Use of maleic anhydride–grafted polyethylene as compatibilizer for HDPE–tapioca starch blends: Effects on mechanical properties

Tapioca starch in both glycerol‐plasticized and in unplasticized states was blended with high‐density polyethylene (HDPE) using HDPE‐g‐maleic anhydride as the compatibilizer. The impact and tensile properties of the blends were measured according to ASTM methods. The results reveal that blends containing plasticized starch have better mechanical properties than those containing unplasticized starch. High values of elongation at break at par with those of virgin HDPE could be obtained for blends, even with high loading of plasticized starch. Morphological studies by SEM microscopy of impact‐fractured specimens of such blends revealed a ductile fracture, unlike blends with unplasticized starch at such high loadings, which showed brittle fracture, even with the addition of compatibilizer. In general, blends of HDPE and plasticized starch with added compatibilizer show better mechanical properties than similar blends containing unplasticized starch. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 863–872, 2001     

Preparation and characterization of soy protein plastics plasticized with waterborne polyurethane

Utilizing anionic waterborne polyurethane (WPU) as a plasticizer, for the first time, we prepared new soy protein isolate (SPI) plastics. The WPU was prepared by using the emulsion‐extending‐chain method, and mixed with soy protein in aqueous dispersion. The mixture was cast, cured, pickled and hot‐pressed to form SPI plastics plasticized with WPU. The plastics sheets were characterized by infrared spectroscopy, scanning electron microscopy, ultraviolet spectrophotometry and wide‐angle X‐ray diffraction, and their properties were measured by using dynamic mechanical analysis, differential scanning calorimetry and tensile testing. The results revealed that SPI plastics plasticized with WPU possess good mechanical properties, such as a tensile strength (σ_b) of 7–19 MPa, water resistance (σ_b(wet)/σ_b(dry) = 0.4–0.5), optical transmittance and thermal stability, because of the good miscibility and strong interaction between WPU and SPI. With an increase of WPU content from 20 to 50 wt%, the elongation at break (ε_b) value of the sheets increased from 50 up to 150 %, and is much higher than that of the pure SPI sheet. WPU as a plasticizer can play an important role in improving the properties of SPI plastics. Copyright © 2004 Society of Chemical Industry     

甲基丙烯酸缩水甘油酯对大豆蛋白塑料改性作用研究

用模压的方法制备了甲基丙烯酸缩水甘油酯(GMA)改性大豆分离蛋白质(SPI)塑料。表征了GMA改性SPI塑料的力学性能、耐水性,并分析了GMA与SPI之间的相互作用。结果表明GMA在模压过程中,环氧基与蛋白质分子间发生接枝和交联反应,同时自聚,在GMA含量较低时可以同时对SPI塑料起到增强和增塑作用,但是随着GMA含量增加,交联作用增强,塑料的断裂伸长率下降。     

The effect of plasticizer and cellulose nanowhisker content on the dispersion and properties of cellulose acetate butyrate nanocomposites

We studied the effects of plasticizer and cellulose nanowhisker content on the dispersion and properties of cellulose acetate butyrate (CAB)‐based bionanocomposites. The cellulose nanowhiskers in an aqueous medium were solvent‐exchanged to nonaqueous polar solvent (acetone) and used for nanocomposite processing by solution casting. The plasticized and unplasticized nanocomposites with 5 and 10 wt % cellulose nanowhisker content were prepared. Atomic force microscopy indicated nanoscale dispersion of whiskers in the CAB matrix. The dynamic mechanical analysis showed an increase in storage modulus with addition of cellulose nanowhiskers, especially above the glassy‐rubbery transition region. Thermogravimetric analysis showed an improvement in thermal stability with increased whisker content for both unplasticized and plasticized nanocomposites. The plasticized nanocomposites showed better transparency than the unplasticized composites, indicating a better dispersion of cellulose nanowhiskers in CAB, in the presence of a plasticizer. The dynamic mechanical properties and thermal stability increased, whereas transparency decreased with increased CNW content. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Thermal and mechanical properties of plastics molded from urea-modified soy protein isolates

Soy protein has been considered as a potential alternative of some petroleum polymers in the manufacture of plastics. The purpose of this investigation was to characterize the thermal and mechanical properties of plastics made from urea-modified soy protein. Soy protein isolate was separated from the defatted soy flour, modified with various urea concentrations, and compression-molded into plastics. Differential scanning calorimetry showed that the temperatures of denaturation and the enthalpies of denaturation of the modified soy protein decreased as urea concentrations increased above 1 M. At the same urea concentration, molded plastics made from the modified soy proteins showed a similar temperature of denaturation as the modified soy protein, but a lower enthalpy of denaturation. Tensile strength and Young's modulus of the molded plastics from the modified soy proteins increased as urea concentration increased and reached their maximum values at 8 M urea modification. Both storage modulus and glass transition temperature of the plastics from the modified soy proteins increased as urea concentration increased. The plastics made from the 2 M urea-modified soy proteins showed improvements in elongation, tough fracture behavior, and water resistance. The urea may function as a denaturant, a plasticizer, and a filler.     

