Molecular alignment in polymethyl methacrylate and polystyrene

Chain alignment has been induced in commercial atactic polymethyl methacrylate and atactic polystyrene by deformation just below the glass transition temperature. The resultant fiber-type X-ray diffraction patterns when azimuthally averaged are not distinguishable from the concentric diffuse halos typical of the “as-received” polymers. The conclusion is drawn that both the polymers examined contain domains within which neighboring chains are aligned parallel. The experiment also indicates that the extra structural information which can be extracted from the fiber-type diffraction pattern of the deformed polymers is also relevant to the unoriented state.