Four natural rubber-based phase changing materials (PCMs) were synthesized and evaluated with the goal of achieving controlled stiffness modulation at elevated temperatures (∼100-120 °C). The phase changing was achieved through either the glass transition or melt transition of one of four phase changing fillers: polystyrene, poly(methyl methacrylate), low density polyethylene, and indium tin alloy. The PCM stiffness was analyzed using dynamic mechanical analysis and the results showed that all four PCMs exhibited two thermal transitions: a low temperature transition at −58 °C due to the glass transition of the natural rubber matrix and a high temperature transition at ∼100-120 °C due to the thermal transitions in the four filler materials. The degree of stiffness change of all PCMs at 100-120 °C was found to be strongly influenced by the type of the phase changing filler as well as the type of thermal transition (glass transition versus melt transition). The compatibilities of the phase changing materials were analyzed using the Flory-Huggins interaction parameter and it was shown that natural rubber and low density polyethylene had the best compatibility. All systems exhibited effective stiffness modulation with the change in temperature, enabling them to be used for applications requiring variable stiffness control.

合成并评估了四种天然橡胶基相变材料（PCM），目的是在升高的温度（〜100-120°C）下实现可控的刚度调节。通过以下四种相变填料之一的玻璃化转变或熔融转变来实现相变：聚苯乙烯，聚（甲基丙烯酸甲酯），低密度聚乙烯和铟锡合金。使用动态力学分析法分析了PCM的刚度，结果表明所有四个PCM均表现出两个热转变：由于天然橡胶基质的玻璃化转变，在-58°C发生了低温转变，而在〜100-C发生了高温转变由于四种填充材料的热转变，温度为120°C。发现所有相变材料在100-120°C时的刚度变化程度受相变填料类型以及热转变类型（玻璃化转变与熔融转变）的强烈影响。利用Flory-Huggins相互作用参数分析了相变材料的相容性，结果表明天然橡胶和低密度聚乙烯具有最佳的相容性。所有系统都随温度变化显示出有效的刚度调制，使其能够用于需要可变刚度控制的应用。利用Flory-Huggins相互作用参数分析了相变材料的相容性，结果表明天然橡胶和低密度聚乙烯具有最佳的相容性。所有系统都随温度变化显示出有效的刚度调制，使其可用于需要可变刚度控制的应用。利用Flory-Huggins相互作用参数分析了相变材料的相容性，结果表明天然橡胶和低密度聚乙烯具有最佳的相容性。所有系统都随温度变化显示出有效的刚度调制，使其能够用于需要可变刚度控制的应用。