X-RAY-SCATTERING FROM AMORPHOUS ACRYLATE AND METHACRYLATE POLYMERS - EVIDENCE OF LOCAL ORDER

X-ray scattering patterns from amorphous polymers frequently contain halos corresponding to distances significantly greater than that of van der Waals packing of carbon atoms. Regularities in the positions of such halos as a function of pendant group size have been reported, primarly for the 'crystallizable' comb polymers. This work concerns n-alkyl acrylate, n-alkyl methacrylate, and cycloalkyl methacrylate polymers with small alkyl groups: regularities in halo position with alkyl group size are seen, but the behavior with size is quantitatively different from that of the comb polymers. A case is made for the existence of a moderate amount of intersegmental order as the normal condition in the condensed amorphous state. The behavior of poly(methyl methacrylate) is anomalous and studies on it may not be used to generalize about the structure of the amorphous state.