| 摘要 |
PROBLEM TO BE SOLVED: To obtain a substituted starch derivative which is thermoplastic even in the absence of a plasticizer by substituting reactive hydroxyl groups of the same starch molecule with short-chain hydrocarbon-containing and long-chain hydrocarbon-containing groups while adjusting each of the degrees of substitution with both the hydrocarbon-containing groups. SOLUTION: The long-chain hydrocarbon-containing group is a 6-24C hydrocarbon-containing group; and the short-chain one, a 2-4C one provided the case when both the groups are acyl is excluded. Preferably, both the hydrocarbon-containing groups are aliphatic, and they are each selected from among alkyl, alkoxyalkyl, acyl, and derivatives of these group. Preferably, the degree of substitution with the long-chain hydrocarbon-containing group is 0.06-2.0; that with the short-chain one, 0.9-2.7; and their sum, 1.5-2.95. This substituted starch derivative usually has a glass transition temperature of 140 deg.C or lower, preferably 80-130 deg.C.
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