Mechanical reinforcement of room-temperature-vulcanized silicone rubber using modified cellulose nanocrystals as cross-linker and nanofiller

Despite the excellent properties of room-temperature-vulcanized silicone rubber (RTVSR), such as good temperature resistance, low toxicity, and low cost, its industrial application is limited owing to its poor mechanical properties. Herein, we employed cellulose nanocrystals modified by acid hydrolysis and reaction with 3-isocyanatopropyltrimethoxysilane (ICNCs) as the cross-linking agent to reinforce RTVSR. Structural analyses of ICNCs confirmed the chemical modification of the cellulose nanocrystal surface and preservation of the crystalline structure. The ICNCs improved the thermostability of RTVSR and also acted as a nanoscale filler in the RTVSR/ICNCs nanocomposite. The thermostability and mechanical properties of RTVSR/ICNCs expectedly improved with increased ICNC content. Moreover, compared with unmodified silicone rubber, RTVSR/ICNCs nanocomposites exhibited high haze and high transparency. Our work indicates that ICNCs are well dispersed in the RTVSR matrix and effectively improve its properties.