Interface properties of RTM and prepreg process co-curing system

There was an interface when the RTM and prepreg process was co-cured. Interphase reaction of RTM and prepreg process was investigated by differential scanning calorimetry (DSC)and fourier transform-infrared (FTIR) spectrometer analysis. The size and concentration of free volume were tested by positron annihilation spectroscopy. As a result, the reaction peak of the RTM and prepreg process is 160°C, and reaction peak of co-curing system is 275.14°C. Heat release of RTM, prepreg and co-curing is 236.2 J/g, 193.9 J/g and 83.15 J/g, respectively. Free volume size and concentration of co-curing system are larger than RTM and prepreg process. Bending strength of co-curing system is 83.4 MPa, which is less than RTM (140.2 MPa) and prepreg process (105.4 MPa). Curing agents of RTM and prepreg process react each other and lead to a weak interphase.