Structure and Properties of Isotactic Polypropylene/Polybutene-1 In-reactor Alloys

摘要

The composition and structure of polymer largely determine the properties of its final products.As a novel polymer material,the composition,structure,and properties of the isotactic polypropylene/polybutene-1 in-reactor alloy(PPIPB alloy)synthesized by sequential two-stage polymerization with Ziegler-Natta catalyst were correlated for the first time in this work.The iPP/PB alloy was fractionated by temperature rising elution fractionation(TREF)in a broad temperature ranged from-30℃ to 140℃,and the chain microstructures and sequence distributions of isolated fractions were analyzed by DSC,GPC,13C-NMR,and FTIR.The iPP/IPB alloy was composed of five components,namely high isotactic PB(PB,85.8 wt96),medium isotactic PB(mPB,5.1 wt%),polyl(butene-1)-block propylene copolymers(PB-6 PP,4.1 wt%6)which contained PB and PP blocks with dfferent lengths according to the isolation temperature,isotactic PP(iPP,2.7 wt%6),and atactic PB(aPB,2.3 wt96).Compared to other commercial pipe materials,the P/iPB alloy presented outstanding thermal creep resistance and gas permeability resistance,high strength and low deformation at high temperature,and appropriate flexural strength.The roles of PP and PB-b-PP components in the alloy were interpreted.This work is expected to elucidate the potential application of PPIPB aloy as pipe materials and provide solutions for the design and synthesis of high performance pipe materials.