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To explore the tailoring of hydrophobicity in 3D-printed polylactide (PLA) composites for advanced applications using additive manufacturing (AM), this study focuses on the use of Fused Deposition Modeling (FDM) 3D printing. PLA, a material derived from renewable sources, is favored for its eco-friendliness and user accessibility. Nonetheless, PLA's inherent hydrophilic properties result in moisture absorption, negatively affecting its performance. This research aims to modify PLA with organosilicon compounds to enhance its hydrophobic and anti-icing properties. Incorporating fluorinated siloxane derivatives led to significant increases in water contact angles by up to 39%, signifying successful hydrophobic modification. Mechanical testing demonstrated that the addition of organosilicon additives did not compromise the tensile strength of PLA and, in some instances, improved impact resistance, especially with the use of OSS-4OFP:2HEX:2TMOS, which resulted in an increase in the tensile strength value of 25% and increased impact strength by 20% compared to neat PLA. Differential scanning calorimetry (DSC) analysis indicated that the modified PLA exhibited reduced cold crystallization temperatures without altering the glass transition or melting temperatures. These results suggest that organosilicon-modified PLA has the potential to expand the material's application in producing moisture and ice-resistant 3D-printed prototypes for various industrial uses, thereby facilitating the creation of more durable and versatile 3D-printed components. [ABSTRACT FROM AUTHOR]

With the increase in air pollutants and bacteria hazards, conventional melt-blown cloth of polypropylene (PP), which is widely used as the filtering medium, can no longer meet people's needs due to its insufficient filtration efficiency, lack of antibacterial function, etc. In this study, the nanoparticles of the zinc and cobalt imidazolate framework (ZnCo-ZIF) were synthesized and directly incorporated into polylactide (PLA) to prepare PLA/ZnCo-ZIF fibrous membranes through electrospinning methodology. The addition of ZnCo-ZIF resulted in a decrease in the average diameter of fiber from 1.01 μm of pure PLA membrane to 0.72 μm of PLA/ZnCo-ZIF (3 wt%) membrane. The PM filtration and antimicrobial properties of PLA/ZnCo-ZIF fibrous membranes were tested. The PLA/ZnCo-ZIF (2 wt%) membrane displayed great filtration ability, and the filtration efficiencies for PM2.5 and PM10 were 90.88% and 93.00%, compared to 75.76% and 79.37% of PP melt-blown cloth. In addition, the antibacterial rates of the PLA/ZnCo-ZIF (3 wt%) membrane reached 100% and 93.24% against E. coli and S. aureus, which were higher than 85.80% and 90.59% of the PLA/ZIF-8 (3 wt%) membrane. The prepared membranes could be used in the field of masks instead of PP melt-blown fabric, and they solved the problem of the non-degradability and non-functionalization of melt-blown fabric. [ABSTRACT FROM AUTHOR]

The widespread application of polylactide (PLA) has been limited by its slow crystallization rate and poor toughness. In the present work, a low molecular weight nucleator, TMC 301, and polyamide elastomer (PAE) were incorporated into PLA through melt blending to mediate both the crystallization capability and impact toughness. It was found that the introduction of TMC 301 decreased the crystallization temperature of PLA during the cooling process, while enhancing its cold crystallization capacity of PLA in the heating scan. Accordingly, the presence of TMC 301 shortened the half-crystallization time of PLA at 95°C in the ternary blends with minimal influence on the Avrami index. Moreover, the dispersion size of PAE decreased when the concentration of TMC 301 increased to 0.3 wt%, leading to a substantial increase in the tensile toughness and the impact strength of the PLA/PAE/TMC 301 blend. It is suggested that the size of the elastomer particles is a critical factor influencing the toughening efficiency of TMC301 in PLA/PAE blends. The nucleator TMC 301 and polyamide elastomer (PAE) were incorporated into PLA through melt blending to enhance both crystallization capability and toughness. The phase structure, crystallization behavior and the mechanical performances were studied. [ABSTRACT FROM AUTHOR]

Blending polylactide (PLA) with poly(propylene carbonate) offers potential solution to mitigate the greenhouse effect due to PLA's lower carbon dioxide (CO2) emissions and its use of CO2 as a monomer in PPC synthesis. In this investigation, a series of PLA and PPC blends were prepared using the solvent casting method to address their respective weaknesses. The blends exhibited partial compatibility, as evidenced by a noticeable shift in the glass transition temperatures toward each other. Tensile testing revealed that the incorporation of PPC improved the elongation properties of PLA. The degradation characteristics of the blend films were evaluated based on changes in the monolayer's occupied area, the properties of the bulk film, and changes in surface morphology. Results indicated that PPC content accelerated hydrolytic degradation but slowed enzymatic degradation in the blends. Hydrolytic and enzymatic degradation significantly impacted the mechanical properties of PLA/PPC blends, prolonging the degradation process through chain scission. [ABSTRACT FROM AUTHOR]

In this study, the aliphatic N,N‐bisguanidine zinc complex [Zn(DMEG2ch)2](OTf)2 ⋅ THF is introduced as a promising candidate for the chemical recycling of (bio) polyesters. This catalyst is highly active in the ring‐opening polymerization (ROP) of lactide (LA) and ϵ‐caprolactone (CL). The combination of polymerization and depolymerization activity creates new pathways towards a sustainable circular economy. The catalytic activity of [Zn(DMEG2ch)2](OTf)2 ⋅ THF for the chemical recycling of polylactide (PLA) via alcoholysis was investigated by detailed kinetic and thermodynamic studies. It is shown that various high value‐added alkyl lactates can be obtained efficiently under mild reaction conditions. Catalyst recycling was successfully tested using ethanol for the degradation of PLA. In addition, LA can be recovered directly from PLA, enabling either open‐ or closed‐loop recycling. Selective PLA degradation from mixtures with polyethylene terephthalate (PET) and polymer blends are presented. For the first time, a cascade recycling reaction of a PLA/polycaprolactone (PCL) blend is tested with a zinc‐based bisguanidine catalyst, whereby PLA is degraded selectively at first and subsequent modification of the reaction conditions leads to efficient degradation of the remaining PCL. The highly active, universally applicable benign zinc catalyst allows the implementation of a circular plastics economy and thus the reduction of plastic pollution in the environment. [ABSTRACT FROM AUTHOR]

