Effect of Acid on Surface Properties of Modified Attapulgite and Performance of Styrene Butadiene Rubber Filled by Modified Attapulgite

摘要

The composite modified attapulgite powder (CMAT) was obtained by using silane coupling agent bis-(Y-triethoxy silicon propyl) disulfide modification for acid purified attapulgite. On the basis, CMAT/SBR composite rubber (ARC) was prepared by using CMAT as filler for styrene butadiene rubber (SBR), and the effect of acid on surface properties of modified attapulgite and performance of styrene butadiene rubber filled by modified attapulgite were also studied. The surface group of different modified attapugite, Zeta potential, surface free energy and TG curve of CMAT were measured by FTIR, Zeta electric potential analyzer, surface tension instrument and differential thermal analyzer. The results showed that a small amount of acid has obvious influence on the properties and morphology of CMAT, and the mechanical properties of SBR filled by acid and coupling agent treated attapulgite reached the best value when the concentration of hydrochloric acid was 0.1%. The surface free energy and the ratio of dispersive component of modified attapulgite with acid treatment at 0.1% were decreased obviously compared with that of modified attapulgite without acid treatment, and the above values were decreased from 187.3 mJ/m~2 and 94.4% to 40.82 mJ/m~2 and 28.0%, respectively. When the filler content was 80 phr, the tensile strength and tear strength were increased from 17.23 MPa and 80.30 kN · m~(-1) to 19.84 MPa and 101.34 kN·m~(-1), respectively, compared with that of SBR filled by modified attapulgite without acid treatment. The above results indicated that an appropriate amount of acid could promote the dissociation and dispersion of attapulgite crystal bundles effectively, and the organic modification effect was improved due to the increase of contact area between coupling agent surface and attapulgite fibers. Moreover, interfacial affinity and compatibility between attapulgite fibers and rubber matrix were enhanced, and the mechanical properties of the filled composite rubber were improved by the increase of CMAT dispersion in rubber.