Small-angle X-ray scattering study of craze formation and dynamics in thermoplastics

a detailed investigation of the microscopic mechanisms of tensile stress de formation was performed. The experiments involved two different thermoplast ic materials: high impact polystyrene (HIPS! and a novel polystyrene CPS)-p olybutadiene (PB) blend, at temperatures ranging from 30 to 70 degrees C, d eformed at a constant uniaxial strain rate. Real-time measurements of the a pplied stress, X-ray absorption by the sample, and small-angle scattering w ere used to identify the presence of shear and craze deformation stages. Cr aze fibril surface energies were determined from calculations of the fibril diameter in order to distinguish between craze growth by the competing mec hanisms of chain scission and forced reptation.