Synthesis Of New Poly(arylene Ether Nitrile) And Properties Of Modified Epoxy Resin

Epoxy resin is widely used in various industrial fields of national economy because of its excellent mechanical properties,bonding properties and solvent resistance.With the improvement of polymer compatibility theory,the maturity of toughening technology and modification process,the toughening and functional modification of epoxy resin have developed rapidly.Thermoplastic resin has good toughness,heat resistance and high modulus.When used to toughen epoxy resin,the thermoplastic resin will not reduce the modulus and heat resistance of matrix resin,which is its unique advantages.Poly(arylene ether nitriles)(PEN)is a kind of poly(arylene ether).The PEN has high glass transition temperature,excellent mechanical properties,good processability,radiation resistance and flame retardancy.It is widely used in the fields of automotive,electronic coatings,adsorption materials and foamed plastics,etc.The PEN has high melting temperature,poor solubility in low boiling solvents,and these properties limit its application in solvent-free paste system.Therefore,some functional groups are introduce into PEN through the structure design,which destroy the regularity of PEN's structure,and a kind of functional PEN with good solubility and low melting temperature is obtained,and the properties of epoxy resin modified with a series of PEN are explored.In this paper,the 2,6-dichlorobenzoic acid was introduced into the polymerization of PEN(BPA),and a series of poly(arylene ether nitriles)containing carboxyl(CPENs)with different molecular weights are synthesized.Their structures are verified by infrared spectroscopy,Their molecular weights are measured by gel permeation chromatography,and their solubility in common solvents are explored.The changes of their thermal properties with molecular weights are analyzed by differential scanning calorimeter and thermogravimetric analyzer.It is found that the introduction of carboxyl structure can effectively improve the solubility of PEN,and the CPENs can be dissolved in toluene,ethyl acetate and acetone.And the CPENs can be melted in epoxy resin at 120?to obtain uniform eutectic.The CPENs/EP modified resin system is prepared,and its thermal properties,mechanical properties and bonding properties are tested.The micro morphology of the fracture surface is observed through the scanning electron microscope.The effects of CPENs with different molecular weight and different addition amount on the properties of the modified resin system were analyzed.The results show that the addition of CPENs does not reduce the thermal properties of modified epoxy resin,and the failure mode changes from brittle fracture to ductile fracture,and the tensile strength,impact strength and bonding properties are significantly improved.When the content of CPENs-20 is 15 phr,the comprehensive properties of CPENs-20/EP are the best,and its tensile strength,impact strength and shear strength at room temperature are increased by 12.82%,96%and 34.63%respectively.Furthermore,the poly(arylene ether nitriles)containing-CF₃ group(FPEN)was synthesized with BPAF and 2,6-dichlorobenzonitrile,and the properties of epoxy resin modified with FPEN were investigated.The tensile strength,flexural strength,impact strength and shear strength at room temperature of FPEN(40 phr)/EP increased by 40%,38.73%,148%and 62.78%,respectively.The introduction of the-CF₃ group also improves the dielectric properties of epoxy resin.At different frequencies,the dielectric constant and dielectric loss decrease with the increase of FPEN addition amounts.