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In recent years, many studies have been conducted on the production of edible films from emerging gums, which are mostly made from botanical sources. However, each one interacts differently with the film compounds, producing films with different properties that may improve or hinder their utilization in food packaging. Therefore, the aim of this review was to investigate and compare the physical, mechanical, thermal and structural properties of edible films produced with these emerging gums. The results of this review showed that it is possible to produce edible films with desirable physical, mechanical and thermal properties by optimizing the amounts and type of compounds in film formulations such as plasticizers, nanoparticles, lipid compounds, crosslinkers and combination of gums with other biopolymers. The future trends of this research include the deepening of knowledge to understand the molecular structures of emerging gums and to address the shortcomings of films based on these gums for their industrial-scale application in food packaging., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In recent years, the synthesis of polymer electrolyte systems derived from biopolymers for the development of sustainable green electrochemical devices has attracted great attention. Here electrolytes based on the red seaweeds-derived polysaccharide κ-carrageenan (κ-Cg) doped with neodymium triflate (NdTrif₃) and glycerol (Gly) were obtained by means of a simple, clean, fast, and low-cost procedure. The aim was to produce near-infrared (NIR)-emitting materials with improved thermal and mechanical properties, and enhanced ionic conductivity. Cg has a particular interest, due to the fact that it is a renewable, cost-effective natural polymer and has the ability of gelling in the presence of certain alkali- and alkaline-earth metal cations, being good candidates as host matrices for accommodating guest cations. The as-synthesised κ-Cg-based membranes are semi-crystalline, reveal essentially a homogeneous texture, and exhibit ionic conductivity values 1⁻2 orders of magnitude higher than those of the κ-Cg matrix. A maximum ionic conductivity was achieved for 50 wt.% Gly/κ-Cg and 20 wt.% NdTrif₃/κ-Cg (1.03 × 10 -4 , 3.03 × 10 -4 , and 1.69 × 10 -4 S cm -1 at 30, 60, and 97 °C, respectively). The NdTrif-based κ-Cg membranes are multi-wavelength emitters from the ultraviolet (UV)/visible to the NIR regions, due to the κ-Cg intrinsic emission and to Nd 3+ , ⁴F 3/2 →⁴I 11/2-9/2 .

Purified chitin-glucan complex (CGCpure) was extracted from Komagataella pastoris biomass using a hot alkaline treatment, followed by neutralization and repeated washing with deionized water. The co-polymer thus obtained had a β-glucan:chitin molar ratio of 75:25 and low protein and inorganic salts contents (3.0 and 0.9 wt%, respectively). CGCpure had an average molecular weight of 4.9 × 10(5)Da with a polydispersity index of 1.7, and a crystallinity index of 50%. Solid-state NMR provided structural insight at the co-polymer. X-ray diffraction suggests that CGCpure has α-chitin in its structure. CGCpure presented an endothermic decomposition peak at 315°C, assigned to the degradation of the saccharide structures. This study revealed that K. pastoris CGC has properties similar to other chitinous biopolymers and may represent an attractive alternative to crustacean chitin derived-products, being a reliable raw material for the development of new/improved pharmaceutical, cosmetic or food products., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Poly(3-hydroxybutyrate-4-hydroxybutyrate-3-hydroxyvalerate) (P(3HB-4HB-3HV)) terpolymers of low 3-hydroxyvalerate (3HV) content (1.7-6.4%) with 4-hydroxybutyrate (4HB) molar fractions from 1.8% to 35.6% were produced by fed-batch cultivation of Cupriavidus necator DSM545. Waste glycerol, γ-butyrolactone and propionic acid were used as main carbon source, 4HB and 3HV precursors, respectively. Uniaxial tensile tests were performed on the corresponding biopolymers. The Young's modulus and tensile strength of P(3HB-4HB-3HV) decreased, whereas the elongation at break increased with the 4HB molar%, following the general trend described for poly(3-hydroxybutyrate-4-hydroxybutyrate) (P(3HB-4HB)) but with pronounced lower elasticity. Differential scanning calorimetry results indicate that the temperature of crystallization and enthalpy of melting decreased as the 4HB% increased. No crystallization was observed in terpolymers containing more than 30% of heteromonomers (4HB and 3HV) even though multiple melting events were detected. Terpolymer fractions of different composition were obtained by solvent-fractionation of the original bacterial terpolymers., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Highlights The objective of this study is to improve the properties of polylactic acid (PLA), a biopolymer produced from renewable resources, without compromising its environmentally friendly “natural composite” properties. The aim was to expand the application range of PLA by making it suitable for the production of high performance composites. With this in mind, it was decided to use inorganic and environmentally friendly materials such as basalt fiber (BF) and boric acid (BA) as reinforcements. Adhesive wear and tensile tests were used to investigate the tribological and mechanical performance of the composites. Differential scanning calorimetry (DSC) and dimensional stability analysis (DSA) methods were used to investigate the thermal properties. Scanning electron microscopy analysis was also used to investigate the morphological properties of the samples. In addition, a matrix modification process using Joncryl®, an epoxy‐based chain extender chemical, was applied to enhance the interfacial interaction between the composite components and improve the composite properties by improving the dispersion of reinforcing materials. As a result of the characterization tests, it was observed that a significant improvement in the properties of the material type containing 10 wt% BF, 0.25 wt% BA and 2 wt% Joncryl® was achieved. A 19% increase in tensile strength of this type of material was observed compared with unreinforced PLA, while the sharp peak increase in the coefficient of friction (COF) curve was shifted from 20 m to 60 m. As a result, it has been presented that environmentally friendly and inorganic materials such as BF and BA can be used to produce composite materials that will serve sectors where the need and use of high performance materials is intense, especially in the automotive, aerospace and aviation sectors. The properties of PLA matrix composites were improved by the simultaneous use of BF and BA and the addition of Joncryl®. The structural properties of PLA, an environmentally friendly polymer, have been improved without compromising this characteristic. PLA matrix natural composites with performance that can be used in the automotive, aerospace and aviation sectors have been developed. [ABSTRACT FROM AUTHOR]

The use of biodegradable polymers in the plastics industry has been increasing in recent years. The study of the chemical, physical, thermal, and mechanical properties of films based on biodegradable components is of interest to technologists because these properties determine their applicability for food packaging. In this work, films based on natural polymers such as linseed mucilage (LM) and chitosan (CH), as well as poly(acrylic acid) (PAA) were obtained through the casting method and using V‐50 as the initiator. The films were characterized through Fourier Transform Infrared spectroscopy, and thermogravimetric analysis, and their water absorption and swelling capacity, and thermal and mechanical properties were determined. Homogenous flexible, translucid, amber‐colored films, with low absorption and solubility in water were obtained. It was demonstrated through Fourier Transform Infrared analysis the chemical interaction between C–H, CO, and C–O chemical groups of LM, CH, and PAA. In addition, films showed high resistance to thermal decomposition between 125 and 425°C. The mechanical tests of tension allowed the composition of LM in the film, the behavior variates between a plastic and/or elastic material and with tensile strength (Rm) values between 10.8 and 16.4 MPa and elastic modulus (E) values between 56.2 and 169.2 GPa, we observed that at higher quantities of LM and thickness, both E and Rm tend to increase, while %EL decreases. This led us to conclude that the material transitioned from ductile and malleable to rigid and brittle. The films obtained with different ratios of LM/CH/PAA may exhibit a semi‐interpenetrating polymeric networking type morphology. Highlights: Thermal and mechanical properties are of interest in food packaging materials.Water absorption can impact the packaged food.Films can be processed on existing machines for conventional plastics.Some conventional plastics could be replaced by these biodegradable films.Biodegradable films are of great interest to the industry of food packaging. [ABSTRACT FROM AUTHOR]

