In situ synthesis of polybutene-1/polypropylene spherical alloys within a reactor with an MgCl2-supported Ziegler-Natta catalyst

A series of isotactic polybutene-1/polypropylene (PB/PP) alloys with spherical morphology were prepared by MgCl2-supported Ziegler-Natta catalyst with sequential two-stage polymerization technology. The first formed PP particles were used as micro-reactors to initiate the bulk precipitation polymerization of butene-1 further. The porous PP particles as a hard framework may prevent the adhesion of PB particles during the bulk precipitation polymerization process. At the same time, the bulk precipitation polymerization process allows for maximization of the butene-1 polymerization rate and simplifies the butene-1 polymerization process considerably. Finally, spherical PB alloys with a super-high molecular weight PB component and adjustable PP component were synthesized in situ within the reactor. The structures and properties of the PB/PP alloys were characterized by gel permeation chromatography, 13C nuclear magnetic resonance, Fourier transform IR, scanning electron microscopy, differential scanning calorimetry and X-ray diffraction. The results showed that the MgCl2-supported Ziegler-Natta catalyst showed relatively high stereospecificity and efficiency for both propylene and butene-1 polymerization. The incorporation of propylene on the PB matrix affects the properties of the final products markedly. The PB/PP alloys are expected to have a broader range of applications as a new family of high performance materials. Copyright (C) 2012 Society of Chemical Industry