THERMAL-DEGRADATION OF MICROBIAL COPOLYESTERS - POLY(3-HYDROXYBUTYRATE-CO-3-HYDROXYVALERATE) AND POLY(3-HYDROXYBUTYRATE-CO-4-HYDROXYBUTYRATE)
THERMAL-DEGRADATION OF MICROBIAL COPOLYESTERS - POLY(3-HYDROXYBUTYRATE-CO-3-HYDROXYVALERATE) AND POLY(3-HYDROXYBUTYRATE-CO-4-HYDROXYBUTYRATE)
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DOI：
10.1021/ma00209a009
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发表时间：
1990-04-02
期刊：
影响因子：
5.5
通讯作者：
DOI, Y
中科院分区：
文献类型：
--
作者：
KUNIOKA, M;DOI, Y
在100-200 ℃温度范围内，通过监测熔体样品分子量随时间的变化，研究了微生物共聚酯的热降解过程。在本研究中使用两种类型的共聚酯，聚（3-羟基丁酸酯-共-3-羟基戊酸酯）（P（3 HB-co-3 HV）; 3 HV = 0-71摩尔%）和聚（3-羟基丁酸酯-共-4-羟基丁酸酯）（P（3 HB-co-4 HB）; 4 HB = 0-82摩尔%）。所用的所有样品在170 ℃以上都是热不稳定的，它们的分子量随时间迅速下降。热降解过程中分子量随时间的变化遵循酯基无规断链的动力学模型。无规断链速率与共聚酯的组成无关，但强烈依赖于温度。这些样品在低于160 ℃的温度下是热稳定的。已表明熔融温度低于160 ℃的微生物共聚酯适用于常规塑料加工方法。
Thermal degradation processes of microbial copolyesters were studied in the temperature range 100-200 C by monitoring the time-dependent changes in molecular weights of melt samples. Two types of copolyesters, poly (3-hydroxybutyrate-co-3-hydroxyvalerate)(P (3HB-co-3HV); 3HV= 0-71 mol%) and poly (3-hydroxybutyrate-co-4-hydroxybutyrate)(P (3HB-co-4HB); 4HB= 0-82 mol%), were used in this study. All copolyester samples used were thermally unstable at temperatures above 170 C, and their molecularweights decreased rapidly with time. The time-dependent changes in molecular weights during the thermal degradation followed the kinetic model of random chain scission at ester groups. The rates of random chain scission were independent of the compositions of the copolyesters but dependent strongly on temperature. These copolyester samples were thermally stable at temperatures below 160 C. It has been suggested that the microbial copolyesters with melting temperatures below 160 C are applicable to conventional plastics processing methods.