Effect of adding a reactive plasticizer on the mechanical,thermal, and morphology properties of nylon toughened wheat gluten materials

Blends of wheat gluten (WG) with up to 30% aliphatic nylon were prepared by mixing in 70% aqueous ethanol solution at 110 °C in a sealed reactor. After solvent removal and mechanical milling, rigid plaques were compression molded from the powdered blends. The microstructure of the molded plaques was studied via scanning electron microscopy. All compositions showed a phase separated morphology with seemingly poor compatibility between the two components. Up to 10% addition, the nylon was dispersed within the gluten matrix as discrete particles with an average diameter >10 μm. At higher nylon volume fractions there was evidence for the presence of gluten sub‐inclusions within the nylon phases. The dispersion of particles in a blend containing 10% nylon was improved and the particle size was decreased to roughly 5 μm by addition of an epoxy functionalized ethylene glycol oligomer. The additive simultaneously lowered the modulus of the WG matrix and appeared to improve the interfacial bonding between the gluten and the nylon. In cross‐sections of the ternary blends, fine filaments were observed spanning the gluten/nylon phases at the phase boundary. The compression molded plaques continued to exhibit brittle failure in mechanical bending tests characteristic of glassy gluten materials, however, the mechanical toughness was boosted to almost three times that of reference gluten plaques by the combined addition of the nylon and reactive plasticizer. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45931.     

Evaluation of disulfide chain extender effect on the mechanical properties of unsaturated polyurethane‐urea networks

4‐Aminophenyl disulfide and bis(4‐aminophenyl)methane chain extenders containing hydroxyl‐terminated polybutadiene‐based polyurethane‐ureas are prepared one‐shot to explore the effect of the chain extender structure on the elastomers mechanical properties. However, the results revealed that the participation of the disulfide chain extender in side reactions like thiol‐ene and proton abstraction prevented disulfide metathesis reaction due to decomposing chain extender in the polyurethane‐urea matrix. Also, these side reactions improved the phase mixing via chemical crosslinking between polyurethane‐ureas soft and hard segments, too. Tensile test results showed higher stress strength of the elastomers in the presence of the disulfide chain extender in comparison with the nondisulfide bond containing elastomers. This result was in agreement with the observed result in dynamical mechanical analysis. Dynamic mechanical analysis results established that the absence of the disulfide bond in the polyurethane‐urea matrix led to the higher viscous modulus. The swelling test revealed chemical crosslinking increased in the presence of the disulfide bond. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46309.     

Strong orientation correlation and optical anisotropy in blend of cellulose ester and poly(ethylene 2,6‐naphthalate) oligomer

Molecular orientation of two aromatic additives in cellulose acetate propionate (CAP) matrix was investigated from orientation birefringence data and an intermolecular orientation correlation represented by nematic interaction (NI) was evaluated. Poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN) oligomers with low molecular weight (ca. 400 g mol^?1) were used as the additives. The NI strengths of CAP‐PET and CAP‐PEN were determined to be 0.28 ± 0.05 and 0.96 ± 0.15, respectively. In particular, compared with other polymer/polymer and polymer/small additive blends, the NI value in CAP/PEN blend is much stronger and represents the perfect orientation correlation. The strong orientation correlation is possibly due to the rigid naphtalate structure in PEN. Contrary, a relation between birefringence and orientation function for CAP in bulk and blend showed the same trend, suggesting that the orientation behavior of CAP determines the orientation birefringence. As two ester groups in CAP are responsible for birefringence, the alignment of the ester groups is affected by only the main chain orientation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40570.     

二苯基二硫类金属塑解剂的合成及塑解性能分析

研究了二邻氨基苯基二硫化物与吡啶甲酸和不同无机盐的反应。以与吡啶-3-甲酸和氯化锌无机盐的反应为例,对反应最佳原料配比进行了分析,确定反应时间、添加剂种类等因素给合成结果带来的影响,完成了1#、2#、3#金属塑解剂制备。相较于纯DBD,1#塑解剂的门尼黏度仅为61.5,展现出了较DBD更优的塑解性能。     

