The properties of poly(dimethyl butadiene) (“methyl rubber”) have been an interesting topic in polymer science. The RAFT polymerization of dimethyl butadiene (DMB) and surface-initiated RAFT polymerization (SI-RAFT) on silica nanoparticles have been investigated. In this work, we studied the effects of chain graft density, RAFT agent selection, and polymerization solvent on molecular weight, polydispersity and polymerization kinetics. The free RAFT and SI-RAFT polymerization rates were studied and it was found that the free RAFT polymerization rate was slower than the SI-RAFT polymerization. The (PDMB-g-SiO2) were cured to obtain matrix-free nanocomposites as rubbery films which exhibited good dispersion of silica nanoparticles and large improvements in mechanical properties compared with the unfilled cured rubber. Additionally, preliminary results were obtained on mixing the grafted nanoparticles in different matrices to investigate the mechanical properties and grafted particle dispersion. The inherent attractive properties of methyl rubber, e.g., low glass transition temperature (Tg), low degradability, and ability to be further modified through the double-bond-rich composition, combined with well dispersed nanoparticles provide a new platform for property enhancement in this rubbery polymer.

SI-RAFT polymerization of dimethyl butadiene on silica nanoparticles for matrix-free “methyl rubber” nanocomposites

256th National Meeting (2018)

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