Structure and mechanical properties of soy protein materials plasticized by Thiodiglycol

Thiodiglycol (TDG) is a relatively nontoxic compound from organic wastes. By using TDG as a plasticizer with weights from 2.5 to 40%, we prepared soy protein isolate (SPI) films by a compression‐molding technique at 140°C and 15 MPa. The TDG‐plasticized films (SPI–TDG films) were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, dynamic mechanical thermal analysis, thermogravimetric analysis, optical transmittance, and water uptake experiments. The SPI–TDG film plasticized with 25% TDG exhibited good mechanical properties, such as a tensile strength and modulus of 20.3 and 582 MPa, respectively, whereas the SPI–glycerol film with 25% glycerol had a tensile strength and modulus of 16.2 and 436 MPa, respectively. The results from the thermogravimetric analysis and water uptake experiments indicated that the thermal stability and water resistance of the TDG‐plasticized SPI materials were higher than that of the glycerol‐plasticized one. The improvements in the mechanical properties, water resistance, and thermal stability of the SPI–TDG films could be attributed to the strong intermolecular hydrogen bonding between soy protein and TDG and the presence of fewer hydroxyl groups in TDG, as compared structurally with glycerol. This study provided a new plasticizer for the preparation of soy protein materials. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Comparison between pea and soy protein-based bioplastics obtained by injection molding

The elaboration of bioplastics from renewable polymers (e.g., proteins) is a field with great potential for industrial applications such as food packaging and agriculture. This study evaluates the development of bioplastic systems by injection molding using two different raw materials: soy protein isolate (SPI) and pea protein isolate (PPI). Both proteins are by-products, which lowers the price of processed bioplastics. However, it is necessary to control their properties during the manufacture processing, in order to ensure that they can replace conventional plastics. Therefore, the main objective of this work was to compare the properties of SPI and PPI bioplastics processed at different injection times (150, 300, and 450 s) and different mold temperatures (70 and 130°C). Thus, mechanical properties, water uptake capacity, and transparency were evaluated. The results show the potential of these raw materials to produce bioplastics that can replace conventional plastics, and that the processing conditions can be modified to obtain the desired final properties.     

Thermal and mechanical properties and water absorption of guanidine hydrochloride‐modified soy protein (11s)

Thermal and mechanical properties and water absorption of guanidine hydrochloride (GuHCl)‐modified 11S soy protein and molded plastics made from it were studied using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), mechanical tests, and scanning electron microscopy (SEM). The DSC results showed that the denaturation temperature of GuHCl‐modified 11S solutions was higher than that of the control sample and the high concentration GuHCl completely denatured 11S. Nonfreezing water of the modified 11S solution exhibited a minimum value at 0.9M GuHCl. Both DSC and DMA results showed that GuHCl was a plasticizer of 11S and the glass transition temperature of modified 11S plastics decreased with increasing GuHCl concentration. Both the stress and strain of modified 11S plastics reached their highest values at a 0.9 GuHCl concentration. The SEM observations supported these results. A water‐absorption test showed an improvement in the water resistance of 11S plastics with GuHCl modification. The water absorption had a minimum value at 0.9M GuHCl. The interaction between GuHCl molecules and 11S protein was found to have important effects on the thermal and mechanical properties and the water absorption of 11S plastics. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1063–1070, 2000     

Properties of molded soy protein isolate plastics

Thermal property of soy protein isolates (SPI) was studied with differential scanning calorimetry and thermogravimetric analysis. The weight loss of pure SPI is about 300°C. The glass transition temperature (T_g) is above 200°C. The best molding temperature of glycerin plasticized SPI plastics were then given. It is between 125 and 140°C. Subsequently the special property of molded SPI plastics was investigated. Results show that the atmosphere humidity affects the mechanical property and thermal property of SPI plastics. With the increasing humidity, the tensile strength decreases. While the elongation at breakage and peak area of the differential scanning calorimetry curve increases. At high temperature even at 140°C the molding temperature SPI plastics still have tensile strength though it decreases with the increasing test temperature while elongation at breakage increases. Dynamic mechanic thermal analysis test show that the storage modulus decreases with the rising temperature. The mechanical loss peak appears at lower temperature with the increasing amount of glycerin content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Silane cross-linking of PVC. II. Influence of silane type and conditions on cross-linking by water