Hydrophilization of polypropylene films by using migratory additives

Linear and branched hydrophilic additives of various molecular weights (MWs) were extruded with polypropylene (PP) to make blend films. The surface‐modifying additives included polyethylene glycol (PEG), hydroxyl‐terminated four‐arm polyethylene oxide (PEO), and a commercial hydrophilic additive, Irgasurf HL560. Films were extruded by using a twin‐screw microcompounder at 200°C, and the resulting film thickness was 100 μm. Attenuated total reflectance (ATR)‐FTIR spectrometry and water contact angle measurements were performed on the film surfaces over time to investigate the additive migration behavior. Although ATR‐FTIR detected concentration increases for all additives in the subsurface region, there was no significant improvement in surface hydrophilicity for the PEGs and four‐arm PEOs in the same period of time as water contact angles were measured on the surfaces. Among the linear additives, low MW PEG (1 kDa) was found to migrate faster than the high MW varieties. The linear PEG and four‐arm PEO with MW higher than 2 kDa did not exhibit significant migration to the surface within a month. Irgasurf was found to change the surface wettability effectively in a relatively short time. J. VINYL ADDIT. TECHNOL., 13:57–64, 2007. © 2007 Society of Plastics Engineers.     

Aqueous electrospinning of wheat gluten fibers with thiolated additives

The molecular weight distribution (MWD), rheology and electrospinning of a series of wheat gluten (WG) mixtures with poly(vinyl alcohol) (PVA), dithiothreitol (DTT), and thiolated poly(vinyl alcohol) (TPVA) in water/1-propanol (1/1) were investigated by size-exclusion chromatography, steady-shear viscosity measurements and scanning electron microscopy. Thiolated additives reduce disulfide bonds between protein subunits and thus increase WG solubility. Accordingly, Newtonian behavior is observed for pure components and PVA/WG, and shear-thinning for DTT/WG and TPVA/WG. Concentration, viscosity and additive type affect WG electrospinnability. At higher concentrations, PVA/WG fibers are thicker than WG ones, whereas DTT/WG and TPVA/WG fibers are thinner and beadless. While at low concentrations both DTT/WG and TPVA/WG generate poor fibers, lowering TPVA thiolation level results in better fibers, unobtainable with DTT. Thus, although using only the lower end of the WG MWD, reasonably good fibers can nonetheless be obtained with an inexpensive aqueous system and very low additive amounts.     

Effect of hydrolysis and denaturation of wheat gluten on adhesive bond strength of wood joints

In this study the adhesive bond strength of different wheat gluten modifications and the relationship between molecular weight and adhesive strength was examined. Guanidine hydrochloride and sodium hydroxide were used as denaturation and dispersing agent. Additionally wheat proteins were hydrolyzed by alkaline conditions and enzymes. Effects of different treatments were observed by viscosity measurements and gel electrophoresis. Wood lap joints were prepared with modified proteins and tensile shear strength was tested under dry and wet conditions. In situ hardening of different formulations was analyzed by means of DMA with two‐layered specimens in a three‐point bending test set‐up. Higher solubility had no positive effect on dry bonding strength and wet bonding strength was even reduced. Depending on the degree of hydrolysis, significant improvement of adhesive bond strength was observed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of geometry and loading fractions on energy absorbing properties of fiberglass polymer composite under quasi‐static and low‐velocity impact loadings

The focus of this study is to experimentally investigate the mechanical properties of fiberglass reinforced composite with various aspect ratios and loading fractions in the quasi‐static and low‐velocity impact loading conditions. In this study, short fiberglass reinforced polycarbonate composite materials were fabricated via a solution mixing method and characterized for their tensile properties by varying both fiberglass loading fraction and aspect ratio. The tensile properties including tensile toughness of the fiberglass reinforced composites were characterized and compared. It was observed in this study that the toughness of the composite was dramatically improved whereas the tensile strength and Young's modulus were moderately enhanced over the neat polymer, which were measured to be only up to 15% and 70% increase, respectively. The low‐velocity impact behaviors of the fiberglass composites were also investigated and compared to the tensile toughness of the corresponding composites. Besides, the effect of thickness on their low‐velocity impact properties was investigated. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40821.     

