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Journal ArticleDOI

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

AbstractBlends 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.

Topics: Starch (53%)

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Journal ArticleDOI
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.

135 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
Abstract: Packaging bags from thermo-compressed films of thermoplastic corn starch containing talc nanoparticles (0, 1, 3 and 5% w/w) were developed. Mechanical properties of films were studied by two different techniques (tensile tests and quasi-static assays) revealing starch films reinforcement by talc addition. Strength improvement of thermoplastic starch films with talc concentration higher than 3% w/w was reflected in an increase in both Young's modulus and yield stress. Talc particles modified failure mode of thermo-seal of thermoplastic starch films giving another bags opening possibility. Usually, bags based on starch films could be only opened by tearing while those of starch-talc bionanocomposites could be torn or peeled off. Finally, in order to evaluate packaging bags tightness, films barrier properties were determined. Water vapor and oxygen permeability were reduced 54 and 26%, respectively, by talc addition (3% w/w) to thermoplastic starch.

105 citations


Journal ArticleDOI
Abstract: Three different types of amphiphilic molecules — Tween 60, linoleic acid, and zein were used as additives for the production of thermoplastic starch (TPS). The addition of those amphiphiles resulted in: (i) improved plasticization and processability, (ii) enhanced extensibility, (iii) increased crystallinity, and (iv) decreased stiffness, strength and rigidity of the TPS materials. Zein facilitated more effective plasticization, melting and processability of TPS material than did linoleic acid and Tween 60, respectively. However, Tween 60 allowed greater reduction of Tg and produced softer TPS material than did linoleic acid and zein, respectively. Binary blends of those TPS materials and poly(lactic acid) (PLA) were also fabricated by varying PLA content, i.e. 30, 50 and 70% (w/w). The melt flow index, tensile strength and elastic modulus of the TPF-PLA blends increased significantly with increasing PLA content. In addition, amphiphiles facilitated processability, flowability and extensibility of the blends. Linoleic acid was a more effective additive to enhance flowability of the TPS–PLA blends than were Tween 60 and zein, respectively.

82 citations


Journal ArticleDOI
TL;DR: The characterization of the materials indicates that, compared to glycerol, the use of [BMIM]Cl leads to less hygroscopicity, a more efficient plasticization of both starch and zein phases and a compatibilization of starch/zein blends.
Abstract: An ionic liquid (1-butyl-3-methyl imidazolium chloride [BMIM]Cl) was used as a plasticizer in starch, zein and their blends; and compared to glycerol, a classical plasticizer of starch. Thermoplastic plasticized biopolymer materials were obtained by melt processing using a twin screw microcompounder. Such a device allows simulating a twin screw extrusion process on small batches of a few grams, and to evaluate the necessary specific mechanical energy input for native starch destructurization; and the final apparent melt viscosity. Both were shown to be significantly reduced for starch in presence of [BMIM]Cl (compared to glycerol), while zein processing behavior was less sensitive to the plasticizer used. This induces significant starch/zein viscosity ratio differences, which affect melt mixing of the starch zein blends. In starch rich blends, this results in smaller zein aggregates in the case of [BMIM]Cl. The characterization of the materials indicates that, compared to glycerol, the use of [BMIM]Cl leads to less hygroscopicity, a more efficient plasticization of both starch and zein phases and a compatibilization of starch/zein blends.

81 citations


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

  • ...Corradini et al. (2007) observed a similar behavior for starch–zein blends plasticized by glycerol in a brabender type mixer with a torque rheometer....

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  • ...Influence of plasticizers on water uptake and thermomechanical properties As observed by Corradini et al. (2007), the water uptake of glycerol plasticized starch/zein blends decreases with zein content (Table 2)....

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  • ...A t p r F m t 50/50 – 90/10 – − 100/0 – ccording to Corradini et al. (2006, 2007), they are attributed o the starch rich and the zein rich phases, for the low temerature (2nd peak) and the high temperature (3rd peak) espectively. ig....

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Journal ArticleDOI
TL;DR: The nanocomposites of a red-algae-derived carrageenan, mica, and their blends with zein prolamine obtained by solvent casting can have significant potential to develop packaging films and coatings for shelf-life extension of food products.
Abstract: The present study presents the development and characterization of biocomposites of a red-algae-derived carrageenan, mica, and their blends with zein prolamine obtained by solvent casting. The morphology of the blends was characterized by scanning and transmission electron microscopy (SEM and TEM), optical microscopy, and atomic force microscopy (AFM). Mechanical behavior, water barrier, water uptake, and UV−vis protection of the cast films were also investigated. The results indicated that the addition of 10 wt % glycerol to the blends resulted in a better dispersion of the additive and, for that reason, a better improvement for the studied properties. The composites were seen colored but transparent and exhibited the ability to block the UV−vis radiation because of the characteristic absorbing properties of the filler. Nevertheless, the main conclusion from the work is that the nanocomposites were seen to act as a reinforcing plasticizer and also led to significantly reduced water permeability and uptak...

79 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

20,482 citations



Journal ArticleDOI
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.

1,759 citations


Journal ArticleDOI
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.

606 citations


Journal ArticleDOI
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.

419 citations