Degradable Polymers Prepared from Alkyl Sorbates and Oxygen under Atmospheric Conditions and Precise Evaluation of Their Thermal Properties
Degradable Polymers Prepared from Alkyl Sorbates and Oxygen under Atmospheric Conditions and Precise Evaluation of Their Thermal Properties
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常压条件下山梨酸烷基酯和氧气制备的可降解聚合物及其热性能的精确评价
DOI：
10.1295/polymj.35.640
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发表时间：
2003
期刊：
影响因子：
2.8
通讯作者：
A. Matsumoto
中科院分区：
文献类型：
--
作者：
H. Hatakenaka;Yôji Takahashi;A. Matsumoto
我们在此报道二烯单体与氧的交替共聚物作为一类具有巨大潜力的新型可降解聚合物。在偶氮引发剂的存在下，在大气条件下有效地制备山梨酸烷基酯与氧的交替共聚物而不分解。所产生的交替共聚物在加热时以类似的机制放热分解，而与山梨酸酯的酯烷基的种类无关；即甲酯、乙酯、十八烷基酯和三氟乙酯。初始和最大分解温度（Tinit 和 Tmax）通过氮气流中的差热分析 (DTA) 和热重分析 (TG) 确定：Tinit = 106–112 °C (DTA)，Tmax = 147–152 °C (DTA) 或 144–148 °C (TG)。对不同加热速率下获得的TG曲线进行动力学分析，以通过多种方法评估分解的活化能。由山梨酸甲酯获得的聚合过氧化物的分解速率常数以及总活化能也可以在 80-120 °C 温度范围内的等温分解过程中通过两种不同的方法精确测定； Ea = 86.7和84.7 kJ mol-1，分别基于通过TG分析监测的聚合物的重量损失和通过凝胶渗透色谱法测定的聚合物分子量的变化。已经表明，在作为聚合过氧化物的交替共聚物的热分解过程中，过氧键的热断裂和随后的连续的β-断裂产生富马醛单酯和乙醛。
We report here the alternating copolymers of diene monomers with oxygen as a new class of degradable polymer with great potential. The alternating copolymers of alkyl sorbates with oxygen are efficiently prepared without decomposition under atmospheric conditions in the presence of an azo initiator. The produced alternating copolymers exothermically decompose upon heating in a similar mechanism irrespective of the kind of the ester alkyl group of the sorbates; i.e., the methyl, ethyl, octadecyl, and trifluoroethyl esters. The initial and maximum decomposition temperatures (Tinit and Tmax) are determined by differential thermal analysis (DTA) and thermogravimetric analysis (TG) in a nitrogen stream: Tinit = 106–112 °C (DTA), Tmax = 147–152 °C (DTA) or 144–148 °C (TG). The TG curves obtained at a different heating rate are kinetically analyzed to evaluate an activation energy for decomposition by several methods. The decomposition rate constants, as well as overall activation energy, for the polymeric peroxide obtained from methyl sorbate are also precisely determined during the isothermal decomposition in a temperature range of 80–120 °C by two different methods; Ea = 86.7 and 84.7 kJ mol-1 on the basis of the weight loss of the polymer monitored by TG analysis, and the change in the molecular weight of the polymer determined by gel permeation chromatography, respectively. It has been revealed that the thermal cleavage of the peroxy linkage and the subsequent successive β-scission produce fumaraldehyde monoester and acetaldehyde during the thermal decomposition of the alternating copolymers as the polymeric peroxides.