Preparation And Performance Of Continuous Glass Fiber Reinforced Thermoplastic Poly(Hydroxyaminoether) Composites

Continuous fiber reinforced thermoplastic composites has the advantage of light quality, good toughness, specific strength and specific modulus etc., which are widely used in aerospace, automotive parts and electrical appliances and other industries. But, the melt viscosity of thermoplastic resin is usually very big (>1000 Pa·s) after molten and its liquidity is poor which cannot fully and evenly infiltrate fiber. These make the interfacial cohesiveness of resin/fiber poor and make the mechanical performance of composites influenced. In this paper, bisphenol A diglycidyl ether (DGEBA), p-Anisidine and piperazine was uesd as monomers to establish reaction systems, and continuous glass fiber reinforced thermoplastic poly(hydroxyaminoether) (PHAE) composites was prepared by means of in-situ polymerization.Firstly, the reaction characteristics of DGEBA/p-Anisidine reaction system and basic physical properties of poly(hydroxyaminoether) prepared by this system. The system had an activation energy of 51.52 kJ·mol-1, exothermic peak temperature of 134.9℃ and a lower viscosity at room temperature for a long time. PHAE can soluble in polar solvent like DMF, tetrahydrofuran, etc. The glass-transition temperature(Tg) of PHAE was 86.7℃ and the temperature of initial decomposition was 310.2℃. The best reaction ratio of DGEBA and p-Anisidine was 1:1.07, at which PHAE castings had a bending strength of 126.9MPa, bending modulus of 10.2GPa and impact strength of 7.0 kJ·m-2.And then the mechanics performance, interfacial properties and heat resistance properties of continuous glass fiber reinforced PHAE (GF/DGEBA/p-Anisidine) unidirectional composites was studied. When the glass fiber volume fraction was 59.3%, the mechanical performance of composite reached its maxmum point whose bending strength was 1327.2MPa, bending modulus was 21.8GPa and interlaminar shear strength was 86.2MPa; The glass-transition temperature(Tg) was 96.6℃ and the initial decomposition temperature was 349.6℃; SEM analysis results showed that the impregnation effect of DGEBA/p-Anisidine reaction system to glass fiber bundle was good.Finally, The basic performance of DGEBA/piperazine system and DGEBA/piperazine/p-Anisidine system and the effect of the content of piperazine component on mechanical properties and heat resistance of copolymerized-PHAE castings and its composites were studied. DGEBA/piperazine system had an exothermic peak temperature of 61.℃, the applicable period at room temperature of 30 min which easily causes violent polymerization. The addition of piperazine component significantly improved the mechanical properties and heat resistance of PHAE. When the fraction of piperazine component was 73.75%, the bending strength and impact strength of copolymerized-PHAE castings reached its maxmum point which had a bending strength of 170.2MPa, impact strength of 17.1kJ·m-2, bending modulus of 5.2GPa, initial decomposition temperature of 344.2℃. At this time, the copolymerized-PHAE composites had a bending strength of 1405.4MPa, bending modulus of 19.7 GPa, interlaminar shear strength of 52.1 MPa, initial decomposition temperature of 364.2℃, glass-transition temperature(Tg) of 104.6℃. SEM analysis results showed that the interfacial performance copolymerized-PHAE composites had better adhesive interface with glass fiber than GF/DGEBA/piperazine composites.