Comparison of carbon nanofiller-based polymer composite adhesives and pastes for thermal interface applications

Abstract

Graphite nanoplatelets (GNP), carbon black (CB) and carbon nanotubes are extensively researched to produce thermal interface materials (TIMs). This work reports comparison of interfacial thermal conductance (ITC) of carbon nanofiller-based polymer composite adhesives and pastes. The results show that total thermal contact resistance (TTCR) of GNP/rubbery epoxy composite was the same as that of an equivalent glassy epoxy composite. Although CB-based rubbery epoxy and silicone composites can be applied as thin bondlines, their TTCRs were significantly higher than GNP/rubbery epoxy. GNPs incorporation into CB/rubbery epoxy composite improves the ITC of the CB/rubbery epoxy composites but the performance of CB/GNP/rubbery epoxy was inferior to GNP/rubbery epoxy. The thermal paste of GNP/polyetheramine had TTCR of 4.8 × 10 -6 m 2 .K/W which is comparable to commercial TIMpaste. The paste produced with silicone had relatively poor ITC versus that prepared with polyetheramine. The paste having smaller particle sized GNPs offers lower TTCR than that prepared with large sized GNPs. The GNP/rubbery epoxy adhesives produced from precursor pastes gave the lowest TTCRs in comparison with the other adhesives. This study suggests that GNPs offer potential for enhancing ITC of TIMs and that ITC of adhesives depends on fillers' thermal conductivity and their interfacial contact with substrates.

Study on epoxy resin-based thermal adhesive filled with hybrid expanded graphite and graphene nanoplatelet

“…The synergistic effect and high aspect ratio of both micro-and nanoparticles help to increase the thermal conductivity up to 3.0 W/m K. Similarly, Fig. 9c, d represents SEM image of the fractured surface at a different region which indicates that flexible and loose bunch of GNP layers formed in between enlarged layers of expanded graphite and epoxy matrix phase which are dispersed randomly at interfaces [17,26,45,46]. However, there are some agglomerations, cracks and holes presence which are formed during adhesive preparation.…”

“…It has an inherent thermal conductivity of nearly 1500 W/m K and contains both amorphous and crystalline regions of GNP layer units inside EG porous structure which cannot restack after composite formation due to permanent breakage of van der Walls forces [17][18][19][20][21][22][23][24]. Further, hybrid formulation of different carbon-based fillers inside reinforced polymer composites influences the size, shape and aspects ratio of fillers and produces additive or synergistic effect toward thermal conductivity enhancement of composites [11,[25][26][27][28][29][30][31][32][33][34][35]. In this paper, we focus our attention on expanded graphite and GNP's use in epoxy-based TIMs.…”

Thermal contact resistance of various carbon nanomaterial-based epoxy composites developed for thermal interface applications

“…These dispersions were laid as a thin layer "bond line" between copper blocks and then cured for testing in a thermal contact resistance measurement rig, designed according to ASTM D5470 [5]. Thermal contact resistance (TCR) of nanocarbon/epoxy composites as adhesives was studied under steady state conditions following the procedures described in [5,6]. All composites were developed at a loading of 4 wt.% for comparative analysis.…”

“…The total TCRs of 4 wt.% FLG/REP, 4 wt.% GNP/REP, 4 wt.% MWCNT/REP composite coatings are presented in Table 1. 4 wt.% FLG/REP by CSS 5.2 × 10 -5 4 wt.% commercial GNP/REP by CSS 5.1 × 10 -5 4 wt.% MWCNT/REP 1.36 × 10 -4 15 wt.% commercial GNP/REP produced by roll mill [7] 2.6 × 10 -5…”

Thermal, mechanical, and dielectric properties of aluminium oxide and solid glass microsphere‐reinforced epoxy composite for electronic packaging application

“…Copper and nickel , aluminium , tin , and silver particles are used as a metallic filler material to improve the thermal conductivity of polymers. Carbon and graphene filler possesses further high thermal conductivity as compared with metals, had also been used as filler for such purpose . In‐spite of having high thermal conductivity, metals and carbon fibers are not the suitable for present application because of their high electrical conductivity.…”