Plastic deformation in polyimides, with new implications on the theory of plastic deformation of glassy polymers

The plastic deformation behaviour of a series of glassy aromatic polyimides, derivatives of resorcinol, hydroquinone, oxydiphenyl, and pyromellitic acid, have been investigated between room temperature and a temperature 20 K below their respective glass transition temperature. The results are analysed by means of a theory due to Argon (1973) for plastic flow in glassy polymers, and show that, as the spacing between natural hinges on polymer molecules increases with increasing chemical complexity, the thermally activated complex grows in size, and plastic deformation becomes less local.