| Popis: |
The aim of this paper is to introduce a new parameter to characterize the non-elastic behaviour of glassy polymers, namely the workhardening rate. The change in molecular microstructure induced by non elastic deformation during the pre-yield stage is treated as a defect nucleation rate. Such defect nucleation is very sensitive to the past thermomechanical history of the material and therefore the parameter K , which characterizes the ability of the polymer to deform non-elastically, will be influenced by any structural variation. Application to physical ageing of atactic poly(methylmethacrylate) PMMA is presented. |
