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Synthesis and morphology of ABC heteroarm star terpolymers ...

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.

A series of polystyrene-block-poly(1,2-butadiene)-block-poly(2-vinylpyridine) (SBV) triblock terpolymers were used to prepare blends with symmetric polystyrene-block-poly(2-vinylpyridine) (SV) and poly(2-vinylpyridine)-block-poly- (cyclohexyl methacrylate) (VC) diblock copolymers. Morphological characterization was carried out by transmission electron microscopy. These triblock terpolymers self-assemble into various core-shell type or lamellar morphologies. In the SBV/SV blends, macrophase separation between the two block copolymers, continuous centrosymmetric lamellae and stacks of non-centrosymmetric lamellae with antiparallel orientation were found. In the blends of SBV/VC, macrophase separation was never observed, what is due to the specific interactions between S and C domains. These systems showed among other morphologies also a cylindrical morphology in which rings surround the cylinders.