Direct Preparation of Transparent Isotactic Polypropylene with Supported Ziegler–Natta Catalysts Containing Novel Eco-friendly Internal Electron Donors

This study reported novel eco-friendly Ziegler–Natta catalysts containing bioderived maleic rosinate tri-n-butyl and maleic rosinate tri-n-octyl as internal electron donors for propylene polymerization to obtain transparent isotactic polypropylene. Surprisingly, on the one hand, rosin acid esters can function as internal electron donors to improve the stereoselectivity of the catalyst where the isotacticity of polypropylene obtained reaches 97.85%. On the other hand, they act as nucleating agents to greatly improve the transparency of polypropylene, with a light transmittance of 93.8% and haze of 4.4%, due to internal electron donors evenly dispersed on the surface of the catalyst particles. Furthermore, the catalysts were used to carry out propylene polymerization and showed the highest catalytic activity value of 31.9 kgPP·gCat–1·h–1.