LAUSR

Polymers with benzene rings have the potential to act as macromolecular β-nucleating agents and rigid organic particles for isotactic polypropylene (iPP). The dispersibility in iPP matrix is a key factor for their β-nucleating efficiency and mechanically strengthening ability. In this paper, comb-like branched polystyrenes (cPSs) with different side chain lengths were introduced into iPP. The effect of entanglement upon branching on dispersibility, β-nucleating and mechanically strengthening ability of PS in iPP was investigated in detail. Compared with the linear polystyrene with the same length of backbone, the incorporation of side chains intensifies the entanglement between cPS chains, not facilitating their dispersion in iPP matrix. However, short side chains (chain length lower than the critical chain entanglement molecular weight of PS) facilitate the interdiffusion between the cPS and iPP chains and ultimately lead to favorable dispersibility and high β-nucleating efficiency, as well as prominent toughening and reinforcing effect on iPP.