Abstract:

Polypropylene/ethylene octene copolymer/polystyrene(PP/POE/PS) ternary alloys were prepared via diffusion and subsequent polymerization of styrene (St) in PP/POE alloy granules. St could diffuse into the center of the PP/POE alloy granules and PS phases mostly included in POE phases with a particle size from several tens of nanometers to several hundred nanometers. The size of PS particles was influenced by the \{amount of styrene adsorbed and the size of the POE phases. The PS particles in POE phases formed in the center of the granules were the smallest. The diffusion and polymerization process of St in PP/POE(mass ratio, 80:20) was studied. The diffusion rate and the maximum adsorption of styrene in PP/POE were larger than those in pure PP as existence of amorphous POE phase was beneficial for diffusion of monomer. The content of PS in PP/POE/PS alloys can be tailored by changing the amount of monomer. Incorporation of PS into POE domains made the POE domains bigger and then resulted in lower melting temperatures and crystalline temperatures of PP, and PS dispersed in PP/POE/PS with a high PS content acted as a nucleation agent of PP.

Key words: Polypropylene(PP), Ethylene octene copolymer(POE), Polystyrene(PS), Diffusion and polymerization