ANALYSIS OF THE MODES OF PACKING OF THE ALPHA-FORM AND BETA-FORM OF SYNDIOTACTIC POLYSTYRENE

Packing energy calculations have been performed on the alpha and beta forms of syndiotactic polystyrene by using three different sets of pot ential functions. In the case of the a form the modes of packing of th e chains in the R3, P3, R3BAR, and P3BAR space groups have been consid ered. In the case of the beta form the P2(1)2(1)2, and Cmcm space grou ps have been considered. The results indicate that the energy of the b eta form is lower than that of the alpha form for all the space groups considered, while the energies corresponding to the space groups of t he alpha form are very similar. A statistical positioning of the chain s can be realized at a low energy cost for both crystalline forms.