Research On Amino-functionalization Of Carbon Fibers And Their Reinforced BPFER/mXDA/TG-Siloxane Composites

Due to its low viscosity, high insulation, high temperature resistance, solventresistance and good adhesive properties, Bisphenol F epoxy resin (BPFER) hasbecome one of the most important resin matrixes for composite materials. Carbon fiberhas high specific strength, high specific modulus and other characteristics amd it iswidely used as reinforced materials to fabricate high performance polymers basedcomposite materials. In the present paper, using m-xylylenediamine (mXDA) as thecure agent and N, N, N’, N’-tetraglycidyl-1,3-diamino-propyl-1,1,3,3-tetramethyldisiloxane (TG-Siloxane) as modifier, novel amine-functional carbon fiber(CF)reinforced Bisphenol F epoxy resin (BPFER) composites were prepared, and theircuring, mechanical, thermal performance were studied. The main contents are asfollows:(1) The kinetics of curing reaction for TG-Siloxane/BPFER with mXDA as cureagent was monitored by the differential scanning calorimetry (DSC). The characteristictemperatures such as gelation temperature (Tgel), curing temperature (Tcure) andpostcuring temperature (Tpostcure) were acquired by using T-β graph extrapolation. Theapparent activation energy (Ea) was obtained by Starink equation. The kineticparameters such as the frequency factor A and the value of reaction order n, m wereobtained based on Autocatalytic model. Kinetic equations suggested that the curingreaction was influenced greatly by heating rate. It was shown that the predicted resultswere very close to the better heat-resistance than that of BPFER/mXDA.(2) Lacking of chemical active functional groups on the surface, the performanceof the CF to complex with the resin matrixes is poor. To modify the surface adhesiveperformance between the CF and resin matrixes, carbon fibers were modified bysurface treatment. Firstly,-COOH groups were introduced on the surface of carbonfibers. Secondly, the-COOH groups were converted in acyl chloride groups by treatedof sulfoxide chloride. Finall, functionalized CF was produced by amination of mXDA.The samples at different steps were characterised by FT-IR, XPS and SEM. (3) Functionalized carbon fibers reinforced BPFER/mXDA/TG-Siloxanecomposite was prepared, and their mechanical performance and heat-resistenceproperty were investigated. The results of mechanical tests and SEM analysis suggestthat, compared with that of untreated carbon fibers/BPFER/mXDA/TG-Siloxane resinsystem, performance of the composits is modified greatly by the amine functionalizedcarbon fibers. And when1.0%(mass ratio) amine functionalized carbon fibers wasadded, the composite have best mechanical properties, for example, their tensilestrength was76.34MPa, their breaking elongation was8.39%, their flexural moduluswas4.76GPa, their flexural strength was89.82MPa.