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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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TL;DR: The biodegradability and biocompatibility of zein and other inherent properties associated with zein’s structure allow a myriad of applications of such materials with great potential in the near future.
Abstract: Zein is a biodegradable and biocompatible material extracted from renewable resources; it comprises almost 80% of the whole protein content in corn. This review highlights and describes some zein and zein-based materials, focusing on biomedical applications. It was demonstrated in this review that the biodegradation and biocompatibility of zein are key parameters for its uses in the food-packing, biomedical and pharmaceutical fields. Furthermore, it was pointed out that the presence of hydrophilic-hydrophobic groups in zein chains is a very important aspect for obtaining material with different hydrophobicities by mixing with other moieties (polymeric or not), but also for obtaining derivatives with different properties. The physical and chemical characteristics and special structure (at the molecular, nano and micro scales) make zein molecules inherently superior to many other polymers from natural sources and synthetic ones. The film-forming property of zein and zein-based materials is important for several applications. The good electrospinnability of zein is important for producing zein and zein-based nanofibers for applications in tissue engineering and drug delivery. The use of zein’s hydrolysate peptides for reducing blood pressure is another important issue related to the application of derivatives of zein in the biomedical field. It is pointed out that the biodegradability and biocompatibility of zein and other inherent properties associated with zein’s structure allow a myriad of applications of such materials with great potential in the near future.

186 citations


Cites background from "Preparation and characterization of..."

  • ...Several studies involving zein and starch blends are reported in the literature [2,59,60]....

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Journal ArticleDOI
TL;DR: In this paper, the authors developed packaging bags from thermoplastic corn starch containing talc nanoparticles (0, 1, 3, 3 and 5% w/w) and evaluated the properties of these bags by tensile tests and quasi-static assays.

135 citations

Journal ArticleDOI
TL;DR: In this paper, a review of various processing techniques used to produce starch based polymers and composites with their properties to address the poor properties of starch is presented, including low toxic and good compatibility natural plasticizers are of great interest in the processing of thermoplastic starch.
Abstract: In recent years, interest in agro polymers has created great interest among researchers and industry alike, as these materials are found to be biodegradable and eco-friendly. Since the fossil fuel based polymers have created greater environmental concern, these bio-based polymers are addressing the concerns in some of impactful areas such as food packaging and contribute significantly to the sustainable development with minimum ecological problems. Among agro polymers, starch based polymers have made major stride to marketable products in food packaging field. It is estimated that by the year 2020, the biocomposite materials demand will touch 20% of total plastic utilization. This review enlightens various processing techniques used to produce starch based polymers and composites with their properties to address the poor properties of starch. Low toxic and good compatibility natural plasticizers are of great interest in the processing of thermoplastic starch (TPS). Further emphasis is also given on essential packaging film properties such as barrier, biodegradation, mechanical, and thermal properties for TPS based materials. The overview of literature indicates that, Final properties of the thermoplastic starch can be improved by using different fillers, as well as by changing the source of the starch. Since the quest to produce better, cheaper, and eco-friendly materials never stops, a multidisciplinary approach is required to achieve further improvement in the existing materials and to produce new class of materials that are eco-friendly which can extend smarter and efficient services to customers. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers

119 citations

Journal ArticleDOI
TL;DR: Stress relaxation measurements indicated that the bioelastomers have strain energy dissipation factors that are lower than those of conventional rubbers, rendering them as promising green substitutes for plastic mechanical energy dampeners.
Abstract: Designing starch-based biopolymers and biodegradable composites with durable mechanical properties and good resistance to water is still a challenging task. Although thermoplastic (destructured) starch has emerged as an alternative to petroleum-based polymers, its poor dimensional stability under humid and dry conditions extensively hinders its use as the biopolymer of choice in many applications. Unmodified starch granules, on the other hand, suffer from incompatibility, poor dispersion, and phase separation issues when compounded into other thermoplastics above a concentration level of 5%. Herein, we present a facile biodegradable elastomer preparation method by incorporating large amounts of unmodified corn starch, exceeding 80% by volume, in acetoxy-polyorganosiloxane thermosets to produce mechanically robust, hydrophobic bioelastomers. The naturally adsorbed moisture on the surface of starch enables autocatalytic rapid hydrolysis of polyorganosiloxane to form Si–O–Si networks. Depending on the amount...

100 citations

Journal ArticleDOI
TL;DR: In this paper, three different types of amphiphilic molecules (Tween 60, linoleic acid, and zein) were used as additives for the production of thermoplastic starch (TPS).

