Solid phase graft copolymerization. I. Effect of initiator and catalyst

Polypropylene–maleic anhydride (PP–MA) graft copolymers were produced from isotactic homopolymer polypropylene (molecular weight > 150,000) utilizing the technique of solid phase graft copolymerization. A high degree of graft (about 8–10%) was achieved on 150 mesh (U.S. Standard Sieve) samples using this process. This free‐radical‐initiated, catalyst‐aided grafting process was effective at low temperatures (100–120°C), atmospheric pressure, and low residence times (60 min). The powder was mixed in a low shear, fixed speed, continuous mixer where the ingredients were added in stages to effect the reaction. The interfacial agent was used to etch the polymer to provide sites for the reaction. The powder was removed from the reactor on completion of the reaction. This process can be further applied to graft other reactive monomers on polypropylene (PP).