EFFECT OF THE COMPOSITION OF STRUCTURED RUBBER PARTICLES ON THE TOUGHNESS OF POLY(METHYLMETHACRYLATE)

Composite natural rubber (NR) and monodisperse poly(n-butylacrylate) ( PBuA) based latex particles were tested as possible impact modifiers f or a poly(methylmethacrylate) (PMMA) matrix. A continuous extrusion pr ocess was used for the incorporation of wet latexes directly into a tw in-screw extruder. All latexes had been coated by a PMMA shell. Furthe rmore, polystyrene (PS) subinclusions were introduced into the NR core . The impact resistance of the prepared PMMA blends can be most effect ively improved by NR particles containing a large weight fraction of c ompatibilising PMMA in the shell. The degree of crosslinking of the sh ell polymer has to be restricted. PBuA based latex particles of 180 nm in size are ineffective to toughen the PMMA matrix. The degree of gra fting of the NR phase in core-shell particles containing PS subinclusi ons is not crucial. Scanning electron microscopy was used to analyse t he failure processes in composite rubber particle toughened PMMA blend s at fast (impact conditions) and slow (tensile testing) deformation s peeds.