Synthesis and characterization of compatibilizers for blends of polypropylene carbonate and polybutylene succinate via free‐radical grafting of maleic anhydride

This study focuses on creating an optimal grafting compatibilizer for blends of polypropylene carbonate (PPC) and polybutylene succinate (PBS). PPC and PBS were blended separately with different amounts of maleic anhydride (MAH) and with and without dicumyl peroxide (DCP) to aid the free‐radical grafting. Titration analysis evidenced that MAH reacted with the polymers terminal groups and backbones using free‐radical functionalization. Thermogravimetric analysis (TGA) and gas permeation chromatography (GPC) results demonstrated how the thermal stability of PPC improves with the addition of MAH. Proton NMR proved that, in both PPC and PBS formulations, ring‐opening reactions and grafting of the intact MAH ring occur, as well as interchain grafting producing network structures. The rheological analysis showed that small quantities of MAH and DCP increase the viscosity of the resins. The compatibilizer that was determined to be most reactive and stable of all the formulations analyzed was PPC with 2% MAH and DCP and its effect in the morphology of PPC‐PBS blends was proven successful by a reduction of the PPC droplet size.