Thermoplastic Blends from Albumin and Zein: Plastic Formation and Mechanical Properties Including Modeling

The use of proteins in blending with traditional polymers in the formation of thermoplastics can produce plastics with properties that are superior to traditional petroleum-based plastics. We investigated the physical and thermal properties of albumin and zein thermoplastic blends plasticized with glycerol and mixed with varying amounts of low-density polyethylene (LDPE). Several mechanical models were utilized to determine how tensile properties will be altered when varying amounts of protein/LDPE were added into the thermoplastic blend. When analyzed for thermal properties, we found that as the amount of LDPE in the thermoplastic blend increased, the resulting plastic possessed thermal properties that were more similar to pure LDPE plastics. In terms of mechanical properties, comparison between the experimental data and model predictions points to a synergistic effect between albumin and LDPE that leads to higher modulus, while a potential lack of compatibility between zein and LDPE leads to a plastic with lower modulus. Based on our results, the use of albumin and zein proteins when blended with LDPE in the production of thermoplastics has potential use in the areas of medical and food packaging applications.     

Production of Biodegradable Films of Zein Containing Mentha asiatica Essential Oil and Copper Oxide Nanoparticles: Investigation of Physicochemical,Antimicrobial, and Antioxidant Properties

Journal of Polymers and the Environment - The objectives of the present study were to prepare an active biodegradable film based on zein-containing copper oxide nanoparticles (CuO NPs) and Mentha...     

Effects of Weathering on Mechanical,Antimicrobial Properties and Biodegradation Process of Silver Loaded TPE Compounds

The incorporation of antimicrobial metals such as silver is an alternative to protect the material against microbial attack. However, loaded polymer can lose its antimicrobial properties after some time of use, and the additive may even leak out into the environment becoming harmful to non-target organisms. This study aims to evaluate the mechanical properties and antimicrobial activity of silver containing thermoplastic elastomer (TPE) samples exposed to weathering and the influence of additive incorporation in material biodegradation in the soil. For this purpose, silver ions (Ag⁺_bentonite, Ag⁺_phosphate) and silver nanoparticles (AgNp_silica) based additives were blended in a formulation of SEBS, polypropylene and mineral oil. The test samples were exposed to natural ageing over nine months, and were then evaluated according to their mechanical properties, antimicrobial activity, and degree of crystallinity and surface characteristics. The biodegradation process before and after natural ageing was evaluated through the generation of carbon dioxide. The results show that the action of natural ageing reduced the mechanical properties of loaded and unloaded TPE, and modified the degree of crystallinity and the chemical characteristic of the TPE surface. The presence or type of additive did not influence material resistance after being exposed to weathering. A decrease in antimicrobial activity in samples after natural ageing was observed. At a variable level and according to the chemical content, generation of carbon dioxide from TPE samples was greater in aged samples than in unexposed ones.     

Blends of Zein and Nylon-6

Blends of zein and nylon-6 (55?k) in formic acid were used to produce solution cast films and electrospun fibers. When the amount of nylon-6 was 8?% or less blends were formed that had improved tensile strength and reduced solubility. The blends were analyzed using physical property measurements, DSC and IR spectra. Using between 2 and 8?% nylon-6 provided a 33?% increase in tensile strength. Young??s modulus increased by over 50?% in this range. In general elongation was lower for all formulations. Surprisingly the cast films having 0.5?C8?% nylon-6 had improved solvent resistance to 90?% ethanol/water. Electrospun fibers were produced from formic acid solutions of zein and nylon-6 where the amount of nylon was 0, 2 and 6. Fibers produced from 27?% spinning solids had average diameters on the order of 0.5???m. Reducing the spinning solids to 21?% provide slightly smaller fibers however, the fibers had more defects.     

Compatible Blends of Zein and Polyvinylpyrrolidone

Blends of zein and polyvinylpyrrolidone (PVP) were compared based on their tensile properties, thermal properties and morphology. Zein was blended with polyvinylpyrrolidone of varying molecular weights (10, 55, and 1,300 kDa) and films were cast from ethanol solutions. Films cast using the higher molecular weight polymers showed an improvement in tensile strength, up to a 24% increase, compared to control. Differential scanning calorimetry data for the blends showed single T_m and T_g values of an intermediate value between those of zein and PVP control samples. Field emission scanning electron microscopy images show no obvious inhomogeneities, and confocal fluorescence microscopy showed no decreased uniformity in the PVP/zein films compared to control. Electrospun fibers of the zein/PVP blends were also obtained. These findings suggest that zein and polyvinylpyrrolidone combine to form a compatible blend, the first such blend of zein with a synthetic polymer.     