Polymer biocompositions of poly(3-hydroxybutyrate) (P3HB) and linear polyurethanes (PU) with aromatic rings were produced by melt-blending at different P3HB/PU weight ratios (100/0, 95/5, 90/10, and 85/15). Polyurethanes have been prepared with 4,4′-diphenylmethane diisocyanate and polyethylene glycols with molar masses of 400 g/mol (PU400), 1000g/mol (PU1000), and 1500 g/mol (PU1500). The compatibility and morphology of the obtained polymer blends were determined by infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The effect of the polyurethane content in the biocompositions on their thermal stability and mechanical properties was investigated and compared with those of the native P3HB. It was shown that increasing the PU content in P3HB-PU compositions to 10 wt.% leads to an improvement in the mentioned properties. The obtained results demonstrated that the thermal stability and mechanical properties of P3HB were improved, particularly in terms of increasing the degradation temperature, reducing hardness, and increasing impact strength. The best thermal and mechanical properties were shown by the P3HB-PU polymer compositions containing 10 wt.% of polyurethane modifiers, especially PU1000, which was also confirmed by the morphology analysis of these biocompositions. The presence of polyurethanes in the resulting polymer biocomposites decreases their glass transition temperatures, i.e., makes the materials more flexible. The resulting polymer biocompositions have suitable mechanical properties and thermal properties within the processing conditions for the predicted application as biodegradable, short-lived products for agriculture. [ABSTRACT FROM AUTHOR]

Tamarind seed polysaccharides (TSPs), in conjunction with alkali nitrate, specifically lithium nitrate (LiNO3), were utilized at various concentrations. The aforementioned precursor was dispersed in an aqueous solvent medium using the solution casting route to synthesize thin film polymer electrolytes based on TSP:LiNO3. A comprehensive characterization, incorporating X-ray diffraction (XRD), Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), impedance analysis, and linear sweep voltammetry (LSV), was conducted to elucidate key properties, including crystallinity state (crystalline or amorphous), vibrational band shifts, endothermic point characteristics, ionic conductivity, mobility (both cationic and anionic), diffusion coefficients (both cation and anion), transference number, and electrochemical stability. The investigation revealed that the structural properties of the polymer electrolytes are notably influenced by the varying concentrations of LiNO3 in the polymer host. The maximum ionic conductivity was found to be 1.41 × 10−3 S cm−1 for the composition of 750 mg TSP:250 mg LiNO3. The electrochemical stability value and transference number of the prepared TSP:LiNO3 are 4 V and 0.68, respectively. Primary lithium-ion cell has been constructed for highest conducting sample which delivered an open circuit voltage of 1.5 V, and also, the discharge profile with 1 MΩ load has been studied. [ABSTRACT FROM AUTHOR]

Biopolymer blend composite films based on polyvinyl alcohol (PVA) and chitosan (CS) incorporated with varying amounts of chicory extract (CE) have been developed by the green solution casting technique. The impact of CE content on structural, thermal, mechanical and electrical properties was thoroughly examined. The existence of intermolecular interactions in the blend composite was confirmed by Fourier‐transform infrared and ultraviolet spectroscopy. The x‐ray diffraction pattern proved the successful preparation of PVA/CS/CE composite film. The scanning electron microscopy images of the composites showed shape and grain size for the different bio‐filler contents. The thermal transition temperature of the blend composites was significantly improved by the addition of CE extract deduced from differential scanning calorimetry. The dielectric study showed that the permittivity remarkably increases with decreasing frequency and maximum dielectric constant was observed for 15 wt% loading. The activation energy obtained from the AC conductivity decreased as the temperature increased. The addition of CE extract improved the hardness and tensile strength of the PVA/CS blend composite in comparison with a pristine pure blend. The controllable mechanical, thermal, optical, and electrical characteristics of the PVA/CS blend composite suggest that it might be an attractive optical material for the advancement of futuristic flexible‐type optoelectronic and energy storage systems. [ABSTRACT FROM AUTHOR]

Medicated jellies are widely used by a large part of patients, especially by people with swallowing difficulties. Preformulation studies play an essential role in the development of new pharmaceutical formulations. The present study aimed to formulate and evaluate medicated jellies containing perphenazine, an antipsychotic drug from the group of phenothiazine compounds used to treat schizophrenia and other mental disorders. Typical gelling agents such as sodium alginate (Alg), gelatine (Gel), and pectin (Pec) were used to develop the medicated jellies. In addition to the biopolymers, components such as benzoic acid (BenzAc), citric acid (CitAc), sodium citrate (NaCit), sorbitol (Sorb) and xylitol (Xyl) were also used. Before preparing the jellies, the moist binary mixture between each component of the jelly and the active substance was analysed to investigate the compatibility of the substances. The active substance, moist binary mixture, and medicated jellies were analysed by FTIR_UATR spectroscopy, UV-Vis spectroscopy and thermogravimetry. [ABSTRACT FROM AUTHOR]

This study aimed to determine the effects of the ozone treatment of film-forming solutions (FFSs) containing whey protein concentrate (WPC) and gelatine on biopolymer films' physical, mechanical, and thermal properties. Film samples were produced from a FFS that was ozone-treated at 0 (control), 5, 10, and 30 min. Ozone treatment caused an increase in the pH values of the FFS, whereas the zeta potential remained negative. The films became lighter in colour, slightly greenish, and more opaque with longer ozonation times. The control sample showed the highest thermogravimetric weight loss (92.15%). The weight loss of the samples decreased with increasing ozone treatment time. The application of ozone treatment on the FFS enhanced the films' mechanical properties. Increased ozone treatment time improved the film samples' tensile strength, elongation at break, and toughness values. In conclusion, the results of this study demonstrate that the ozone treatment of FFS containing whey protein concentrate and gelatine can significantly enhance the physical, mechanical, and thermal properties of biopolymer films. These results highlight the potential of ozone treatment as a viable method for improving the performance and quality of biopolymer films used in food packaging, offering promising advantages for sustainable and environmentally friendly packaging solutions. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the morphological and thermo-mechanical properties of a bioplastc film obtained from orange peel. Design/methodology/approach: Pectin, a polysaccharide obtained from orange peel, has the potential to be used as a raw material in the bioplastics industry. The samples obtained were characterized by the Scanning Electron Microscopy (SEM) technique, mechanical tension and by thermogravimetric analysis (TGA). Results: The elastic modulus was in the range of 7.7 to 29.9 MPa, depending on the plasticizer content. The thermogravimetric analysis showed a thermal decomposition between 134.42 to 153.98 °C depending on the plasticizer content and up to five events were identified. Limitations of the study/implications: During the process, a pectin yield of 75% of orange peel was obtained. Findings/conclusions: In developing countries such as Mexico, waste from agricultural and agro-industrial activities represents an important source of natural carbohydrate polymers that can be used to produce bioplastics, intended to replace petroleum-derived materials. In the case of orange peel, it can become a potential raw material to obtain value-added products in sectors of the food industry. These results indicated that our pectin has suitable properties to be used as raw material for the manufacture of bioplastics. [ABSTRACT FROM AUTHOR]

