PLASTICITY OF RUBBER-TOUGHENED POLY(METHYL METHACRYLATE) - EFFECT OF RUBBER PARTICLE-SIZE

The plastic deformation of rubber-toughened poly (methyl methacrylate) has been investigated in compression at constant strain rate as a function of particle volume fraction and particle size. The behaviour at yield appears insensitive to particle size for particle diameters d in the range 80 nm < d < 300 nm. In contrast, work-hardening rate measurements in the pre-yield region reveal an abrupt change in the material's ability to develop plasticity. This transition from difficult to easy shear-band formation as the rubber volume fraction is varied is shown to occur for the same surface-to-surface interparticle distance, whatever the particle size.