Environmentally Friendly Polyurethane Composites: Preparation, Characterization and Mechanical Properties

The waterborne polyurethane (PU) prepolymer was prepared based on isophorone diisocyanate (IPDI), polyester polyol (N220), dimethylol propionic acid (DMPA) and hydroxyethyl methyl acrylate (HEMA). The modified waterborne polyurethane–acrylate (PUA) emulsions were obtained with different proportions of acrylate (butyl acrylate and methyl methacrylate) and initiating agent by in situ dispersion technique. The structures and thermal properties of prepared PU and PUA were analyzed and characterized with FT-IR, UV–Vis spectroscopy and DSC. The PUA hybrid samples had lower glass transition temperature of hard segment and higher decomposition temperatures than PU sample. Performances of the emulsion and film were studied by means of apparent viscidity, particle size and polydispersity, surface tension and mechanical properties. The results indicated that the particle sizes of the PUA dispersions were larger than those of the pure PU and the solvent resistance, mechanical properties of PUA films was improved compare with the unmodified polyurethane film. The film had the biggest hardness and the least water absorption when the BA/MMA mass ratio 5:5 modified PU. The obtained PUA have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings and wood finishes.     

Effect of Casting Process Conditions on Mechanical Properties and Water Solubility of Films Made from Wolf Fruit and Its Optimization

Journal of Polymers and the Environment - Biodegradable films based on wolf fruit flour were prepared by the casting process using glycerol as a plasticizing agent. The influence that the process...     

The Effect of Nanoclays on the Properties of PLLA-modified Polymers Part 1: Mechanical and Thermal Properties

Organically modified montmorillonite clays were incorporated at a 5% loading level into film grade of poly-L-lactic acid (PLLA) using a variety of masterbatches based on either semi-crystalline or amorphous poly-(lactic acid), as well as biodegradable aromatic aliphatic polyester. The PLLA masterbatches and compounded formulations were prepared using a twin screw compounding extruder, while the films were prepared using a single screw cast film extruder. The thermal and mechanical properties of the films were examined in order to determine the effect of the clay and different carriers on the polymer–clay interactions. In the optimal case, when a PLLA-based masterbatch was used, the tensile modulus increased by 30%, elongation increased by 40%, and the cold crystallization temperature decreased by 15 °C, compared to neat PLLA. The properties improvement of PLLA films containing nano clays demonstrated the possibility to extend the range of biodegradable film applications, especially in the field of packaging.     

Extruded Cornstarch-Glycerol-Polyvinyl Alcohol Blends: Mechanical Properties, Morphology, and Biodegradability

Elongation properties of extruded cornstarch were improved by blending with glycerol. Further blending of starch-glycerol with polyvinyl alcohol (PVOH) resulted in significant improvements in both tensile strength (TS) and elongation at break. Samples of starch-glycerol without PVOH equilibrated at 50% relative humidity had a TS of 1.8 MPa and elongation of 113%, whereas those containing PVOH had a TS and elongation of 4 MPa and 150%, respectively. Dynamic mechanical analysis (DMA) of starch-glycerol-PVOH blends showed that decreases in glass transition temperatures (T _g values) were proportional to glycerol content. Scanning electron microscopy (SEM) of fractured surfaces revealed numerous cracks in starch-glycerol (80:20) samples. Cracks were absent in starch-glycerol (70:30) samples. In both blends, many starch granules were exposed at the surface. No exposed starch granules were visible in blends with added PVOH. Starch-glycerol samples incubated in compost lost up to 70% of their dry weight within 22 days. Addition of PVOH lowered both the rate and extent of biodegradation.     

Properties of Distillers Grains Composites: A Preliminary Investigation

Interest in renewable biofuel sources has intensified in recent years, leading to greatly increased production of ethanol and its primary coproduct, Distillers Dried Grain with Solubles (DDGS). Consequently, the development of new outlets for DDGS has become crucial to maintaining the economic viability of the industry. In light of these developments, this preliminary study aimed to determine the suitability of DDGS for use as a biofiller in low-cost composites that could be produced by rapid prototyping applications. The effects of DDGS content, particle size, curing temperature, and compression on resulting properties, such as flexural strength, modulus of elasticity, water activity, and color were evaluated for two adhesive bases. The composites formed with phenolic resin glue were found to be greatly superior to glue in terms of mechanical strength and durability: resin-based composites had maximum fiber stresses of 150–380 kPa, while glue composites had values between 6 kPa and 35 kPa; additionally, glue composites experienced relatively rapid microbial growth. In the resin composites, both decreased particle size and increased compression resulted in increased mechanical strength, while a moderate DDGS content was found to increase flexural strength but decrease Young’s modulus. These results indicate that DDGS has the potential to be used in resin glue-based composites to both improve flexural strength and improve potential biodegradability.     

