Thermally Conductive, Healable Glass Fiber Cloth Reinforced Polymer Composite based on -Hydroxyester Bonds Crosslinked Epoxy with Improved Heat Resistance

To simultaneously endow thermal conductivity, high glass transition temperature (T-g) and healing capability to glass fiber/epoxy (GFREP) composite, dynamic crosslinked epoxy resin bearing reversible beta-hydroxyl ester bonds was reinforced with boron nitride nanosheets modified glass fiber cloth (GFC@BNNSs). The in-plane heat conduction paths were constructed by electrostatic self-assembly of polyacrylic acid treated GFC and polyethyleneimine decorated BNNSs. Then, the GFC@BNNSs were impregnated with the mixture of lower concentration (3-glycidyloxypropyl) trimethoxysilane grafted BN micron sheets, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and hexahydro-4-methylphthalic anhydride, which accounted for establishing the through-plane heat transport pathways and avoiding serious deterioration of mechanical performances. The resultant GFREP composite containing less boron nitride particles (17.6 wt%) exhibited superior in-plane (3.29 Wm(-1)K-1) and through-plane (1.16 Wm(-1)K-1) thermal conductivities, as well as high T-g of 204 degrees C (T-g of the unfilled epoxy=177 degrees C). The reversible transesterification reaction enabled closure of interlaminar cracks within the composite, achieving decent healing efficiencies estimated by means of tensile strength (71.2%), electrical breakdown strength (83.6%) and thermal conductivity (69.1%). The present work overcame the disadvantages of conventional thermally conductive composites, and provided an efficient approach to prolong the life span of thermally conductive GFREP laminate for high-temperature resistant integrated circuit application.