In situ synthesis of novel trans-1, 4-polyisoprene/isotactic polybutene reactor blends with multi-component structure

Abstract

In this paper, a series of novel trans-1, 4-polyisoprene/isotactic polybutene (TPI/iPB) in-reactor blends were synthesized by isoprene and butene sequential two-stage polymerization technology with spherical TiCl₄/MgCl₂ type Ziegler-Natta catalyst. The components, structures, and properties of the as-obtained TPI/iPB reactor blends were characterized by gel permeation chromatography, Fourier transform Infrared spectroscopy, and differential scanning calorimetry. The active trans-1, 4-polyisoprene (TPI) particles obtained in the initial isoprene polymerization by the Z-N catalyst can be acted as microreactors to initiate butene polymerization subsequently. The TPI/iPB reactor blends with varied components were in situ synthesized within the reactor. The preparative-temperature rising elution fractionation (p-TREF) technique was used to fractionate the TPI/iPB reactor blends based on the elution temperature ranged from −40°C to 90°C. The weight distribution and microstructure of each fraction were investigated. The reactor blends are composed of crystallizable high trans-1, 4-uint polyisoprene obtained from the first-stage isoprene polymerization, high isotactic polybutene obtained from the second-stage butene polymerization and TPI-b-iPB block copolymer with different sequence structure obtained from the initial time of the second stage. This work is expected to propose the possible polymerizations of a-olefins and conjugated dienes by using heterogeneous Ziegler-Natta catalyst and provide a kind of novel rubber/plastic reactor blend materials.