Curing behaviour of syndiotactic polystyrene–epoxy blends: 1. Kinetics of curing and phase separation process

Abstract

The modification of the curing behaviour and the phase separation process for an epoxy resin blended with a crystalline thermoplastic was investigated in the case of the diglycidylether of bisphenol‐A (DGEBA)/4,4′‐methylene bis(3‐chloro‐2,6‐diethylaniline) (MCDEA) blended with syndiotactic polystyrene (sPS) and cured at 220 °C. Phase separation taking place during curing of the blend was investigated by differential scanning calorimetry (DSC) and optical microscopy in order to get a better understanding of the complex interactions between cure kinetics of epoxy matrix and crystallisation of sPS, both influenced by blend composition. Results suggested that phase separation and crystallisation of sPS occurred at almost similar times, with phase separation just being ahead of crystallisation. DSC and near‐infrared measurements were used for the determination of the cure kinetics. Slow delays on the cure reactions were observed during the first minutes for the sPS‐containing blends compared with the neat DGEBA/MCDEA system but, after some time, the reaction rate became faster for the blends than for the neat matrix. Phase separation occurring in the mixtures may explain this particular phenomenon. Copyright © 2004 Society of Chemical Industry

Mechanical properties of poly(styrene‐co‐acrylonitrile)‐modified epoxy resin/glass fiber composites

“…However, because of their highly crosslinked structure, these materials have some undesirable properties such as low toughness and poor crack resistance, which constraint many of its applications. The most successful methods of improving the toughness of epoxy resin are incorporating secondary rubbery phase particles in to the crosslinked polymer10–12 and the modification with engineering thermoplastics 13, 14. These studies indicate that in most cases, thermoplastic modification resulted in improved toughness of the resin.…”

Microwave curing of initially compatible epoxy–poly(ethylene terephthalate) blends: DSC kinetic study and nano-structure analysis☆

“…The brittle fracture and low impact strength are the disadvantages of epoxies. The addition of initially soluble TP is consciously used to improve the toughness of epoxy materials [10][11][12][13][14][15][16][17][18][19][20][21]. The cited references comment DGEBA modified ER having weight average molecular mass, M w , within the range 340-390 kg kmol À1 .…”

“…These groups are capable of interacting with the end groups of PET through hydrogen bonding. On the other hand, DGEBA are good solvents of other TPs having different chemical formulas, e.g., polystyrene, PS [13], polymethyl methacrylate, PMMA [14], polyvinyl methylether, PVME [15], polyether imide, PEI [16], polyether sulphone PES [17] and others, see [10][11][12] and references herein. It can be assumed that hydrogen bonding is the probable reason that causes solubility of TP in DGEBA.…”

Morphology and contact angle studies of poly(styrene-co-acrylonitrile) modified epoxy resin blends and their glass fibre reinforced composites

“…The reinforcement (chopped E-glass fibre mat) was supplied by Ceat Ltd., India. The density of glass fibre is 2.51 g/cm 3 . The chemical structures of epoxy resin and DDS are given in Figure 1.…”

“…Many studies have been made to improve their toughness and crack resistance. In recent years, high performance thermoplastics have been extensively used to toughen thermosetting resins because of their high modulus and glass transition temperatures [2][3][4]. Morphology of the resulting polymer blends depends on the selection of the thermoplastic polymer, the epoxy precursors, hardener and on the curing cycle parameters [5][6][7].…”