RELAZIONE TRA SNERVAMENTO E FRATTURA IN POLI(METILMETACRILATO) TENACIZZATO CON GOMMA

Toughening of polymethylmethacrylate (PMMA) is achieved, as usually done for many brittle polymers, through the addition of a dispersed rubbery phase. In this work, the effect of dispersed phase content and dimensions on the fracture toughness has been examined at varying strain rate. It has been assumed that the energy dissipation occurring during fracture may be separated into two contributions, the first associated with generalized yielding occurring at the crack tip and the second due to deformation processes highly localized at the crack tip, in which new surfaces are formed. Results indicate that toughness is related to energy dissipation mechanisms taking place in the second zone.