Synthesis And Temperature Resistance Of Carbon Fiber Resin Based RTM

Carbon fiber resin matrix composites have excellent mechanical properties,such as very high specific strength,good electrical conductivity,anti-friction,and corrosion resistance.They are well-suited as materials for automotive lightweighting.The paper prepares 692-9G epoxy resin as the matrix by resin transfer molding(RTM)process;the composite laminate with 24K-T300 plain weave fabric as the reinforcement is prepared.After modifying the properties of the resin,the optimal RTM process parameters and the modification scheme of the epoxy resin were selected by testing the resin’s intrinsic properties,process optimization,and mechanical property tests.When the content of titanate coupling agent was 0.4%,the DSC showed the largest exothermic peak area and obvious exotherm,which indicated that the amount of coupling agent was appropriate;when the content of silicone resin was 2%,the gel curve showed the enormous exotherm temperature;when the content of silicone resin,was 2%and the content of coupling agent was 0.4%,the thermogravimetric curve was the smoothest,and the thermal properties were the best.The composite layup was designed using Abaqus,and the simulated process parameters were verified using RTM for the design,and the[0/90]degree layup was better than the 0-degree layer.The composites were prepared under different parameters and tested for tensile mechanical properties:the results of orthogonal experiments showed that the optimal RTM process injection pressure was 2.5 MPa,the RTM process injection speed was 40 ml/min,and the injection temperature was 80°C.The mechanical properties of the modified material were improved from 766.16MPa to 1105.33 MPa,and the bending properties were improved from 542 MPa to 1171.5MPa.The improvement of mechanical properties was excellent.After 10 days of aging,the tensile properties of the pre-modified material decreased to 651,8 MPa,and the bending properties decreased to 263 MPa;the tensile properties of the modified material decreased to 649 MPa and the bending properties decreased to 682 MPa.The materials’fracture morphology confirmed that the modified composites’interfacial properties were better than those of the unmodified materials.The number of fibers pulled out of the modified matlimitedas significantly reduced with the same fracture mode.The thermomechanical properties of the composites show that after aging the material,t_g will first move in the direction of high temperature due to post-curing.When the aging time becomes longer,it can be seen from the comparison of IR that the structure of the matrix changes in the thermal oxygen state,and the resin starts to degrade,generating more carbonyl groups.Then chain segments become larger,t_g moving to the left.From the results of mechanical properties,the modified composites can serve at higher temperatures than the unmodified materials;at room temperature,the modified materials have higher tensile and bending strengths and a more comprehensive service range.