Many therapies require the transport of therapeutic compounds or substances encapsulated in carriers that reduce or, if possible, eliminate their direct contact with healthy tissue and components of the immune system, which may react to them as something foreign and dangerous to the patient's body. To date, inorganic nanoparticles, solid lipids, micelles and micellar aggregates, liposomes, polymeric micelles, and other polymer assemblies were tested as drug carriers. Specifically, using polymers creates a variety of options to prepare nanocarriers tailored to the chosen needs. Among polymers, aliphatic polyesters are a particularly important group. The review discusses controlled synthesis of poly(β-butyrolactone)s, polylactides, polyglycolide, poly(ε-caprolactone), and copolymers containing polymacrolactone units with double bonds suitable for preparation of functionalized nanoparticles. Discussed are syntheses of aliphatic polymers with controlled molar masses ranging from a few thousand to 106 and, in the case of polyesters with chiral centers in the chains, with controlled microstructure. The review presents also a collection of methods useful for the preparation of the drug-loaded nanocarriers: classical, developed and mastered more recently (e.g., nanoprecipitation), and forgotten but still with great potential (by the direct synthesis of the drug-loaded nanoparticles in the process comprising monomer and drug). The article describes also in-vitro and model in-vivo studies for the brain-targeted drugs based on polyester-containing nanocarriers and presents a brief update on the clinical studies and the polyester nanocarrier formulation approved for application in the clinics in South Korea for the treatment of breast, lung, and ovarian cancers. [ABSTRACT FROM AUTHOR]

In laboratory conditions, composite sutures based on polylactide (PLA) containing chitin nanofibrils modified with polyethylene glycol (CN‐PEG) and poviargol (silver nanoparticles stabilized with poly(N‐vinylpyrrolidone)) were obtained, studied, and used as a prototype. Surgical sutures threads with the addition of CN‐PEG have stable mechanical properties both in air and in a buffer simulating the environment of a living organism. The yield strength of oriented threads decreased by an average of 15%, whereas for non‐oriented threads the decrease was 3–4 times. The strength values in simple units of unfilled PLA, PLA containing 5 wt % CN‐PEG, and PLA with 1 wt % Poviargol were on average 50% higher than the national standard 31620‐2012. The results of in vivo experiments on albino rats (cross‐linking skin and muscle tissue in the linea alba area) showed that composite sutures are best for suturing muscle tissue, whereas unfilled PLA sutures are more suitable for suturing skin. When suturing muscle tissue, suturing with composite sutures increased the number of collagen fibers of different diameters. [ABSTRACT FROM AUTHOR]

In particular, foams have been given a lot of attention in the packaging industry and other sectors over the years. In this study, low-density white lactirofoam is created using micronized polylactide particles, and the essence of making it environmentally friendly is considered. A new approach covering four key stages was used in the synthesis of lactirofoam, involving a ring-opening polymerization process for L-lactide, emulsion micronization solution preparation, deposition, and molding. Characterization by ATR-IR and 1H-NMR techniques confirmed the synthesis of the polylactide polymer. The optical micrograph showed that the process of micronization of the lactirofoam particles was quite efficient. The GPC analysis confirmed that the key to controlling the molecular weight of the final polymer during ROP in order to achieve the desired density of lactirofoams was a specific choice of molar ratios for starting monomers. In addition, lactirofoam's temperature properties have been determined using TG/DTG/DTA. With the molecular weight of the polymer, they confirmed an increase in the thermal stability of lactirofoam. [ABSTRACT FROM AUTHOR]

Today, an important feature of scientific research consists in environmentally safe and biodegradable polymeric materials. Polylactide (PLA) and compositions based on this polymeric compound are being active investigated in world science. One of the main issues that should be considered before using PLA consists in understanding the mechanisms of its biodegradation including mixtures based on this polymer. This work is aimed at studying the mixtures based on PLA with polycaprolactone (PCL) and natural rubber (NR) in the course of biodegradation. After incubation in soil, pure polycaprolactone demonstrates clearly visible structural defects and mycelium on the surface. It has been established that both polycaprolactone and natural rubber undergo biodegradation more rapidly than polylactide. Obtaining PLA/PCL and PLA/NR compositions makes it possible to enhance the effect of biodegradation. As a result of the study, a change in the thermophysical characteristics of the mixtures has been revealed, which indicates the onset of the destruction process. [ABSTRACT FROM AUTHOR]

Porphyrin–polymer systems are promising materials for their use in biotechnology, biochemistry, and medicine. The creation of composite materials from porphyrins expands the possibilities of using both high molecular weight compounds and porphyrins. Polylactide–porphyrin film samples obtained by solution watering method are studied in this work. It was found that the density of the film compositions decreases with an increase in an amount of porphyrin in the polymer matrix. A Soret peak of porphyrin immobilized into the polylactide matrix splits (425 and 447 nm) and shifts bathochromically. The addition of 5,10,15,20-tetrakis(4-n-hexyloxyphenyl)porphyrin changes the elastic behavior and strength properties. Shear modulus, elastic modulus, and tensile strength decrease with an increase in an amount of porphyrin in the polylactide matrix. Relative elongation at break increases slightly, and the Poisson's ratio is almost unchanged compared to those of starting polylactide. [ABSTRACT FROM AUTHOR]

Modern trends focused on green technologies are driving the increasingly widespread use of biodegradable polymers in agriculture. The development of composite materials based on polylactide (PLA) is aimed at increasing the efficiency of using covering materials for growing plants in agriculture, as well as reducing the amount of polymeric wastes. In this work, mixtures of polylactide/polycaprolactone (PLA/PCL) and polylactide/natural rubber (PLA/NR) have been studied. It is established that, when about 10–15 wt % of PCL and NR are added to the PLA matrix, the structure changes and almost spherical domains are formed. In the course of studying the effect of UV radiation with a wavelength of 254 nm exerted on PLA/PCL and PLA/NR polymeric materials, it has been revealed that the presence of additives in the mixture already in an amount of 10 wt % promotes the inhibition of photolytic processes. [ABSTRACT FROM AUTHOR]

