Physical and Mechanical Behavior of Polymer Glasses. IV. Cross-Linked Poly(Methyl Methacrylate)

Temperature-induced relaxation of plastic deformation in cross-linked PMMA samples was studied. For cross-linked PMMA with low concentration of cross-linking agent (less, than 5.2 mol.%), relaxation curves: involve low-temperature component at temperatures well below glass transition temperature and high-temperature component at temperatures close to glass transition. Increasing concentration of cross-linked agents in polymer samples to 11.2 mol.% is accompanied with degeneration of high-temperature component of relaxation, and complete relaxation of plastic deformation proceeds via low-temperature component. The effect of cross-linking on temperature-induced relaxation of plastic deformation was discussed in terms of restriction of segmental mobility within certain structural regions in polymer sample.