present several key functional properties that can protect human skin from ultraviolet (UV) light. Photoprotection ability that can absorb most of the UV light as a result of aromatic compounds in its structures has drawn vast interest to harness its excellent properties for various applications. Major drawbacks shown by organic molecules as UV absorber that limits their application includes their short lifespan. Encapsulation of the compound by various shell materials has been extensively studied to further optimize and extend its shielding efficiency from UV radiation. Polylactide (PLA)-based copolymers are widely used in encapsulation of various active compounds, due to their biocompatibility and biodegradability, promoting the sustained release of the active compounds. In this study, stereocomplex PLA (sc-PLA) formed by blending of poly(D-lactide-caprolactone-D-lactide), P(DLAb-CL-b-DLA), triblock copolymer with linear poly(L-lactide), PLLA, was employed in the encapsulation of eumelanin. An oil in water emulsion (O/W) approach followed by solvent evaporation was performed in encapsulation process. Effect of eumelanin distribution in PLA’s enantiomers and ultrasonication on physicochemical properties, encapsulation efficiency, and release behavior of nano/microparticles was evaluated. The potential application of the resulting particles for sunscreen was also examined by measuring the UV absorbance and in vitro sun protection factor (SPF) of sunscreen containing particles in the UVA-UVB region. FTIR spectra of the particles show characteristic peaks of sc-PLA with the changes in the intensity of significant peaks that correspond to eumelanin, denoting the success of the encapsulation process. Morphological image analysis reveals that the resulting particles have spherical shaped with the particle size that can be controlled by applying ultrasonication. Distribution of eumelanin in copolymer and ultrasonication process promote the g

Some crop by-products are considered to be promising materials for the development of novel biobased products for industrial applications. The flammability of these alternatives to conventional materials is a constraint to expanded applications. Polylactide (PLA) composites containing a combination of oxidized corn pith fiber (OCC) and a biobased flame retardant (PA-THAM) have been prepared via an in situ modification method. SEM/EDS, FTIR and TGA were performed to establish that PA-THAM was coated onto the surface of OCC. The mechanical properties, thermal stability and fire behavior of PLA-based biocomposites were investigated. The incorporation of 5 phr PA-THAM imparted biocomposite good interfacial adhesion and increased decomposition temperature at 10% mass loss by 50 °C. The flame retardant properties were also improved, as reflected by an increased LOI value, a UL-94 V-2 rating, reduction of PHRR, and increased formation of char residue. Therefore, the introduction of 5 phr PA-THAM can maintain a good balance between flame retardancy and mechanical properties of this PLA/OCC system., Peer Reviewed, Postprint (published version)

Eumelanin as a natural pigment present several key functional properties that can protect human skin from ultraviolet (UV) light. Photoprotection ability that can absorb most of the UV light as a result of aromatic compounds in its structures has drawn vast interest to harness its excellent properties for various applications. Major drawbacks shown by organic molecules as UV absorber that limits their application includes their short lifespan. Encapsulation of the compound by various shell materials has been extensively studied to further optimize and extend its shielding efficiency from UV radiation. Polylactide (PLA)-based copolymers are widely used in encapsulation of various active compounds, due to their biocompatibility and biodegradability, promoting the sustained release of the active compounds. In this study, stereocomplex PLA (sc-PLA) formed by blending of poly(D-lactide-caprolactone-D-lactide), P(DLAb-CL-b-DLA), triblock copolymer with linear poly(L-lactide), PLLA, was employed in the encapsulation of eumelanin. An oil in water emulsion (O/W) approach followed by solvent evaporation was performed in encapsulation process. Effect of eumelanin distribution in PLA’s enantiomers and ultrasonication on physicochemical properties, encapsulation efficiency, and release behavior of nano/microparticles was evaluated. The potential application of the resulting particles for sunscreen was also examined by measuring the UV absorbance and in vitro sun protection factor (SPF) of sunscreen containing particles in the UVA-UVB region. FTIR spectra of the particles show characteristic peaks of sc-PLA with the changes in the intensity of significant peaks that correspond to eumelanin, denoting the success of the encapsulation process. Morphological image analysis reveals that the resulting particles have spherical shaped with the particle size that can be controlled by applying ultrasonication. Distribution of eumelanin in copolymer and ultrasonication process promote the g

