Molecular orientation behaviors with optical measurement and X-ray diffraction for strip-biaxially stretched syndiotactic polypropylene films

We have explored the coordinates of carbon chain and C-H bonds in the cryst al unit cell of syndiotactic polypropylene (st-PP) proposed by Corradini et al. The polarizabilities of crystal unit cells and non-crystalline units f or st-PP were calculated with using the polarizabilities of C-C and C-H bon ds proposed by Bunn er al., Vulk, and Denbigh. The refractive indices of pr incipal axes for crystal unit cells and non-crystalline units of st-PP were calculated by using Lorentz-Lorenz equation. The intrinsic birefringences of crystalline and non-crystalline phases were estimated from the refractiv e indices of two phases. The orientation factors introduced from intrinsic birefringence were compared with the orientation factor for wide angle X-ra y diffraction. The intrinsic birefringences in crystalline and non-crystall ine phases were estimated as 19.6 X 10(-3) and 17.4 x 10(-3) using the aver age values of bond polarizabilities proposed by Bunn et al. and Vulk.