Development of In-house Unidirectional Carbon/epoxy Prepregs and its Characterization for Aerospace Applications

Abstract

Abstract The primary objective of this work is to develop an in-house Unidirectional Carbon/Epoxy prepreg manufacturing technology suitable for Aerospace applications. Modifications were made to the existing in-house prepreg manufacturing facility to improve the quality of prepregs. Physical tests were carried out to assess the quality of prepregs. The mechanical tests have been performed at both prepregs and laminate level. To quantify the cure extent of epoxy (B-stage curing), fiber volume fraction in the prepreg SDT (Simultaneous differential scanning calorimeter and thermos-gravimetric analysis) is used. A plasma surface treatment has been performedon carbon fibers to improve surface roughness and induce functional groups to improve adhesion between carbon fibers and epoxy resin. The effect of plasma on carbon fibers was studied by conducting FTIR to identify required functional groups on treated and untreated fibers. Further tests performed at laminate level include matrix digestion test, SDT. Using ASTM D2734, void volume fraction is estimated. A 0° laminate is prepared, and a tension test is performed to quantify modulus and the strength. Tension tests of [±45]S and 90° laminates were also conducted to check proper impregnation (fiber/matrix interfacial bonding strength). The characterization of UD prepreg has given an in-depth insight into prepreg manufacturing technology and therefore, contributed to obtaining a good quality in-house prepreg.