Due to the growing interest in biopolymers, biosynthesizable and biodegradable polymers currently occupy a special place. Unfortunately, the properties of native biopolymers make them not good enough for use as substitutes for conventional polymers. Therefore, attempts are being made to modify their properties. In this work, in order to improve the properties of the poly(3-hydroxybutyrate) (P3HB) biopolymer, linear aliphatic polyurethane (PU) based on 1,4-butanediol (BD) and hexamethylene 1,6-diisocyanate (HDI) was used. The conducted studies on the effect of the amount of PU used (5, 10, 15 and 20 m/m%) showed an improvement in the thermal properties of the prepared polymer blends. As part of the tested mechanical properties of the new polymer blends, we noted the desired increase in the tensile strength, and the impact strength showed a decrease in hardness, in particular at the presence of 5 m/m% PU. Therefore, for further improvement, hybrid nanobiocomposites with 5 m/m% PU and organically modified montmorillonite (MMT) (Cloisite 30®B) were produced. The nanoadditive was used in a typical amount of 1–3 m/m%. It was found that the obtained nanobiocomposites containing the smallest amount of nanofillers, i.e., 1 m/m% Cloisite®30B, exhibited the best mechanical and thermal properties. [ABSTRACT FROM AUTHOR]

Natural fiber-reinforced polymer composites are presently receiving the attention of scholars and industrialists due to their specific properties, such as being naturally eco-friendly, biodegradable, economical, viable, available, and sustainable. The key problems associated with natural fiber polymer composites, including fiber/matrix compatibility, high moisture absorption, and, especially, thermal degradation in engineering plastics (high-temperature plastics), constitute the most critical thrust of this review. It is noted that at high temperatures, natural fibers degrade and this has adversely restricted their usage with only commodity thermoplastics having relatively low melting temperatures, such as polypropylene (PP) and polyethylene (PE). This review paper, therefore, provides valuable research highlights on utilizing and improving the mechanical and thermal properties of natural kenaf fibers as reinforcement in engineering polymer composites for high-temperature engineering applications using polymer matrices, such as polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), and polyphenylene ether (PPE). The initial and various chemical treatments of natural fibers, their effect on the thermal and performance properties of natural fiber engineering thermoplastic composites, and the advanced treatment of epoxy coatings are reviewed. Applications of natural fiber-reinforced thermoplastic composites in the construction and automotive industries, as well as in other applications, are outlined. It was established that the adhesion and thermal stabilities between polymer matrix and natural fibers are better improved by surface coating with diluted epoxy resin thermoset. This eventually improved the overall thermal and performance properties of the resultant composites and will serve as a data bank and guide for manufacturers and future research directions using high-end engineering polymers with higher processing temperatures. [ABSTRACT FROM AUTHOR]

Nanocellulose derived from cellulose, the abundant natural polymer, is used in various applications due to its superior chemical, mechanical and thermal properties along with good biocompatibility and biodegradability. This paper reports an investigation of the extraction of nanocellulose from two freely available natural precursors-watermelon rinds and water hyacinth leaves. Cellulose isolation was carried out through chemical methods, including acid and alkali treatments followed by bleaching. The chemical composition, percentage crystallinity and particle size were studied using various characterization techniques. FTIR spectra indicate the removal of hemicelluloses, pectin, and lignin resulting in the effective isolation of cellulose from both precursors. Results of XRD indicate a high concentration of Cellulose Nanocrystals (CNCs) in the treated sample. The FESEM and SEM-EDAX images also confirm the formation of CNCs. TGA and DSC results show excellent thermal stability for both CNCs. Investigations on the properties of a CNC-reinforced epoxy composite are also reported. Results indicate considerable improvement in the mechanical properties, thermal stability and thermal conductivity of the composites compared to the pristine polymer. [ABSTRACT FROM AUTHOR]

Natural and biodegradable polymers with pH-responsive properties, such as alginate and chitosan, are widely exploited for drug delivery applications, most notably in the form of biocompatible microspheres. In addition, thermo-responsive poly(N-isopropyl-acrylamide) (PNIPAM) is often added to biomedical delivery systems due to its lower critical solution temperature close to human physiological conditions. In this work, multi-responsive microspheres (MRMs) consisting of a hydrogel matrix made of alginate, chitosan, and PNIPAM were successfully prepared by extrusion dripping and proposed as delivery system for Ozoile (Stable Ozonides) derived from biological olive oil. Ozoile acts as a biological inducer, regulating the main metabolic pathways and stimulating the endogenous defence system. The MRMs containing Ozoile were prepared from alginate/NIPAM emulsions integrating the lipophilic bioactive principle. The MRMs were further optimised with a chitosan coating to improve their stability and control the degradation behaviour of the hydrogel matrix, with subsequent release of Ozoile. Results in terms of chemical composition from Fourier transform infrared (FTIR) spectroscopy, thermo-responsive properties from differential scanning calorimetry (DSC) analysis, swelling and degradation behaviour were used to establish the potential use of the MRMs for the therapeutic release of Ozoile at specific inflammatory sites. [ABSTRACT FROM AUTHOR]

Hybrid polymer composites are utilized in biomechanical design and orthopedic surgery training to imitate the thermomechanical behavior of human bones. Despite extensive research on the mechanics of hybrid composites in biomechanical design, information on their thermomechanical response during orthopedic drilling operations is scarce. This paper presents a new experimental study to characterize the force and temperature generated during the drilling of hybrid composites that simulate human bones. To simulate the hybrid multi-layer structure of bones, the studied composite comprises a Polyurethane core sandwiched between Glass-Fiber Reinforced Polymer (GFRP) layers—the former resembling the cancellous part of the bone and the latter cortical layers. This study also identifies an empirical relationship between thrust force, temperature, drilling feed and speed, and composite composition. Empirical models are developed using multivariate polynomial regression (MPR) and artificial neural network (ANN) to predict the force and temperature during drilling. The models have a correlation coefficient of above 0.9 between predicted and measured results and can be used to improve orthopedic drilling design and control. [ABSTRACT FROM AUTHOR]

The current research is devoted to the investigation of the plasticization of polyhydroxybutyrate (PHB) and polyhydroxybutyrate-co-hydroxyvalerate (PHBV) with triethyl citrate (TEC). Three different PHB or PHBV-based systems with 10, 20, and 30 wt.% of TEC were prepared by two-roll milling. The effect of TEC on the rheological, thermal, mechanical, and calorimetric properties of the developed compression-molded PHB and PHBV-based systems was determined. It was revealed that the addition of TEC significantly influenced the melting behavior of both polyhydroxyalkanoates (PHA), reducing their melting temperatures and decreasing viscosities. It was also revealed that all the investigated systems demonstrated less than 2% weight loss until 200 °C and rapid degradation did not occur until 240–260 °C in an oxidative environment. Apart from this, a remarkable increase (ca 2.5 times) in ultimate tensile deformation εB was observed by increasing the amount of TEC in either PHB or PHBV. A concomitant, considerable drop in ultimate strength σB and modulus of elasticity E was observed. Comparatively, the plasticization efficiency of TEC was greater in the case of PHBV. [ABSTRACT FROM AUTHOR]

