The Impact of Nano CaCO3 Modified in situ with Methacrylic Acid on the Structure and Properties of Natural Rubber

Natural rubber (NR) was reinforced in situ with nano CaCO3 that had been modified with methacrylic acid (MAA)(M-CaCO3). The structures and properties of the resulting composites were studied using attenuated total reflection Fourier transform infrared spectroscopy(ATR-FTIR), scanning electron microscopy(SEM), and Mooney viscometer and mechanical tests. The results show that when NR is physically blended with CaCO3 and MAA, (Ca2+)-(−OOC) is formed in situ. When dicumyl peroxide (DCP) is added, the (Ca2+)-(−OOC) self-homopolymerizes, and during the curing process poly-(Ca2+)-(−OOC) is formed and grafts to the molecular chains of the NR via carbon-carbon double bonds. The NR/M-CaCO3 composites formed have close interfacial interaction and are well dispersed. Compared with the NR composites reinforced with unmodified nano CaCO3, the NR/M-CaCO3 composites have very different cure characteristics, rheological behavior, and mechanical properties, and these characteristics and properties show a significant relationship with the loading of M-CaCO3.