Although extensive investigations on rubber/clay nanocomposites have been conducted and essential progress in industrial applications have been achieved in this area, the tailor-made interfaces in such kind of elastomeric composites have not always been approached. Based on the nearly 20 years experiences in this field in Zhang’s group (CAEM@BUCT), we have still been pursing the realization of tailor-made structures in these nanocomposites, aiming at higher performances. In this paper, we introduce three typical cases with such purpose. In a newly developed biobased elastomer, poly(dibutyl itaconate-co-isoprene), pyridine groups were deliberately introduced in the chains. With increasing pyridine content, the dispersion state of clay platelets were demonstrated to be largely improved due to the increasing interfacial interaction between pyridine oniums and negatively charged clay sheets. As a consequence, the mechanical properties were significantly increased and the gas permeability was strikingly lowered. Although silanization is common practice in clay treatment, the grafting efficiency is usually not sufficient for creating strong covalent interface. To address this issue, acid pretreatment of montmorillonite (MMT) was conducted. With this step, the protons penetrate into the layers and interlamellar cations are replaced. Then the protons attack the OH groups, resulting in more hydroxyl groups at the edges and faces of layered silicate. As a consequence, the highly efficient interlamellar silylation was realized and high performance rubber/MMT nanocomposites were successfully prepared. Nanotubular halloysite have already been used as rubber reinforcement. However, its reinforcing efficiency is inferior to that possessed by commonly used nanosilica. Recently, we wrapped halloysite via polyrhodanine through redox polymerization of rhodanine on the tubes. The modified halloysite (PRd-HNTs) exhibited a prominent reinforcing effect for rubber. Such profound changes in the reinforcement were attributed to the formation of the covalent linkages between the PRd-wrapped HNTs and the rubber through the participation of PRd-HNTs in the curing process.

Tailoring interface in elastomer/clay nanocomposites for improved reinforcing efficiency and lowered permeability

251st National Meeting (2016)

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