Study On An Environmental Friendly Amino-terminated Polyether/Epoxy With High Strength And Toughness

Cured products of epoxy resins generally have high mechanical strength, low creep and curing shrinkage, strong anticorrosion, and good electrical properties, and are thus widely used in structural adhesives, composite materials, surface coatings and electrical laminates. However, these materials also have a main shortcoming of low toughness due to their high crosslinking density and are therefore prone to fracture at room temperature and low temperature. On the other hand, epoxy resins are insoluble in water and only soluble in aromatics, ketones, alcohols and other organic solvents. So the application of traditional epoxy resin is limited to the organic solvent systerms. Recentlly, the traditional solvent-based paint contamination problem has aroused great attention of the entire community. Therefore, environment-friendly water-based epoxy resin has been the main trend in the development of coatings industry. In this paper, a series of amino-terminated poly(ethylene glycol) compounds (ATPE) which including both regid phenyl and flexible poly(ethylene glycol) segment were synthesized and were used to reinforce or to prepare water-based epoxy resin. The structure and physical properties of the amino-terminated poly(ethylene glycol) compounds modified epoxy resin and nonionic water-based epoxy resin were studied.The main contents and conclusions are described as follows:Theα,ω-bischlorine end-capped polyethyleneglycol with different moleculer were synthesized by polyethyleneglycol and thionyl chloride. Three amino-terminated polyethers were prepared byα,ω-bischlorine end-capped polyethylene glycol and 4-aminophenol (4-hydroxybenzylamine and 4-hydroxyphenethylamine) in the condition of phase transfer catalysis. Effects of reaction condition on the purity of ATPE and effect ofα,ω-bisaminophenyl terminated poly(ethylene glycol) content on the mechanical properties of BAMPTPE-DGEBA epoxy resin adhesives were studied respectively.An advanced amorphous AB-type thermosetting resin without nanophase separation was synthesized by directly moulding diglycidyl ether of bisphenol A (DGEBA) andα,ω-bisaminophenyl terminated poly(ethylene glycol) (BAMPTPE). The stress-strain curves, dynamic mechanical thermal analysis and morphologies of impact fracture surfaces of the cured products were investigated as functions of flexible poly (ethylene glycol) segment length (MPE). The results show that the homogeneous epoxy resin without nanophase separation are available by incorporating poly (ethylene glycol) segments into epoxy crosslinked networks via chemically linked with DGEBA at both terminals, beneficial for increasing free volume fractions and strain relax rates.A high performance thermosetting epoxy resin crosslinkable at room temperature is obtained via directly moulding diglycidyl ether of bisphenol A (DGEBA) and flexibleα,ω-bisamino(n-alkylene)phenyl terminated poly(ethylene glycol). The influences of the n-alkylene inserted into amino phenyl of flexible amino-terminated polythers (ATPE) on the curing kinetics, mechanical properties and fractographs of the ATPE-DGEBA cured products were studied. The results show that the insertion of n-alkylene group into the aminophenyl group of the ATPE, on one hand, can remarkably enhance the reactivity of amine with epoxy, much accelerating the curing rate of the ATPE-DGEBA systems. On the other hand, it can significantly increase the strain relaxation rate and decrease glass transition temperature of the ATPE-DGEBA cured products, resulting in slight decrease of the Young's modulus and tensile strength, and significant increase of the toughness and elongation of the ATPE-DGEBA cured products.A facile approach to the preparation of a gradient polymer with a broad damping temperature has been synthesized using diglycidyl ether of bisphenyl A epoxy resin (E44) and three kind of curing agents, i.e. the amino terminated polyether (BAMPTPE600),4,4'-Diaminodiphenylmethane (DDM) and polyoxypropylene diamines (D400). The dynamic mechanical properties, morphology and mechanical behaviors of the three gradient polymers (BAMPTPE600-D400/E44, D400-DDM/ E44 and BAMPTPE600-DDM/E44) were investigated. The results show that the BAMPTPE600-DDM/E44 gradient polymer exhibits a wide transition range of over 180℃and excellent mechanical properties. The mechanism of forming the gradient structure is also discussed. Polyether amine grafting epoxy resins were prepared through propylene oxide modified p-methoxypolyethylene glycol benzylamine (PO-p-MPEGBA) reacting with the epoxy group of the polyfunctional group novolac epoxy resin(F51). The structure of PEG grafted epoxy resins (PEGF51) were characterized by using infrared spectroscopy. Dynamic mechanical properties, morphology, and damping behavior of the PEGF51 cured by m-xylene-diamine (m-XDA) were investigated as function of poly (ethylene glycol) segment length (MPE). The results show that the homogeneous polymers without nanophase separation are available by chemically incorporating poly (ethylene glycol) segments into epoxy resin crosslinked networks. When MPE is extended, the glass transition temperature of PEGF51/m-XDA cured product decreased. The as-obtained homogeneous polymer exhibits its potential as a material for damping application by a broad loss factor (tanδ)≥0.3 spanning a temperature range of approximately 52℃.A new kind of nonionic self-emulsified waterborne epoxy resin (MPEGE44) containing hydrophilic polyether segment was synthesized by using bisphenol A epoxy resin (E44) and p-methoxypolyethylene glycol benzylamine (p-MPEGBA). The impact mechanical properties and water absorption of the D230-MPEGE44 cured products were investigated as functions of flexible PEG chain length (MPE). The results show that waterborne epoxy resins are available by chemically incorporating PEG segment into epoxy resin molecular structure. It is beneficial to increase hydrophilicity of MPEGE44 and strain relaxtion rates of the D230-MPEGE44 crosslinked networks.A new kind of nonionic type active waterborne epoxy resin emulsifier containing hydrophilic polyether segment was prepared through reacting propylene oxide modified p-methoxypolyethylene glycol benzylamine (PO-p-MPEGBA) with the epoxy group of the polyfunctional group novolac epoxy resin (F51). The modified epoxy resins (PEGF51) have good emulsification to low molecular weight epoxy resin F51. The results show that the active epoxy resin emulsifiers are available by incorporating poly (ethylene glycol) segments into epoxy molecular structure via chemically linked with F51, beneficial for increasing hydrophilic and strain relax rates. The D230-PEGF51/F51 cured products which exhibit excellent tensile strength, modulus and impact strength at room temperature are obtained by the facile optimization of the concentration of the PEGF51/F51.