The Synthesis And Application Research Of The New Epoxy Resin Curing Agent

Epoxy resin has chemical stability, strong bonding sthength, excellentelectrical performance, and other features, is one of the important substratematerials for preparing high-powered composite material, can give materialhigh mechanical properties and physical properties. As one of the majormodification amines, Polyamide accounts for a large propotion of the epoxyresin curing agent,but the performance index of low the molecularpolyamides in the existing market has some defect, especially the largerviscosity which leads to the bad mating with the low viscosity epoxy resinand the limits of in the RTM（Resin Transfer Molding）, RIM（ReactionInjection Molding） and other advanced technology of application.In thisarticle,we use binary acid and dibasic acid esters insteading of vegetable oildimer acid components used in the preparation of low molecular polyamideto synthesize low viscosity polyamide by reacting withtetraethylenepentamine,the concrete research content as follows:（1）Through the experiment, we discussed the reactiontemperature,reaction time and the ratio of raw materials and their effects onthe amine value and viscosity of the synthetic product, and concludes thebest of synthetic technology conditions.With the adipic acid、tetraethylenepentamine as raw meterials,the reaction temperature160℃，the reaction time1h,the molar ratios of acid to amine is1:3,the products ofpolyamide resin amine value is718mgKOH/g, viscosity（25℃） is12200mPa·s; with dimethyl terephthalate and tetraethylenepentamine as the rawmaterials,the reaction temperature110℃,the reaction time1h, the molarratios of acid to amine is1:3, the products of polyamide resin amine value is702mgKOH/g, viscosity（25℃） is11800mPa·s.（2）Through the analysis of the isothermal method,we get the cureddynamic equation of synthesizing polyamide for the acid components,that is da/dt=6.45×10⁵exp（-47.8/RT）（1-a）^0.88, and the apparent activation energyis47.8KJ/mol, preexponential factor is6.45×10⁵s^-1. The cured dynamicequation of synthesizing polyamide for the ester components isda/dt=8.08×10⁵exp（-50.1/RT）（1-a）^0.88, the apparent activation energy is50.1KJ/mol, preexponential factor is8.08×10⁵s^-1.（3）Through the mechanical test,we get some results of the polyamidecondensates which are synthesized by the acid components,they are, tensilestrengt32.4MPa, bending sthength81.5MPa, impact strength19.6KJ/m²;and by the ester components,the tensile strengt is37.9MPa,bending sthength104.6MPa, impact strength16.5KJ/m². then, through thehot weightlessness analysis, we know that acid components, polyamidecured system weightless50%when temperature is400℃and the eventuallyweightlessness rate is90%, on the other hand, ester components polyamidecured system weightless50%when temperature is430℃, and the eventuallyweightlessness rate is74%.