Enhancing thermal conductivity in polypropylene random copolymer through rotational shear processing

Abstract

Intrinsic thermally conductive polymers are highly attractive for a wide range of applications due to their low cost, lightweight, and chemical resistance. Herein, we used a Rotational Shear System to regulate molecular chains of Polypropylene Random Copolymer (PPR) for enhancing thermal conductivity and mechanical strength. The SEM images showed the formation of a shish-kebab structure, indicative of highly ordered polymer chains, particularly at a rotational speed of 8 rpm. The sheared sample exhibited an in-plane thermal conductivity increase from 0.202 W/(mK) to 0.381 W/(mK), meanwhile the out-plane thermal conductivity also improved from 0.1731 W/(mK) to 0.206 W/(mK). This configuration led to a fast heat dissipation rate, and an elevation in Vicat softening temperature from 71.2 °C to 104.9 °C. Furthermore, an optimal tensile strength of 77.02 MPa was achieved, compared to 40.48 MPa for the unsheared sample. These enhancements in the thermal mechanical properties suggest that PPR produced via rotational shear has potential to be used for applications requiring effective thermal management, such as electronic components, heat exchangers, or automotive parts.