This paper explores the effect of nanoclay for improving the interfacial properties of starch bioplastic material filled with cellulose-nanoparticles (CNPs). The CNPs were prepared through acid-hydrolysis process by using acid concentration to break the amorphous region of chopped fiber to produce nano-cellulose. Various CNPs concentration (0.5 – 2.5 wt.%) were dispersed in cornstarch biopolymer matrix to form bioplastic films through solution casting method and listed for thermal and mechanical properties. Cornstarch bioplastic filled with 1.5 wt.% of CNPs showed optimum improvement in thermal and mechanical properties. Furthermore, nanoclay (NC) of varying weight percentage (0.1 – 0.5 wt. %) were added to the optimum improved 1.5 wt.% CNPs filled cornstarch bioplastic material. Hence, the hybrid cellulose-nanoparticles/nanoclay (CNPs/NC) filled cornstarch was improved both thermally and mechanically. The stiffness parameter ( β f ) and confinement region (C ) of the bioplastic during relaxation stage were 0.70 and 1.03 respectively for hybrid fillers at 1.5/0.3_CNPs/NC, which is an indication that nanoclay had a very good reinforcing effect on the starch polymer system. Improved tensile modulus and tensile strength of the CNPs/NC by 639% and 97% respectively were found when compared to CNPs filled cornstarch bioplastic material. Furthermore, the addition of nanoclay slow down the effect of water absorption rate. Hence, the water uptake of the bioplastic film was normalized. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) is being used more widely because of the simplicity of the operating procedures. It decreases material consumption during part production and eliminates material waste. Fused deposition modeling (FDM), a well‐known AM process, uses thermoplastic polymer as a feedstock to manufacture the end design. Pure thermoplastic‐based products are still utilized as prototypes in several sectors due to their lack of strength and durability. This problem has been solved by strengthening the thermoplastics by adding a reinforcing element. Composites are made of polymers and various constituents known as reinforcing components. This article overviews natural reinforced polymer composites used in the FDM process. Mechanical and Thermal properties are presented based on natural filler percentage, and this article only considered natural composite filaments for the FDM process. [ABSTRACT FROM AUTHOR]

Poly(butylene succinate) (PBS) is a worthy biodegradable thermoplastic polyester for blending along with other biopolymers, especially with poly (lactic acid) (PLA), to overcome its inadequacies in mechanical and thermal characteristics. Since binary blends of PLA and PBS showed that they are incompatible, compatibilization is required. In this work, multi‐epoxide polyhedral oligomeric silsesquioxane (Glycidyl POSS) was added to PLA and PBS using the melt blending method to make them compatible. The blends were prepared at different weight ratios having different amounts of compatibilizer. SEM analysis showed that the Glycidyl POSS impacted the interfacial adhesion and other properties of PLA and PBS blends. Noticeable improvements in mechanical properties were revealed by tensile and impact test results. Tensile strength and Young's modulus were improved when epoxy‐POSS was added up to 1 and 3 wt% into ternary blends, but further increasing POSS concentrations resulted in lower values. FTIR analysis showed a strong interaction between the epoxide group of POSS and the end groups of PBS or PLA. The thermal properties of samples were analyzed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The shifts in glass transition temperatures of the PLA phase towards lower values appeared in DSC, confirming the enhanced compatibility of PLA and PBS. Also, the reinforcing ability of the POSS inorganic core structure impacted the thermal stability of the blends. [ABSTRACT FROM AUTHOR]

Highly methylated apple pectin (HMAP) and pork gelatin (PGEL) have been proposed as gelling agents for pumpkin purée-based films. Therefore, this research aimed to develop and evaluate the physiochemical properties of composite vegetable films. Granulometric analysis of film-forming solutions showed a bimodal particle size distribution, with two peaks near 25 µm and close to 100 µm in the volume distribution. The diameter D4.3, which is very sensitive to the presence of large particles, was only about 80 µm. Taking into account the possibility of creating a polymer matrix from pumpkin purée, its chemical characteristic was determined. The content of water-soluble pectin was about 0.2 g/100 g fresh mass, starch at the level of 5.5 g/100 g fresh mass, and protein at the level of about 1.4 g/100 g fresh mass. Glucose, fructose, and sucrose, the content of which ranged from about 1 to 1.4 g/100 g fresh mass, were responsible for the plasticizing effect of the purée. All of the tested composite films, based on selected hydrocolloids with the addition of pumpkin purée, were characterized by good mechanical strength, and the obtained parameters ranged from about 7 to over 10 MPa. Differential scanning calorimetry (DSC) analysis determined that the gelatin melting point ranged from over 57 to about 67 °C, depending on the hydrocolloid concentration. The modulated differential scanning calorimetry (MDSC) analysis results exhibited remarkably low glass transition temperature (Tg) values, ranging from −34.6 to −46.5 °C. These materials are not in a glassy state at room temperature (~25 °C). It was shown that the character of the pure components affected the phenomenon of water diffusion in the tested films, depending on the humidity of the surrounding environment. Gelatin-based films were more sensitive to water vapor than pectin ones, resulting in higher water uptake over time. The nature of the changes in water content as a function of its activity indicates that composite gelatin films, with the addition of pumpkin purée, are characterized by a greater ability to adsorb moisture from the surrounding environment compared to pectin films. In addition, it was observed that the nature of the changes in water vapor adsorption in the case of protein films is different in the first hours of adsorption than in the case of pectin films, and changes significantly after 10 h of the film staying in an environment with relative humidity RH = 75.3%. The obtained results showed that pumpkin purée is a valuable plant material, which can form continuous films with the addition of gelling agents; however, practical application as edible sheets or wraps for food products needs to be preceded with additional research on its stability and interactions between films and food ingredients. [ABSTRACT FROM AUTHOR]

Chitosan is one of the most commonly employed natural polymers for biomedical applications. However, in order to obtain stable chitosan biomaterials with appropriate strength properties, it is necessary to subject it to crosslinking or stabilization. Composites based on chitosan and bioglass were prepared using the lyophilization method. In the experimental design, six different methods were used to obtain stable, porous chitosan/bioglass biocomposite materials. This study compared the crosslinking/stabilization of chitosan/bioglass composites with ethanol, thermal dehydration, sodium tripolyphosphate, vanillin, genipin, and sodium β-glycerophosphate. The physicochemical, mechanical, and biological properties of the obtained materials were compared. The results showed that all the selected crosslinking methods allow the production of stable, non-cytotoxic porous composites of chitosan/bioglass. The composite with genipin stood out with the best of the compared properties, taking into account biological and mechanical characteristics. The composite stabilized with ethanol is distinct in terms of its thermal properties and swelling stability, and it also promotes cell proliferation. Regarding the specific surface area, the highest value exposes the composite stabilized by the thermal dehydration method. [ABSTRACT FROM AUTHOR]

The study developed and designed polyvinyl acetate (PVAc) foams using advanced freeze-drying technology, which exhibited good heat-insulating ability, flame retardancy, and mechanical properties. Different combinations of bleach kraft pulp, water-soluble chitosan, and zinc borate were used to reinforce the foams. The foams exhibited desirable compression and flexural properties, with compression strength and compression modulus ranging from 0.01 MPa to 0.08 MPa and 0.05 MPa to 0.29 MPa, respectively, while flexural strength and flexural modulus ranged from 0.12 MPa to 5.37 MPa and 9.86 MPa to 260,85 MPa, respectively. The use of zinc borate as a reinforcement resulted in improved thermal properties and reduced mass loss at 600°C by 20.69%. Thermal conductivity tests indicated that the foams had low thermal conductivity values ranging from 0.037 W/mK to 0.074 W/mK. The foams with zinc borate (60 g /L) and high molecular weight water-soluble chitosan (70 g /L) reinforcement exhibited high limiting oxygen index (LOI) of 28.72%. Overall, the results suggest that the PVAc foams could serve as a promising sustainable alternative in thermal insulation and construction fields. [ABSTRACT FROM AUTHOR]

