Hydroxyl terminated poly(ether ether ketone) oligomer with pendant methyl group (PEEKMOH) was prepared. Ternary nanocomposites were processed by blending PEEKMOH oligomer with diglycidyl ether of bisphenol-A (DGEBA) epoxy resin along with organically modified montmorillonite (Cloisite 25A) followed by curing with 4,4'-diamino diphenyl sulfone. Tensile moduli and flexural moduli were increased, while the tensile strength and Izod impact strength were decreased with increase in clay content. Similarly, storage moduli and loss moduli were increased and glass transition temperature was decreased as the percentage of clay increased. X-ray diffractograms showed exfoliated morphology even with higher concentration of clay content (8 phr). Scanning electron microscopy of fractured surfaces and tensile failed specimens revealed slow crack propagation and increase in river markings with nanoclay incorporation confirming the improvement in toughness. The domain size of PEEKMOH was decreased with the incorporation of nanoclay into the epoxy matrix, indicating the restriction of growth mechanism by nucleation during phase separation. With increase in clay content, phase separation disappeared indicating gelation occurs before phase separation. Fracture toughness was increased with the addition of PEEKMOH and clay in epoxy resin. Coefficient of thermal expansion of nanocomposites decreases up to 3 phr clay concentrations thereafter it increases. A marginal increase in thermal stability was observed with increase in clay content.

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Epoxy-clay ternary nanocomposites were processed by melt blending of hydroxyl terminated poly (ether ether ketone) oligomer with pendant methyl groups (PEEKMOH) with diglycidyl ether of bisphenol A (DGEBA) epoxy resin along with organically modified montmorillonite (OMC-OH) followed by curing with 4,4 0 -diamino diphenyl sulfone. Small angle X-ray diffraction and transmission electron microscopy revealed an intercalated morphology. Tensile, flexural, storage, and loss moduli were increased whereas the tensile, flexural, and impact strength and glass transition temperature were decreased with increase in clay content for the PEEKMOH toughened epoxy system. Fracture toughness and percentage strain were increased by 66% and 45% respectively whereas the coefficient of the thermal expansion was decreased by 27% with the incorporation of 1 phr OMC-OH to the PEEKMOH toughened epoxy system compared with neat epoxy. The scanning electron microscope pictures of fracture and tensile failed surfaces revealed crack path deflection and ductile fracture with the incorporation of OMC-OH confirming the improvement in toughness. The domain size and the distance between the domains of thermoplastic phase were decreased with the addition of nanoclay into the epoxy matrix indicating the restriction of the growth mechanism by nucleation during phase separation.

Poly(ether sulfone) (PES)‐toughened epoxy clay ternary nanocomposites were prepared by melt blending of PES with diglycidyl ether of bisphenol A epoxy resin along with Cloisite 30B followed by curing with 4,4′‐diaminodiphenylsulfone. The effect of organoclay and thermoplastic on the fracture toughness, permeability, viscoelasticity and thermomechanical properties of the epoxy system was investigated. A significant improvement in fracture toughness and modulus with reduced coefficient of thermal expansion (CTE) and gas permeability were observed with the addition of thermoplastic and clay to the epoxy system. Scanning electron microscopy of fracture‐failed specimens revealed crack path deflection and ductile fracture without phase separation. Oxygen gas permeability was reduced by 57% and fracture toughness was increased by 66% with the incorporation of 5 phr clay and 5 phr thermoplastic into the epoxy system. Optical transparency was retained even with high clay content. The addition of thermoplastic and organoclay to the epoxy system had a synergic effect on fracture toughness, modulus, CTE and barrier properties. Planetary ball‐milled samples gave exfoliated morphology with better thermomechanical properties compared to ultrasonicated samples with intercalated morphology. Copyright © 2010 Society of Chemical Industry

Ternary nanocomposites are prepared by blending hydroxyl‐terminated poly ether ether ketone having pendant methyl groups (PEEKMOH) with epoxy resin along with Nanolin DK1, followed by curing with 4,4′‐diamino diphenyl sulphone. Differential scanning calorimetry shows a two‐stage cure behavior indicating the catalytic effect of the primary amine and proton, which are generated by the dissociation of organic modifier. Tensile and flexural moduli are increased while tensile strength and glass transition temperature are decreased with increase in clay concentration. Fracture toughness and strain at break are increased by 59 and 62%, respectively, with 1 phr clay loading. Transition electron microscopy and X‐ray diffraction (XRD) analysis reveal exfoliated morphology for the nanocomposites. Scanning electron micrographs show a decrease in both, domain size as well as inter domain distance of the thermoplastic phase with the addition of clay, indicating the occurrence of gelation before phase separation. Analysis of the fracture surface reveals crack path deflection and ductile fracture behavior, confirming that toughness has been improved with the addition of clay and PEEKMOH. Coefficient of thermal expansion (CTE) of the nanocomposites is decreased up to 3 phr clay loading. Oxygen gas permeability is compared with Bharadwaj's and Neilson's models. A marginal improvement in thermal stability is observed with the addition of clay. Copyright © 2009 John Wiley & Sons, Ltd.