Thermal Conductivity Enhancement of Liquid Crystal Polymer–Solid Particle Composites by Grafting a Main-Chain-Type Liquid Crystal Polymer onto Particle Surfaces

Abstract

Thermally conductive composites comprising filler particles dispersed in a polymer matrix can effectively enhance the thermal conductivity (TC) by increasing the TC of the matrix; however, the TCs of polymers are difficult to increase. This study demonstrates that a liquid crystal polymer (LCP) that forms the matrix of a composite increases the TC to the value that is measured along the liquid crystal (LC) director orientation (λ // ). The LCP used here comprised a thiol−ene-type monomer that enabled grafting of the main-chain-type LCP onto allyl-functionalized magnesium oxide particles (MgOPs) with a diameter of 10 μm. The mixtures of LCP-grafted MgOPs and the LCP formed composite films with the MgOPs well dispersed in the LCP matrix at a MgOP volume fraction (v MgO ) of up to 34%. These films increased the TC up to 2.0 W m −1 K −1 as the v MgO increased, indicating that the LCP matrix increased the TC to 0.66 W m −1 K −1 . This matrix TC value was similar to the λ // value of the LCP (0.63 W m −1 K −1 ), suggesting that effective heat paths formed between the particles. These heat paths are associated with the matrix LCP aligning the director to follow the lines connecting the particle surfaces. This LCP director distribution was promoted by grafting LCP chains on the particle surfaces.

Enhanced Thermal Pad Composites Using Densely Aligned MgO Nanowires

“…Our analysis determined that the aligned composite with 4 vol% filler exhibited a similar or higher thermal conductivity than that of composites with a filler content of 10 vol% or higher. Additionally, the aligned composites with a similar filler content (approximately 12 vol%) were considerably superior (>100%) to previously reported MgO composites (Figure 4e) [31][32][33][34][35][36]. Therefore, the obtained results verified that the proposed technique of manufacturing TIM composites can be an outstanding method for obtaining high-performance thermal pads compared with previously reported MgO polymer composites.…”

Enhanced mechanical properties of polyphenylene sulfide and liquid crystal polymer composites by interfacial bonding capacity of graft‐modified graphene oxide and glass fibers

“…Consequently, it is extensively utilized in various industries such as food, machinery, chemical, automotive, electronics, aerospace, and others. [1][2][3][4][5][6][7] The drawbacks of PPS primarily revolve around its limited toughness, prompting the exploration of two commonly employed methods to address this issue.…”

“…A high‐performance semi‐crystalline polymer, PPS, is composed of interconnected phenyl rings and sulfur atoms, granting it exceptional properties such as remarkable heat resistance, outstanding abrasion resistance, excellent flame retardancy, and favorable mechanical characteristics. Consequently, it is extensively utilized in various industries such as food, machinery, chemical, automotive, electronics, aerospace, and others 1–7 . The drawbacks of PPS primarily revolve around its limited toughness, prompting the exploration of two commonly employed methods to address this issue.…”