Rosin modified aminopropyltriethoxysilane (RA) was prepared via an epoxide ring opening reaction of rosin based glycidyl ester with aminopropyltriethoxysilane. The structure of RA was confirmed by Fourier transform infrared spectroscopy (FT-IR), 1H NMR, and 13C NMR. RA was used as a cross-linking agent to prepare room temperature vulcanized (RTV) silicone rubber with hydroxy terminated polydimethylsiloxane (PDMS) matrix in the presence of an organotin catalyst. Morphological, thermal, and mechanical properties of the rosin modified RTV silicone rubbers were characterized by scanning electron microscope (SEM), thermal gravimetric analysis (TG), universal testing machine, and dynamic mechanical analysis (DMA), respectively. Compared to the silicone rubber using tetraethoxysilane (TEOS) as the cross-linking agent, the RA modified RTV silicone rubber exhibited a significant enhancement in thermal stabilities and mechanical properties due to the strong rigidity and polar hydrogenated phenanthrene ring structure of rosin and the uniform distribution of RA in the RTV silicone rubber.

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Acrylpimaric acid-modified aminopropyltriethoxysilane (APA-APTES) was prepared and confirmed by FT-IR, 1 H NMR, and 13 C NMR. The prepared APA-APTES was used as a cross-linking agent in the preparation of modified room-temperature-vulcanized (RTV) silicone rubber. The effects of APA-APTES on the thermal stability and mechanical properties of the modified silicone rubber were investigated. The APA-APTES-modified RTV silicone rubbers have significantly improved thermal stability and mechanical properties compared with unmodified silicone rubber. Such improved properties are due to the presence of hydrogenated phenanthrene ring in APA-APTES, which induces a cross-linking network structure in the modified RTV silicone rubber. In addition, RTV silicone rubber modified with APA-APTES also exhibited better performance than that modified with rosin acid or bisphenol A. This work also demonstrates that a rigid structure dispersed in silicon rubber can more effectively improve the rubber's properties.

Rosin-grafted polydimethylsiloxane (RGSO) was prepared via ring-opening reaction of glycidyl ester of rosin acid (ER) with hydroxy-terminated amino polydimethylsiloxane (PDMS).