Chirality Constraints in Crystal−Crystal Transformations: Isotactic Poly(1-butene) versus Syndiotactic Polypropylene
Chirality Constraints in Crystal−Crystal Transformations: Isotactic Poly(1-butene) versus Syndiotactic Polypropylene
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DOI：
10.1021/ma9810215
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发表时间：
1998-12
期刊：
影响因子：
5.5
通讯作者：
B. Lotz;C. Mathieu;A. Thierry;A. J. Lovinger;C. Rosa;O. R. Ballesteros;F. Auriemma
中科院分区：
文献类型：
--
作者：
B. Lotz;C. Mathieu;A. Thierry;A. J. Lovinger;C. Rosa;O. R. Ballesteros;F. Auriemma
聚合物中的固态晶体-晶体转化受到构象和空间约束的限制，当螺旋手参与转化的初始、最终或两个阶段时。的限制说明了（a）相II相I转换的全同立构聚（1-丁烯），它保留了螺旋的手性，和（B）的生成不寻常的，手性的间同立构聚丙烯的晶体相时，从一个扩展链的晶体相，而稳定的结构是完全反手性。在后一种情况下，所得螺旋相的等手性表明该转变是一个协同过程。
Solid-state crystal−crystal transformations in polymers are limited by conformational and steric constraints when helical hands are involved in the initial, final, or both stages of the transformation. The constraints are illustrated by (a) the phase II to phase I transformation in isotactic poly(1-butene), which preserves the chirality of the helices, and (b) the generation of unusual, chiral crystal phases of syndiotactic polypropylene when starting from an extended-chain crystal phase, whereas the stable structure is fully antichiral. In the latter case, the isochirality of the resulting helical phase indicates that the transformation is a cooperative process.