This work examines the effects of high shear on polymer degradation and bend compatibility. A reactive blending scheme was investigated for biobased blends of poly(propylene carbonate) and poly(butylene succinate) (PPC/PBS) in twin screw extrusion. Additionally, degradation in unfilled polymer resins was studied and modeled using reaction kinetics combined with computational fluid dynamics simulation. The effects of screw profile and process parameters were investigated for homopolymers and blends compounded at speeds up to 4000 rpm using a novel high speed twin screw extruder. It was found that blends are more sensitive to thermomechanical degradation than neat polymers, and extent of chain scission is related to the inherent shear thinning behavior. Morphology investigation showed that the reactively compounded blends had smaller droplet size with a broader shape distribution than batch mixed blends. Effects of interfacial modification on morphology and physical properties were also characterized. The results indicate that in order for extreme shear to provide improved properties, the screw design must be optimized to minimize degradation in polymer blends.