An updated organic solvation-assisted intercalation and collection (OAIC) strategy was developed to prepare high-quality 2D transition metal carbon/nitride (MXene) and evaluate its effects on the structure and properties of polylactide (PLA). Then, PLA composites with different MXene contents were prepared by solution casting method. Transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, UV–visible spectrometry, x-ray diffraction, differential scanning calorimetry, polarized optical microscopy and mechanical tests were used to characterize the MXene/PLA composites. Also, physical models were established to describe the modification mechanism of MXene on PLA. The results show that our updated OAIC strategy successfully prepared single-layered, large-sized MXene nanosheets, which can disperse in both aqueous phase and organic solvent uniformly and stably. MXene and PLA are physically blended in the resultant composites, since PLA shows the typical spherulite morphology. Crystallite size of PLA was refined by the as-synthesized MXene nanosheets. The MXene/PLA composites illustrated prominent UV shielding effect: its UV shielding performance is very close to 100% when the MXene reaches up to 4.0 parts per hundreds of resins (phr). Elongation at break increases to 95.85% with 3.5 phr of MXene, which is 4.32 times that of pure PLA. Thermal conduction of the resultant PLA composites was greatly improved with small amount of MXene: its thermal conductivity was increased up to 0.59 W·m−1·K−1 with 1.0 phr of MXene, which is 2.2 times that of pure PLA. [ABSTRACT FROM AUTHOR]

In this work, polylactide (PLA) was loaded with wood flour (WF) or hazelnut shells (HSs) (10% and 20% of fillers). The matrix and biocomposites were fully characterized from a mechanical and rheological point of view to test their processability and mechanical performance. Compost burial degradation test (30 days), with or without a prior photo‐oxidation step, assessed their biodegradability after an outdoor application, and was monitored by weight loss (WL). The viscosity of the biocomposites was lower than that of the matrix and this unusual result can be attributed to a limited adhesion between the PLA and fillers. Both fillers increased the elastic modulus but decreased the tensile strength and elongation at break. As for the weathering, the degradation of PLA was mostly due to hydrolytic chain scission due to the presence of humidity. Resistance of PLA to UV irradiation improved in presence of both the two fillers. Their lignocellulosic nature was responsible for this behavior. Both fillers induced a high resistance and lower degradation in compost: WL percentages of virgin PLA was about 26%, biocomposites with 20% of WF or HS showed WL of about 10% and 14%, respectively. Photo‐oxidation (36 h with condensation cycle) increased the compost degradation rate of both biocomposites and WL of PLA with 20% of WF or HS were about 15% and 21%, respectively, after 30 days. Highlights: Poor adhesion between the matrix and fillers reduced the biocomposites viscosity.Fillers increased the elastic modulus but decreased the properties at break.Both fillers improved the resistance of PLA to UV irradiation.Biocomposites showed a lower susceptibility to compost degradation than PLA.Photo‐oxidation increased the compost degradation rate of biocomposites. [ABSTRACT FROM AUTHOR]

The present work is devoted to studying the effect of the synergistic action of Si-O-Si and NH-CO groups on the flammability and thermal properties of polylactide (PLA). For this purpose, using the Layer-by-Layer (LbL) technique, 5, 10, and 15 bilayers of chitosan (CS) and nanosilica (NS) were deposited onto the surface of PLA and PLA/NS composite (PLA/A200). More than a 20% reduction in flammability was achieved (sample (15BL) PLA/A200). Studying the effect of LbL-deposited bilayers on two types of surfaces, an identical relationship was found: the more layers adsorbed, the lower thermal stability, and vice versa the more layers, the higher flame retardancy. In turn, the lower the thermal stability, the faster the ability to form char, and the more solid residue, the lower the flammability and longer the burning time. This means that the application of CS-NS bilayers results in decomposition reactions in the condensed phase, which reduces the amount of flammable gases released. [ABSTRACT FROM AUTHOR]

This study showed that a polylactide (PLA)-based composite filled with nanostructured hydroxyapatite (HAp) and a natural extract from the rhizome of Curcuma longa L. could provide an alternative to commonly used fossil-based plasticsfor food packaging. The incorporation of HAp into the PLA matrix had a positive effect on improving selected properties of the composites; the beneficial effect could be enhanced by introducing a green modifier in the form of an extract. Prior to the fabrication of the composite, the filler was characterized in terms of morphology and composition, and the composite was then fully characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman and Fourier transform infrared spectroscopy (FT-IR), and the mechanical, thermal, thermomechanical, and optical properties were investigated. The proposed material exhibits antioxidant properties against DPPH radicals and antibacterial performance against Escherichia coli (E. coli). The results showed that the nanocomposite has the highest antioxidant and antibacterial properties for 10 wt% HAp with an average diameter of rod-shaped structures below 100 nm. In addition, the introduction of turmeric extract had a positive effect on the tensile strength of the nanocomposites containing 1 and 5% HAp. As the resulting material adsorbs light in a specific wavelength range, it can be used in the medical sector, food-packaging, or coatings. [ABSTRACT FROM AUTHOR]

The drastic increase in the amount of packaging waste from conventional plastics, caused by improper waste management, is a serious challenge for the planet. It is therefore worth considering how we can solve this problem. Thus, it is necessary to develop new polymeric materials that retain the functional properties of traditional plastics but are susceptible to degradation with the participation of microorganisms. The development of new eco-friendly materials requires a holistic approach in terms of their disposal. Organic recycling enables the disposal of biodegradable packaging along with food remains that are difficult to remove. The article presents a study on the degradation of biocomposites of polylactide with cork in various environments (water, buffer, and compost). The obtained results indicate a clear influence of the presence of the filler and its amount on the degradation profile of the composites. In addition, the effect of sample shrinkage was observed, especially during degradation in water, where the pH decreases during the process due to the appearance of degradation products. This effect may be important not only for the degradation profile of the packaging but also during its use. Packaging distorted due to shrinkage may be a sign of improper product storage. [ABSTRACT FROM AUTHOR]

