Starch-based plastic research and development background, process principle
Starch-based plastics use chemical reaction to chemically modify starch, reduce the hydroxyl group of starch, change its original structure, thereby changing the corresponding properties of starch, and turning the original starch into thermoplastic starch.
R&D background
Starch is the natural polymer that is second only to cellulose in the world. It is rich in source, renewable and inexpensive. It can be used to produce starch-based plastics through modified plasticization. As an important category in bio-based materials, starch-based plastics have successfully achieved industrial production and application. Starch-based plastic is a kind of plastic product which is made of starch as the main raw material, modified and plasticized and then blended with other polymers. It is a kind of bioplastic. Starch-based bioplastics can be divided into bio-based plastics and biodegradable plastics.
Starch-based biodegradable plastics are generally blends of modified starches with biodegradable polyesters (such as PLA/PBAT/PBS/PHA/PPC, etc.), which are fully biodegradable, compostable, environmentally friendly, and suitable for waste. Composting, landfill and other treatment methods. Starch-based bio-based plastics are generally a mixture of modified starch and polyolefins (such as PP/PE/PS, etc.). Its environmental significance is to reduce the use of petrochemical resources, reduce carbon dioxide emissions, and waste is suitable for incineration. Both materials can replace traditional petroleum-based plastics and are widely used in plastic packaging materials, shock-proof materials, plastic films and plastic bags, disposable tableware, food containers, toys, and the like.
Process principle
Starch is a natural high molecular polymer with a large amount of hydroxyl groups in its molecule (molecular structures II and III), so the interaction between starch macromolecules is strong, which makes the original starch difficult to melt process, and is shared with other polymers. The compatibility with other polymers in the mixing process is also poor. However, these hydroxyl groups can undergo chemical reactions such as esterification, etherification, grafting, and crosslinking. These chemical reactions are used to chemically modify the starch to reduce the hydroxyl group of the starch and change its original structure, thereby changing the corresponding properties of the starch and turning the original starch into a thermoplastic starch.
1. Esterification, transesterification or etherification
In order to change the hydrophilicity of the starch to hydrophobicity, the hydroxyl group on the starch molecule is esterified and transesterified with a fatty acid, a fatty acid ester or the like to form a starch ester.
2, cross-linking reaction
In order to increase the strength and heat resistance of the starch material, the starch is cross-linked with a compound having two or more functional groups (such as a polybasic acid, etc.) to cause moderate crosslinking of the starch.
3, blending and reforming copolymerization independent innovation
Most starch plastics are prepared by blending and blending starch with other polymer materials. The resulting product has limited compatibility due to poor compatibility and limited use. Starch-based plastics also copolymerize starch during the starch modification process to obtain a graft copolymer of starch and other polymers, thereby improving the compatibility of starch with other polymer materials. Through chemical modification, the starch modification was realized: the hydrophilicity was changed to hydrophobicity; the heat sensitivity was changed to temperature resistance; the hard and brittleness was changed to plasticity. This modification solves the worldwide problem of starch modification and lays a good foundation for subsequent processing.
we offer patented full biodegradable film and PVA bag, all products are made by casting equipment, It is different from traditional blow molding products, all blow molding products are non full biodegradable. We can produce pva films and bags in all transparent and various colors.
we also offer organic material full biodegradable film and bags with patented raw material and production Process. our corn based starch-based plastic and bamboo based starch-based plastic get Vincotte OK Biobased certificate.
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