Effect of Common Chemical Treatments on the Process Kinetics and Mechanical Properties of Flax/Epoxy Composites Manufactured by Resin Infusion

Chemical treatments are widely employed to improve the fiber-matrix adhesion in composites based on eco-friendly fibers such as flax. To better understand the influence of these treatments on processing behavior, this study characterized the surface chemistry and morphology of woven flax fabrics treated by acetone, alkaline, silane and diluted epoxy. Flax/epoxy composites were then manufactured by resin infusion and the flow front and preform thickness evolution was monitored. The alkaline treatment was shown to result in a 50 % increase in equivalent permeability due to an increase in porosity which led to a decrease in flexural properties. The processing results were found to be in good agreement with predictions of a 1-dimensional model. This study suggests that infusion times are not considerably affected by the observed changes in surface energy. However, other implications of the treatments such as an increase in fibrillation can alter the infusion times significantly.

     

Biobased Polyurethanes from Rapeseed Oil Polyols: Structure, Mechanical and Thermal Properties

Biobased polyols were synthesized from rapeseed oil (RO) with diethanolamine (DEA), triethanolamine (TEA) and glycerol (GL) at different molar ratios. The structures of the synthesized polyols were analyzed using FTIR-ATR spectroscopy. Polyurethane (PU) networks from RO/DEA polyols and polymeric MDI showed higher tensile strength, modulus and hardness, but their elongation at break decreased, compared to the case of the PU obtained from RO/TEA and RO/GL polyols. The tensile strength and modulus of PU networks increased with increasing PU cohesion energy density (CED) and decreasing molecular weight between crosslinks M _c . From the thermogravimetric analysis and its derivative thermograms, at the first stage of destruction (below 5 % weight loss) in the air and inert atmosphere, the PU obtained from RO polyols were ranked in the following order: PU RO/GL > PU RO/TEA > PU RO/DEA, and their thermostability was higher than that of the PU based on propylene oxide.     

Dynamic Mechanical Properties of Soy Protein Filled Elastomers

Dynamic mechanical properties including temperature effect, stress softening, and Payne effect are studied on the elastomer composites filled with soy protein or carbon black. The comparison of protein composite with well-known carbon black composites provides further insight into the protein composites. The elastomers filled with soy protein aggregates give substantial reinforcement effect when compared with the unfilled elastomers. Approximately 400 times increase in shear elastic modulus was observed when 40% by weight of protein is incorporated into the elastomers. The sample films were cast from the particle dispersion of soy protein isolate and carboxylated styrene–butadiene latex. At the higher temperatures, the shear elastic modulus of soy protein-filled composites does not decrease as much as that of the carbon black-filled composites. The behavior of elastic and loss modulus under the oscillatory strain of different magnitude is similar to that of carbon black reinforced styrene–butadiene rubber. However, carbon black composites show a better recovery behavior after eight cycles of dynamic strain. The reduction of shear elastic modulus with dynamic strain (Payne effect) was compared with Kraus model and the fitting parameter related to the aggregate structure of the soy protein. A reasonable agreement between the theoretical model and experiment was obtained, indicating the Payne effect of the protein-related network structure in the elastomers could also be described by the kinetic agglomeration de-agglomeration mechanism.     

Mechanical and Thermal Properties of Bamboo Microfibril Reinforced Polyhydroxybutyrate Biocomposites

In the present investigation, microfibrils were extracted from raw bamboo and characterized using scanning electron microscope. Composites based on polyhydroxybutyrate (PHB) and bamboo microfibril were prepared with various microfibril loading. The mechanical and thermal properties of the resulting composites were measured. Tensile strength and impact strength of the composites were found to be increasing with increase in the loading of bamboo microfibrils, reached an optimum and thereafter decreased with further increase in microfibril loading. Percentage crystallinity was found to be increasing with increase in fibril loading. Thermal stability of the composite was higher than that of pure PHB. The composite could be developed further for various structural applications.     

