Dielectric relaxation of grafted polyimides with long polytretbuthylmethacrylate side chains

Molecular mobility of polyimide brushes, grafed polymers with long polytretbuthylmethacrylate side chains, was investigated by dielectric method. In the glassy state two local relaxation processes, β and β1, whose molecular mobility depends weakly on side chain lengths, were found. In the viscous elastic state the α cooperative relaxation process caused by segmental motion of side chains was observed. For the α process, the molecular mobility decreases with the length of polytretbuthylmethacrylate side chains.