In this study it is suggested that the initiation of localized deformation zones in glassy polymers, like crazes or shear bands, is related to the specific flow properties of these materials, where small stress fluctuations lead to large local strain rate differences. This view is supported by a stress optical study on polycarbonate, showing development of inhomogeneous deformation below the yield point. Moreover, it is shown for a commercial grade of polystyrene that the strain rate dependence of craze initiation is equivalent to that of yielding, indicating that both processes originate from the same molecular mechanism.
|Title of host publication
|Conference papers 9th international conference on deformation, yield and fracture of polymers, Cambridge, UK, 11-14 April 1994
|Place of Publication
|The Institute of Materials
|Published - 1994