Mechanical Properties of Kenaf/Polypropylene Nonwoven Composites

With an industrial trend of going green, the use of natural fibers in polymer composites is growing rapidly, especially in the automotive industry. The objectives of this research are to investigate mechanical performance of kenaf/polypropylene nonwoven composites (KPNCs) in production of automotive interior parts, and to develop preliminary linear models for quantifying elastic range of the KPNCs under various loading conditions. Using polypropylene (PP) fiber as bonding fiber, the KPNCs were fabricated with 50/50 blend ratio by weight. Unlike the manufacturing method of fiber reinforced plastics, all KPNCs were produced by carding and needle-punching techniques and thermally bonded by a panel press with 3-mm thickness gauge. Mechanical properties of the KPNCs in terms of uniaxial tensile, open-hole tensile, tensile at different strain rates, flexural, and in-plane shear were measured instrumentally. It was found that sample which was processed at higher temperature (230?°C) but shorter time (60?s) had the best mechanical performance. KPNCs were relatively insensitive to the notch but sensitive to strain rates. The linear elastic finite element model of KPNCs agreed well with the experimental results in the valid strain range of 0?C0.5?% for uniaxial tensile test and 0?C1?% for flexural test.     

Aliphatic Polyester-Based Green Renewable Eco-composites from Agricultural Residues: Characterization and Assessment of Mechanical Properties

The biodegradability, morphology, and mechanical properties of composite materials consisting of maleic anhydride-grafted poly(butylene succinate adipate) (PBSA-g-MA) and agricultural residues (wheat bran, WB) were evaluated. Composites containing maleic anhydride-grafted PBSA (PBSA-g-MA/WB) exhibited noticeably superior mechanical properties compared with those of PBSA/WB because of greater compatibility with WB. PBSA/WB exhibited a tensile strength at break of approximately 2–15 MPa more than PBSA-g-MA/WB. The dispersion of WB in the PBSA-g-MA matrix was highly homogeneous as a result of ester formation and the subsequent creation of branched and cross-linked macromolecules between the anhydride carboxyl groups of PBSA-g-MA and hydroxyl groups in WB. Additionally, the PBSA-g-MA/WB composites were more easily processed due to their lower melt viscosity. Water resistance of PBSA-g-MA/WB was higher than that of PBSA/WB, although weight loss of composites buried in Azospirillum brasilense BCRC 12270 liquid culture medium compost indicated that both were biodegradable, especially at high levels of WB substitution. After 60 days, the weight loss of the PBSA-g-MA/WB (40 wt%) composite was greater than 90 %. PBSA/WB exhibited a weight loss of approximately 4–8 wt% more than PBSA-g-MA/WB. The PBSA/WB and PBSA-g-MA/WB composites were more biodegradable than pure PBSA, which implies a strong connection between WB content and biodegradability.     

Mechanical and Thermal Properties of PLLA/PCL Modified Clay Nanocomposites

Poly(l-lactic acid) (PLLA)/poly(caprolactone) (PCL) and two types of organoclay (OMMT) including a fatty amide and ocatdecylamine montmorillonite (FA-MMT and ODA-MMT) were employed to produce polymer nanocomposites by melt blending. Materials were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), elemental analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Mechanical properties were also investigated for these nanocomposites. The nanocomposites showed increasing mechanical properties and thermal stability. XRD results indicated that the materials formed nanocomposites. SEM morphology showed that increasing content of OMMT reduced the domain size of phase separated particles. TEM outcomes have confirmed the intercalated type of nanocomposite. Additionally, a solution casting process has been used to prepare these nanocomposites and characterized to compare these results with the above process.     

Mechanical,Barrier and Antioxidant Properties of Chitosan Films Incorporating Cinnamaldehyde

Chitosan films (CF) [1 and 2% w/v] alone and with cinnamaldehyde (CNE) [0.25, 0.5 and 1% v/v] were prepared using an emulsion method, and the obtained films were characterized in terms of water vapor permeability (WVP), water solubility and optical, mechanical and antioxidant properties. The incorporation of CNE at 1% (v/v) significantly decreased the water solubility of the film by approximately 4% for the 1 and 2% CF films, whereas the WVP increased (2.5–3.5 times). The incorporation of CNE (0.25 and 0.5%) into 2% CF significantly increased the tensile strength (TS) (62 and 34%, respectively) and the percent elongation (%E) values, 26, 30 and 52% for CF that contained 0.25, 0.5 and 1% CNE, respectively. The largest value of the elasticity modulus (EM) was observed for 2% CF with 0.25% CNE. All films exhibited a yellow appearance (b*), but the CNE content had a marked impact on the coloration of the films. The CNE recoveries of the CF films (1 and 2%) with 1% of CNE were high (43 and 67%). The antioxidant activities indicated that the incorporation of 1% CNE into CF films (1 and 2%) increased the antioxidant activity. The protective effects of the films with and without CNE on erythrocytes were very strong (36–72% hemolysis inhibition). These results suggest there are potential applications for CF-CNE films as active packaging for the preservation of food products.