Efficient exfoliation and dispersion of expanded graphite through dry ice explosion synergized shear flow field for high-thermal conductive NR/EG composite preparation in large-scale

Thermal interface materials (TIMs) are one of the important components of materials used in electronic packaging processes to reinforce the interface heat transfer between electronic components. High thermal conductive filler-reinforced polymer composites are receiving increasing attention in electronic packaging for their excellent thermal conductivity and low cost, but their applications are limited by complex preparation processes and difficult to produce on large scale. This paper presents an efficient blending method with dry ice airburst synergistic shear force field for large-scale preparation of natural rubber/expanded graphite (NR/EG) polymer composites. The thermal conductivity of the composite in presence of dry ice airburst is 2.317 W/(m·K) for EG content of 30 wt%, compared to 1.206 W/(m·K) for the control sample without dry ice airburst, an improvement of 92.1%, indicating a significant improvement in thermal conductivity. In addition, after introduction of dry ice, tensile strength and elongation at break of composites increased by 33.7% and 9.2%, respectively, showing promising mechanical properties. The calculations showed that the shear flow field strength was increased 68.2 times by heat absorption of dry ice, and the EG exfoliation mechanism was proposed. The strategy proposed in this work provide green, simple and efficient method to prepare high thermal conductive composites without the involvement of chemical solvents, which has enormous potential in large-scale preparation of high thermal conductivity filler reinforced polymer composites.