Recycleable Elastomers: Properties of Stereoblock Polypropylene

小行星9528636 本研究探讨了弹性聚丙烯合成的创新性新策略。 本研究的目的是探讨丙烯均聚物为基础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具有环保吸引力的替代品，但对其性能知之甚少。 具体目标是：（i）建立分子结构、固态组织以及物理和机械性能之间的关系，（ii）制备一系列聚合物微观结构具有系统变化的弹性聚丙烯，以及（iii）研究弹性聚丙烯微观结构的变化如何影响固态结构和组织。 实验方法包括弹性聚丙烯的表征，以探测这些材料的结构在一定范围的长度尺度，从原子长度尺度（微观结构）的长度尺度适合表征全同立构螺旋长度，微晶尺寸和大规模的形态特征。 一组补充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，但又具有聚烯烃热塑性塑料的生产和加工优势。 这种新材料的开发应该能够替代对环境不太有吸引力的硫化橡胶。 弹性聚丙烯的环境效益来自于生产、加工和可回收性方面的高效率。 加热时流动和冷却时固化的能力允许制造商使用熔融挤出机、吹塑机和其他节能热塑性加工设备来生产橡胶类材料。 可以避免昂贵、浪费和耗能的配混和分散步骤，并且可以重新使用来自模制品的废料。 这些材料可以以最少的浪费制造，以提供具有弹性体特性但具有聚烯烃的回收特性的材料。 弹性体聚丙烯应容易地结合到普通聚丙烯再循环流中。 该计划的一个重要特点是在一个基本的和技术上重要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. ***