Keratin–polyhydroxyalkanoate melt‐compounded composites with improved barrier properties of interest in food packaging applications

Sustainable biocomposite materials based on the combination of polyhydroxyalkanoates with a keratin additive derived from poultry feathers were successfully developed via melt compounding. Suitable dispersions for low loadings of the additive in the biopolymeric matrix were achieved by the melt‐mixing technique. A good physical interaction between the polymeric matrix and the additive was observed by scanning electron microscopy (SEM). Reductions in water, limonene, and oxygen permeability of the pure polymer to less than a half of its initial value for the composite containing 1 wt % of keratin additive were achieved. This composition was also found to exhibit optimum mechanical performance. As a result, these materials offer significant potential in fully renewable packaging applications based on polyhydroxyalkanoates with enhanced barrier performance. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39947.     

Comparative study of physical properties of water‐blown rigid polyurethane foams extended with commercial soy flours

The use of renewable resources (mainly carbohydrates) in rigid polyurethane foam has been known to offer several advantages, such as increased strength, improved flame resistance, and enhanced biodegradability. Less attention has been directed to inexpensive protein‐based materials, such as defatted soy flour. The objectives of this study were to develop water‐blown rigid polyurethane foams, containing defatted soy flour, that have acceptable or improved physical properties which also lower the cost of the foam formulation and to compare the properties of developed foams extended with three kinds of commercial soy flour. Water‐blown low‐density rigid polyurethane foams were prepared with poly(ether polyol)s, polymeric isocyanates, defatted soy flour, water, a catalyst mixture, and a surfactant. Soy flour and the initial water content were varied from 0 to 40% and from 4.5 to 5.5% of the poly(ether polyol) content, respectively. A standard laboratory mixing procedure was followed for making foams using a high‐speed industrial mixer. After mixing, the mixture was poured into boxes and allowed to rise at ambient conditions. Foams were removed from boxes after 1 h and cured at room temperature for 24 h before measurement of the thermal conductivity and for 1 week before other property tests. Foam properties were determined according to ASTM procedures. Measurement of the physical properties (compressive strength, modulus, thermal conductivity, and dimensional stability under thermal and humid aging) of these foams showed that the addition of 10–20% of three kinds of soy flour imparted water‐blown rigid polyurethane foams with similar or improved strength, modulus, insulation, and dimensional stability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 10–19, 2001     

Development of elastic and plastic properties of polyoxymethylene during bending fatigue

The development of the plastic and viscoelastic properties and the corresponding failure limits of the acetal homopolymer polyoxymethylene were studied in unidirectional cyclic fatigue. Samples with molecular weights (MWs) ranging from 90 to 142 kg/kmol were tested in displacement‐controlled conditions, resulting in maximum stress amplitudes between 30 and 59 MPa and strain amplitudes between 35.8 and 92.6 με. The zero‐hour material properties and the cycle‐dependent property development were predominantly dictated by deformations in the crystalline regions and showed a negligible dependence on MW. However, the final failure limits were found to be primarily dependent on the length of the amorphous tie chains that connect the crystallites. As such, fatigue life analysis showed a strong dependence on MW. Results are interpreted in light of the primary mechanical failure mechanisms and the corresponding molecular deformations. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40762.     

Multi‐Parameter Study of Nanoscale TiO2 and CeO2 Additives in Composite AP/HTPB Solid Propellants

A statistical Taguchi L8 matrix was used to conduct a multi‐parameter study of the use of nanoscale additives in composite solid propellants. The additives studied were TiO₂ (titania) and CeO₂ (ceria). The other parameters involved in the experiment were the oxidizer loading and distribution, additive percentage and size, additive size (nano‐scale or μm‐scale), and the mixing method. Four baseline propellants without additives were also produced for comparison. The propellants were tested from 3.45 to 13.78 MPa in a strand bomb, and burning rate curves were determined for all formulas. By analyzing the Taguchi matrix, the sensitivity of each parameter according to the pressure sensitivity and burning rate of the propellant was calculated. The dominant factors depend on whether the additive is needed for modifying the pressure index or the absolute value of the burning rate. In general, the effectiveness of the additives was most influenced by oxidizer percentage, oxidizer size distribution, and additive type. The amount of additive, mixing method, and additive size all had relatively minor impacts on the effectiveness of the additives.     