The utilization of renewable resources is a challenging and an importantaspect towards development of sustainable plastic products. Therefore,commercial biomass conversion to produce biobased chemicals isnecessary to replace current fossil-based chemicals. In this thesis, a libraryof plasticizers was designed utilizing the biobased platform chemical,levulinic acid (LeA), as the building-block. In combination with othercurrent or future biobased constituents, LeA esters and their derivativesserved as a versatile plasticizer library for the biobased and biodegradablethermoplastic polylactide (PLA).The successful syntheses of thirteen plasticizers were confirmed, includingnine monomeric plasticizers employing a classic Fischer-esterification andfour oligomeric plasticizers by means of polycondensation, or a two-stepprocedure with ring-opening polymerization (ROP) of L-lactide, followedby Fischer-esterification with LeA. Utilizing nuclear magnetic resonance(NMR) spectroscopy, as the primary method, the reaction process wasmonitored and the structures of the designed plasticizers were determined.The structural characterization was further supported by electrosprayionization mass spectrometry (ESI-MS). From a plasticizer designperspective, the structure of the plasticizer molecules in combination withthe polymer matrix determines the plasticizer performance. The designedplasticizers with linear and flexible cores, ethylene glycol (EG) or 1,4-butanediol, demonstrated great potential, lowering the glass transitiontemperature (Tg) of PLA from 59 °C to 15 °C and 16 °C respectively andincreasing the strain at break of PLA from 5% to 546% and 227%respectively at 20 wt% addition. The introduction of branching (utilizingglycerol as a core) or cyclic and rigid cores (isohexide and 1,2-cyclohexanediol) lowered the plasticization efficiency. A cis-/trans stereoisomerism of the rigid cores could, to some extent, tune theplasticizing effect and the thermal stability of the plasticizer, Att använda förnybara resurser för utveckling av hållbara plastprodukterär en utmaning. Därför behöver de kommersiella teknikerna föromvandling av biomassa generera biobaserade kemikalier, som kan ersättanuvarande fossilbaserade kemikalier, utvecklas. I denna avhandling har ettbibliotek av mjukningsmedel med den biobaserade plattformskemikalienlevulinsyra (LeA), som en central byggsten, designats. I kombination medandra befintliga eller framtida biobaserade byggstenar fungerar estrarna avLeA och deras derivat som en mångsidig plattform av mjukningsmedel förbiobaserad och biologiskt nedbrytbar termoplastisk polylaktid (PLA).Totalt syntetiserades tretton LeA-baserade mjukningsmedel, vilketinkluderar nio monomera mjukningsmedel syntetiserade genom enklassisk Fischer-förestringsmetod och fyra oligomera mjukningsmedelsom framställdes genom polykondensation eller ett tvåstegsförfarande medringöppningspolymerisation (ROP) av L-laktid följt av Fischer-förestringmed LeA. Genom kärnmagnetisk resonans (NMR)-spektroskopi, somprimär karakteriseringsmetod, följdes reaktionsprocessen och strukturernaverifierades hos de designade mjukningsmedlen. Strukturerna bekräftadesytterligare med elektrosprayjonisering masspektrometri (ESI-MS). Ur ettdesignperspektiv bestämmer kombinationen av mjukningsmedlens ochpolymermatrisens struktur materialens prestanda.Mjukningsmedel med linjära och flexibla centra, etylenglykol (EG) eller1,4-butandiol, visade stor potential som mjukningsmedel genom att sänkaglasövergångstemperaturen (Tg) för PLA från 59 °C till 15 °C och 16 °Coch öka töjningen vid brott av PLA från 5% till 546% och 227% vid tillsatsav 20 vikts%. Ett förgrenat centrum (glycerol) eller cykliska och styvacentra (isohexid och 1,2-cyklohexandiol) minskademjukningseffektiviteten. Cis-/trans-stereoisomerismen hos styva centrakunde till viss del justera mjukningseffekten och mjukningsmedlenstermiska stabilitet. När ketoner av LeA omvandlades till ketaler med EGsom reagens, ökade mjukningsmed, QC 2021-08-30