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Journal ArticleDOI

Preparation and characterization of thermoplastic starch/zein blends

TL;DR: The use of zein in thermoplastic starch compositions causes a decrease in the water sensitivity of these materials and lower its melt viscosity during processing making zein a suitable and very promising component in TPS compositions as mentioned in this paper.
Abstract: Blends of starch and zein plasticized with glycerol were prepared by melting processing in an intensive batch mixer connected to a torque rheometer at 160 °C. The resulting mixtures were compression molded and then characterized by scanning electron microscopy, differential scanning calorimetry, wide-angle X ray diffraction and water-absorption experiments. The blends were immiscible, showing two distinct phases of starch and zein. The water uptake at equilibrium and its diffusion coefficient were determined. The water uptake at equilibrium decreased with increasing zein content. The diffusion coefficient fell sharply on addition of 20% zein and remained constant as zein content was increased. No appreciable effect of zein on starch crystallization was observed by X ray diffraction. The use of zein in thermoplastic starch compositions causes a decrease in the water sensitivity of these materials and lower its melt viscosity during processing making zein a suitable and very promising component in TPS compositions.

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Citations
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Journal ArticleDOI
TL;DR: In this article , chitosan (CS) and potato starch (PS) biopolymers are blended to prepare proton conducting solid electrolytes based on the X-ray diffraction (XRD) inspection.
Abstract: The need for flexible energy storage devices for advanced technologies has encouraged researchers to focus on environmental-friendly biopolymers. In this work, chitosan (CS) and potato starch (PS) biopolymers are blended to prepare proton conducting solid electrolytes. Based on the X-ray diffraction (XRD) inspection, the most amorphous blended film with the lowest crystallinity degree was selected to prepare polymer electrolytes. The variation in Fourier-transform infrared spectroscopy (FTIR) bands were used to investigate the occurrence of interactions among the ammonium thiocyanate (NH4SCN) salt and CS:PS polymer blends. The experimental results of electrochemical impedance spectroscopy (EIS) were simulated with electrical equivalent circuit (EEC) modeling to determine the circuit elements. The highest value of 1.07 × 10 − 5 S cm−1 was recorded for the sample included 40 wt.% of dopant salt. The dielectric analyses were helpful in separating the regions ascribed to electrode and molecular polarizations. The combination of circuit elements achieved from the EEC modeling and Koops phenomenological interpretation is used to understand the behavior of the loss tangent (tanδ) pattern. The AC conductivity pattern followed Jonscher's power law. The relaxation dynamics interrelated with ions is explained using electric modulus approaches. The peaks hidden in the dielectric loss ( ε ′ ′ ) spectra, were manifested in the imaginary part of electric modulus ( M ′ ′ ) pattern. The M ′ - M ′ ′ patterns were used to shed light on the coupling between ionic motion and polymer chain dynamics.

13 citations

Journal ArticleDOI
TL;DR: In this paper , the authors explored the possibility of developing a starch-based bioplastic product using fiber from banana inflorescence waste as a filler and found good adhesion between the filler and the starch matrix.

13 citations

Journal ArticleDOI
TL;DR: Graft copolymerization of poly(acrylonitrile) onto cassava starch was carried out with potassium persulphate (PPS) as the free radical initiator using a response surface Box-Behnken design as discussed by the authors.
Abstract: Graft copolymerization of poly(acrylonitrile) onto cassava starch was carried out with potassium persulphate (PPS) as the free radical initiator using a response surface Box–Behnken design. Different levels of monomer concentration, initiator concentration, and temperature were used, and regression models were generated in terms of these factors, which can be used to predict the grafting level and efficiency at a given level of the factors. The grafted starches were characterized by FTIR, XRD, and SEM analyses and determination of %grafting (%G), N-content, thermal properties, water and saline solution retention, and rheological properties. Under the conditions used, %G was found to depend only on the temperature used for the reaction. The maximum %G of 120.1 was obtained for the sample synthesized under the following conditions: weight of AN = 0.753 mol/10 g starch, weight of PPS = 0.284 g and temperature = 55°C, and the grafting efficiency was 30.03%. The absorption bands at 2243 cm−1 for the nitrile group (CN) in the FTIR spectra of the products confirmed the grafting reaction. There was a decrease in crystallinity and disappearance of the granular structure after grafting of the starch. The melting temperatures of the graft copolymers determined by differential scanning calorimetry analysis were higher than that of the native starch. The grafted starches exhibited very high thermal stability as observed from the thermogravimetric analysis. The superabsorbent polymer prepared from the grafted starch by alkali saponification exhibited a maximum water absorbency of 636 g/g. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

11 citations

Journal ArticleDOI
TL;DR: In this article, the effect of the ratio of uncomplexed starch, zein and starch complexed with stearic acid on the tensile, water vapour and oxygen barrier and thermal properties of the composite films were investigated.

