High thermal conductivity epoxies containing substituted biphenyl mesogenic

Abstract

In this work, a series of high thermal conductivity epoxies containing substituted biphenyl mesogenic were prepared and characterized. The liquid crystalline phase structure of substituted biphenyl epoxies was determined by polarized optical microscopy. Differential scanning calorimetry and thermogravimetric were used to characterize the thermal properties of substituted biphenyl epoxies. The relationship between thermal conductivity and liquid crystalline domain structure was discussed in our paper. The samples show high thermal conductivity up to 0.28 W/(m*K), owing to the introduction of biphenyl mesogenic into epoxes, which indicates that the thermal conductivity was apparently better than that of conventional epoxy systems. The high glass transition temperatures ranging from 128 to 178°C and high thermal resistance can make contribute to a stable fixed shape. The high thermal conductivity and high thermal properties can make this epoxy very suitable for the application in microelectronics.

Self‐healable and reprocessible liquid crystalline elastomer and its highly thermal conductive composites by incorporating graphene via in‐situ polymerization

“…Therefore, it can be concluded that the oriented molecular structure of polydomains in the network can increase thermal-energy transmission of the lattice vibration (phonon) by suppressing the phonon scattering, leading to an enhancement of thermal conductivities. 21,24…”

“…21 In our previous studies, we have synthesized a series of liquid crystalline polymers with high thermal conductivities ranging from 0.27 to 0.4 Wm −1 K −1 . [22][23][24][25] Another method, considered as the most simple and effective method, is introducing thermally conductive fillers such as silicon carbide (SiC), alumina (Al 2 O 3 ), boron nitride (BN), magnesium oxide (MgO), graphene, and carbon nanotube (CNT) into the polymer matrix, which indeed improves the thermal conductivities well. [26][27][28][29][30][31][32][33][34] Among various thermal conductive fillers, graphene nanoplates (GNPs), because of its excellent flexibility and extremely high in-plane thermal conductivity (approximately 5300 Wm −1 K −1 ), 35,36 are an ideal filler for fabricating polymer composites with high thermal conductiy.…”

“…For example, Kim synthesized a liquid crystalline epoxy resin that exhibited a remarkable thermal conductivity of 0.4 Wm −1 K −1 , which was two times greater than that of traditional epoxies 21 . In our previous studies, we have synthesized a series of liquid crystalline polymers with high thermal conductivities ranging from 0.27 to 0.4 Wm −1 K −1 22–25 . Another method, considered as the most simple and effective method, is introducing thermally conductive fillers such as silicon carbide (SiC), alumina (Al 2 O 3 ), boron nitride (BN), magnesium oxide (MgO), graphene, and carbon nanotube (CNT) into the polymer matrix, which indeed improves the thermal conductivities well 26–34 .…”

Temperature-Triggered/Switchable Thermal Conductivity of Epoxy Resins

“…Two main strategies have been reported for the enhancement of the thermal conductivity of polymers and polymer-based composites; that is, compounding with inorganic particles that exhibit high thermal conductivity (e.g., λ (BN) = 600 W·m −1 ·K −1 [ 17 ] λ (SiO 2 ) = 0.7 W·m −1 ·K −1 [ 18 ]) on the one hand, and blending with organic moieties with a high content of aromatic units capable of forming (crystalline) regions by π-π-stacking on the other [ 19 , 20 , 21 ]. The so-called percolation threshold [ 22 ] has to be considered within both strategies, which commonly results in high degrees of compounding/blending and influences various other macroscopic properties such as the mechanical properties.…”

Analysis of the Raman Frequency as an Order Parameter Close to the Melting Point in Biphenyl

“…Studies on the physical and chemical properties of biphenyl have also been reported in the literature. Some of those studies are the following: surface melting in biphenyl, chemical shift in the solid state of biphenyls, calorimetric study on two biphenyl liquid crystals, phase equilibria and heat capacity of diphenyl ether + biphenyl, electro-optic and dynamic studies of biphenyl benzoate ferroelectric liquid crystals and thermal conductivity epoxies containing substituted biphenyl mesogenic [14][15][16][17][18][19].…”