Various environmental concerns motivate scientists and researchers to look out for unique new materials in science and technology. In order to address the demand for polymeric materials with partial biodegradability, the usage of lignocellulosic fibre in the polymer matrix has risen. Lignocellulosic fibres are a cheap, easily renewable resource that is readily available in all regions. Cellulosic plant fibres also have a plethora of possibilities for use in polymer reinforcement because of their properties. Many researchers put their effort into developing a natural polymer with better mechanical properties and thermal stability using nanotechnology and the use of natural polymers to make its composites with lignocellulosic fibres. This study provides a review of the biodegradable composite market, processing methods, matrix-reinforcement phases, morphology, and characteristic improvements. In addition, it provides a concise summary of the findings of significant research on natural fibre polymer composites (NFRCs) that have been published. Indeed, a noticeably brief discussion is provided on the significant issues faced during composite extraction as well as the challenges encountered during the machining. Recent developments in the study of lignocellulosic fibre composites or NFRCs have demonstrated their enormous potential as structural elements in vehicles, aerospace structures, buildings, ballistics, soundproofing, and other structures. [ABSTRACT FROM AUTHOR]

Oriented polylactic acid (PLA)/graphene oxide (GO) nanosheets tapes were prepared via uniaxial solid state drawing. The effect of various drawing conditions, including drawing ratio (DR), temperature (DT), and speed (DS) on mechanical, thermal, structural, and barrier properties were studied. Structural studies showed oriented structure for the drawn tapes with aligned polymer chains and GO nanosheets. Differential scanning calorimetry revealed improved glass transition temperature (Tg) and crystallinity (Xc) after drawing. In addition, Tg and Xc were increased more by increasing DR and DT. The highest Tg and Xc were achieved for 3/70/50 tape with values of 73°C and %22, respectively. Higher thermal stabilities and enhanced barrier properties were achieved after drawing, especially at the higher DR. Finally, tensile testing revealed simultaneous improvement in stiffness and toughness due to strain hardening for all the drawn tapes. The strength and elastic modulus were increased after increasing DR, DS, and DT and reached the highest values of 149 MPa and 3.6 GPa for 3/70/50. Overall, the properties were controllable by the processing conditions. [ABSTRACT FROM AUTHOR]

This work focused on the preparation of biopolymer blend nanocomposites from chitin (CT) and cashew tree gum (CTG) with different contents of copper sulphide nanoparticles (CuS) by solution casting method. The formation of nanocomposites have been characterized by FT infrared (FTIR), UV spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), thermogravimetry (TGA), differential scanning calorimetry (DSC) and impedance analysis. The characteristic absorption of nanoparticles in the FTIR spectra and shift in UV spectra of blend composites revealed the strong interaction between CuS nanoparticles and the polar segments of CT/CTG blend. With the increase in dosage of nanoparticles, a decrease in amorphous domains has been noted in the XRD scans. The uniform distribution of nanoparticles in CT/CTG network has been confirmed by the SEM analysis. HRTEM of the blend composites reveals the formation of hemispherical nanoparticles with a diameter of 15–30 nm. The glass transition temperature of blend composites increased with the addition of nano-CuS in the polymer matrix. Compared to the pure CT/CTG blend, the prepared nanocomposite showed higher thermal stability. Mechanical properties such as tensile strength and hardness of the blend nanocomposites were greatly enhanced by the reinforcement of CuS into the CT/CTG matrix. The AC conductivity and dielectric properties of the nanocomposites increased with the concentration of fillers and the magnitude of these properties was higher than the pure polymer blend. [ABSTRACT FROM AUTHOR]

Research in bio-based composites is rapidly rising in terms of fundamental experiments and industry applications. Natural fibres are one of the common bio-based materials used in composites. Natural fibres have many advantages, including low cost, biodegradable, good thermal conductivity, and may also be used as an alternative to synthetic polymer composites. However, the hydrophilic characteristic of natural fibres can lead to poor interfacial adhesion between natural fibres reinforced and matrix phases, which can affect the properties of bio-based composites. To overcome this problem, the surface modification of natural fibres is required to improve the hydrophobic properties of the composite. A few studies revealed that silane improved the hydrophobicity, tensile strength and thermal stability of bio-based composites. The highest water contact angle of the treated bio-based composite was reported at 135°. Meanwhile, the tensile strength of silane-treated bio-based composite can increase up to 40%. The onset decomposition temperature of silanes treated with bio-based composite is 20 ° C higher compared to untreated bio-based composite. This article provides an insightful review of the surface treatment of bio-based composites via silane treatment on mechanical properties, thermal properties, water absorption, and water contact angle. [ABSTRACT FROM AUTHOR]

The rising cost of petrochemicals owing to the rapid depletion of fossil resources has gradually divert research interest to novel chemicals derived from biomass feedstock. In this study we explored the synthesis, properties and ecotoxicity of a series of sustainable poly(hexylene 2,5-thiophenedicarboxylate-co-bis(2-hydroxyethoxybenzene)s (PTBHs) copolyesters suitable as form-fil-seal packaging materials. From the results, simply varying the ratios of HDO/BHEB afford control over the copolymers crystallinity, thermal and mechanical properties including degradability. The thermal analysis revealed the copolyesters possess satisfactory glass transition temperature (Tg) ranging from 75 to 112 °C and melting point from 160 to 205 °C, which are comparable to poly(ethylene furanoate) PEF and superior to poly(ethylene terephthalate) PET. These novel biopolymers exhibit tensile strength between 53 and 72 MPa and elongation at break of over 780%, higher than their corresponding homopolyesters. These promising properties were optimized with the increase of TH content, ranging from TB-enriched to TH-enriched copolyesters, exhibiting satisfactory heat-seal strength in the range of 0.77–0.45 N/mm. The biopolymers exhibit the potential as mere replacements to PETs, but their cost-rentability still needs to be investigated. The authors synthesized a novel class of fully non-toxic thiophene biopolymers and showed the synergistic effect of HDO on the structure, thermal and mechanical properties. [ABSTRACT FROM AUTHOR]

In this work, new furan-based poly(ester amide)s of various compositions were synthesised by the melt polycondensation method. The chemical structure and composition were determined by nuclear magnetic resonance spectroscopy (1H NMR) and Fourier transform infrared (FTIR) analyses. The optical properties were studied by UV-Vis spectroscopy. The thermal properties were investigated by means of differential scanning calorimetry (DSC). The thermo-oxidative stability of PEAs was also tested. Additionally, the free volume by positron annihilation lifetime spectroscopy (PALS) technique and mechanical properties were examined. It was found that the incorporation of poly(propylene furanamide) (PPAF) units significantly affects the thermal and mechanical properties of co-polymers based on poly(hexylene 2,5-furandicarboxylate) (PHF). Depending on the composition, both semi-crystalline and amorphous co-polymers were obtained. Moreover, the values of the free volume radius (R) and the free volume fractions (fv) were strongly affected by the mole fraction of PPAF units.

