Various microfibrillar composites were prepared in situ using boron nitride as a thermally conductive filler. The multistage stretching extrusion process was used in an effort to improve thermal conductivity and mechanical properties. It was found that the addition of laminating-multiplying elements (LMEs) improved the dispersion of BN in the composite polymers and they also improved the tensile and impact strength of the polymers. It was also found that the thermal ...