The mechanical properties of three grades of PMMA, one linear and two crosslinked, are investigated in tension below and above the glass transition temperature. It is found that strain-hardening decreases gradually with temperature in the glassy state, but keeps a significant value in the rubbery state. The results are analyzed in terms of an entropy-based statistical model (van der Giessen and Wu, 1992) which describes the stress-strain response of a chain network. The junctions of the network are not only associated with the chemical crosslinks, but additionally with physical entanglements, which are more numerous in the glassy state.

Issue Section:
Technical Papers
Topics:
Chain, Entropy, Glass transition, Junctions, Mechanical properties, Polymers, Stress, Temperature, Tension, Work hardening
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