A commercial polybutadiene (PB) was modified by a simple three-step polymer analogous reaction (epoxidation, oxirane ring-opening, and sulfonyl isocyanate addition), and the degree of modification is quantitatively controlled by epoxidation reaction. Because of the introduction of sulfonyl urethane groups (−O−CO−NH−SO2−) which is prone to self-complementary thermoreversible supramolecular hydrogen-bonding (HB) networks, the PB was modified from a rubbery material to a thermoplastic elastomer. The modified rubbers were characterized by using 1H NMR, FTIR, DSC, and dynamic mechanical analyses. FTIR spectra showed a shift of SO stretching to lower frequency with increasing degree of modification as a result of the formation of HB complexes. DSC analysis showed that the crystalline melting was suppressed, and the glass transition was elevated to higher temperatures. From the dynamic mechanical analysis it revealed much clearer the crystallization suppression and the glass transition shifts. The changes in thermal and mechanical properties were attributed to the formation of HB supramolecular networks in the modified polybutadienes.

In this paper “smart” nanocomposites comprising Stöber silica nanoparticles of two different surface polarities and a novel thermoreversible crosslinking rubber carrying self‐complementary hydrogen bonding (HB) moiety were presented. This strategy is based on the idea that the introduction of HB between silica and the modified rubber improves both the filler–rubber interaction and the mechanical properties. The resulting nanocomposites were mainly characterized using transmission electron microscopy (TEM) and dynamic mechanical analysis. It is found that the competition and symbiosis between the filler–filler, filler–rubber and rubber–rubber HB interaction, as well as the dynamic mechanical properties were controllable simply by changing the silica loading, the degree of rubber modification and the temperature. Besides, the TEM micrographs showed that the modifications of both silica nanoparticles and rubber promoted better silica dispersion in the rubber matrix. By this strategy it is evident that the Payne effect was reduced and it is possible to modify the mechanical properties of such silica filled composites in a controlled way, which could, as an example, meet the requirements for tire applications. Copyright © 2006 John Wiley & Sons, Ltd.