环碳酸酯型聚氨酯的玻璃化温度分子模拟

Molecular simulation of glass transition temperature of non-isocyanate polyurethane

非异氰酸酯环碳酸酯型路线合成聚氨酯不同于传统异氰酸酯合成聚氨酯,为研究非异氰酸酯合成聚氨酯的分子结构的反应合成机理,提出一种分子模拟法预测线型非异氰酸酯聚氨酯的玻璃化温度.首先通过软件建立非异氰酸酯聚氨酯的分子结构模型,基于Monte Carlo方法建立典型的构象结构,再通过分子动力学模拟得到不同温度条件下体积,最后通过体积-温度曲线的转折点确定玻璃化温度.结果表明:两种线型结构的非异氰酸酯聚氨酯的模拟值与实验值吻合较好,两种刚性结构的非异氰酸酯聚氨酯的模拟值与实验值有较大偏差;分子模拟方法可以应用于聚合物结构与性质的研究中.

A method was put forward to predict the glass transition temperature of non-isocyanate polyurethane.Firstly,non-isocyanate polyurethane molecular structure model was constructed with Materials Studio 4.2 software based on DREIDING molecular field and typical conformation structures were set up by Monte Carlo method.Then the molecular volumes at different temperatures were determined through molecular dynamics simulation and the glass transition temperatures were calculated as turning point of the volume-temperature figures.The results show that simulation values of the glass transition temperatures fit in well with the experimental values for non-isocyanate polyurethane composed of flexible chain structure; while there is deviation between simulation values of the glass transition temperatures and the experimental values for non-isocyanate polyurethane composed of rigid chain structure; the calculated glass transition temperatures coincide with the experimental results,which indicates that the molecular simulation method can be used to study the structures and properties of polymers.