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Abstract：
Isotactic poly (1-butene) (iPB) is an interesting semi-crystalline thermoplastic material characterized by notable physical and mechanical attributes encompassing superior creep and stress resistance, elevated toughness, stiffness, and thermal endurance. These distinctive features position iPB as a viable candidate for specific applications; however, its widespread utilization is hindered by certain inherent limitations. Indeed, iPB manifests an intricate polymorphic behavior, and the gradual and spontaneous transition of the kinetically favored form II to the thermodynamically favored form I during aging introduces alterations to the material\'s properties. Despite its potential, the attainment of iPB with an exceedingly high molecular mass remains elusive, particularly when employing homogeneous catalysts renowned for their efficacy in propene polymerization. In this study we analyze the mechanistic aspects governing 1-butene polymerization by using DFT calculations modelling the regioselectivity of 1-butene insertions and the termination reactions occurring after primary (1,2) and secondary (2,1) insertions. Finally, the isomerization pathways leading to the formation of 4,1 units in iPB samples synthesized by homogenous catalysts is also discussed. All these aspects, furnish a mechanistic picture of the main drawbacks of an \"old\" but still interesting material.
摘要：
同立构聚（1-丁烯）（iPB）是一种有趣的半结晶热塑性材料，其特征在于具有出色的抗蠕变性和抗应力性，高韧性，刚度,和耐热性。这些独特的功能将iPB定位为特定应用的可行候选；然而，它的广泛使用受到某些固有局限性的阻碍。的确,iPB表现出复杂的多态行为，在老化过程中，动力学上有利的II型逐渐自发地转变为热力学上有利的I型，从而改变了材料的性能。尽管有潜力,获得具有极高分子量的iPB仍然难以捉摸，特别是当使用以其在丙烯聚合中的功效而闻名的均相催化剂时。在这项研究中，我们通过使用DFT计算对1-丁烯插入的区域选择性以及在主要（1,2）和次要（2,1）插入之后发生的终止反应进行建模，分析了控制1-丁烯聚合的机理方面。最后,还讨论了通过均相催化剂合成的iPB样品中导致4,1单元形成的异构化途径。所有这些方面,提供“旧”但仍然有趣的材料的主要缺点的机械图片。
