Morphology and crystallinity of nascent sPS in bulk polymerization with homogeneous metallocene catalyst

Powdery syndiotactic polystyrene (sPS) was synthesized in a bulk process with the homogeneous metallocene catalyst system, mono(η5-pentamethylcyclopentadienyl) trichloride titanium/methylaluminoxane/triisobutyl aluminum. The morphology of the nascent polymer particles were investigated and an interesting splaying morphology was observed when the conversion ranged from 0.9% to 1.7%. The crystallinities of the as-polymerized polymer samples at different conversions were studied also. The experimental results suggested that manipulating the relative crystallizing rate to exceed the relative polymerizing rate in the initial stage of the polymerization is feasible to prepare the powder product.