University of North Texas 
Witold Brostow (a), Victor M. Castaño (a, b) and Gonzalo Martinez-Barrera (a,c)
(a) Laboratory of Advanced Polymers and Optimized Materials (LAPOM), Department of
Materials Science, University of North Texas, Denton, TX 76203-5310, USA; Denton,
TX 76203, USA
(b) Centro de Fisica Aplicada y Tecnologia Avanzada (CFATA), Universidad Nacional
Autonoma de Mexico, AP 1-1010, Queretaro, Qro. 76001, Mexico
(c) Laboratorio de Investigacion y Desarrollo de Materiales Avanzados (LIDMA), Facultad
de Quimica, Universidad Autonoma del Estado de Mexico, Km. 12 de la carretera Toluca-Atlacomulco,
San Cayetano 50200, Mexico
ABSTRACT
Blends with 0, 5, 10 and 13 weight % of styrene/butadiene (SBR) copolymer embedded in a rigid polystyrene matrix were prepared. Microhardness was determined and morphology evaluated by scanning electron microscopy (SEM) before and after gamma irradiation. We relate the morphology to chemical structure and to composition of the SBRs as well as to irradiation dosages. We also connect the microhardness to the impact strength determined previously.