Thermal properties of a novel form -stable phase change thermal interface materials olefin block copolymer/paraffin filled with Al 2 O 3

Thermal contact resistance (TCR) between the thermal interface materials (TIMs) and the upper and lower contact surfaces plays an important role in the heat dissipation process of electronic devices. Moreover, TCR is mainly affected by temperature, pressure and fluidity of TIMs. When the critical operating temperature of the electronic device is reached, if solid-solid contact between two contact surfaces is changed into solid-liquid contact, TCR will be greatly reduced. Based on this idea, a novel form-stable phase change TIMs is proposed. The thermal conductivity of paraffin wax (PA) is improved by filling Al2O3 particles. The addition of olefin block copolymer (OBC) improves the stability and solves the leakage problem of PA. In addition, the effects of temperature and pressure on the TCR, especially near the phase transition point, are systematically studied. These results confirm that TCR of phase change Al2O3/OBC/PA is very sensitive to temperature. When the temperature rises from 37 °C to 41 °C, TCR of all samples decreases sharply from 10~20 K⋅cm2/Wto 1~2K⋅cm2/W. TCR of all samples decreases slowly with the increase of pressure (10~50 Psi, 45 °C) and is very close to the TCR of common thermal grease. Finally, when the mass fraction of Al2O3 is higher than 60 wt%, the thermal conductivity of the Al2O3/OBC/PA increases sharply with the increase of Al2O3. Therefore, form-stable Al2O3/OBC/PA is an important development direction to solve the heat dissipation in electronic technology. © 2020