Preparation And Properties Of Thermoplastic Starch Based Polymer Materials

In this article, the chlorides were used to esterify the native starch. The thermoplastic composites with good mechanical properties were prepared based on esterified starch. The infulence of esterification starch on the properties of thermoplastic materials was studied, and the results were as follows:1. The esterified starch was fabricated by esterification reaction of chloride and strarch. The chemical structure of esterified starch was characterized by IR and 1H NMR and the results implied the chloride and native starch had been successfully performed. It could be found that esterified starch was easily prepapred by using chloride and the degree substitution was determined by the chemical structure of chlorides. The results of swelling capacity, the contact angle and gelatinization ability indicated that esterified starch had improved hydrophobicity and stability. Moreover, the results of XRD showed that the crystalline of esterified starch diminished.2. The infulence of different contents of stearic chloride on the properties of esterified starch was investigated. The PCL/starch composites were fabricated by melt blending with PCL and the esterified starch. It was shown that processing torque of esterified starch/PCL composites became stable within 5 min and much lower than that of native starch/PCL ones. Clearly, the processibility of PCL/esterified starch composites was elevated even without plasticizer. Compared with the native PCL/starch blends, the tensile tensile and elongation at break of the esterified PCL/starch composite were significantly increased. As the DS was 1.50, the tensile strength increased to 9.1 MPa, which were almost 4 times of PCL/native starch. SEM results indicaited that the compatibility between PCL and esterified starch was improved. Moreover, the water resistance of PCL/esterified starch composites was dramatically decreased. PCL/esterified starch composites exhibited good biodegradability.3. The esterified starch with carbon-carbon double bonds was prepared by the esterification reaction of acryloyl chloride and native starch. Based on methyl methacrylate, the copolymers(ES-g-PMA) were obtained by free radical graft copolymerization of esterified starch. The grafting ratio and grafting efficiency was high. The mechanical properties results showed that ES-g-PMA exhibited good mechanical properties. When DS was 0.4, the tensile strength and the elongation at break were 22 MPa and 487% respectively. The water absorption results showed that the water absorption of ES-g-PMA was decreased with increasing the DS. When the DS was 0.75, the water absorption of the copolymers reduced to 5%. In addition, it was shown that ES-g-PMA was still partly biodegradable.