Preparation, structural characterization, and antioxidative behavior in natural rubber of antioxidant GM functionalized nanosilica

To restrain the migration and extractability of the antioxidants and improve the dispersion of nanosilica in natural rubber (NR), antioxidant 2‐tert‐butyl‐6‐(3‐tert‐butyl‐2‐hydroxy‐5‐methylbenzyl)‐4‐methyphenyl acrylate (GM) functionalized nanosilica was prepared using antioxidant coupling agent (KH590‐GM) as functional modifier, which was first synthesized through thiol‐ene reaction between the mercapto group of γ‐mercaptopropyl trimethoxysilane (KH590) and the CC double bonds of antioxidant GM. Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance confirmed the structure of KH590‐GM and GM functionalized nanosilica. Thermogravimetry analysis indicated that the grafting rate of GM functionalized nanosilica reached 13.4%, and the antioxidant had good thermal stability. Scanning electron microscope and mechanical properties measurement showed GM functionalized nanosilica was dispersed uniformly in NR vulcanizates, and helpful for the increase of the tensile strength and tensile stress of NR vulcanizates. Based on the study of the antioxidative behavior and extraction resistance of the NR vulcanizates, it was found that in contrast to NR vulcanizates with GM, the ageing coefficient and oxidation induction time of that with GM functionalized nanosilica increased to 0.66 and 39 min from 0.58 and 30 min, respectively. Furthermore, the NR vulcanizates with GM functionalized nanosilica also exhibited excellent extraction resistance. POLYM. COMPOS., 38:1241–1247, 2017. © 2015 Society of Plastics Engineers