98 citations

References
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Journal ArticleDOI
TL;DR: In this paper, a brief literature review is presented which shows that, in the 1970's, starch containing low (10-30%) water contents was extruded at elevated temperatures to give a thermoplastic melt exhibiting no residual starch crystallinity.
Abstract: Recent patents in the starch-based plastics area have claimed melted or “destructurized” starch as a new type of material. The term “destructurized starch” has apparently been coined after the physically modified state of starch obtained by the disruption of the granular state, resulting in the loss of order and crystallinity. A brief literature review is presented which shows that, in the 1970's. starch containing low (10–30%) water contents was extruded at elevated temperatures to give a thermoplastic melt exhibiting no residual starch crystallinity. Differential scanning calorimetry studies of starch-g-polymethyl acrylate and blends of starch with poly (ethylene-co-acrylic acid) are also presented. These data indicate that these materials, prepared in the 1970's, also contain starch which was partially or completely destructurized. Thus, although ideas and uses for destructurized starch in plastic items have proliferated in recent years, completely melted or “destructurized” starch had been conceived and used much earlier. Die Entwicklung von auf Starke basierenden Kunststoffen. Eine Uberprufung ausgewahlter Polymersysteme aus historischer Perspektive. Neuere Patente auf dem Gebiet der starkebasierenden Kunststoffe erforderten geschmolzene oder „destrukturierte” Starke als neues Material. Der Begriff „destrukturierte Starke” wurde offenbar gepragt nach dem physikalisch modifizierten Status von Starke, die nach dem Zerreisen des kornigen Zustandes erhalten wurde unter Verlust der Ordnung und der Kristallinitat. Ein kurzer Literaturuberblick wird aufgezeigt, welcher darlegt, das in den 1970er Jahren Starke mit geringem Wassergehalt (10–30%) bei erhohten Temperaturen extrudiert wurde, um eine thermoplastische Schmelze zu ergeben, die keine restliche Kristallinitat enthielt. Differential-Raster-Kalorimetrie-Untersuchungen von Starke-g-Polymethylacrylat und Mischungen von Starke mit Poly(ethylen-co-Acrylsaure) werden ebenfalls aufgezeigt. Diese Daten zeigen, das diese in den 1970er Jahren hergestellten Materialien ebenfalls teilweise oder vollstandig destrukturierte Starke enthielten. Somit haben sich in den vergangenen Jahren Vorstellungen und Verwendungen fur destrukturierte Starke in plastischen Artikeln entwickelt, obwohl vollstandig geschmolzene oder „destrukturierte” Starke schon viel fruher verwendet worden waren.

179 citations


"Preparation and characterization of..." refers background in this paper

  • ...biodegradable plastics is starch, a natural renewable polysaccharide obtained from a great variety of crops( 1 )....

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Journal ArticleDOI
TL;DR: In this article, thermoplastic starch/natural rubber polymer blends were prepared using directly natural latex and cornstarch, with natural rubber content varying from 2.5 to 20%.

165 citations


"Preparation and characterization of..." refers background in this paper

  • ...materials(3) and with both degradable(4, 5 ) and non-degradable polymers(6)....

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Journal ArticleDOI
TL;DR: In this article, it was shown that the amount of B-type crystallinity in compression-moulded, glycerol-plasticised potato starches was strongly dependent on both the properties of the potato starch used and the applied processing conditions.

110 citations


"Preparation and characterization of..." refers methods in this paper

  • ...Table 1 gives the crystallinity index data for the B-type and V h –type crystalline structures, calculated as de- scribed by Hulleman et al.10....

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  • ...Table 1 gives the crystallinity index data for the B-type and V h –type crystalline structures, calculated as described by Hulleman et al.(10)....

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Journal ArticleDOI
TL;DR: Starch plastic sheets were prepared by extrusion processing of mixtures of granular high-amylopectin and highamylose starches in the presence of glycerol and water as plasticizers.
Abstract: Starch plastic sheets were prepared by extrusion processing of mixtures of granular high-amylopectin and high-amylose starches in the presence of glycerol and water as plasticizers. Amylose content varied between 0 and 70% (w/w). Structural characterization and determination of the mechanical properties of the sheets were performed after aging the materials between 40–65% relative humidity for 2 and 35 weeks and at 90% relative humidity for two weeks. The materials were semicrystalline and viscoelastic. The materials were described as complex heterogeneous multiphase materials. They consisted of amorphous and crystalline phases of amylose and amylopectin as well as granular structures and domains of amylose, amylopectin and amylose-amylopectin helices. Single-helical type crystallinity was formed solely by amylose directly after processing while B-type crystallinity was rapidly formed in amylose-rich materials and slowly during aging of amylopectin-rich materials. The stress-strain and stress-rel...

102 citations

Journal ArticleDOI
TL;DR: The structural and mechanical properties of compression-molded normal and high-amylose maize starches were studied as a function of processing water content and ageing time in this paper, where it was concluded that both lead to differences in the starch network.
Abstract: The structural and mechanical properties of compression-molded normal and high-amylose maize starches were studied as a function of processing water content and ageing time. Rubbery thermoplastic starches were produced by compression molding of four maize starches with differences in amylose content and amylopectin structure. Glycerol (30% on the basis of dry starch) and water (between 10 and 35% on the basis of total mass) were used as plasticizers. After processing, the amorphous thermoplastic starch materials crystallized during ageing. The semicrystalline materials contained both E-type and V-type, as well as B-type crystallinity. The properties of the thermoplastic starch materials are dependent on water content during processing, starch source, and ageing time. The normal maize starch materials are highly flexible with elongations between 56 and 104%. The elongations of the high-amylose maize starch materials were between 5–35%. The tensile stress and E-modulus of the normal maize starch materials were in the range of 3.9–6.7 and 27–131 MPa, respectively. The tensile stress and E-modulus of the high-amylose maize starch materials increased from approximately 0.5 to 23 and 5 to 700 MPa, respectively, with increasing water content during processing from 10 to 35%. The differences in mechanical properties of the normal and high-amylose materials were explained by differences in the structure of the amylose and amylopectin structure. It was concluded that both lead to differences in the starch network. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 631–644, 1997

95 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.