The cross-linking of plasticized and unplasticized poly(vinyl chloride) (PVC) grafted with amino- and mercaptoalkyltrialkoxysilanes has been studied in water and in air at 20–140°C. In both media, the cross-linking occurs faster for plasticized PVC grafted with aminosilanes; however, at temperatures above 100°C, the effect of degradation cross-linking is apparent. For mercaptosilanes, a marked dependence of the cross-linking rate on the silane structure was found; plasticized PVC with grafted 3-mercaptopropyltrimethoxysilane was cross-linked in water at 100°C after 6 h, whereas this process took 12 h for 5-mercaptopentyltriethoxysilane. Practically no cross-linking occurred in unplasticized PVC below T_g, whereas the rate at 100°C was comparable with that for plasticized PVC. The cross-linking rate is affected by the chain mobility, water content, and diffusion of water into the material; a very slight dependence on the thickness of the material was found for plasticized PVC. © 1993 John Wiley & Sons, Inc.     

Epoxidized Mesua ferrea L. seed oil‐plasticized thermostable PVC and PVC‐clay nanocomposites

The use of vegetable‐oil‐based polymeric plasticizers with nanotechnology can create new applications for plasticized poly(vinyl chloride) (PVC). Epoxidized Mesua ferrea L. (Ceylon Ironwood) seed oil was used as a plasticizer for PVC. Further, nanocomposites were prepared through an ex‐situ technique using epoxidized‐oil‐swelled organically modified montmorillonite (5 wt%) and PVC. Notable improvement in thermal and processing characteristics of the nanocomposites was observed over those of the virgin polymer (in both unplasticized and plasticized PVC), as studied by TGA. The prepared nanocomposites were characterized by FTIR, SEM, TEM, and XRD techniques. A dramatic decrease in viscosity (7‐fold) was observed in THF for a 10% solution of epoxidized‐oil‐modified PVC compared to unplasticized PVC in THF, as measured by Brookfield viscometer. Isothermal analysis at three different temperatures (100, 150, and 200°C) reveals sufficient stability of the epoxidized oil modified PVC nanocomposites, as confirmed by gravimetric and FTIR analysis. Augmentation of thermostability and good retention of mechanical properties of the (Mesua ferrea L.)‐plasticized‐PVC/clay nanocomposites with respect to rigid PVC vouch for the utility of the former as advanced industrial materials. J. VINYL ADDIT. TECHNOL., 18:168–177, 2012. © 2012 Society of Plastics Engineers     

Thermal and mechanical properties and water absorption of sodium dodecyl sulfate‐modified soy protein (11S)

The thermal and mechanical properties and water absorption of sodium dodecyl sulfate (SDS)‐modified 11S soy protein and molded plastics made from it were studied using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), mechanical tests, and scanning electron microscopy (SEM). The DSC results showed that both the temperature and enthalpy of thermal denaturation of modified 11S solutions decreased as the SDS concentration increased. Nonfreezing water of the modified 11S solution had a minimum value at 1.0% SDS. The ordered structure of SDS‐modified 11S protein was recovered and/or newly formed during the freeze‐drying process. Both DSC and DMA results showed that SDS was a plasticizer of 11S, and the glass transition temperature of modified 11S plastics decreased with increasing SDS concentration. Both the tensile strength and elongation of modified 11S plastics first decreased and then increased as the SDS concentration increased, and 5.0% SDS‐modified 11S plastic had the highest tensile strength and elongation. The SEM observations supported these results. A water‐absorption test showed a reduction in the water resistance of 11S plastics after SDS modification. The rate of water absorption increased with increasing SDS concentration. The hydrophobic interaction between SDS molecules and 11S protein was found to have important effects on the thermal and mechanical properties and the water absorption of 11S plastics. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 166–175, 2001     

大豆分离蛋白/淀粉可生物降解材料的性能研究

大豆分离蛋白(SPI)和淀粉混合物经丁二酸酐改性,经甘油和水增塑之后,热压得到力学性能较好的可生物降解材料。以材料的断裂伸长率和拉伸强度作为力学性能的考察指标,并利用FTIR对其进行了分析,结果表明:添加淀粉后,材料的力学性能有了很大提高,SPI与淀粉发生了Maillard反应,断裂伸长率为353%,拉伸强度为7.30MPa。     

