No abstract

To prepare silica/rubber composites for low roll resistance tires, a novel strategy was proposed in this study, in which autonomous monodisperse silica (AS) was prepared and modified using 3-mercaptopropyloxy-methoxyl-bis(nonane-pentaethoxy) siloxane (Si747), after which silica/emulsion styrene butadiene rubber (ESBR) master batches were produced using the latex compounding technique. Meanwhile, the commercial precipitated silica (PS) was introduced as a control. In this study, the effects of amount of Si747 and pH value on the properties of the silica/ESBR composites were systematically analyzed. Thermal gravimetric analysis (TGA) and Fourier transform infrared (FTIR) results indicated that Si747 reduced the silanol group by chemical grafting and physical shielding, and the optimum amounts of Si747 for AS and PS modification were confirmed to be 15% and 20%, respectively. Under a pH of 9, ESBR/modified AS (MAS) composites with 15% Si747 presented better silica dispersion and a weaker Payne effect, compared with ESBR/modified PS (MPS) composites with 20% Si747. Meanwhile, in terms of dynamic properties, the ESBR/MAS composites exhibited a better balance of lower rolling resistance and higher wet skid resistance than the ESBR/MPS composites.

In order to inhibit the agglomeration of silica in the rubber matrix, a new multifunctional rubber chemicals 2-propanol, 1-(2-benzothiazolylthio)-3-[3-(triethoxysilyl) propoxy] silane (Si-GM) was synthesized by (3-glycidyloxypropyl) trimethoxysilane (A-1871) and 2-mercaptobenzothiazole (MBT). Natural rubber (NR)/silica composites were prepared with different Si-GM contents and its application in silica/NR composites obtained were researched. Experimental results show that the maximum and minimum torques of silica-filled NR decrease with increasing the content of Si-GM. With the addition of Si-GM, the rubber compound has excellent characteristics of both fast vulcanization rate and high processing safety. Si-GM can effectively improve the dispersion of precipitated silica in composites and strengthen the interaction between silica particles and NR matrix. It was found that Si-GM considerably enhanced the mechanical properties such as the tensile and tear strength, dynamic compression property, and abrasion resistance of silica/NR composites, and the enhancements reached the maximum at the 5-phr content of Si-GM. In addition, by adding 4-phr Si-GM into the system, silica/NR composites acquired the superior comprehensive dynamic performances.