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This paper presents a new approach for the preparation of poly(ethylene terephthalate) ( PET)/clay nanocomposites using surfactant-free clay (sodium montmorillonite, Na- MMT) with trisilanolphenyl polyhedral oligomeric silsesquioxane (Tsp- POSS) as dispersant. The dispersion of clay in the PET/Na- MMT/Tsp- POSS nanocomposites is enhanced over that in PET/Na- MMT by using a very small amount of Tsp- POSS, which acts as functional spacer to keep clay platelets apart and pull monomers in, and, at the same time, acts as a PET chain extender. As a result, thermomechanical properties and thermo-oxidative stability of PET/Na- MMT/Tsp- POSS are improved simultaneously compared with those of PET/organoclay nanocomposites. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: In this article, we report novel epoxy-based hybrids prepared via incorporating 1,2-dimethyl-3-(benzyl-heptaisobutyl-POSS) imidazolium chloride (POSS-IMC) and POSS-IMC-modified clay (POSS-MMT) into the resin based on 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate (ECHM) and hexahydrophthalic anhydride (HHPA). We demonstrate that both POSS-IMC and POSS-MMT can reduce the cure temperature of the epoxy/anhydride system, and the catalyzing effect involves chemical reactions between POSS-IMC and ECHM/HHPA, which may lead to the attachment of POSS cages at chain ends. The incorporation of the POSS-IMC, free and ionically bonded in clay, gives rise to dissimilar morphologies that affect the thermo–mechanical properties of the hybrids. The ECHM/HHPA/POSS-IMC resin exhibits a slight improvement in glassy modulus as compared with the neat ECHM/HHPA resin, which is attributed to the formation of sub-micron and nano-sized POSS domains that act as physical cross-link points hindering polymer chain motions. The much enhanced reinforcing effect of POSS-MMT is ascribed to the effective stress transfer between the matrix and clay layers that may originate from the strong interactions between the pendent POSS in the network and POSS attached to the clay surfaces. Reduction in coefficient of thermal expansion (CTE) was also found for the hybrids. [Copyright &y& Elsevier]