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In this article, silicone rubber (SiR) is filled with industry preferred micro-silica and specialty hexagonal boron nitride (h-BN) nanosheets, by varying the ratio between the two fillers, while keeping the filler to matrix ratio the same in all three composites. The fillers are added to SiR using an electrostatic disperser which aids in homogenizing the filler-polymer mixture by means of shearing force along with elongation. The performance of synthesized silicone composites are evaluated using thermal, erosion resistance, morphological, mechanical, and high-temperature dielectric properties. Addition of as low as 5 wt% h-BN fillers significantly improved the thermal properties; 6%–20% improvement in thermal conductivity and in less than half the weight loss compared to only silica filled composites with laser erosion. The morphological and mechanical analyses showed improved filler dispersion and filler to silicone matrix interaction owing to good filler dispersion achieved through the electrostatic dispersing method. The dielectric properties measured in wide frequency range, between 10−4 and 103 Hz and at elevated temperatures (up to 175 °C) showed a negligible effect of increase in h-BN content. Thus, this article implies that low amounts of h-BN in silica-silicone composites improve thermal conductivity and erosion resistance significantly and not altering the dielectric responses of these hybrid composites even at elevated temperatures. Hence these composites can find applications both in the high voltage industry and as electronic packaging materials. [ABSTRACT FROM AUTHOR]

Increased demand on the mechanical and thermal properties on the thermal interface and die attach material creates a demand for materials with tailored material properties. Solder matrix fiber composites (SMFCs) have been shown to address these challenges, but have, so far, required complicated procedures and components. In this paper, we present the fabrication of a new type of SMFC based on commercially available fiber networks infiltrated with Sn–Ag–Cu alloy (SAC305) or indium using equipment for large-volume production. The composite material exhibits similar thermal properties compared to pure solder, and mechanical properties that can be tailored toward specific applications. We also show that the handling properties of the SMFC allows it to be used in process flows where multiple reflow cycles are required and can achieve a well-defined bond line thickness (BLT) and good bonding using fluxless reflow under pressure. [ABSTRACT FROM AUTHOR]

A reliable thermal interface material (TIM) typically has a low storage modulus ( \textG^\prime ) and a tan( $\delta$ ) less than one; these mechanical properties are crucial for minimizing contact resistance ( \mathbf {R}_{\mathbf {c}} ). This paper demonstrates the correlation between storage modulus ( \textG^\prime ) and the crosslink density of silicone gels. Formulations span between 0.30 and 1.00 hydride to vinyl (H:Vi) ratios for the vinyl terminated and hydride pendent polymers used in the gel. These gels are tailored for TIM applications by adding highly conductive particles to improve thermal conductivity. During this study, when 80 wt% conductive filler was added to gels with a 0.6 H:Vi ratio, the \textG^\prime increased by 6025%. In order to minimize \textG^\prime , the crosslinker in the formulation was replaced with a chain extender. With this formula substitution, the modulus of the filled gel can be successfully lowered to the original value of the unfilled gel while maintaining the crucial properties of a reliable TIM. In effect, it is possible to independently optimize the thermal conductivity of a TIM while creating a compliant gel that maintains surface contact and minimizes contact resistance. [ABSTRACT FROM AUTHOR]