Thermal Properties and Crystallization Behavior of Highly Deproteinized Natural Rubber
Thermal Properties and Crystallization Behavior of Highly Deproteinized Natural Rubber
复制标题
高脱蛋白天然橡胶的热性能和结晶行为
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
Yasuyuki Tanaka
中科院分区：
文献类型：
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作者：
S. Kawahara;Takashi Kakubo;Michio Suzuki;Yasuyuki Tanaka
摘要采用蛋白水解酶和表面活性剂对天然橡胶进行脱蛋白处理，使橡胶中氮含量降至0.02%以下。脱蛋白橡胶通过丙酮萃取，然后与甲醇钠进行酯交换来进一步纯化。通过脱蛋白和酯交换反应，橡胶的密度降低，热膨胀系数增加。脱蛋白和酯交换后，玻璃化转变温度Tg略有降低。这些被解释为与橡胶的凝胶含量的减少有关。这些处理的平衡熔融温度，Tm 0，几乎是不变的。在-30 ° C和-10 °C之间的低温结晶受到以混合物形式存在的游离脂肪酸和与橡胶链连接的脂肪酸基团的显著影响。结晶行为与Tg和Tm 0值无关。
Abstract Natural rubber was deproteinized with a proteolytic enzyme and surfactant to reduce nitrogen content less than 0.02%. The deproteinized rubber was further purified by acetone-extraction followed by transesterification with sodium methoxide. The density of rubber decreased and the thermal expansion coefficient increased by deproteinization and transesterification. The glass transition temperature, Tg, was slightly reduced after deproteinization and transesterification. These were explained in relation to the decrease in gel content of the rubber. The equilibrium melting temperature, Tm0, was practically unchanged by these treatments. The low-temperature crystallization between −30 and −10 °C was significantly influenced by free fatty acids present as a mixture and fatty acid groups linked to the rubber chain. The crystallization behavior was independent of Tg and Tm0 values.