New materials based on polybutene-1: Effect of low amount of propylene on crystallization, polymorphism and properties

等规聚丁烯-1属于一类可结晶聚烯烃，具有特殊的应用相关性能，如高热变形温度，低蠕变或高应力抗裂性。聚丁烯-1的主要缺点是从不稳定的中间相转变为亚稳晶体，在加工后或熔体冷却时凝固后立即以固态发生，持续时间长达数天。这种相变与体积收缩和材料性能的明显变化有关。通过在丁烯-1大分子中随机加入少量的共基，可以有效地改变中间相-晶体相变的动力学。这包括在聚丁烯-1中插入丙烯共基，其结晶行为和特定的中间相/晶体多态性尚未研究。因此，本项目的目的是建立随机丁烯-1/丙烯共聚物中丙烯共基的浓度与中间相-晶体相变动力学之间的关系，包括分析相变过程中力学性能随时间的依赖性。要进行的研究将包括评价凝固的主要条件对多态性的影响，重点是在实际的聚丁烯-1加工方案中明显的条件。该项目将有助于基于聚丁烯-1的新型聚合物材料的开发，并将进一步了解这种重要聚合物在实际加工中相关条件下的结构形成。

Isotactic polybutene-1 belongs to the group of crystallizable polyolefins with special application-relevant properties like high heat distortion temperature, low creep, or high stress cracking resistance. A major disadvantage of polybutene-1 is a phase transition from an unstable mesophase into a metastable crystal which occurs in the solid state immediately after processing or solidification of the melt on cooling, covering a period up to several days. This phase transition is connected with volume shrinkage and distinct change of materials properties. The kinetics of the mesophase- crystal phase transition can advantageous be changed by random incorporation of low amount of co-units into the butene-1 macromolecule. This includes the insertion of propylene co-units into polybutene-1 with the crystallization behavior and the particular mesophase/crystal polymorphism not investigated yet. Therefore, it is the aim of this project to establish a correlation between the concentration of propylene co-units in random butene-1/propylene copolymers and the kinetics of the mesophase-crystal phase transition including the analysis of dependence of mechanical properties as a function of time during the phase transition. The research to be performed will include the evaluation of the effect of the primary condition of the solidification on the polymorphism focusing on conditions as are evident in real polybutene-1 processing schemes. The project will contribute to the development of new polymeric materials based on polybutene-1 and will provide further knowledge about structure formation of this important polymer at conditions relevant in real processing.