Effect of Feed Composition in Gas-phase Polymerization on Structure and Properties of In Situ Impact Polypropylene Copolymer

In this work, three in situ impact polypropylene copolymer(IPC) samples were prepared through Ziegler-Natta catalyst only changing the feed composition (ethylene to ethylene and propylene molar ratio, C2/C2+C3) in gas-phase polymerization reactor. Polymer (IPC) were characterical by solvent classification, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), successive self-nucleation and annealing (SSA), nuclear magnetic resonance(C-13-NMR) and scanning electron microscopy(SEM). The mechanical properties of IPC samples were tested. The results indicate that with similar ethylene content, the feed composition which determines the content and structure of EPR and EbP component in IPC, further impacts the rubber phase size and distribution in IPC, plays an key role in determining the impact toughness of IPC.