Preparation and characterization of hydrogenated syndiotactic polystyrene

Syndiotactic polystyrenes (sPS) with different molecular weights were hydro genated over the Ni/SiO2 and Pd-BaSO4 catalysts. Although the Ni catalyst y ielded a completely hydrogenated sPS with a lower molecular weight, the hyd rogenation of sPS with a high molecular weight was incomplete. On the other hand, the Pd catalyst was capable of hydrogenating sPS with a high molecul ar weight. However, the hydrogenated sPS (HsPS) was found to contained a sm all quantity of isolated styrene units. From a detailed analysis of the HsP S by differential scanning calorimetry (d.s.c.) and X-ray, it was revealed that this HsPS has a potential as a crystalline material with an excellent heat-resistance. (C) 1998 Elsevier Science Ltd. All rights reserved.