A variety of nano and micro-sized boron nitride (BN) particles were dispersed in a polyimide (PI) precursor polyamic acid (PAA) using a surfactant in order to generate a thermally conductive polyimide composite film with excellent thermal properties. The observed thermal conductivities varied with the BN weight % and the particle size. BN weight % was raised as high as 30%, which resulted in a thermal conductivity of 1.2 W/mK. Glass transition and thermal ...