Improved understanding of in-situ polymerization of zinc dimethacrylate: The solid bulk polymerization

In this work, we chose the HNBR/ZDMA composite as a system reinforced by the metal salt of unsaturated carboxylic acids (MSUCA) and systematically studied the evolution of the in-situ polymerization of ZDMA particles during peroxide curing. Differential scanning caborimetry, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and polarization microscopy were used in this study. The microstructure of the remaining micron-sized dispersions in the cured HNBR/ZDMA was verified for the first time, and a new mechanism for in-situ polymerization of ZDMA, i.e., the solid bulk polymerization initialized onto the surface of ZDMA particles, was put forward. Moreover, we discussed how the micron-sized dispersions generated by the solid bulk polymerization of undiffused ZDMA particles affected the crosslink structures and mechanical properties of the vulcanizate.