| 摘要 |
PURPOSE:To obtain a polymer or copolymer of a hydroxypolycarboxylic acid by a simple operation, by plycondensing a specified hydroxypolycarboxylic acid or its mixture with its ester by heating in a vacuum. CONSTITUTION:A hydroxypolycarboxylic acid of the formula or its mixture with its ester is polycondensed by heating in a vacuum. In the formula, R is H, methyl, ethyl, phenyl, -COOH or -CH2COOH, X and Y are each H, methyl or ethyl, provided that either of them may be hydroxy and n is 0, 1 or 2, provided that all the carboxyl groups except at least one may be in the form of an ester. The reaction temperature is usually in the range of 50-200 deg.C through it depends on the kind of a starting material, a degree of vacuumness, the desired degree of polymerization, and a polymerization time. The obtained polymer can find utility in absorbable sutures, materials for cementing bones, artificial blood vessels and slow-releasing carriers for fixing medicines, food additives or agricultural chemicals.
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