【作者】 卢颖；

【导师】 彭宗林；

【作者基本信息】 上海交通大学 ， 材料学， 2007， 硕士

【摘要】 丙乙橡胶(Vistamaxx或VM)是一种新型的丙烯乙烯共聚物,是ExxonMobil化学公司使用特殊的离散茂金属催化剂及溶液聚合法制得的可以严格控制性能的聚合物。与乙烯辛烯共聚物(POE)及乙丙橡胶(EPR)不同,该聚合物是一种乙烯含量低的热塑性弹性体。目前对该种新型的已工业化生产的材料进行系统研究的报道较为少见。本文综合运用红外光谱(FTIR),广角X射线衍射(WAXD),示差扫描量热(DSC)等多种手段系统地表征了VM的结构与性能,并且对VM增韧聚丙烯PP进行了研究,还与POE增韧了PP进行了比较。探讨了聚合物共混结晶及弹性体增韧机理。首先,本文对VM的结构与性能进行了较为全面的表征。结果表明:FTIR可以定量的检测VM中乙烯的质量含量,VM中的乙烯质量含量在20%以下;VM的Tg在-24℃以下;VM的结晶度较低,其结晶具有聚丙烯α-型晶体结构特点,分子链中较短的链段可以在室温以下结晶,表现出二次结晶现象;VM是一种透明性高、力学性能优异的热塑性弹性体材料。在VM中加入填料后,VM的流动性变差;加入碳酸钙使VM的拉伸强度下降,加入炭黑或白炭黑都提高了VM的拉伸强度。其次,本文用VM增韧PP,考察了PP/VM共混物的力学性能、微观形态结构以及结晶性能,并与PP/POE体系进行了对比。结果表明,用VM或POE与PP共混,用VM或POE与PP共混,常温下VM增韧效果优于POE,PP/VM体系拉伸性能优于PP/POE体系,共混物的拉伸强度显著降低,伸长率明显增加,在VM和POE用量相当的情况下,VM保持了比POE更好的拉伸性能。VM是PP优异的增韧剂。DSC及WAXD综合分析结果表明,VM具有与PP相同的晶型,VM的加入使PP的晶粒尺寸变小;随着VM或POE在共混中的比例增加,材料断裂面由脆性断裂逐渐变为韧性断裂,弹性体的分散相尺寸由小变大;弹性体在PP内的粒径分布服从对数正态分布,VM在PP中表现出比POE更好的分散性。更多还原

【Abstract】 Vistamaxx (VM) is a novel metallocene catalyst thermoplastic elastomer synthesized by propylene and ethylene comonomer, with a propylene content over 80wt%. The composition and crystallization of VM are intermediate between amorphous EPR and semicrystalline isotactic polypropylene. VM is a tough polyolefin with soft and ealstic properties. Because VM was industrial manufactured several years ago, detail investigation of its structure and and propertities, as well as its application were rarely reported.FTIR, WAXD, DSC and mechanical tests were applied to characterize structure and propertities of VM. The mechanical, micromorphology and crystallization behavior of PP/VM blends was analyzed comparing with PP/POE blends. The crystallization and toughening mechanism of PP/elastomer blends were also studied.At first, structure and propertities of VM were investigated in detail. The results show that: FTIR spectrum detect ethylene content in VM quantitively, the ethylene mass content in VM is fewer than 20%. The Tg of VM is below -24℃. VM has a lower crystallinity with a crystal structure similar toαpolymorph of PP. The short sequences of propylene will crystallize at room temperature witch shows a secondary crystallization. VM is a thermoplastic elastomer with high transparency and good mechanical properties. The flow propertities of VM become worse after the addition of fillers. The tensile strength of VM decreases after addition of CaCO3, while increases with the addition of Carbon Black or silica.Next, VM was used as toughening agent for PP. The mechanical properties, micromorphology and crystallization behavior of PP/VM blends ware analyzed comparing with PP/POE blends. The results show that the tensile strength decreases and the elongation at break increases greatly for both PP/VM and PP/POE blends, VM has a better strength strength than POE at the same content at PP blends, VM has the same crystal form as PP, and the blends keep the PP crystal structure, the addition of VM makes the PP crystal particles smaller; the distribution of elastomer particles is according to the log-normal distribution; with the increase of VM or POE content the size of the dispersed elastomer became larger, the fracture surface transfers from brittle to tough.更多还原