Preliminary investigations of mechanical attrition (MA) resulted in particle size reduction, amorphization of semicrystalline polymers, and relatively insignificant effects on PEO or PVP molecular weight distributions. Cryogenic mechanical alloying (CMA) was extensively used to blend immiscible polymers. Globar FT-IR confirmed that no chemical compatibilizaton occurred during CMA, while a novel chemical mapping protocol developed with synchrotron FT-IR microspectroscopy allowed for qualitative and quantitative estimation of blend heterogeneities. The uniqueness of the PS/PET system led to extensive study of domain characteristics, the extent of compatibilization, and changes in PET crystallizability with CMA. Various PS/PET blend compositions (nominal 30, 50, and 70 weight percent PET) were processed by CMA and extrusion and studied comparatively. CMA compatibilized PS and PET more efficiently and controllably than extrusion. These results agreed with trends observed for domain size distribution, and CMA also created nonspheroidal domains, i.e., an efficient way to increase interphase contact. CMA, in effect, created a rigid amorphous PET phase that served the dual purpose of enhancing compatibility and stabilizing the morphology during post-CMA heating
