Preparation of methyl methacrylate-maleic anhydride copolymers via reactive extrusion by regulating the trommsdorff effect

Abstract

In this study, the influence of shear rate on the Trommsdorff effect was investigated using rotational rheometer and torque rheometer firstly, then the bulk copolymerization of methyl methacrylate (MMA) and maleic anhydride (MAH) were carried out via two connected twin-screw extruders. Based on the assumption of utilizing the Trommsdorff effect, new monomers were continually added during the copolymerization process. The results indicated that the polymerization rate was greatly accelerated and copolymers with high molecular weight and narrow distribution were obtained. Under the high temperature and high pressure in extruder, the copolymerization of MMA and MAH approached to the ideal copolymerization, which was different from the solution copolymerization. Compared with the homo-polymethyl methacrylate, the Tg and Td50 of the copolymer was respectively increased by 12 °C and 24 °C while maleic anhydride units were uniformly distributed in the MMA-MAH copolymer. The flexural strength and modulus increased by 8.2% and 20%, respectively. The high efficiency and environment friendly of reactive extrusion technology provide a way for the large-scale industrialization of MMA-MAH copolymer.