Over the past years, poly(lactic acid) or polylactide (PLA) is commonly researched as a possible replacement for traditional fossil‐based polymers because of its compostability, biocompatibility, and high mechanical properties. PLA has a variety of applications in packaging, biomedical, and structural. However, PLA has limitations, such as high brittleness, low thermal stability, and a slow crystallization rate, which limits the wide range of applications. To overcome these limitations, the literature reports that blending PLA with other polymers, such as poly(ε‐caprolactone) (PCL), is an economically viable approach. Although blending PLA with PCL is considered a feasible approach, the blend system still suffers from immiscibility, depending on the blend composition. This review aims to highlight recent developments from 2014 to date on the processing of PLA/PCL blends, including their composites, with a primary focus on morphological characteristics and mechanical and thermal properties, including their potential applications in various sectors. [ABSTRACT FROM AUTHOR]

Polylactide materials present a promising alternative to petroleum-based polymers due to their sustainability and biodegradability, although they have certain limitations in physical and mechanical properties for specific applications. The incorporation of nanoparticles, such as layered silicate (clay), carbon nanotubes, metal or metal oxide, cellulose nanowhiskers, can address these limitations by enhancing the thermal, mechanicals, barriers, and some other properties of polylactide. However, the distinct characteristics of these nanoparticles can affect the compatibility and processing of polylactide blends. In the polylactide nanocomposites, well-dispersed nanoparticles within the polylactide matrix result in excellent mechanical and thermal properties of the materials. Surface modification is required to improve compatibility and the crystallization process in the blended materials. This article reviews the development of polylactide nanocomposites and their applications. It discusses the general aspect of polylactides and nanomaterials as nanofillers, followed by the discussion of the processing and characterization of polylactide nanocomposites, including their applications. The final section summarizes and discusses the future challenges of polylactide nanocomposites concerning the future material's requirements and economic considerations. As eco-friendly materials, polylactide nanocomposites offer significant potential to replace petroleum-based polymers. [ABSTRACT FROM AUTHOR]

Abstract—Nonwoven fibrous materials based on polylactide (PLA) and ozonide of oleic acid triglyceride (glycero-(9,10-trioxolane)-trialeate) in a range of concentrations of 1–5 wt % intended for hygienic and medical devices are obtained by electrospinning. The introduction of ozonide leads to plasticization of PLA, which manifests itself in the cleavage of the primary jet of the forming solution and appearance of ultrathin nanofibers; here, the porosity and relative elongation at break increase. The optimum weight fraction of ozonide introduced into PLA is determined to be 3 wt %. [ABSTRACT FROM AUTHOR]

Interfacial compatibilization of polylactide/ethylene-methyl acrylate-glycidyl methacrylate random terpolymer (PLA/EG-MA) incompatible blends is crucial for fabricating super-tough PLA materials. To regulate and control the interfacial reaction and adhesion between PLA and EG-MA, 1-carboxymethyl-3-methylimidazole bromide salt (ILs) was selected as an interfacial compatibilizer and controller for PLA/EG-MA blends. Morphologies, crystallization, and relaxation behaviors of the blends were systematically investigated. The results proved that the reaction between the end groups of PLA and the epoxy groups of EG-MA could be catalyzed by carboxyl-functionalized ILs. The phase morphology structure of blends changed from sea-island to co-continuous structure with the increase of ILs. Notably, the impact strength and elongation at break of the PLA/EG-MA/2ILs blend reached 67 kJ/m2 and 284%, respectively, which is a 71 and 22 fold increase caused by the formation of interfacial crosslinking. Vigorous interfacial adhesion obviously increased the crystallinity and induced co-continuous morphology, which triggered massive shear yielding. Super-tough PLA blends were easily fabricated owing to the interfacial catalytic crosslinking of carboxyl-functionalized ILs. [ABSTRACT FROM AUTHOR]

Composite biomaterials comprising polylactide (PLA) and hydroxyapatite (HA) are applied in bone, cartilage and dental regenerative medicine, where HA confers osteoconductive properties. However, after surgical implantation, adverse immune responses to these composites can occur, which have been attributed to size and morphology of HA particles. Approaches to effectively modulate these adverse immune responses have not been described. PLA degradation products have been shown to alter immune cell metabolism (immunometabolism), which drives the inflammatory response. Accordingly, to modulate the inflammatory response to composite biomaterials, inhibitors were incorporated into composites comprised of amorphous PLA (aPLA) and HA (aPLA + HA) to regulate glycolytic flux. Inhibition at specific steps in glycolysis reduced proinflammatory (CD86+CD206-) and increased pro-regenerative (CD206+) immune cell populations around implanted aPLA + HA. Notably, neutrophil and dendritic cell (DC) numbers along with proinflammatory monocyte and macrophage populations were decreased, and Arginase 1 expression among DCs was increased. Targeting immunometabolism to control the proinflammatory response to biomaterial composites, thereby creating a pro-regenerative microenvironment, is a significant advance in tissue engineering where immunomodulation enhances osseointegration and angiogenesis, which could lead to improved bone regeneration.

The drastic increase in the amount of packaging waste from conventional plastics, caused by improper waste management, is a serious challenge for the planet. It is therefore worth considering how we can solve this problem. Thus, it is necessary to develop new polymeric materials that retain the functional properties of traditional plastics but are susceptible to degradation with the participation of microorganisms. The development of new eco-friendly materials requires a holistic approach in terms of their disposal. Organic recycling enables the disposal of biodegradable packaging along with food remains that are difficult to remove. The article presents a study on the degradation of biocomposites of polylactide with cork in various environments (water, buffer, and compost). The obtained results indicate a clear influence of the presence of the filler and its amount on the degradation profile of the composites. In addition, the effect of sample shrinkage was observed, especially during degradation in water, where the pH decreases during the process due to the appearance of degradation products. This effect may be important not only for the degradation profile of the packaging but also during its use. Packaging distorted due to shrinkage may be a sign of improper product storage.

The bottleneck in the widespread use of carbon multiwall nanotube polymer composites is the lack of manufacturing technology that can be used on an industrial scale. In this article, we describe a two-step composite manufacturing technology based on screw extrusion that produces composites characterizing with good dispersion of carbon nanotube filler in polylactide matrix. The first stage involved the fabrication of highly filled masterbatches of 25 wt% of carbon nanotubes. In the second stage, by screw extrusion of the masterbatch mixture with neat polymer, we obtained homogeneous composites with the target filler concentration. The resulting composites with nanotube content ranging from 0.1 to 2 wt%. Mechanical tests including static tension, tensile strength, tensile modulus, three-point bending and impact strength has shown that optimal concentration of the carbon nanotube filler is ranged between 0.5 and 1 wt%. Samples were examined also by SEM, FTIR-ATR, DSC and MFR methods.

