Syndiotactic polystyrene (sPS) is a well-known semicrystalline polymer that forms a thermoreversible gel with various solvents. The polymerization of styrene to sPS is a precipitation polymerization because the polymer is insoluble in styrene or any other solvent at its typical reaction temperature below 100oC [1]. Recent morphological studies of solvent induced crystallization and gelation of sPS show the formation of fibrillar networks [2-5]. In this study, we have investigated the nascent morphology of sPS over homogeneous and heterogeneous metallocene catalysts. The sPS synthesized also shows fibrillar structure in a liquid slurry polymerization condition (Figures). The sPS fibrils are of about 50 nm in diameter and their length is far greater than the diameter. The observed SEM micrographs also indicate that the sPS is extremely porous because of its fibrillar morphology. This new experimental observations and the proposed polymer growth mechanism will be presented at the meeting.

References

[1] Lee, H. W.; Chung, J. S.; Choi, K. Y. Physical transitions and nascent morphology of syndiotactic polystyrene in slurry polymerization with embedded Cp*Ti(OMe)3/methyl aluminoxane catalyst, Polymer, 2005, 46, 5032-9.

[2] Malik, S.; Rochas, C.; Deme, B.; Guenet, J. M. Thermoreversible gelation of syndiotactic polystyrene in naphthalene, Macromolecular Symposia, 2005, 222, 73-9.

[3] Itagaki, H.; Mochizuki, J. Size and distribution of free volume in thermoreversible gels of syndiotactic polystyrene, Macromolecules, 2005, 38, 9625-30.

[4] Daniel, C.; Avallone, A.; Guerra, G. Syndiotactic polystyrene physical gels: Guest influence on structural order in molecular complex domains and gel transparency, Macromolecules, 2006, 39, 7578-82.

[5] Guenet, J. M. Microfibrillar networks: Polymer thermoreversible gels vs organogels, Macromolecular Symposia, 2006, 241, 45-50.