Preparation and characterization of thermoplastic starch/zein blends
01 Sep 2007-Materials Research-ibero-american Journal of Materials (Materials Research)-Vol. 10, Iss: 3, pp 227-231
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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TL;DR: Data support the potential use of zein-starch mixed films for colonic targeting purposes and show that under simulated colonic conditions, the drug release was significantly more rapid from 1:5 HAS/Zein, compared to the zein alone coating formulation.
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TL;DR: In this article, a bio-plastic starch (BPS) was produced from melt processing of Malaysian sago starch with the addition of glycerol as plasticizer and water as well as citric acid (CA) as a secondary additive.
Abstract: Starch is a biodegradable polymer produced in abundance from many renewable resources. In this research, bio-plastic starch (BPS) was produced from melt processing of Malaysian sago starch with the additions of glycerol as plasticizer and water as well as citric acid (CA) as a secondary additive. The main objective was to investigate the influence of CA and water contents with presence of glycerol on the mechanical properties of BPS. The CA content varies from 0 to 40 w/wt% while water was also varied from 0 to 40 w/wt%. The materials were prepared by melt blending in the Haake Rheomix at 130°C, followed by injection molding process. The properties of BPS with different CA and water content, are investigated through Fourier transform infrared (FT-IR) and tensile testing. FT-IR spectroscopy proved that acid citric improve the properties of BPS and water give negative effects to the carbon hydrogen-bond. The samples were also tested by scanning electron microscopy (SEM). It is obvious that the addition of the CA at 30 wt/wt% improve the mechanical property of BPS to more than 40% compare to the addition of water.
30 citations
Cites background from "Preparation and characterization of..."
...If two polymers formed completely immiscible blends, there were no appreciable changes in the FT-IR spectra of the blends with the respect of co-addition of each component (Corradini et al., 2007)....
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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
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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.
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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
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