New Type Of Polyolefin Elastomer Modified High-flow Properties Of Polypropylene

As a novel polefin elastomer, metallocene ethylen, a-butene and a-hexene copolymer(mEBHC) can be used as toughening material for high-fluid polypropylene(HF-PP) modification with narrow molecular distribution, low density and comprehensive performance.mEBHC/HF-PP composites were prepared through mechanical blending. The processibility, mechanical properties, thermal stability and crystallization behavior of blends were characterized by molten index tester, capillary rheometer, scanning electron microscope, thermogravimetric analysis, and differential scanning calorimeter. The results showed that blending melt performanced paeudoplastic, and the fliudity decrased with increasing mEBHC content. The effect of mEBHC on HF-PP toughening was obvious, impact strength of HF-PP at room temperature increased from 5.506 kJ/m2 to 14.190 kJ/m2 with 30wt% mEBHC, but decreased in stiffiness, SEM micrographs showed an uniform dispersion of elastomer particles on the surface of contious phase, and the sea-island structure could been observed. The thermal decompose activation energy (Eα) of mEBHC/HF-PP blends were calculated by Kissinger method and Ozawa method, respectively. The thermal degradation temperaature and Eαincreased with the addition of mEBHC. The melt and crystallization behavior of HF-PP is influenced significantly by mEBHC, both of the melt ang crystallization temperature of HF-PP decreased with increasing mEBHC content. The crystal structure of PP was disturbed by the addition of mEBHC, which resulted in decreasing crystallinity and crystal thickness, While the crystal type of HF-PP was invariant. Nonisothermal crystallizatiom kinetics showed Mo method could well descrip crystallization process of mEBHC/HF-PP blends, the crystallizatyion rate of HF-PP decreased firstly and then increased with increasing the addition of mEBHC.