This work attempts to assess the influence of process parameters on the change of mechanical properties and the degree of crystallinity of polylactide (PLA). PLA is a biodegradable material that has been widely used in various areas—from packaging, through medicine, to 3D printing, where it is used to produce prototypes. The method of processing is important, because the technological process and its parameters have a significant impact on the quality of the finished product. Their appropriate selection depends on quality and mechanical properties. The process parameters have an impact on the structure of PLA, specifically on the share of the crystalline phase, which is also important from the point of view of the functional properties of the finished product. This work assessed the impact of the technological parameters of the injection process on the final properties of the obtained samples. The obtained results of static tensile strength, hardness and differential scanning calorimetry (DSC) analysis confirm that changing these parameters affects the material properties. [ABSTRACT FROM AUTHOR]

In the process of storage and delivery, food products are subjected to physical changes, resulting in moisture exchange between the product and the environment, mechanical damage, chemical processes occurring in the product itself, as well as microbiological damage. The use of packaging materials on the basis of polyolefins, reduce the influencing factors leading to rapid corruption of food products. However, by their nature, polyethylene and polypropylene films do not have antimicrobial properties. Therefore, in order for the packaging based on them to protect the product from microbiological damage, various technological techniques are used for the processing of packaging, as well as the introduction of special antimicrobial agents into the composition of the film. The present study developed a method of synthesis of copper oxide nanoparticles stabilized with gelatin and pectin. The synthesis was carried out by direct chemical sedimentation. Copper chloride was used as a precursor to the synthesis of copper oxide. Gelatin and pectin were used as stabilizers. Gelatin and pectin were used as a stabilizer as an environmentally friendly component of the film. In addition, consumers are interested in innovative, economical, harmless and effective food packaging materials. The results showed that CuO nanoparticles, stabilized with gelatin and pectin, have a high potential for use in food packaging - both as a stand-alone nanoplane and as part of other packaging materials. [ABSTRACT FROM AUTHOR]

Polylactide is an important material in biomedical applications, but its slow degradation rate, low hydrophilicity, and lack of reactive side-chain groups limit its use. To overcome these limitations it is crucial to functionalize it with reactive groups. By introducing reactive functional side groups, biologically active compounds can be attached with the possibility of controlled release. Additionally, introducing suitable functional groups can improve hydrophilicity, which is essential for drug delivery. There are several ways to introduce reactive functional side groups to the polylactide chain, with the most versatile being the introduction of a reactive group into monomeric lactide and its subsequent polymerization or copolymerization with lactide. This approach allows the preparation of polylactides with pendent functional groups via the polymerization of functional (substituted) monomers. Therefore, the synthetic strategy based on functional monomers is considered the primary option to access a broad range of functional polylactides. This review focuses on the modification of polylactide by incorporating functional groups into monomer molecules and their subsequent polymerization. Through this approach, it is possible to improve the properties of polylactide for various biomedical applications. In the following sections, we will discuss the different methods for functionalization and their potential impact on the biomedical field. [ABSTRACT FROM AUTHOR]

In recent years, there has been continuous growth in the market for polylactide/poly(lactic acid) (PLA) which can be attributed to the increasing preference for environmentally friendly products derived from renewable resources. Apart from its established biomedical applications, polylactide is being considered as a replacement for petroleum-based polymers in various industries, including packaging, electronics, automotive, and textiles. However, PLA modification is necessary to meet the properties of common thermoplastics for target applications. One of the modification methods involves the synthesis of PLA block copolymers, including widely exploited polymers of vinyl monomers (PVM). This review article covers a wide range of applications suggested for PLA/PVM block copolymers as discussed in recent articles. A brief overview of the synthesis methods for PLA/PVM block copolymers is provided. The tendency of block copolymers to self-assemble, leading to specific morphologies, is discussed, and applications that take advantage of this behavior, such as polymeric micelles or porous materials, are highlighted. Examples of using micelles for the delivery of biologically active compounds are presented. Other biomedical applications, such as materials for tissue engineering and medical devices, are also discussed. Finally, the article covers materials for common plastic applications obtained through reactive blending/extrusion, which produces PLA/PVM copolymers in situ. [ABSTRACT FROM AUTHOR]

This study focuses on the preparation of hybrid block copolymers of polylactide (PLA) and polystyrene (PS) involving 2,5-dihydroxy-1,4-benzoquinone (DHBQ) as a dual initiator. At the first stage, in the presence of AcONa, 2,5-dihydroxy-1,4-benzoquinone opens the lactide ring, resulting in a carboxylic end group that further facilitates the growth of the PLA chain. The polymerization proceeds at a moderate rate to high conversion degrees to form the polymers with well-defined molecular weight (MW) characteristics. The presence of internal DHBQ fragment in the polymer was proven by IR, UV–VIS, NMR and MALDI-TOF techniques. Obtained polymer can be considered as macroquinone (MQ). The styrene polymerization initiated by MQ/Bu3B proceeds at a moderate rate leading to the formation of hybrid three-arms PLA/PS copolymer. Linear increase in Mn with conversion and polydispersity reduction were observed during copolymerization. As evidenced by relatively low content of polystyrene in the copolymer (8.1 wt. %), the process has a good selectivity. The introduction of styrene units into the copolymer leads to a four-fold increase in E modulus compared to homo-PLA. [ABSTRACT FROM AUTHOR]

High-molecular-weight ABA triblock copolymers (PLA–PEs–PLA), consisting of poly-l-lactide (PLLA: A) and two types of polyethers (PEs: B), i.e., poly(oxyethylene) (PEG: polyethylene glycol) and Pluronic® [PN: poly(oxyethylene)-b-poly(oxypropylene)-b-poly(oxyethylene)], were synthesized by ring-opening polymerization of l-lactide by using bis-hydroxyl-terminated PEs as macroinitiators. Polymer films of these block copolymers were fabricated by the conventional hot-pressing method and uniaxially cold drawn to five times at 80 °C. Evaluation of the mechanical properties of these films revealed that the drawn films can retain high strength (ca. 100 MPa) and improved flexibility (2 GPa in modulus). It was therefore evident that the drawn films of PLLA–PEs triblock copolymers are highly useful as flexible films that can be controlled by the PEs content. The A–B–A triblock copolymers consisting of PLLA and polyethers (PE: PEG and PN) were synthesized by the ROP of l-lactide in the presence of telechelic PE as the macroinitiators. The drawn films of these block copolymers were found to compete with the conventional petroleum plastic films and exceed the current biobased and biodegradable polymer films in terms of toughness. Thus, the oriented copolymer films were shown to be highly useful for flexible PLLA-based films. [ABSTRACT FROM AUTHOR]