Despite the fact that amino cellulose (AC) is biodegradable, biocompatible, and has excellent film-forming properties, AC films have poor mechanical properties and are not thermally stable. An AC-based composite film prepared from AC and curcumin-stearylamine based benzoxazine (C-st) is reported in order to improve its performance and promote its application. As starting materials, C-st and AC were used to produce a C-st/AC composite film possessing a synergistic property through chemical cross-linking and hydrogen bonds. Two salient features with respect to the curing behavior were obtained. Firstly, the onset of curing was reduced to 163 °C when the benzoxazine monomer was synthesized from fully bio-based precursors (such as curcumin and stearylamine). Secondly, a synergistic effect in curing behavior was obtained by mixing C-st with AC. As a result of tensile tests and thermal analysis, the poly(C-st) benefited the composite films with pronounced mechanical and thermal properties, even at elevated temperatures. There was a 2.5-fold increase in tensile strength compared to the AC film, indicating that the composite films have the potential to be used for functional purposes. These poly(C-st)/AC films with improved mechanical and thermal properties have the ability to replace naturally occurring polymer films in film-related applications. [ABSTRACT FROM AUTHOR]

Toughening efficiency of poly(ethylene-n-butylene-acrylate-co-glycidyl methacrylate) (EBA-GMA) in poly(lactic acid) (PLA) matrix has been found to significantly increase at elevated blending temperature. In the case of PLA/EBA-GMA blends having 10.0 or 12.5 wt% EBA-GMA contents, the accelerated PLA degradation at raised processing temperature resulted in reduced mechanical performance. At 15.0 wt% EBA-GMA ratio, however, increased elongation and by 250% improved notched Izod impact strength was achieved when the blending temperature was raised from 240 to 260 °C. This beneficial effect is attributed to the accelerated compatibilization reactions between the components in the presence of shortchain PLA molecules, which allow the rapid formation of a toughening enhancer interphase (TEI) during melt processing. As a result, the brittle-ductile transition can be reached at lower elastomer content than expected. Decreased melt flow index (MFI) values besides stabilized blend morphology indicated efficient PLA--EBA-GMA compatibilization at elevated processing temperature. Accordingly, enhanced nucleation ability of the PLA/EBA-GMA interphase and hindered chain crystallization of PLA were found by differential scanning calorimetry (DSC) analyses. In association with the intensified compatibilization reactions cross-linking of the terpolymer was also revealed using the thermally stimulated depolarization current (TSDC) technique. [ABSTRACT FROM AUTHOR]

With the increase in environmental pollution, studies on the use of sustainable resources are increasing day by day. For this purpose, the use of natural fiber-reinforced polymer composites is encouraged in many areas such as automotive, transportation, construction, and home textiles. However, they are flammable and therefore seriously threaten the safety of people and property. Various flame retardant additives have been used to improve the flame retardancy properties of these composites. In this study, silicon dioxide (SD) and zinc borate (ZB) microparticles in different weight percentages (3, 5, 7, and 10%) were reinforced to give flame retardant properties to jute-epoxy composites. In addition, composites containing both SD and ZB microparticles were produced and they were labeled as HB. Then, thermal conductivity, flammability, water absorption, and mechanical properties of these composites were investigated. The burning rate of the composites decreased as the amount of microparticle increased. 5ZB5SD, including %5 SD and %5 SD microparticles, showed 36.60% less burning rate than the neat jute-epoxy composite. 5ZB showed 10.84% higher tensile strength than the neat juteepoxy. The impact strength of the specimens increased with the increase in the filling ratio, and 5ZB5SD showed approximately 2.50 times the impact strength of the jute-epoxy composite. [ABSTRACT FROM AUTHOR]

In the past few years, a new passion for the growth of biodegradable polymers based on elements derived from natural sources has been getting much attention. Natural fiber-based polymer matrix composites offer weight loss, reduction in cost and carbon dioxide emission, and recyclability. In addition, natural fiber composites have a minimal impact on the environment in regards to global warming, health, and pollution. Polylactic acid (PLA) is one of the best natural resource polymers available among biodegradable polymers. Natural fiber–reinforced PLA polymer composites have been extensively researched by polymer researchers to compete with conventional polymers. The type of fiber used plays a massive part in fiber and matrix bonds and, thereby, influences the composite's mechanical properties and thermal properties. Among the various natural fibers, low density, high strength bamboo fibers (BF) have attracted attention. PLA and bamboo fiber composites play a vital character in an extensive range of structural and non-structural applications. This review briefly discussed on currently developed PLA-based natural bamboo fiber–reinforced polymer composites concentrating on the property affiliation of fibers. PLA polymer–reinforced natural bamboo fiber used to establish composite materials, various composite fabrication methods, various pretreatment methods on fibers, their effect on mechanical properties, as well as thermal properties and applications on different fields of such composites are discussed in this study. This review also presents a summary of the issues in the fabrication of natural fiber composites. [ABSTRACT FROM AUTHOR]

Recently, the global demand for plastics rose to its maximum mainly due to the rapid increase in population and the growing demand for automobiles. The mass production and disposal of synthetic fiber-based composites pollutes the environment and emission of greenhouse gases. Natural fibers prove to be a suitable alternative to synthetic fibers and the green composites made by reinforcing them with biopolymers find widespread use in various engineering applications. In this paper, the physico-chemical, mechanical, and thermal properties of novel cellulosic fibers extracted from the bark of Madhuca longifolia tree have been investigated through standard test procedures. Test results revealed the presence of cellulose (50.64 wt.%), lignin (17.44 wt.%), and wax (0.60 wt.%) in Madhuca longifolia fiber (MLF). High strength, high rigidity, and better interfacial bonding characteristics with polymer matrix results due to the presence of these chemical constituents. Lower density (1510 kg/m3) and higher activation energy (67.04 kJ/mol) make MLF suitable for making lightweight green composites. The tensile strength and modulus of MLF were found to be 140.96-317.50 MPa and 4.29-5.90 GPa, respectively. The morphology of MLF surface examined through FESEM images revealed the existence of a rough, porous surface, which is essential for making biodegradable composites. [ABSTRACT FROM AUTHOR]

Recent years have observed a significant increase in the use of degradable materials in medicine due to their minimal impact on the patient and broad range of applicability. The biodegradable polymer Polydioxanone (PDO) provides a good example of the use of such one polymer that can represent the aforementioned medical materials in the field of medicine, due to its high level of biocompatibility and interesting mechanical properties. PDO is used to produce absorbable medical devices such as sutures and stents, and is also suitable for the fabrication of certain orthopedic implants. Polydioxanone can be processed using the injection molding method due to its thermoplastic nature; this method allows for the precise and easily-controllable production of medical materials without the need for toxic additives. A number of small commercial polymer implants have recently been introduced onto the market based on this processing method. It is important to note that, to date, no relevant information on the molding of PDO is available either for the scientific or the general public, and no study has been published that describes the potential of the injection molding of PDO. Hence, we present our research on the basic technological and material parameters that allow for the processing of PDO using the laboratory microinjection molding method. In addition to determining the basic parameters of the process, the research also focused on the study of the structural and mechanical properties of samples based on the thermal conditions during processing. A technological frame work was successfully determined for the processing of PDO via the microinjection molding approach that allows for the production of samples with the required homogeneity, shape stability and surface quality in a laboratory scale. The research revealed that PDO is a polymer with a major share of crystalline phases, and that it is sensitive to the annealing temperature profile in the mold, which has the potential to impact the final crystalline structure, the fracture morphology and the mechanical properties. [ABSTRACT FROM AUTHOR]

This study gives an overview of the most relevant processing and performance properties of a wide selection of biobased and biodegradable plastic materials that are currently commercially available. It provides the most extensive and up-to-date scientific overview of critical properties of biobased and biodegradable plastics. Materials that are tested include fully biobased polymers (polylactic acid, polyethylene, polyamide 10,10 and a range of polyhydroxy alkanoates), partially biobased polymers (polybutylene succinate, polybutylene succinate adipate, cellulose acetate, cellulose acetate propionate, polyethylene terephthalate, polytrimethylene terephthalate, an isosorbide based polycarbonate, a thermoplastic urethane and a starch based blend) and a number of fossil-based materials (polycaprolactone, polybutylene adipate terephthalate, polyglycolic acid and polypropylene). The mechanical (tensile, flexural, impact resistance and hardness), thermal (glass transition temperature, melting temperature, melt-flow index and haul-off force) and barrier (oxygen transmission rate, water vapour transmission rate) properties of all these materials were measured and are presented in a comprehensive overview. This overview shows that the majority of functionalities that are currently being offered by fossil based polymers can be met by biobased alternatives and by biodegradable materials if this is considered to be favourable at end-of-life.

