Surface Modification of Waste Silicone Rubber Via Alcoholysis Reaction and Its Application in Polypropylene Toughening

With the development of power industry, the recycling of waste insulator silicone rubber (WSR) remains a significant challenge. Herein, an efficient alcoholysis strategy for the surface modification of WSR was explored by using nerol as alcoholysis reagent, and then the nerol modified WSR (Nerol-WSR) was utilized in polypropylene toughening. FTIR spectra indicate that nerol can served as nucleophilic reagent to cleave the Si–O bonds in WSR, resulting in an efficient surface grafting of nerol moieties on WSR. The grafting content of nerol moieties gradually increases with alcoholysis times. Morphology investigation demonstrates that with the increase of alcoholysis time, the dispersion state of Nerol-WSR particles in PP matrix is significantly improved, along with a much smaller particle size. Accordingly, with the addition of 10 wt.% of Nerol-WSR, the resulting PP composites can achieve a remarkable increase of approximately 200% in impact strength. This should be due to the grafted nerol moieties can substantially improve the interfacial adhesion of the composites and hence facilitate the dispersion of WSR particles in PP matrix. Therefore, the stress concentration of PP can also be effectively delivered to the adjacent Nerol-WSR and thus retard the propagation of cracks. In addition, the addition of Nerol-WSR can also increase the loss tangent values of the composites, which indicates its potential application in polymer damping.