While the brittle polylactide (PLA) has a high durability among bioplastics, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) with certain ductility exhibits facile compostability. The addition of polybutylene adipate terephthalate (PBAT) may also be used to improve the ductility and toughness of brittle bioplastics. Binary and ternary blends of PLA/PBAT/PHBH based on either PLA or PHBH as the matrix have been manufactured using a twin-screw extruder. The melt rheological, mechanical, and morphological properties of the processed samples were examined. Binary blends of PLA/PHBH show superior strength, with the PLA75/PHBH25 blend exhibiting a tensile strength of 35.2 ± 3.0 MPa, which may be attributed to miscible-like morphology. In contrast, blends of PLA with PBAT demonstrate low strength, with the PLA50/PBAT50 blend exhibits a tensile strength of 9.5 ± 2.0 MPa due to the presence of large droplets in the matrix. PBAT-containing blends exhibit lower impact strengths compared to PHBH-containing blends. For instance, a PLA75/PBAT25 blend displays an impact strength of 1.76 ± 0.1 kJ/m2, whereas the PHBH75/PBAT25 blend displays an impact strength of 2.61 ± 0.3 kJ/m2, which may be attributed to uniformly dispersed PBAT droplets. [ABSTRACT FROM AUTHOR]

Tissue engineering scaffolds have been dedicated to regenerating damaged tissue by serving as host biomaterials for cell adhesion, growth, differentiation, and proliferation to develop new tissue. In this work, the design and fabrication of a biodegradable bilayer scaffold consisting of a ternary PLLA/PCL/CAB blend film layer and a PLGA/curcumin (CC) electrospun fiber layer were studied and discussed in terms of surface morphology, tensile mechanical properties, and molecular interactions. Three different compositions of PLLA/PCL/CAB—60/15/25 (TBF1), 75/10/15 (TBF2), and 85/5/10 (TBF3)—were fabricated using the solvent casting method. The electrospun fibers of PLGA/CC were fabricated using chloroform (CF) and dimethylformamide (DMF) co-solvents in 50:50 and 60:40 volume ratios. Spherical patterns of varying sizes were observed on the surfaces of all blend films—TBF1 (17–21 µm) > TBF2 (5–9 µm) > TBF3 (1–5 µm)—caused by heterogeneous surfaces inducing bubble nucleation. The TBF1, TBF2, and TBF3 films showed tensile elongation at break values of approximately 170%, 94%, and 43%, respectively. The PLGA/CC electrospun fibers fabricated using 50:50 CF:DMF had diameters ranging from 100 to 400 nm, which were larger than those of the PLGA fibers (50–200 nm). In contrast, the PLGA/CC electrospun fibers fabricated using 60:40 CF:DMF had diameters mostly ranging from 200 to 700 nm, which were larger than those of PLGA fibers (200–500 nm). Molecular interactions via hydrogen bonding were observed between PLGA and CC. The surface morphology of the bilayer scaffold demonstrated adhesion between these two solid surfaces resembling "thread stitches" promoted by hydrophobic interactions, hydrogen bonding, and surface roughness. [ABSTRACT FROM AUTHOR]

Various approaches to the optical diagnostics of evolving polymer foams formed as a result of a decrease in the external pressure according to a given scenario in the "polymer-supercritical fluid" systems are considered. Formed polymer foams are considered as a material platform for the creation of scaffolds for biomedical applications. Diagnostics of the current state of the foam was carried out by statistical analysis of the spatiotemporal fluctuations of the probe laser radiation, multiple scattered in the volume of the evolving foam, or by analyzing the fluorescent response during foaming of the "polymer-fluorophore" mixture, pumped by laser radiation in the absorption band of the fluorophore. A relationship has been established between the average lifetime of dynamic speckles in scattered laser light and a generalized parameter characterizing the foam expansion dynamics. It was also found that the waveguide effect in the walls of the formed pores has a significant influence on the fluorescent response of the evolving foam, leading to an increase in the characteristic dwell time of fluorescence radiation in the walls and, accordingly, to an increase in the contribution of the induced component to the fluorescent response. [ABSTRACT FROM AUTHOR]

Polymeric thin films based on polylactide with an addition of poly(ethylene glycol) as a plasticizer and flavonoids in the form of quercetin and berberine were subjected to tests that were particularly relevant from the point of view of contact with food. A comparative analysis of the effect of individual flavonoids on the antioxidative properties of tested films and blueberry storage was carried out. The influence of active compounds on the water vapor permeability, as well as UV protection, of the obtained materials was investigated. Also, the specific migration of individual flavonoids from obtained materials to food simulants in the form of acetic acid and ethyl alcohol was determined. The crucial point of this study is the storage of blueberries. The obtained results indicate that the selection of packaging, containing individual active compounds, depends on the purpose and requirements that the packaging must meet for particular types of food. [ABSTRACT FROM AUTHOR]

In the present study, tests were carried out on composite samples on a polylactide matrix containing 25% by weight of mineral filler in the form of diatomaceous earth, base, and silanized with GPTMOS (3-glycidoxypropyltrimethoxysilane), OTES (n-octyltriethoxysilane), and MTMOS (methyltrimethoxysilane) silanes. The addition of two types of waxes, synthetic polyamide wax and natural beeswax, were used as a factor to increase the rheological properties of the composites. The obtained samples were characterized in terms of the effect of filler silanization on the degradation rate of the composites. The tests were conducted under different conditioning conditions, i.e., after exposure to strong UV radiation for 250 and 500 h, and under natural sunlight for 21 days. The conditioning carried out under natural conditions showed that the modified samples exhibit up to twice the degradation rate of pure polylactide. The addition of synthetic wax to the composites increases the tendency to agglomerate diatomaceous earth, while natural wax has a positive effect on filler dispersion. For composites modified with GPTMOS and OTES silanes, it was noted that the addition of natural wax inhibited the degree of surface degradation, compared to the addition of synthetic wax, while the addition of MTMOS silane caused the opposite effect and samples with natural wax degraded more strongly. It was shown that, despite the high degree of surface degradation, the process does not occur significantly deep into the composite and stops at a certain depth. [ABSTRACT FROM AUTHOR]

