Superfine coal powder modified by amorphous silica and its high reinforcing performance in styrene butadiene rubber

Abstract

ABSTRACT Coal has good compatibility with polymer matrix due to the macromolecular feature similar to many polymers, and is considered an attractive alternative filler for carbon black (CB) obtained through expensive energy conversion processes. Therefore, a modified coal- silica reinforcing powder (MCS) was prepared by ultrafine grinding, in-situ coating of silica and surface modification, and compared with CB, fumed silica (FS) and precipitated silica (PS) in terms of enhanced capabilities in vulcanizates. The bulk structure coal particles are dissociated into lamellas about 50 nm in thickness after wet grinding, and evenly coated by nano-level silica particles modified by hexamethyldisilazane. The two particles are closely bound together through the Si−O−C bonds formed by condensation of Si−OH group of the silica and C− OH group of aromatic microcrystalline. The resulted MCS shows good dispersion and compatibility in rubber matrix. The mechanical properties and abrasion resistance of MCS filled vulcanizate are between that of CB filled and FS filled vulcanizates, and the rolling resistance and heat generation are significantly lower than that of CB or FS filled vulcanizates. MCS exhibits excellent comprehensive dynamic performance in rubber, which is a very attractive reinforcement material used as the substitute of CB to reduce vast carbon footprint.