A neutron-scattering study of polyethylene deformed by rolling

Polyethylene mixed crystal mats have been studied after rolling at room temperature to roll ratios up to 2.5, using the LOQ instrument at the ISIS pulsed neutron source (RAL, Chilton). Radius of gyration measurements for vertical (R(v)) and horizontal (R(H)) sectors, where the vertical sector includes the roll direction, show that R(H) is virtually unchanged by rolling, whereas R(V) is increased significantly. Combined with an unchanged intensity from extrapolation to zero angle, these results indicate the absence of local melting during deformation. Intermediate angle measurements show a decrease in intensity, while the 'sheet-like' form of the scattering is retained. This is consistent with the breakup of lamellae into progressively smaller blocks, within which the original stem arrangement is preserved.