Electronic devices play an increasingly vital role in modern society, and heat accumulation is a major concern during device development, which causes strong market demand for thermal conductivity materials and components. In this paper, a novel thermal conductive material consisting of polydimethylsiloxane (PDMS) and a binary filler system of h-BN platelets and Al2O3nanoparticles was successfully fabricated using direct ink writing (DIW) 3D printing technology. The addictive manufacturing process not only endows the DIW-printed composites with various geometries but also promotes the construction of a 3D structural thermal conductive network through the shearing force during the printing process. Moreover, the integrity of the thermal conductive network can be optimized by filling the gaps between the BN platelets with Al2O3particles. Resultingly, the configuration of the binary fillers is arranged by the shearing force during the DIW process, fabricating the thermal conductive network of oriented fillers. The DIW-printed BN/Al2O3/PDMS with 45 wt% thermal conductive binary filler can reach a thermal conductivity of 0.98 W/(m·K), higher than the 0.62 W/(m·K) of the control sample. In this study, a novel strategy for the thermal conductive performance improvement of composites based on DIW technology is successfully verified, paving a new way for thermal management.
In this work, we prepared the epoxy-based adhesives with a binary filler system, which was composed of organosilicon modified hexagonal BN ( h -BN) and α-Al 2 O 3 . H -BN platelets and α-Al 2 O 3 nanoparticles were decorated by aminopropyltrimethoxysilane (APTMS) and glycidylpropyltrimethoxysilane (GPTMS), respectively, to form covalent links to the filler/polymer matrix interface. The surface chemical composition was investigated by Fourrier transform infrared spectroscopy (FTIR) and thermogravimetry analysis (TGA), which demonstrated that the modifiers were successfully grafted onto the surface of fillers. This modification has been confirmed beneficial to thermal conductivity so that the thermal conductivity of adhesives incorporated with modified binary fillers could reach 0.85 w/m k, which is 10% more than specimen filled with unmodified fillers, because covalent links strengthened the interface and prohibited heat diffusion. Modified Hashin–Shtrikman model was utilized to analyze thermal resistance of the binary filler system, indicating that adhesives filled with modified fillers displayed lower thermal resistance. The enhancement of interface also brought about some other positive effect, especially in the decreasing of dielectric constant (< 4.3 at 1000 Hz) and the low values of dielectric loss tangent (10 –3 ) and high electronic resistance (> 10 14 ). Furthermore, the mechanical strength is significantly improved when the modified binary fillers were used.
危险品化学品经营许可证（带存储）