X-ray-diffraction, Conformational-analysis and Stereoregularity of A Crystalline Poly(3-methyl-1,3-pentadiene)

X-ray diffraction patterns of unoriented samples of a recently synthesized highly crystalline poly(3-methyl-1,3-pentadiene) show the presence of two polymorphic forms. For one of these forms a fibre pattern is presented and the identity period of the chain is determined. To obtain information on the type of tacticity of the polymer, geometric and energy analyses and Fourier transform calculations on isolated chain models have been performed. It is suggested that the experimentally observed chain axis repeat value is more easily accounted for by a 1,4-cis-syndiotactic structure