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Keywords:

  • impact polypropylene copolymer (IPC);
  • soft polypropylene alloy (SPP);
  • atmosphere-switching polymerization process (ASPP);
  • monomer feeding policy;
  • number of cycles;
  • mechanical properties

Significance

We report on a novel atmosphere-switching polymerization process (ASPP) that produces advanced polyolefin materials with high performance in a single polymerization reactor through unique monomer feeding policies. In the ASPP, each polymer particle is exposed to “atmosphere A” and “atmosphere B” in an alternating manner and time and again. As a result, “polymer A” and “polymer B” are formed within the polymer particle in an alternating manner and time and again too. Two types of polypropylene (PP) in-reactor alloys are prepared: impact polypropylene copolymers (IPCs) with an exceptional stiffness-toughness balance and soft polypropylene alloys (SPPs) with well-defined, high-rubber content sticking-free particles. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4468–4473, 2013