Functionalized Halloysite Nanotubes–Silica Hybrid for Enhanced Curing and Mechanical Properties of Elastomers
Key Lab of Guangdong High Property and Functional Macromolecular Materials, School of Materials Science and Technology, South China University of Technology, 381 Wushan Road, Guangzhou 510640, China
Author to whom correspondence should be addressed.
The authors contributed equally to this work.
Polymers 2019, 11(5), 883; https://doi.org/10.3390/polym11050883
Received: 25 April 2019 / Revised: 4 May 2019 / Accepted: 8 May 2019 / Published: 14 May 2019
(This article belongs to the Special Issue Advances in Rubber Composites)
Vulcanization and reinforcement are critical factors in governing the ultimate practical applications of elastomer composites. Here we achieved a simultaneous improvement of curing and mechanical properties of elastomer composites by the incorporation of a functionalized halloysite nanotubes–silica hybrid (HS-s-M). Typically, HS-s-M was synthesized by 2-mercapto benzothiazole (M) immobilized on the surface of halloysite nanotubes–silica hybrid (HS). It was found that the HS-s-M uniformly dispersed in the styrene-butadiene rubber (SBR) matrix, offering more opportunity for M molecules to communicate with rubber. In addition, the physical loss of accelerator M from migration and volatilization was efficiently suspended. Therefore, SBR/HS-s-M composites showed a lower curing activation energy and a higher crosslinking density than SBR/HS composites. Moreover, a stronger interfacial interaction between HS-s-M and SBR was formed by the cross-linking reaction, giving a positive contribution to the eventual mechanical properties. The possible vulcanization and reinforcement mechanisms of SBR/HS-s-M composites were also analyzed in detail.