| 초록 |
Polypropylene reactor alloys are in situ blends synthesized by a multistage polymerization process using Mg/Ti Ziegler-Natta catalysts. In the first stage (normally bulk polymerization), isotactic polypropylene (iPP) particles are produced, and in the second stage (normally gas phase polymerization), a rubbery ethylene-propylene copolymer phase (EPR) is produced within the the performed iPP matrix. The content, composition, sequence length distribution and the location in the iPP matrix of EPR are factors affecting the performances of resulting alloys. It is believed that the architecture, and more importantly, the copolymerization ability of the catalyst are most important aspects to the microstructure of the alloy both chemically and physically. In this presentation, polypropylene reactor alloys have been synthesized by using Mg/Ti Ziegler-Natta catalyst with a newly designed internal electron donor to elevate copolymerization ability. The alloys have been made by two stage polymerizations, i.e., bulk polymerization for producing iPP particles, and then gas phase polymerization for producing EP copolymers which would locate in the cavity of iPP sub-particles as designed. The composition, microstructure, morphology, molecular weight and molecular weight distribution of the multiple component alloys have investigated. |
