扩链改性聚对苯二甲酸丁二酯的力学性能研究

利用熔体流动速率测定仪、动态粘弹仪和电子拉力试验机等手段,考察了扩链改性对聚对苯二甲 酸丁二酯(PBT)的拉伸性能、熔体流动指数和动态力学性能的影响。实验结果表明:PBT经扩链改性后,随 其特性粘数增加,相对分子质量提高,熔体流动指数大幅度下降,玻璃化转变温度有所增加;改性后PBT的 储能模量和耗能模量提高2.6-4.6倍,拉伸强度提高50％以上,断裂伸长率提高1倍以上,表明扩链改性起 到了增粘增韧作用。

Study on mechanical properties of polybutylene terephthalate by chain-extension modification

The effects of chain-extension modification on the tensile property, melt flow index and dynamic mechanical properties of polybutylene terephthalate were investigated with melt indexer, dynamic viscoelastometer and electronic tension meter. The experimental results showed that the molecular weight of PBT was increased, but the melt flow index was decreased considerably and the glass transition temperature was raised in some degree while increasing the intrinsic viscosity during chain extension modification. The modified PBT had a storage modulus and loss modulus, tensile strength and elongation at break increased 2.6-4.6 times, at least 50% and 1 time, respectively, which indicated that the chain-extension modification can improve both the strength and toughness.