Plastic performance of soybean protein components

Soybean proteins recently have been considered as petroleum polymer alternatives in the manufacture of adhesives, plastics, and various binders. The objective of this work was to characterize the plastic performance of soybean protein components during molding processes. Two major soybean protein fractions, 7S-rich globulin (7S-RG) and 11S-rich globulin (11S-RG) were separated from defatted soybean flour, and their purity was examined by sodium dodecyl sulfate-polyacrylamide gel eletrophoresis and high-performance liquid chromatography. The thermal transition properties of the two fractions at 10% moisture content were 137.6°C for 7S and 163°C for 11S, as analyzed using differential scanning calorimetry (DSC). Plastics were prepared using a hot press at various molding temperatures that were selected based on the proteins’ thermal transition temperatures obtained by DSC. The plastics were evaluated for mechanical properties, water absorption, and microstructure. The plastics prepared with temperatures at or close to the thermal transition temperature showed a smooth, uniform, and complex structure. Results showed that the plastics made from 11S-RG at its thermal transition temperature were stronger (35 MPa) and had lower water absorption than those made from 7S-RG at 145°C (26 MPa). The plastics made from the 7S- and 11S-RG mixture had the highest tensile strength (39 MPa) and medium water absorption compared to those made from 7S- and 11S-RG alone. These mechanical properties and water absorption behaviors were significantly affected by molding temperatures. The results obtained from this research indicated that interaction between 7S- and 11S-RG could occur during molding and that thermal transition temperature played an important role in thermal processing of soybean proteins.     

Effects of lignin as a filler on properties of soy protein plastics. II. Alkaline lignin

Blend plastics based on soy protein isolate (SPI) strengthened with alkaline lignin (AL) in the weight ratio of 10:0 to 5:5 were prepared with 40 wt % glycerol as a plasticizer by compression molding. The structure and mechanical properties of the blends were investigated by wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), dynamical mechanical thermal analysis (DMTA), and tensile tests. The results indicated that the introduction of AL could effectively increase the tensile strength and Young's modulus, thermal stability, and elongation of the compositive plastics when the AL content ranged from 10 to 20 parts. Moreover, the blend plastics containing 50 parts AL exhibited maximum tensile strength (1.98 MPa) and much higher than that with the SP–AL0 sheet with AL alone (0.89 MPa). In addition, tests of water absorption proved that the introduction of hydrophobic AL effectively reduced water absorption and, hence, decreased water sensibility. Therefore, AL, a relatively low‐cost filler, plays a major role in enhancing the strength and water resistivity of soy protein plastics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3291–3297, 2003     

Properties of soy protein isolate/poly(ethylene‐co‐ethyl acrylate‐co‐maleic anhydride) blends

Blends of soy protein isolate (SPI) with 10, 20, 30, 40, and 50% poly(ethylene‐co‐ethyl acrylate‐co‐maleic anhydride) (PEEAMA), with or without addition of 2.0 wt % methylene diphenyl diisocyanate (MDI), were prepared by mixing with an intensive mixer at 150°C for 5 min, and then milling through a 1‐mm sieve. Blends were then compression‐molded into a tensile bar at 140°C. Thermal and mechanical properties and water absorption of the blends were studied by differential scanning calorimetry (DSC), dynamical mechanic analysis (DMA), a test of modulus and tensile strength (with an Instron tensile tester), a water absorption test, and scanning electron microscopy (SEM). The blends showed two composition‐dependent glass transition temperatures. Furthermore, as the SPI content increased, the melting temperature of PEEAMA remained constant but the heat of fusion decreased. These results indicate that SPI and PEEAMA were partially miscible. Morphology observations support these results. Increasing the PEEAMA content resulted in decreases in the modulus and tensile strengths and increases in the elongation and toughness of the blends. Water absorption of the blends also decreased with increased PEEAMA content. Incorporating MDI further decreased the water absorption of the blends. The mechanism of water sorption of SPI was relaxation controlled, and that of the blends was diffusion controlled. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 407–413, 2003     

Comparison of thermoset soy protein resin toughening by natural rubber and epoxidized natural rubber

