Poly(phenylene ether)/epoxy thermoset blends based on anionic polymerization of epoxy monomer

Abstract

Low molar mass poly (phenylene ether) (LMW-PPE) with phenol-reactive chain ends was used as modifier of epoxy thermoset. The epoxy monomer was diglycidylether of bisphenol A (DGEBA), and several imidazoles were used as initiators of anionic polymerization. The curing and phase separation processes were investigated by different techniques: Differential Scanning Calorimetry, Size Exclusion Chromatography, and Light Transmission measurements. The final morphology of blends was observed by Environmental Scanning Electron Microscopy and Transmission Electron Microscopy. The epoxy network is obtained by imidazole initiated DGEBA homopolymerization. Initial LMW-PPE/DGEBA mixtures show an UCST behavior with cloud point temperatures between 40 and 90°C. PPE phenol end-groups can react with epoxy, leading to a better interaction between phases. The curing mechanism and phase separation process are not influenced by the chemical structure of initiators, except when reactive amine groups are present. The phase inversion is observed at 30 wt % of PPE. The mixtures with amine-substituted imidazole present important differences in the initial miscibility and curing process interpreted in terms of fast room temperature amine-epoxy reaction during blending. Final domain size is affected by this prereaction.

Studies on Cure Kinetics of Poly(phenylene ether)/Epoxy Resin System Using an Advanced Iso-Conversional Method

“…Further, the disadvantages of epoxy resins mentioned here can be overcome by adding PPE [4][5][6] . Today, many researchers agree that using engineering thermoplastic materials in epoxy intractable polymer network can improve dimensional stability, brittleness, toughness and thermal-resistance [7][8][9][10][11] .…”

“…Although considerable research has been devoted to preparation of PPE=EP composites for applications of CCL [2][3][4][5][6] , the precise mechanism and cure kinetics of PPE=Epoxy resin systems are less frequently reported. Benderbosch et al [4] first introduced PPE used in an epoxy intractable polymer network.…”

Compatibilized the thermosetting blend of epoxy and redistributed low molecular weight poly(phenylene oxide) with triallylisocyanurate

“…Phase separation would occur while temperature is lower than UCST. 6,14 In order to obtain high performance thermosetting EP/PPO system, it is extremely essential to improve the compatibility between EP and PPO resin. Some efficient methods include reducing the molecular weight of PPO [15][16][17] or adding reactive monomers as compatibilizer to EP/PPO system.…”

“…Blending PPO with EP resin could not only improve the dielectric properties, toughness, and thermal stability of EP resin, but also overcome the drawbacks of PPO resin as was mentioned above. 6,12,13 The EP/PPO blend was considered as a qualified matrix for high frequency and high speed electronic substrates.…”

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

“…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]. The phase separation upon crosslinking is due to the increase in molecular weight of epoxy resin.…”