A Study On Material Propertities And The Application As Toughening Agent Of Novel Propylene-Ethylene Copolymer

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.