聚丁烯-1树脂的分级及其链结构与晶型转变的关系

Polybutene-1 (PB-1) resin has many excellent properties, and isotactic polybutene-1 is called “plastic gold”，which is widely used in hot water pipes, peeling films and others. PB-1 resin is a semi-crystalline polymer with polymorph (five crystalline forms: I, II, III, I′ and II′). Different crystal forms exhibit different properties. The most important crystals are forms I and II. Although PB-1 resin has been widely investigated from the external factors (crystallization temperature, nucleating agent, etc.), the research on the internal factor (chain microstructure) is less reported in literatures. The relationship between chain microstructure and polymorphic transformation has not yet been established. Therefore, it is firstly chosen a series of typical PB-1 resins which are produced by domestic and international companies. Then three aspects (chain length and distribution, copolymer composition and sequence distribution, isotacticity and distribution) how to influence crystallization kinetics and crystal phase transformation are investigated. Two key issues should be solved, (1) Design and construct a separating equipment in the low temperature, establish the effective fractionation method and obtain the fractions with narrow composition distribution and narrow molecular weight distribution, respectively; (2) Research the crystallization kinetics and crystal phase transformation of PB-1, find out their inherent laws. At last, it hopes to provide some suggestions on how to control morphology through optimizing chain structures.

聚丁烯-1（PB-1）性能优良，全同PB-1被誉为“塑料黄金”，国外广泛用作热水管和易撕膜等材料。作为一种多晶型半结晶性热塑性树脂（晶型I、II、III、I′和II′，共5种），其性能随着晶型的不同有很大差异，尤其是从亚稳态晶型II到稳态晶型I的转变备受关注。虽然近年来人们对树脂的外部因素（结晶温度、成核剂等）进行了广泛研究，但是对内部因素（链结构及其分布等）的研究还欠深入，尤其它与晶型转变的关联还未建立。本项目拟选取典型的国内外PB-1树脂，试图从链长及其分布、共聚组成及其序列分布、等规度及其分布三个方面，研究其对结晶动力学和晶型转变的影响。需要解决的关键问题包括：（1）设计与搭建低温分级装置并建立PB-1的有效制备型分级方法，得到结构组成和分子链长均较单一的级份；（2）跟踪其结晶动力学和晶型转变过程，揭示影响PB-1晶型转变的内在规律。本研究旨在对PB-1链结构的调控提供指导性建议。

聚丁烯-1（PB-1）性能优良，全同聚丁烯被誉为“塑料黄金”，国外广泛用作热水管和易撕膜等材料。作为一种多晶型半结晶性热塑性树脂（晶型I，II，III，I′，II′，共5种），其性能随着晶型的不同有很大差异，尤其是从亚稳态晶型II到稳态晶型I的转变备受关注。虽然近年来人们对树脂的外部因素（结晶温度、成核剂等）进行了广泛研究，但对内部因素（链结构及其分布）的研究还欠深入，尤其它与晶型转变的关联还未建立。因此，本项目根据聚丁烯-1（PB-1）的结晶特点，首先设计与搭建了低温分级装置（组建的装置申请与获得了国内专利授权1项），然后建立PB-1的有效制备型结构分级和分子量分级的分级方法，得到结构组成或分子链长均较单一的级份。尤其是溶剂梯度方法获得窄分子量分布的级份随着良溶剂含量增加，分子量逐渐从3.19×104g/mol增加到1.21×106g/mol，大多数PDI小于1.4，几乎可以媲美标准品。最后利用DSC和WAXD两种方法跟踪了不同分子量级份的结晶动力学和晶型转变过程，揭示了分子量对于亚稳态晶型II到稳态晶型I的转变具有双重作用，暨前期分子量有利于转变，后期反而抑制转变，这为实际生产与应用过程中如何通过链结构的调控来调控提供了重要理论依据。项目实施期间，已经发表论文3篇，此外准备投稿中论文1篇；申请国内专利专利3项，其中已经获得授权专利2项；培养相关人才2名。