11 citations

References
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Book
01 Jan 1956
TL;DR: Though it incorporates much new material, this new edition preserves the general character of the book in providing a collection of solutions of the equations of diffusion and describing how these solutions may be obtained.
Abstract: Though it incorporates much new material, this new edition preserves the general character of the book in providing a collection of solutions of the equations of diffusion and describing how these solutions may be obtained

20,495 citations

Journal ArticleDOI
TL;DR: The combination of bio-fibers such as kenaf, hemp, flax, jute, henequen, pineapple leaf fiber, and sisal with polymer matrices from both nonrenewable and renewable resources to produce composite materials that are competitive with synthetic composites requires special attention as discussed by the authors.
Abstract: Sustainability, industrial ecology, eco-efficiency, and green chemistry are guiding the development of the next generation of materials, products, and processes. Biodegradable plastics and bio-based polymer products based on annually renewable agricultural and biomass feedstock can form the basis for a portfolio of sustainable, eco-efficient products that can compete and capture markets currently dominated by products based exclusively on petroleum feedstock. Natural/Biofiber composites (Bio-Composites) are emerging as a viable alternative to glass fiber reinforced composites especially in automotive and building product applications. The combination of biofibers such as kenaf, hemp, flax, jute, henequen, pineapple leaf fiber, and sisal with polymer matrices from both nonrenewable and renewable resources to produce composite materials that are competitive with synthetic composites requires special attention, i.e., biofiber–matrix interface and novel processing. Natural fiber–reinforced polypropylene composites have attained commercial attraction in automotive industries. Natural fiber—polypropylene or natural fiber—polyester composites are not sufficiently eco-friendly because of the petroleum-based source and the nonbiodegradable nature of the polymer matrix. Using natural fibers with polymers based on renewable resources will allow many environmental issues to be solved. By embedding biofibers with renewable resource–based biopolymers such as cellulosic plastics; polylactides; starch plastics; polyhydroxyalkanoates (bacterial polyesters); and soy-based plastics, the so-called green bio-composites are continuously being developed.

1,921 citations

Journal ArticleDOI
TL;DR: In this paper, the composites were conditioned at various moisture contents in order to evaluate the effect of amylopectin on the composite structure, and the resulting films were characterized using scanning electron microscopy, differential scanning calorimetry, water absorption experiments, and wide-angle X-ray scattering.
Abstract: Nanocomposite materials were obtained using glycerol plasticized starch as the matrix and a colloidal suspension of cellulose whiskers as the reinforcing phase. The cellulose whiskers, prepared from tunicin, consisted of slender parallelepiped rods with a high aspect ratio. After mixing the raw materials and gelatinization of starch, the resulting suspension was cast and evaporated under vacuum. The composites were conditioned at various moisture contents in order to evaluate the effect of this parameter on the composite structure. The resulting films were characterized using scanning electron microscopy, differential scanning calorimetry, water absorption experiments, and wide-angle X-ray scattering. An accumulation of plasticizer in the cellulose/amylopectin interfacial zones was evidenced. The specific behavior of amylopectin chains located near the interface in the presence of cellulose probably led to a transcrystallization phenomenon of amylopectin on cellulose whiskers surface.

622 citations

Journal ArticleDOI
TL;DR: In this article, a review of the early literature on zein is presented, which reexamines the old literature and reconciles it with new zein research to illustrate some of the unique properties of and opportunities for zein.
Abstract: Corn is the largest and most important agricultural commodity in America. Zein, one of the components in corn, has long been investigated for uses other than food and feed. Zein is a unique and complex material, and it is one of the few cereal proteins extracted in a relatively pure form. Today, because of environmental concerns, interest in zein utilization is again growing. Some of the more important research on zein is more than 50 years old. Most of this work has been either forgotten, lost, or difficult to locate. Much of this work was done at the USDA laboratory in Peoria, IL. Since most early zein literature is still easily accessible at that laboratory, this review on zein has been prepared making use of this old literature. This review reexamines the old literature and reconciles it with new zein research to illustrate some of the unique properties of and opportunities for zein.

461 citations

Trending Questions (1)
How does zein and phosphorylated starch form bonds?

The provided paper does not mention anything about the formation of bonds between zein and phosphorylated starch.