| In order to solve the pollution problems brought by the use of plastics, people researched and invented a series of degradable materials. As a natural polymer, starch is abundant, inexpensive , sustainable and degradable, and with a short degradation period and no pollution after degradation, so people pay more attention to starch and hope to get a degradable materials based on starch with excellent properties and low cost. Although native starch have a great crystal degree up to 20% to 45%, a great deal of hydroxies are in the molecular chains, which lead to a strong intermolecular effect, high melting temperature and degradation before its melting point, native starch cannot be processed by conventional technology. Generally, people add many plastizers(glycerol, ethylate amine and ) to eliminate intermolecular effect, and make the starch be processed as the conventional thermoplasics and become thermoplastic starch(TPS) which can be completely degradaed. In addition, it is a way to get a degrable materials by blending starch and conventional plastics, such as stactch/PE blends.Dealing with the processing problems of native starch with long molecular chains, we prepare the low molecuar weight starch with arelative short chains, and do more applaction research as follows:1,we prepared low molecular weight starch (LS) according to changethe content of citric acid and react time at gelatinization temperature,and did more research on the effect of reacting terms and charactertion.With a more strong intermolecular effect, the chains of starch areassembled without ester and carboxyl groups.2,LS was plasticized by glycerol ,then we did reasearch on theprocessing and mechnics properties. At high shear rates, TPLS have agood processing properties; compared to TPNS, the tensile strengthen ofTPLS is improved while the stress at rupture is reduced;3,we prepared the LS/PE blends ,and did reasearch on the interfacialadhesion. The compatibility of LS/PE is not remarkedly improved. |
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