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Mulch films are intensively used to increase productivity in agriculture. A large amount of plastic waste from mulch films is accumulated in the topsoil of agricultural fields around the world. A solution to this problem is the replacement of disposable plastics by biodegradable ones. The paper presents the results of tests of polylactide-based biodegradable materials for agriculture. It is shown that despite hydrophobicity polylactide is easily hydrolyzed, which subsequently leads to destruction of the films based on it. An analysis of the biodegradability of the materials obtained shows that after incubation in a soil for 90 days the weight loss of pure PLA of various grades is lower than that of PLA/PBAT and PLA/NR mixtures and the thermophysical characteristics of PLA change: its melting temperature decreases by 2–5°C and the degree of crystallinity decreases by 2–6%. [ABSTRACT FROM AUTHOR]

Environmental factors, such as light, water, and temperature, have a combined impact on polymer materials. The present work considers the effect of ultraviolet radiation and distilled water on PLA/PBAT mixtures. It is found that as the content of PBAT in the PLA matrix is increased above 40 wt % the photodegradation of the material slows down. For example, after exposure to UV radiation with a wavelength of 254 nm for 100 h, the melting temperature of pure PLA decreases by 7°C, while that in the 70 PLA/30PBAT mixture decreases by 4°C. X-ray diffraction studies show that the crystalline phase of polylactide is destroyed after UV irradiation. The resulting PLA/PBAT materials undergo hydrolytic degradation, which is of importance for application in agriculture. In the composites close to phase inversion, the degree of water uptake increases. [ABSTRACT FROM AUTHOR]

The review is devoted to analyzing published information concerning biodegradable biliary stents, materials and manufacturing technology, and methods of testing. [ABSTRACT FROM AUTHOR]

Although the mesomorphic phase as an intermediate state has been introduced to understand polymer crystallization, the understanding of the mesomorphic phase is far from complete. Here, the effect of chain mobility on the mesophase structuring in melt-quenched poly(ʟ-lactide) (PLLA) treated in low-pressure CO2 at 1.6–2.0 MPa and 0 °C was investigated using infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and atomic force microscopy (AFM). The IR and AFM results demonstrated that the final degree of order and the kinetics of structural evolution during the CO2-induced mesophase formation were critically dependent on the CO2 pressure. This was attributed to the distinct dynamics of conformational evolution (gg to gt conformer transition) due to the different CO2 pressures. The thermal behavior from the DSC results showed that CO2 pressure dominated both the scale and dynamics of the chain motion of PLLA. At a lower CO2 pressure of 1.6 MPa, smaller-scale segmental motion was not replaced by the larger-scale cooperative motion that occurred at a relatively higher CO2 pressure of 2 MPa, which was favorable for faster mesophase formation. Consequently, by inhibiting direct crystallization under limited mobility conditions, it was demonstrated that different chain mobility controlled by CO2 pressure and thus CO2 solubility impacted the dynamics of the mesophase formation of PLLA. The present results have implications for understanding the role of chain mobility in determining the intermediate structural phases in semicrystalline polymers. [ABSTRACT FROM AUTHOR]

In this paper, a novel polylactide-based nanocomposite with the addition of bentonite as a filler, Fusabond, and glycerine as a compatibilizer and plasticizer, were prepared and investigated. Four samples with different contents of bentonite (1, 5, 10, and 15 wt.%), as well as three samples without fillers, were prepared with an easily scalable method: melt blending. The electrical properties of all prepared samples were investigated with broadband dielectric spectroscopy in the frequency range between 0.1 Hz and 1 MHz. Measurements were conducted at nine temperatures between 293.15 and 333.15 K (20 to 60 °C) with steps of 5 K. It was found that the increase in the content of bentonite in polylactide has a significant effect on the electrical properties of the prepared nanocomposites. [ABSTRACT FROM AUTHOR]

Electrospun ultrathin fibers based on binary compositions of polylactide (PLA) and poly(ε-caprolactone) (PCL) with the various content from the polymer ratio from 0/100 to 100/0 have been explored. Combining thermal (DSC) and spectropy (ESR) techniques, the effect of biopolymer content on the characteristics of the crystal structure of PLA and PCL and the rotative diffusion of the stable TEMPO radical in the intercrystallite areas of PLA/PCL compositions was shown. It was revealed that after PLA and PCL blending, significant changes in the degree of crystallinity of PLA, PCL segment mobility, sorption of the Tempo probe, as well as its activation energy of rotation in the intercrystalline areas of PLA/PCL fibers, were evaluated. The characteristic region of biopolymers' composition from 50/50 to 30/70% PLA/PCL blend ratio was found, where the inversion transition of PLA from dispersive medium to dispersive phase where an inversion transition is assumed when the continuous medium of the PLA transforms into a discrete phase. The performed studies made it possible, firstly, to carry out a detailed study of the effect of the system component ratio on the structural and dynamic characteristics of the PLA/PCL film material at the molecular level. [ABSTRACT FROM AUTHOR]

Introducing fillers into polymeric materials is one of the methods of modifying the properties or reducing the costs of polymeric materials. Thanks to their use, it is possible to obtain new materials with interesting mechanical and chemical properties. Some features are often improved among the new materials obtained, while others deteriorate. In this work, an attempt was made to obtain a polymer composite based on PLA filled with cork flour in amounts of 5%, 10%, 15%, 20% and 30% by weight. The processing and sample preparation process using injection molding technology was assessed and the basic mechanical properties were assessed. The research shows that it is possible to obtain PLA products with a cork filler without the mixing process on an extruder, but only by using an injection molding machine and appropriately selecting the parameters of the technological process. Tests of mechanical properties showed deterioration of parameters, but not to such an extent that the obtained composites were disqualified from use in products that are not subject to heavy mechanical loads. The undoubted advantage of the obtained materials is maintaining their so-called "green" character and thus the ability to biodegrade. [ABSTRACT FROM AUTHOR]

