High thermal conductivity of liquid crystalline monomer‐poly (vinyl alcohol) dispersion films containing microscopic‐ordered structure

Li, Chenggong; Li, Ying; Gong, Changdan; Ruan, Kunpeng; Zhong, Xiaomei; Pan, Pan; Liu, Chao; Gu, Junwei; Shi, Xuetao

doi:10.1002/app.49791

Cited by 11 publications

(4 citation statements)

References 40 publications

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“…The key factors that influence the thermal conductivity of a polymer are the degree of crystallinity, orientation ordering, and crystal structure 14 . Increasing the stacking density of the molecular chains and decreasing the entanglement to build the ordered structure to reduce the disturbance to phonon transfer 20 are the key to improving intrinsic thermal conductivity. Hence, the thermal conductivity of epoxy resins can be enhanced through appropriate design, such as modifying the structure of the monomer molecular chain via chemical synthesis or processing 21 .…”

Section: Introductionmentioning

confidence: 99%

Investigation of liquid crystal epoxy resin composites for application in cryogenic environments

Li,

Ma,

Liu

et al. 2024

J of Applied Polymer Sci

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It is well accepted that the intrinsic thermal conductivity is extremely important in achieving excellent thermal conductivity composite and can be improved via incorporation of mesogens. In this work, an azomethine type liquid crystal epoxy (LCE) with aliphatic ether was designed and synthesized with expected structure, and the liquid crystal epoxy resin (LCER), together with KH‐550‐modified boron nitride (K‐BN)/LCER composites, has been obtained. Results show an increase of 31.6% in the thermal conductivity of the matrix, which could result in an enhancement of 57.7% for the composites when compared with E‐51. Additionally, the coefficient of thermal expansion (CTE), dielectric properties, and shear strength of LCER and K‐BN/LCER composites were assessed across a broad temperature range. Remarkably, the 30 wt% K‐BN/LCER composites showed a maximum decrease of 37.8% in CTE, while maintaining adequate shear strength to fulfill the bonding requirement and high thermal conductivity at both RT and −196°C.

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Section: Introductionmentioning

confidence: 99%

Investigation of liquid crystal epoxy resin composites for application in cryogenic environments

Li,

Ma,

Liu

et al. 2024

J of Applied Polymer Sci

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“…The thermal conductivity of epoxy resin can be improved in two ways: one is to improve the order of molecular chain structure by introducing prepolymers or hydrogen bonds with liquid crystal unit structure in the resin, thereby improving the thermal conductivity of the resin matrix to some extent. , However, this method is difficult to be applied in large-scale production due to its complicated operation and high cost. Therefore, many researchers are focusing on alternative method of producing filled thermal conductive resin materials.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Hexagonal Boron Nitride-Containing Foam with Improved Thermal Conductivity of Epoxy Resins

Wang

Zhang

et al. 2023

ACS Appl. Polym. Mater.

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With the continuous development of electrical and electronic devices, the thermal conductivity of dielectric polymer composites within devices is becoming increasingly important. However, improving the thermal conductivity usually requires the incorporation of a large amount of filler in polymer material, which undoubtedly increases the production cost while destroying the processability and the dielectric properties of the material. In this work, an efficient heat transfer network was constructed inside the resin matrix to overcome this drawback. Using the opposite surface potentials of hexagonal boron nitride (h-BN) and polyethyleneimine (PEI) in solvent, h-BN was anchored on the surface of melamine foam (MF) by an electrostatic self-assembly technique to construct a thermal conductive skeleton with a three-dimensional open pore structure, and the corresponding epoxy (EP) composite was prepared by vacuum-assisted impregnation. This EP–MF@BN composite showed a significant increase in the heat arrival rate at an extremely low filler loading. At a h-BN loading of 2.1 wt %, the thermal conductivity of the composite reached 0.433 W/(m·K), which was 147% higher than that of the pure resin matrix. This is mainly attributed to the unique three-dimensional open-hole structure of the MF foam, which formed a three-dimensional frame structure with extremely low thermal resistance after anchoring by h-BN, thus providing a great degree of weakening of the scattering behavior during phonon transport. In addition, the transport behavior of carriers inside the composite under strong electric field conditions was analyzed in the current study. This strategy of constructing an efficient heat transfer network inside the polymer matrix provides an idea and method for the preparation of composites in the field of electrical insulation.

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“…Thermal conductive polymers are widely used in 5G communication, radar technology, new energy vehicles and flexible wearable electronics by reason of their high flexibility, good electrical insulation performance, lightweight, high strength, chemical resistance, low cost, and easy processability 5–10 . Recent years, a lot of studies have been carried out to improve the polymer materials' TC by either synthesizing intrinsically 11–13 thermal conductive polymers or introducing high TC's fillers 14,15 …”

Section: Introductionmentioning

confidence: 99%

Flexible and thermally conductive epoxy‐dispersed liquid crystal composites filled with functionalized boron nitride nanosheets

Huang

et al. 2023

Polymer Composites

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In view of the problem of heat accumulation in electronic devices, the development of new composites with high thermal conductivity (TC) is the current research focus. Nowadays, improving TC often lead to inevitable deterioration of the mechanical properties of materials. In this work, the E‐functionalized boron nitride nanosheets (f‐BNNS)/liquid crystal monomer (LCM)/Epoxy‐thiol films with high TC were prepared by using flexible epoxy‐thiol polymer as matrix and LCM and f‐BNNS as thermal fillers via high voltage orientation molding. The epoxy‐thiol polymer possessed high intrinsic TC due to the regular arrangement of molecular chains and the f‐BNNS showed favorable dispersibility because of the modification by isopropyl tri(dioctylpyrophosphate) titanate (ITDPT). The results show that TC of E‐f‐BNNS/LCM/Epoxy‐thiol films with 30 wt% f‐BNNS content achieves 1.65 W/m·K and is 511.11% higher than that of pure epoxy‐thiol polymer (0.27 W/m·K). The tensile strength and elongation at break increase to 24.9 MPa and 47.41%, respectively. The favorable results are attributed to the ordered arrangement of f‐BNNS and molecular chains, resulting from the hydrogen‐bonding interaction between OH group in f‐BNNS, LCM and epoxy‐thiol polymer. This research provides a simple and feasible method for preparing flexible epoxy polymer films with high TC.Highlights The functional BNNS was achieved by isopropyl tri(dioctylpyrophosphate) titanate. Effects of matrix thermal conductivity on films thermal conductivity are probed. High voltage orientation molding are used for preparing epoxy composite films. The films demonstrate excellent thermal conductivity and favorable tensile strength.

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High thermal conductivity of liquid crystalline monomer‐poly (vinyl alcohol) dispersion films containing microscopic‐ordered structure

Cited by 11 publications

References 40 publications

Investigation of liquid crystal epoxy resin composites for application in cryogenic environments

Investigation of liquid crystal epoxy resin composites for application in cryogenic environments

Preparation of Hexagonal Boron Nitride-Containing Foam with Improved Thermal Conductivity of Epoxy Resins

Flexible and thermally conductive epoxy‐dispersed liquid crystal composites filled with functionalized boron nitride nanosheets

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