Polystyrene: Syndiotactic

Abstract

Polystyrene, athermoplastic polymer, has drawn considerable at tention due to its diverse applications in packaging,electronics, etc. It was discovered by Eduard Simonin 1839, but there alcommercialization has started in the1930s.It is possible toobtain polystyrene with different tacticity by changing the polymerization conditions.Tacticity (isotactic, syndiotactic and atactic)is defined by the arrangement of phenylrings with respect to the polymer chain back bone.The first discovered polystyrene was the atactic one,where the phenylrings are randomly distributed along the polymer chain. In the isotactic form,the phenylrings are arranged on the same side of the polymerchain, where as in the syndiotactic form they are alternatively arranged. Both isotactic and syndiotactic polystyrene (sPS) are stereo regular polymers with semicrystalline nature.On the other hand,a tactic polystyrene, which is not astereo regular polymer,is amorphous in nature.Giulio Natta made the first report on isotactic polystyrene in 1955,which is having a glass transition temperature of B100 1C and high melting point of B240 1C. But commercially the polymer was not feasible due to its poor crystallization rate. After a few decades,in1985,Is hihara et al. reported the preparation of sPS,which shows a glass transition temperature of B100 1C, high melting point(B270 1C), high crystallization rate,excellent chemical resistance, etc.These beneficial properties led to animmediate commercialization of the polymer by Idemitsu Kosan Company in Japan, and by the Dow Chemical Company in the United States