Study On Properties Of Middle-Temperature Curing Prepreg Regulated By Room Temperature Reaction Curing Agent

The qulity of prepreg, the intermediate materials of composite, played an important role in controlling the properties of composites. In order to improve the quality and processing operability of the prepreg, the resin viscosity of prepreg must be controlled to adjust the adhesive of perperg, to realize the resin full impregnation into the reinforcing fiber bundles, in addition the resin flow of perperg must be controlled to reduce flow gum of composite molding process. In this study, the general resin system for middle-temperature curing prepreg were modified by room temperature reaction curing agent, polyether amine and cycloaliphatic amine, and the viscosity of resin system and resin flow of prepreg were regulated by chemorheology.Compared to the general resin system, dynamic DSC showed that the initial reaction temperature of resin system which modified by polyether amine and cycloaliphatic amine was lowered by11℃and13.3℃, and the curing reaction activation energy was lowered by0.81kJ/mol and3.25kJ/mol, respectively. Isothermal DSC tests showed with increasing cure temperature, the peak temperature of curing was reduced, the curing reaction rate was increased. The influence of reaction kinetics on the rheological properties of the resin system was confirmed by dynamic viscosity characteristics and isothermal viscosity characteristics. The relationship between viscosity and temperature and time of the resin system the isothermal rheological model of three kinds of resin systems was established, which provide a basis for the prediction of relationship of viscosity-temperature-time of resin systems.The tensile strength, flexural strength and elongation at break of modified resinwere higher than those of the general resin system, microstructure observations implied the modified resin system showed was tougheness fracture. Based on the curves of gel time-temperature and viscosity-temperature of resin system, the processing parameters of prepregs was established, and the coating and impregnating temeprautre of modified resin were little higher than those of the general resin system The effects of chemorheology tailoring of room-temperature reactive curing agents were investigated, the viscosity of the above two modified resin systems were increased from10700cp and9500cp to16800cp and19500cp, and the resin flow of prepreg decreased to8%and7%respectively, after storaging one week at room temperature. which proved the effect of room temperature reaction properties of polyether amine and cycloaliphatic amine on the resin viscosity.Mechanical properties test of three system prepreg showed, compared with the general resin system, the modulus were improved of the composite which the resin system were modified by polyether amine and glass transition temperature were lower, and the modulus and heat resistance of the composite which the resin system were modified by cycloaliphatic amine were improved, where the interlaminar shear strengths of composites from polyether amine and cycloaliphatic amine systems were enhanced by2.6%and9.9%, respectively. Microstructure observations showed that after adding polyether amine and cycloaliphatic amine, the composite interface interaction was enhanced.