Reduction of volatile organic compound emission. II. Use of alkoxy-modified silsesquioxane for compounding silica-filled rubbers



A class of alkoxy-modified silsesquioxane (AMS) containing less than 5 wt % of latent alcohol that can be used for compounding silica-filled rubbers is described. The AMS derived from octyl-triethoxysilane (OTES) behaves as a good shielding agent in silica-filled rubber to significantly reduce the compound Mooney viscosity and filler flocculation. The co-AMS prepared from OTES and 3-mercaptopropyl-trimethoxysilane yielded an effective shielding and coupling agent for reinforcing the silica-filled vulcanizates. The alcohols released as volatile organic compounds (VOC) are quantified during compounding and processing along with the compound properties of silica-filled vulcanizates containing various silicon compounds such as bis-(triethoxysilyl propyl) disulfide (TESPD), a polyhedral oligomeric silsesquioxanes (POSS), OTES, AMS, or co-AMS. Dynamic mechanical properties such as dependences of hysteresis on temperature (HTD) and storage modulus on strain (MSD) are discussed. Stronger HTD and weaker MSD were found in stocks containing co-AMS or a combination of AMS and a coupling agent when compared with that with TESPD. Stronger HTD and weaker MSD may benefit a tire compound with lower rolling resistance, more stable handling performance, as well as better wet traction. More importantly, the VOC released during the manufacture of rubber articles are significantly reduced in stocks containing AMS (or co-AMS) when compared with those with a silane. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010