Grafting Polymerization of Vinyltriethoxysilane Onto Natural Rubber

Graft polymerization of vinyltriethoxysilane (VTES) onto natural rubber (NR) was carried out in latex using potassium persulfate (KPS) as initiator. The effect of the amount of initiator, the reaction time and the monomer to rubber ratio on the grafting yield of NR (GY) and grafting efficiency of VTES (GE) were studied. Scanning electron microscopy (SEM) was used to study the morphology of the NR-g-VTES (VTES grafted NR) and NR. The structure of the NR-g-VTES was confirmed by the Fourier transforms infrared (FTIR) and proton nuclear magnetic resonance (1H-NMR). The results showed that the GY and GE initially increased with the increasing of reaction time and VTES content, and then thereafter reached to be stable. The GY and GE initially increased with the increasing of KPS content, and reached a maximum and then decreased. The optimum conditions were a KPS content of 0.07 wt%, VTES content of 5.65 wt% at 78-80℃ for 8 h. The thermal stability and tensile strength of NR-g-VTES increased with the increasing of VTES content. The T5 % of NR-g-VTES increased 4.2℃ than that of NR. SEM micrographs results indicated the silica has been formed in the NR-g-VTES vulcanizate.