High-Performance Silicone Rubber Composites via Non-Covalent Functionalization of Carbon Nanotubes

ABSTRACT

A high-performance silicone rubber (SR) composite (denoted as SCT) filled with 5 phr functionalized carbon nanotubes (CNTs) and 40 phr fumed silica (SiO₂) was prepared by mechanical blending. The CNTs were functionalized by tetrakis (phenylmethyl)-thioperoxydi (carbothioamide) (TBzTD); it contains four benzene rings that can interact with the CNTs via π–π interactions. Raman spectroscopy and X-ray photoelectron spectroscopy analysis demonstrated the existence of the π-π interactions between the CNTs and the TBzTD. Transmission electron microscopy and scanning electron microscopy confirmed the uniform dispersion of the CNTs in SR matrix and strong interfacial interactions between the SR and the CNTs. The effects of these non-covalently functionalized CNTs on the mechanical properties of the silica filled SR composites were fully investigated. The results showed that the tear strength of the SCT composite with TBzTD functionalized CNTs was significantly improved, by 249%, compared with that of the composite containing only SiO₂. An obvious crack deflection occurred in the SCT during the tearing process, resulting in the enhanced tear strength.

KEYWORDS:

• Carbon nanotubes
• crack deflection
• mechanical properties
• silicone rubber
• π–π interactions

Acknowledgements

The authors would like to gratefully acknowledge the financial support of the State Key Program of National Natural Science of China (51333004).