Recycleable Elastomers: Properties of Stereoblock Polypropylene

本研究探讨了合成弹性聚丙烯的一种创新的新策略。本研究的目的是研究基于丙烯均聚物的热塑性弹性体的结构和性能。这些材料为传统的硫化弹性体提供了一种环保的替代品，但人们对它们的性能知之甚少。具体目标是：(i)建立分子结构、固态组织和物理机械性能之间的关系，（ii）制备一系列聚合物微观结构有系统变化的弹性体聚丙烯，以及（iii）研究弹性体聚丙烯微观结构的变化如何影响固态结构和组织。实验方法包括表征弹性体聚丙烯，以探测这些材料在一系列长度尺度上的结构，从原子长度尺度（微观结构）到适合表征等规螺旋长度、晶体尺寸和大尺度形态特征的长度尺度。一组补充的实验将研究微观结构的变化如何影响这些材料的固态组织、结构和性能。热塑性弹性体聚丙烯具有硫化橡胶的性能，但生产和加工具有聚烯烃热塑性塑料的优点。这种新材料的开发应该能够取代不太环保的硫化橡胶。弹性体聚丙烯的环境效益来自于制造、加工和可回收性的高效率。加热时流动和冷却时固化的能力使制造商能够使用熔体挤出机、吹塑机和其他节能热塑性加工设备生产类似橡胶的材料。可以避免昂贵，浪费和能源密集的复合和硫化步骤，并且可以重新利用模塑制品的废料。这些材料可以用最少的废物制造，使材料具有弹性体性能，但聚烯烃的回收特性。弹性聚丙烯应很容易地纳入正常的聚丙烯回收流。该计划的一个重要特点是在一个基础和技术意义重大的领域培养研究生和本科生。＊＊＊

9528636 Waymouth This research investigates an innovative new strategy for the synthesis of elastomeric polypropylene. The objective of the proposed studies is to investigate the structure and properties of thermoplastic elastomers based upon propylene homopolymers. These materials offer an environmentally attractive alternative to conventional vulcanized elastomers, but little is known about their properties. Specific aims are: (i) to establish the relationship between molecular structure, solid-state organization, and physical and mechanical properties, (ii) to prepare a series of elastomeric polypropylenes with systematic variations in polymer microstructure, and (iii) to investigate how changes in the microstructure of elastomeric polypropylenes influence solid-state structure and organization. The experimental approach includes characterization of elastomeric polypropylene to probe the structure of these materials over a range of length scales, from the atomic length scale (microstructure) to length scales appropriate for characterizing isotactic helix lengths, crystallite dimensions and large scale morphological features. A complementary set of experiments will investigate how changes in microstructure influence the solid state organization, structure and properties of these materials. %%% Thermoplastic elastomeric polypropylene has the properties of a vulcanized rubber, but the production and processing advantages of polyolefin thermoplastics. The development of this new material should enable the substitution of less environmentally attractive vulcanized rubbers. The environmental benefit of elastomeric polypropylene derives from the high efficiency in manufacturing, processing, and recyclability. The ability to flow upon heating and solidify on cooling allows manufacturers to produce rubber- like materials using melt-extruders, blow molders and other energy-efficient thermoplastic processing equipment. Expensive, wasteful, and energy-inte nsive compounding and vulcanizing steps can be avoided and scrap from molded articles can be re-used. These materials can be manufactured with minimal waste to give materials that have elastomeric properties yet the recycling characteristics of polyolefins. Elastomeric polypropylene should be readily incorporated into normal polypropylene recycling streams. An important feature of the program is the training of graduate and undergraduate students in a fundamentally and technologically significant area. ***