Plastic waste minimization: Compatibilization of polypropylene/polyamide 6 blends by polyalkenyl‐poly‐maleic‐anhydride‐based agents

The present article discloses the properties improvement in PP/PA 6 blends by new type experimental coupling additives. By the experimental agents especially the tensile properties could be improved. For example, the tensile strength and the elongation were 16.5 MPa and 4.4% without additive, which increased to 25.5, 20.1, 46.8 MPa and 8.1, 6.4, 8.6% in specimens containing polyalkenyl‐poly‐maleic‐anhydride‐amide, polyalkenyl‐poly‐maleic‐anhydride‐ester, and MA‐grafted‐low‐polymer additives, respectively. DSC curves shows that compatibilizers influenced thermal properties of the polymer blends and reveal affecting of crystalline phase formation process in the blends due to the compatibilization step. Additives A and B rather leads to influencing of PA crystallinities. According to the SEM and FTIR analysis well separated polypropylene and polyamide phases was observed in case of specimens absence of additives but only one well distributed phase by the applying of the synthetized coupling agents. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and properties of copolymer of 3‐thienylmethyl disulfide and benzyl disulfide for cathode material in lithium batteries

The copolymerization of 3‐thienylmethyl disulfide and benzyl disulfide has been investigated. Two monomers were synthesized in a novel facile way. Copolymer of them, especially poly (3‐thienylmethyl disulfide‐co‐benzyl disulfide), ratio 1 : 4, namely, TcB_1:4, was easily electrocopolymerized to form a stable and higher conductive structure at a lower potential on Pt, Au, or glass carbon electrode. TcB_1:4 and TcB_4:1, especially the former, exhibit better conductivities than those of pure poly 3‐thienylmethyl disulfide and poly benzyl disulfide. The copolymer has larger areas than that of monopolymer by cyclic voltammogram measurement. The copolymer shows a capability of supplying more power and energy than monopolymer itself. Copolymers could be used as cathode materials for lithium secondary batteries because their functional groups could not be destroyed before 80°C. In scanning electron micrography, the copolymers show larger compacter structure. The results of the copolymer systems show that they are potentials as cathode materials for lithium batteries. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,characterization, and in vitro biocompatibility study of novel disulfide cross‐linked hydrogels based on poly(amic acid)

In this study, novel disulfide cross‐linked hydrogels were designed and synthesized. First, ethylenediaminetetraacetic dianhydride reacted with butanediamine and amino‐terminated polyethylene glycol via N‐acylation reaction to give biocompatible poly(amic acid) (PAA) with pendant carboxyl groups; then, the amino groups of cystamine reacted with carboxyl groups of PAA to generate disulfide cross‐linked network polymer (PAA‐SS). Fourier transform infrared spectroscopy, ¹H nuclear magnetic resonance imaging, gel permeation chromatography with multiangle laser light scattering, potentiometric titration, rheology, hydrolytic degradation, morphology, porosity, and in vitro biocompatibility studies were used to qualitatively and quantitatively characterize the obtained polymers. The results indicated that the equilibrium swelling ratio of the PAA‐SS decreased with the increase in Rm. The PAA‐SS provided good mechanical strength to maintain their integrity, and the storage modules (G′) of the hydrogels can be adjusted by Rm. The PAA‐SS presented co‐continuum pores, and the pore size correlated with the cross‐linking degree. The degradation of PAA‐SS could be controlled by regulating the concentration of dithiothreitol. Particularly, the PAA‐SS possessed an excellent biocompatibility, as the average proliferating rate of osteoblasts on PAA‐SS was appreciably higher than that on PAA and glass coverslips. In conclusion, the above obtained results demonstrate that the performance of the PAA‐SS outbalance and facilitate the application in biomedical region, particularly in bone tissue regeneration. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40930.     

Hyperbranched polyglycerols,obtained from environmentally benign monomer,as reactive clays inhibitors for water‐based drilling fluids

To prevent the degradation of the borehole and also the disintegration and dispersion of drilled cuttings, different shale stabilizing additives are used in water‐based drilling fluids (WBFs). Glycols, poly(ethylene glycol), glycerols, and polyglycerol derivatives, also called polyols, have been used to inhibit shales containing reactive clays in WBF. These additives are normally used in conjunction with KCl to reduce clay swelling and dispersion of drilled cuttings. Highly branched polymers have become an important field in current polymer science. Such materials typically exhibit compact, globular structures in combination with an exceptionally high number of sites with functional groups. They have unique properties that differ significantly from their linear counterparts, and the hyperbranched polyglycerol (hPG) is an important hyperbranched polymer that can be produced from an environmentally benign monomer, the glycerol carbonate. In this article, the clay inhibitive properties of hPG were evaluated by different test methods including bentonite inhibition test, cuttings recovery, and X‐ray diffraction measurements. The results show that the hPG has a great potential to be used as an environmental friendly inhibitor additive in WBFs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40384.     