In this work, the development of nanocomposite systems based on reduced graphite oxide (rGO) was combined with the development of crosslinked materials characterized by dynamic covalent bonds, i.e., a covalent associative network, starting from ad-hoc synthesized hydroxyl terminated polycaprolactone (PCL-OH). The crosslinking reaction was carried out using methylenediphenyl diisocyanate (MDI) to create systems capable of bond exchanges via transesterification and transcarbamoylation reactions, in the presence of stannous octoate as a catalyst. The above materials were prepared at two different temperatures (120 and 200 °C) and two PCL-OH:MDI ratios. FT-IR measurements proved the formation of urethane bonds in all the prepared samples. Crosslinking was demonstrated by contacting the samples with a solvent capable of dissolving the star-shaped PCL. These tests showed a significant increase in the crosslinked fraction with increasing the temperature and the PCL-OH:MDI ratio. In order to evidence the effect of crosslinking on rGO dispersion and the final properties of the material, a nanocomposite sample was also prepared using a linear commercial PCL, with the nanofiller mixed under the same conditions used to develop the crosslinked systems. The dispersion of rGO, which was investigated using FE-SEM measurements, was similar in the different systems prepared, indicating that the crosslinking process had a minor effect on the dispersibility of the nanofiller. As far as the thermal properties are concerned, the DSC measurements of the prepared samples showed that the crosslinking leads to a decrease in the crystallinity of the polymer, a phenomenon which was particularly evident in the sample prepared at 200 °C with a PCL-OH: MDI ratio of 1:1.33 and was related to the decrease in the polymer chain mobility. Moreover, rGO was found to act as a nucleating agent and increase the crystallization temperature of the nanocomposite sample based on linear commercial PCL, while the contribution of rGO in the crosslinked nanocomposite samples was minor. Rheological measurements confirmed the crosslinking of the PCL-OH system which generates a solid-like behavior depending on the PCL-OH:MDI ratio used. The presence of rGO during crosslinking generated a further huge increase in the viscosity of the melt with a remarkable solid-like behavior, confirming a strong interaction between rGO and crosslinked PCL. Finally, the prepared nanocomposites exhibited self-healing and recyclability properties, thus meeting the requirements for sustainable materials. [ABSTRACT FROM AUTHOR]

In this paper, chitosan (Chi) was successfully reacted with natural mono ketone namely, camphor (Cam), through a condensation reaction to obtain a novel Chi-Cam polymer. The encapsulation of Chi-Cam polymer into the cavity of β-cyclodextrin biopolymer by inclusion complex method, and the immobilization of TiO 2 NPs into Chi-Cam matrix by metal complex method were performed. A set of characterizations (XRD, FTIR, SEM, UV–Vis., optical band gap, Urbach energy, refractive index, and thermogravimetric analysis) were implemented to incorporate their properties with applications. It was not observed the existence of any strange peaks in diffractogram patterns of all prepared samples, confirming the proper preparation and high purity polymers. The crystalline index was found to be 69.41, 41.58, 58.25 and 44.2 % for Chi, Chi-Cam, polyrotaxane, and nanocomposite, respectively. High surface area, lowest pores size, and lowest pores volume were confirmed the micropores of composite, which also could provide more reactive sites, and enhancing the bioactivity. The tested Chi-Cam/TiO 2 NPs possessed the highest antimicrobial impact, followed by the Chi-Cam/β-CD towards pathogenic microbes. The highest % inhibition of biofilm formation by Chi-Cam, Chi-Cam/β-CD, and Chi-Cam/TiO 2 NPs was noted for S. aureus (40.05 %, 80.21 %, and 87.49 %), E. coli (38.56 %, 74.32 % and 83.32 %), P. aureginosa (32.12 %, 58.80 %, and 74.53 %), and C. albicans (13.69 %, 27.89 % and 70.89 %), respectively. The obtaining findings pave the route towards useful utilization of potential materials for biomedical applications. [ABSTRACT FROM AUTHOR]

Brittleness of poly(lactic acid) (PLA), a biocompatible and biodegradable polymer obtained from renewable and natural sources, hinders its widespread applications. This study provides a convenient and economical way to enhance the toughness of PLA by using hydroxyl terminated polybutadiene (HTPB) liquid rubber to modify PLA. Four types of HTPB with varied hydroxyl values and viscosities were used to prepare PLA/HTPB blends. The effects of HTPB content on the mechanical characteristics, phase structure, thermal and crystalline properties of the toughened blends were systematically investigated. For PLA/HTPB2‐5%, the elongation at break and impact strength was 87% and 58 kJ/m2, respectively, which was 12.8 and 3.5 times that of neat PLA. Due to the relatively lower hydroxyl value and suitable viscosity of HTPB2, PLA/HTPB2‐5% exhibited the best impact toughness and had the highest impact strength. When the content of HTPB exceeded 5%, the mechanical properties of PLA/HTPBs gradually decreased. This could be due to the gradual increase of particle size of the dispersed phase with increasing HTPB content, resulting in serious phase separation between the dispersed phase and continuous phase. The resultant PLA/HTPB2 composites with improved toughness could have potential applications in engineering materials thus enlarging the spectrum of applications for PLA. [ABSTRACT FROM AUTHOR]

Novel electroactive hydrogels were fabricated from carboxymethyl cellulose (CMC) biopolymer incorporated with conductive polythiophene (PTh). The PTh particles dispersed uniformly in the CMC matrix providing higher mechanical properties and thermal stability. The formulation CMC/PTh6 (6%wt PTh) gave the highest tensile strength and elongation at break (0.9456 ± 0.0017 MPa and 123.0398 ± 7.0606%, respectively). The bending response of the hydrogels under an applied electric field was studied in terms of bending angle and bending sensitivity. Under an electric field strength of 100 V mm−1, CMC/PTh10 (10%wt PTh) showed the highest bending angle (52.245 ± 6.054°) while neat CMC gave the lowest bending angle (33.753 ± 8.116°). The bending behavior upon the application of an electric field of the CMC/PTh hydrogels occurs from the polarization of Na+ and H+ in the CMC matrix and S+ in PTh. [ABSTRACT FROM AUTHOR]