Within this research semi‐crystalline polylactide and composites with 50 wt.% native potato starch were compounded and injection molded. The material was mechanically characterized by tensile, three‐point bending, and Charpy impact tests. These tests were carried out in the freshly molded state and after 332 and 792 h of storage at accelerated temperature or humidity. The respective activation energy was calculated by applying the Flynn‐Wall‐Ozawa method. The focus of the study was to investigate the correlation between the activation energy and the related mechanical and thermal properties. The results showed that the addition of native potato starch as a filler prevents the decrease in activation energy over the course of the experiments. Thus, the PLA/starch composite is more resistant to the two aging conditions than the pure PLA. When considering the mechanical properties, the pure PLA showed a large deviation of results compared to the initial value in a range of +63.88% to −33.96% with regard to the respective aging conditions, whereas the PLA/starch composite properties nearly always remained at the initial values. Through the investigation of the mechanical and thermal properties, it was shown that the steady activation energies are consistent with the mechanical properties, as these have shown only a small deviation of the mechanical properties during the duration of experiments for the PLA/starch composite. [ABSTRACT FROM AUTHOR]

The bottleneck in the widespread use of carbon multiwall nanotube polymer composites is the lack of manufacturing technology that can be used on an industrial scale. In this article, we describe a two-step composite manufacturing technology based on screw extrusion that produces composites characterizing with good dispersion of carbon nanotube filler in polylactide matrix. The first stage involved the fabrication of highly filled masterbatches of 25 wt% of carbon nanotubes. In the second stage, by screw extrusion of the masterbatch mixture with neat polymer, we obtained homogeneous composites with the target filler concentration. The resulting composites with nanotube content ranging from 0.1 to 2 wt%. Mechanical tests including static tension, tensile strength, tensile modulus, three-point bending and impact strength has shown that optimal concentration of the carbon nanotube filler is ranged between 0.5 and 1 wt%. Samples were examined also by SEM, FTIR-ATR, DSC and MFR methods. [ABSTRACT FROM AUTHOR]

In this article, we present polymer materials consisting of polylactide (PLA) and nisaplin (N), as well as PLA and natamax (X). These materials were obtained using the solvent method and tested by various test methods, i.e., functional properties—water vapor permeability, light transmission, gloss, and bactericidal activity against strains E. coli (ATCC 8739P), S. aureus (ATCC 65388), and P. aeruginosa (ATCC 8739). Furthermore, analyses were conducted to evaluate their efficacy against pathogenic fungi, including A. niger, A. flavus, A. glaucus, and A. versicolor. Mutagenicity analyses were performed using the standard Ames Test with Salmonella typhimurium. The main test methods used were ISO 22196, ISO 846. The results obtained confirm the potential suitability of the films of PLA with nisaplin and natamax for applications in the food packaging industry. [ABSTRACT FROM AUTHOR]

This study focuses on the development of needle-punched nonwoven composites reinforced with a Triumfetta cordifolia (TC) bast fiber based on a polylactide (PLA) matrix. Flax and hemp fibers, already known for their use in automotive applications, are used as a reference for comparison purposes. TC bast fibers from the equatorial region of Cameroon were extracted by a water retting process. Nonwoven felts were obtained by mixing TC fibers with PLA (50:50 weight ratio) through carding-napping process. The composite materials were obtained by thermocompression of the nonwoven felts with two thickness ranges (2 and 3 mm). The results obtained in tensile and flexural tests showed that composite materials with an optimal thickness of 2 mm displayed better mechanical performances. The anisotropy of the mechanical properties in traction and flexion of these composites was highlighted. It was found that the tensile and flexural mechanical properties in the transverse direction are always superior to those in the machine direction. Compared to flax or hemp nonwoven-reinforced biocomposites, TC fibers-based nonwoven biocomposites showed slightly lower maximum tensile and flexural stiffness values of 2882.7 MPa and 3908.6 MPa respectively. Thermogravimetric analysis revealed that the addition of the plant fibers increased the thermal stability of PLA and the ash content to 8%. [ABSTRACT FROM AUTHOR]

The aim of this work is to explore the effect of surface characteristics of the 3D printed scaffolds on their suitability for Saos-2 cells growth. Two promising materials for bone tissue engineering were examined, both containing poly(3-hydroxybutyrate)/poly(d,l-lactide) plasticized blend and one of them filled with bioactive tricalcium phosphate. The surface free energy (SFE) of samples was determined by contact angle measurement with four liquids. For non-filled sample the water contact angle (WCA) was 74° and its SFE was 40 mN m−1. The composite sample exhibited substantially decreased WCA, 61°. Moreover, the addition of the tricalcium phosphate caused doubling of the polar component of the SFE which increased by a total of 13%. 3D printed surfaces prepared by fused deposition modeling method showed a profound increase of WCA due to the increase in their surface roughness which was analyzed by confocal microscopy. The change in wetting properties strongly affected the behavior of Saos-2 cells on printed surfaces. The number of cells as measured by DNA quantification linearly decreased with increasing surface WCA. The highest number of cells was observed on the pressed samples and 3D printed surfaces made of simple lines and a grid with 50 μm gap between lines. The favored surfaces exhibit WCA under 80° which is important information for the future design of the scaffolds.

Abstract Over the past years, poly(lactic acid) or polylactide (PLA) is commonly researched as a possible replacement for traditional fossil‐based polymers because of its compostability, biocompatibility, and high mechanical properties. PLA has a variety of applications in packaging, biomedical, and structural. However, PLA has limitations, such as high brittleness, low thermal stability, and a slow crystallization rate, which limits the wide range of applications. To overcome these limitations, the literature reports that blending PLA with other polymers, such as poly(ε‐caprolactone) (PCL), is an economically viable approach. Although blending PLA with PCL is considered a feasible approach, the blend system still suffers from immiscibility, depending on the blend composition. This review aims to highlight recent developments from 2014 to date on the processing of PLA/PCL blends, including their composites, with a primary focus on morphological characteristics and mechanical and thermal properties, including their potential applications in various sectors.