An Integrated Approach to Design and Develop High-Performance Polymer-Composite Thermal Interface Material

Abstract

A computational framework based on novel differential effective medium approximation and mean-field homogenization is used to design high-performance filler-laden polymer thermal interface materials (TIMs). The proposed design strategy has the capability to handle non-dilute filler concentration in the polymer matrix. The effective thermal conductivity of intended thermal interface composites can be tailored in a wide range by varying filler attributes such as size, aspect ratio, orientation, as well as filler–matrix interface with an upper limit imposed by the shear modulus. Serval potential polymers and fillers are considered at the design stage. High-density polyethylene (HDPE) and thermoplastic polyurethane (TPU) with a non-dilute concentration (~60 vol%) of ceramic fillers exhibit high thermal conductivity (4–5 W m−1 K−1) without compromising the high compliance of TIMs. The predicted thermal conductivity and coefficient of thermal expansion are in excellent agreement with measured data of various binary composite systems considering HDPE, TPU, and polypropylene (PP) loaded with Al2O3 and AlN fillers in varying sizes, shapes, and concentrations, prepared via the melt-mixing and compression-molding route. The model also validates that manipulating filler alignment and aspect ratio can significantly contribute to making heat-conducting networks in composites, which results in ultra-high thermal conductivity.

UV curing polyurethane–acrylate composites as full filling thermal interface materials

“…(A value of CTE less than 100 ppm °C −1 is considered a target value for achieving a filler–matrix combination to satisfy the structural properties of the intended TIMs.) 39…”

Biomass- and Carbon Dioxide-Derived Polyurethane Networks for Thermal Interface Material Applications

“…Some examples of these materials are thermal grease, gel, and tape, but most of the materials are developed as composites of a polymer matrix and thermal conductive fillers [ 38 ]. This strategy is designed to compensate for the limitations of inorganic conductive fillers and polymer materials: inorganic conductive fillers have high thermal conductivity but poor adhesion, whereas polymer materials have excellent adhesion but low thermal conductivity [ 39 , 40 , 41 ]. Epoxy, silicon, and thermoplastic polyurethane are typical polymers used to develop TIMs [ 39 ].…”

“…This strategy is designed to compensate for the limitations of inorganic conductive fillers and polymer materials: inorganic conductive fillers have high thermal conductivity but poor adhesion, whereas polymer materials have excellent adhesion but low thermal conductivity [ 39 , 40 , 41 ]. Epoxy, silicon, and thermoplastic polyurethane are typical polymers used to develop TIMs [ 39 ]. Of these, polyurethanes have high water resistance and adjustable hardness and elasticity [ 42 , 43 ].…”

Thermal Interface Materials with High Thermal Conductivity and Low Young’s Modulus Using a Solid–Liquid Metal Codoping Strategy

“…The synchronized increase of the two physical properties will result in the dilemma of low thermal conductivity at a small doping volume and high hardness at a large doping volume. Akhtar 17 predicted that the thermal conductivity of the Al 2 O 3 −epoxy composite would increase from 0.18 to 2.37 W/(m•K), and the tensile modulus would increase from 1.3 to 5.3 GPa with an increase in doping volume fraction of Al 2 O 3 from 0 to 60%. Constructing a thermal path inside the composite is an effective method to improve the thermal conductivity under a small doping percentage, and this can be achieved using the freeze-drying method, 18 the template method, 19 the in situ growth method, 20 and other techniques.…”