In 2021, global petroleum-based plastic production reached over 400 million metric tons (Mt), and the accumulation of these non-biodegradable plastics in the environment is a worldwide concern. Polyhydroxybutyrate (PHB) offers many advantages over traditional petroleum-based plastics, being biobased, completely biodegradable, and non-toxic. However, its production and use are still challenging due to its low deformation capacity and narrow processing window. In this work, two linear-chain polyester oligomers were used as plasticizers to improve the processability and properties of PHB. Thermal analyses, XRD, and polarized optical microscopy were performed to evaluate the plasticizing effect on the PHB and the reflection on the mechanical behavior. Both oligomers acted as PHB plasticizers, with a reduction in Tg and Tm as a function of the plasticizer concentration, which can make it easier to handle the material in thermal processing and reduce the probability of thermal degradation. Plasticizer 2 proved to be the most promising between the two with an optimized condition of 20%, in which there was a decrease in elastic modulus of up to 72% and an increase in the maximum elongation of 467%. [ABSTRACT FROM AUTHOR]

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with various 3-hydroxyvalerate (3HV) contents biosynthesized by mixed microbial consortia (MMC) fed fermented dairy manure at the large-scale level was assessed over a 3-month period. The thermal, mechanical, and rheological behavior and the chemical structure of the extracted PHBV biopolymers were studied. The recovery of crude PHBV extracted in a large Soxhlet extractor with CHCl3 for 24 h ranged between 20.6% to 31.8% and purified to yield between 8.9% to 26.9% all based on original biomass. 13C-NMR spectroscopy revealed that the extracted PHBVs have a random distribution of 3HV and 3-hydroxybutyrate (3HB) units and with 3HV content between 16% and 24%. The glass transition temperature (Tg) of the extracted PHBVs varied between −0.7 and −7.4 °C. Some of the extracted PHBVs showed two melting temperatures (Tm) which the lower Tm1 ranged between 126.1 °C and 159.7 °C and the higher Tm2 varied between 152.1 °C and 170.1 °C. The weight average molar mass of extracted PHBVs was wide ranging from 6.49 × 105 g·mol−1 to 28.0 × 105 g·mol−1. The flexural and tensile properties were also determined. The extracted polymers showed a reverse relationship between the 3HV content and Young's modulus, tensile strength, flexural modulus, and flexural strength properties. [ABSTRACT FROM AUTHOR]

Commercial available filaments made from poly(lactic) acid (PLA) are selected for potential use in 3D printed parts by fused deposition modeling. Virgin materials (PLA Eum, Z‐PLA Pro), but also recycled matrices (PLA 2Life, PLA Eubio), and one filled with wood fibers (PLA Woodfir) have been considered. Then, a lab‐made filament (PLA Nature) is realized by extruding PLA pellets. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and rheological measurements are used to determine initial degradation temperature, glass transition, melting temperature, and complex viscosity as a function of time and material pre‐drying. A preliminary investigation of thermal properties enables the materials' processing window to be validated in order to prevent the deterioration during the process. PLA Nature and PLA Woodfir melt around 170°C, whereas all of the other biopolymers show a lower melting point (around 150°C). The temperature at which thermal degradation began is always greater than 260°C. However, good stability of rheological parameters over time at 210°C is not confirmed for all bio‐filaments. In particular, for Z‐PLA Pro and PLA Eubio, a significant reduction of complex viscosity is verified after a few seconds of testing. Drying samples have been shown to improve the long‐term stability of complex viscosity. [ABSTRACT FROM AUTHOR]

In this work, new furan-based poly(ester amide)s of various compositions were synthesised by the melt polycondensation method. The chemical structure and composition were determined by nuclear magnetic resonance spectroscopy (1H NMR) and Fourier transform infrared (FTIR) analyses. The optical properties were studied by UV-Vis spectroscopy. The thermal properties were investigated by means of differential scanning calorimetry (DSC). The thermo-oxidative stability of PEAs was also tested. Additionally, the free volume by positron annihilation lifetime spectroscopy (PALS) technique and mechanical properties were examined. It was found that the incorporation of poly(propylene furanamide) (PPAF) units significantly affects the thermal and mechanical properties of co-polymers based on poly(hexylene 2,5-furandicarboxylate) (PHF). Depending on the composition, both semi-crystalline and amorphous co-polymers were obtained. Moreover, the values of the free volume radius (R) and the free volume fractions (fv) were strongly affected by the mole fraction of PPAF units. [ABSTRACT FROM AUTHOR]

This work deals with the preparation and the study of a new composite obtained from a thermoplastic polymer and a vegetal fiber. The polymer used is a recycled polyvinylchloride (PVC) and the fiber used was extracted from Agave americana, a plant which grows easily under Mediterranean type climates. Prior chemical treatment of the extracted fiber was necessary to modify the surface of the fiber in order to optimize the adhesion between this fiber and the recycled PVC during the preparation of composites from these materials. For this purpose, our investigations led us to attempt various reactions modification of the surface fiber. The method that gave the best results consists of an alkaline treatment followed by a reaction with acetic anhydride. Once completed chemicals treatments of fiber, the material is mixed with the recycled PVC which serves as a matrix to prepare composites at varying rates from 5% to 30% by weight of agave modified fibers. The effects of the incorporation of raw and processed agave fibers on the mechanical, thermal and morphological properties of PVC/agave fiber composites were examined and discussed. [ABSTRACT FROM AUTHOR]

Application of natural fiber‐polymer composites (NFPCs) in different industrial applications provides competitive edge due to their lightweight, higher specific mechanical properties than glass fibers, sustainability, and lower cost involved in production. There are certain challenges associated with natural fibers and their reinforcement in composites such as poor bonding between the fibers and matrix due to their contradictory nature of characteristics, moisture absorption, lower thermal properties, and poor interfacial adhesion between the natural fiber and polymer matrix. The challenges involved in NFPCs need to be overcome to produce materials with relatively equivalent properties to those of conventional composites and other metallic structures. Several researchers around the globe have conducted investigations with the primary attention being paid to the modification of natural fibers and matrix by employing surface treatments and other chemical treatment methods. In order to address the need for eco‐friendly and sustainable materials in different domains, a comprehensive review on natural fibers and their sources, available matrix materials, modification techniques, mechanical and thermal properties of NFPCs, is needed for better understanding of the behavior of NFPCs. This work provides the information and holistic view of natural fiber‐reinforced composites based on the results obtained from modification techniques, with the view of focusing the review in terms of different chemical and physical treatment techniques, modification of fibers and matrix, and enhanced mechanical and thermal properties in the composites. [ABSTRACT FROM AUTHOR]

Poly(3−hydroxybutyrate−co−3−hydroxyhexanoate) (PHBH) films were prepared using a cast film technique. Dioxane was chosen over other polymer solvents as it resulted in homogenous films with better morphology. Several plasticizers with different molecular weights and concentrations were added to the biopolymer solution prior to casting. Thermal, crystalline, and permeability properties were analyzed by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X−ray diffraction (XRD), and both water vapor and oxygen transmission rate analysis. In general, the addition of plasticizers decreased the glass transition temperature (Tg), cold crystallization temperatures (Tcc), melting temperatures, as well as crystallinity degrees and increased the crystallite sizes and water vapor and oxygen transmission rates. The use of isosorbide and low-molecular-weight poly(ethylene glycol) (PEG) lowered the Tg around 30 °C at the highest used concentration, also being the most effective in increasing the crystallite size. When considering isosorbide and low-molecular-weight poly(ethylene glycol) (PEG) as very good plasticizers for PHBH, the question of which plasticizer to use strongly relies on the desired PHBH application. [ABSTRACT FROM AUTHOR]