Fully bio‐based soy protein isolate (SPI) resins were toughened using natural rubber (NR) and epoxidized natural rubber (ENR). Resin compositions containing up to 30 wt % NR or ENR were prepared and characterized for their physical, chemical and mechanical properties. Crosslinking between SPI and ENR was confirmed using ¹H‐NMR and ATR‐FTIR. All SPI/NR resins exhibited two distinctive drops in their modulus at glass transition temperature (T_g ) and degradation temperature (T_d ) at around ?50 and 215 °C, corresponding to major segmental motions of NR and SPI, respectively. SPI/ENR resins showed similar T_g and T_d transitions at slightly higher temperatures. For SPI/ENR specimens the increase in ENR content from 0 to 30 wt % showed major increase in T_g from ?23 to 13 °C as a result of crosslinking between SPI and ENR. The increase in ENR content from 0 to 30 wt % increased the fracture toughness from 0.13 to 1.02 MPa with minimum loss of tensile properties. The results indicated that ENR was not only more effective in toughening SPI than NR but the tensile properties of SPI/ENR were also significantly higher than the corresponding compositions of SPI/NR. SPI/ENR green resin with higher toughness could be used as fully biodegradable thermoset resin in many applications including green composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44665.     

Effects of lignin as a filler on properties of soy protein plastics. I. Lignosulfonate

A series of biodegradable plastics from soy protein isolate (SPI) and lignosulfonate (LS) with a weight ratio of 0:10 to 6:4 were prepared with 40 wt % glycerol as a plasticizer by compression molding. Their properties were investigated by wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), dynamical mechanical thermal analysis (DMTA), scanning electron microscopy (SEM), and tensile tests. The results indicated that the introduction of a moderate LS content from 30 to 40 parts in the blends could simultaneously enhance the tensile strength, elongation, and Young's modulus of soy protein plastics alone. Studies of the water sensitivity of the materials suggested that the strong interaction between LS and SPI could restrict the effect of water on the swelling and the damage of the materials, resulting in lower water absorption. The improvement of the properties was attributed mainly to the existence of the beneficial microphase separation and the formation of crosslinked structures because of the introduction of LS into soy protein plastics. Therefore, a model of a crosslinked network formed from SPI molecules with an LS center was established based on the existence of strong physical interactions between LS and SPI. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3284–3290, 2003     

Mechanical and barrier properties of soy protein isolate films plasticized with a mixture of glycerol and dendritic polyglycerol

Soy protein isolate (SPI) films plasticized with different contents of short and linear glycerol (G) and hyperbranched dendritic polyglycerol (DPG) in the presence of water were prepared for the first time with kneading and compression molding; these were analyzed in relation to their visual, morphological, microstructural, mechanical, and water‐ and oxygen‐barrier properties. It was shown that the film prepared with a mixture of 15G15DPG (where the numbers represent the weight percentage of the respective compound) had a higher tensile strength (∼14.4%), lower elongation at break (∼85.7%), and improved water‐barrier (∼54.6%) and oxygen‐barrier (∼84.1%) properties compared to the SPI film plasticized only with 30G. The attenuated total reflectance–Fourier transform infrared spectra of the plasticized SPI films indicated that such properties were related to the approximately 11.3% higher conversion of SPI from the α‐helical conformation to the intramolecular β‐sheet structures for the 15G15DPG films. This resulted in finer films with lower surface roughnesses and surface areas. On the other hand, further increases in G and DPG revealed an opposite effect and worsened the properties; this was much more pronounced by the increased DPG amount because of SPI unfolding and aggregation and resulted in microporous films. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41837.     

Poly(vinyl chloride) films plasticized with novel poly‐nadic‐anhydride polyester plasticizers

In this work, several novel poly‐nadic‐anhydride polyester plasticizers were developed to be used in poly(vinyl chloride) (PVC) film fabrication for the first time. Mechanical properties of the films, the compatibility of plasticizers in PVC resin, as well as testing of migration of the plasticizers, were performed in order to evaluate the efficiency of plasticization. Scanning electron microscopy, Fourier‐transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry were used to characterize the unplasticized and plasticized polymer. The results demonstrated that the as‐prepared poly‐nadic‐anhydride plasticized PVC film significantly improved the plasticization efficiency of PVC film based on the increase in the break in elongation of the films. According to scanning electron microscopy analysis, the poly‐nadic‐anhydride polyester plasticizers presented good compatibility with PVC resin. In volatility and extraction tests, PVC films plasticized with the poly‐nadic‐anhydrides showed enhanced migration resistance. The plasticizing effects induced by the poly‐nadic‐anhydride polyester plasticizers were also confirmed by a glass transition temperature shift toward lower temperatures in the plasticized films. J. VINYL ADDIT. TECHNOL., 23:321–328, 2017. © 2015 Society of Plastics Engineers