Abstract
In this study, in-situ trans-selective polymerization of isoprene was carried out using titanium-based Ziegler-Natta catalysts. The catalysts were prepared by high-energy ball milling. Individually Large-inner-diameter carbon nanotubes (CNTL), and hydroxylated carbon nanotubes (CNTOH), along with magnesium chloride (MgCl2) were used as the carriers for the catalysts. The optimum ball-milling time for preparing the CNT/MgCl2/TiCl4 Ziegler-Natta catalysts was 4 h. The CNTOH/MgCl2/TiCl4 catalyst showed a higher efficiency than that of the CNTL/MgCl2/TiCl4 catalyst, based on the rate of polymerization. The effects of the CNT-filler type on the isoprene polymerization behaviors and polymer properties were investigated. The morphologies of the trans-1,4-polyisoprene (TPI)/CNT and TPI/CNTOH nanocomposites exhibited a tube-like shape, and the CNTL and CNTOH fillers were well dis-persed in the TPI matrix. In addition, the thermal stability of TPI significantly increased upon the introduction of a small amount of both CNTL/CNTOH fillers (0.15 wt%), owing to the satisfactory dispersion of the CNTL/CNTOH in the TPI ma-trix.
Keywords: Ziegler-Natta catalyst;trans-polyisoprene;carbon nanotubes;ball-milling