Polyvinyl Alcohol Film Materials Containing Biopolymers: Preparation and Properties

The properties and conditions of fabrication of spinning solutions based on polyvinyl alcohol containing the enzyme protease C, a high-molecular-weight antimicrobial, polyhexamethyleneguanidine hydrochloride, and modifying additives of different kinds — the polysaccharide sodium alginate and sodium tetraborate, were investigated. A correlation was established between the proteolytic activity of the film materials, degree of swelling, and composition of the spinning solutions used to prepare them.     

Viscosity behavior of microwave‐heated and conventionally heated poly(ether sulfone)/dimethylformamide/lithium bromide polymer solutions

This article investigates the viscosity behavior of new membrane dope solutions of poly(ether sulfone) (PES) and dimethylformamide with low‐molecular‐weight halogenated lithium bromide (LiBr) additives prepared with two different techniques: (1) a microwave (MW) technique and (2) a conventional heating (CH) technique. In addition, the influence of different concentrations of anhydrous halogenated LiBr additives (0–5 wt %) on the viscosity behavior is analyzed. The viscosity of the dope solutions was assessed with a conical rheometer equipped with a high‐viscosity adapter. The results revealed that the pure PES solutions prepared by the MW and CH techniques exhibited pseudoplastic and Newtonian behavior, respectively. Both the MW and CH PES solutions containing the LiBr additives exhibited dilatant behavior, which obeyed the power law. The apparent viscosity of all the dope solutions prepared with the MW technique was lower than that of those prepared with the CH technique. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Biopolymer blends based on polylactic acid and polyhydroxy butyrate‐co‐valerate: Effect of clay on mechanical and thermal properties

Biodegradable polymer blends consisting of polylactic acid (PLA) and polyhydroxy butyrate‐co‐valerate (PHBV) have been prepared by melt mixing in a twin screw extruder and followed by injection molding technique. Cereplast PLA containing starch as an additive was used to make the blends. The effects of three different types of clay (montmorillonite, bentonite, and chemically modified bentonite) on the mechanical and thermal properties of the blends were studied. The ratio of PLA and PHBV (w/w) was maintained at 70:30 while the weight of clay was fixed at 1%. The addition of clay was found to result in a slight increase in tensile strength and modulus. Viscoelastic studies revealed that the damping property of the blends decreased with the addition of clay. This was attributed to the decreased segmental motion in the molecular chains. The morphology of the blends has been investigated by environmental scanning electron microscopy and a homogenous surface was observed for the blend containing montmorillonite. POLYM. COMPOS., 36:2042–2050, 2015. © 2014 Society of Plastics Engineer     

Modification of vital wheat gluten with phosphoric acid to produce high free swelling capacity

Wheat gluten reacts with phosphoric acid in the presence of urea to produce natural superabsorbent gels. Fourier Transform Infra‐red (FT‐IR) spectroscopy and two‐dimensional gel electrophoresis (2DE) reveal chemical changes from the reaction. Temperatures above 120°C and dry conditions create the opportunity for reaction. FT‐IR analyses confirm the formation of esters, carbamates, and phosphoramides on the gluten samples. 2DE protein composition topographies indicate a shift in the isoelectric point (pI) to lower values along with extensive inter‐protein linkages. A free swelling capacity (FSC) in excess of 85× the mass of the converted gluten is obtainable using a conservative vacuum‐assisted method to recover and quantify the properties of the wet gel. Other methods produce FSC values nearly twice as high. FSC for acid‐treated gluten is lower for solutions containing solutes than the FSC for deionized water. Native gluten produces FSC values that are about 2% of those for treated gluten, but these values are less sensitive to the presence of ionic solutes and increase slightly in the presence of aqueous ethanol up to a mole fraction of 0.25.. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39440.