Functionalization of mild oxidized graphene with O-phenylenediamine for highly thermally conductive and thermally stable epoxy composites

In this study, we investigated the synergistic effects of thermally conductive hybrid carbonaceous fillers of mesophase pitch-based carbon fibers (MPCFs) and reduced graphene oxides (rGOs) on the thermal conductivity of polymer matrix composites. Micro-sized MPCFs with different lengths (50 μm, 200 μm, and 6 mm) and nano-sized rGOs were used as the thermally conductive fillers used for the preparation of the heat-dissipation polymer composites. For all MPCF fillers with a different length, the thermal conductivity values of the MPCF/epoxy composites were proportional to the MPCF length and loading amount (0–50 wt%) of MPCFs. For an MPCF:rGO weight ratio of 49:1 (total loading amount of 50 wt%), the thermal conductivity values of MPCF-rGO/epoxy composites loaded with MPCFs of 50 μm, 200 μm, and 6 mm increased from 5.56 to 7.98 W/mK (approximately 44% increase), from 7.36 to 9.80 W/mK (approximately 33% increase), and from 11.53 to 12.58 W/mK (approximately 9% increase) compared to the MPCF/epoxy composites, respectively, indicating the synergistic effect on the thermal conductivity enhancement. The rGOs in the MPCF-rGO/epoxy composites acted as thermal bridges between neighboring MPCFs, resulting in the formation of effective heat transfer pathways. In contrast, the MPCF-rGO/epoxy composites with MPCF:rGO weight ratios of 48:2 and 47:3 decreased the synergistic effect more significantly compared to rGO content of 1 wt%, which is associated with the agglomeration of rGO nanoparticles. The synergistic effect was inversely proportional to the MPCF length. A theoretical approach, the modified Mori-Tanaka model, was used to estimate the thermal conductivity values of the MPCF-rGO/epoxy composites, which were in agreement with the experimentally measured values for MPCF-rGO/epoxy composites loaded with short MPCF lengths of 50 and 200 μm.

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High thermally conductive epoxy composite inks cured by infrared laser irradiation for two-dimensional/three-dimensional printing technology

Journal of Composite Materials ◽

10.1177/0021998320935154 ◽

2020 ◽

Vol 54 (29) ◽

pp. 4635-4643

Author(s):

Gi-Tae Park ◽

Sung Jun Lee ◽

Byeong Guk Kim ◽

Sang Hun Lee ◽

Jae Wook Kang ◽

...

Keyword(s):

Thermal Conductivity ◽

Three Dimensional ◽

Diglycidyl Ether ◽

Epoxy Composites ◽

Printing Technology ◽

Three Dimensional Printing ◽

Bisphenol A Diglycidyl Ether ◽

Electrical Conductivities ◽

Thermally Conductive ◽

Absorbing Material

We propose a new fabrication method of high thermally conductive epoxy composites for 3 D printing technology, which is based on a thermosetting epoxy system containing graphene nanoplate (GNP) as an IR-absorbing material. Firstly, we developed highly heat-dissipating inks based on bisphenol A diglycidyl ether (DGEBA) type epoxy resins containing graphene nanoplate (GNP) which was used as a heat dissipating filler and, simultaneously, an IR-absorbing material for heat induced rapid curing of printed layer. h-BN was also added as a heat dissipating filler in order to increase the thermal conductivity and to decrease the electrical conductivity of the composite. Secondly, by using a micro dispenser equipped with an IR laser, 2D/3D line patterns of thermally conductive epoxy composites were printed and cured in-situ. Thermal and electrical conductivities of the resulting composites were discussed with respect to the resin compositions and the irradiation conditions. The highest thermal conductivity of 2.77 W/m·K was achieved when the contents of GNP and h-BN were 15.0 and 20.0 phr, respectively.

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An efficient approach for constructing 3-D boron nitride networks with epoxy composites to form materials with enhanced thermal, dielectric, and mechanical properties

High Performance Polymers ◽

10.1177/0954008318772331 ◽

2019 ◽

Vol 31 (3) ◽

pp. 350-358 ◽

Cited By ~ 7

Author(s):

XinYu Leng ◽

Chao Xiao ◽

Lu Chen ◽

Zheng Su ◽

Kang Zheng ◽

...

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Boron Nitride ◽

Epoxy Composites ◽

Template Method ◽

Thermal Stabilities ◽

Thermally Conductive ◽

Epoxy Material ◽

Dielectric And Mechanical Properties ◽

Scanning Electron

Thermally conductive epoxy composites of 3-D boron nitride (BN) networks were synthesized via a facile template method, wherein an epoxy was infiltrated into the network. The 3-D BN network skeletons, which use polystyrene (PS) microspheres as a framework support, were prepared by hot compression and ablation techniques. Field emission scanning electron microscope indicated that the content of BN filler and its dispersion greatly influences the integrity and density of the resultant network. With a BN loading of 40 vol%, the composites showed a maximum thermal conductivity of 1.98 W mK−1, which is 1000% times higher than the pristine epoxy material. In addition, the thermal stabilities, mechanical properties, and dielectric properties of the fabricated BN/epoxy composites were also largely improved. This facile method is an effective approach to designing and fabricating composites with high thermal conductivities.

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A Novel Method to Prepare Transparent, Flexible and Thermally Conductive Polyethylene/Boron Nitride Films

Nanomaterials ◽

10.3390/nano12010111 ◽

2021 ◽

Vol 12 (1) ◽

pp. 111

Author(s):

Mingming Yi ◽

Meng Han ◽

Junlin Chen ◽

Zhifeng Hao ◽

Yuanzhou Chen ◽

...

Keyword(s):

Thermal Conductivity ◽

Boron Nitride ◽

Thermal Management ◽

Self Assembly ◽

High Performance ◽

High Thermal Conductivity ◽

Polyethylene Film ◽

High Concentration ◽

Thermally Conductive ◽

Novel Method

The high thermal conductivity and good insulating properties of boron nitride (BN) make it a promising filler for high-performance polymer-based thermal management materials. An easy way to prepare BN-polymer composites is to directly mix BN particles with polymer matrix. However, a high concentration of fillers usually leads to a huge reduction of mechanical strength and optical transmission. Here, we propose a novel method to prepare polyethylene/boron nitride nanoplates (PE/BNNPs) composites through the combination of electrostatic self-assembly and hot pressing. Through this method, the thermal conductivity of the PE/BNNPs composites reach 0.47 W/mK, which gets a 14.6% improvement compared to pure polyethylene film. Thanks to the tight bonding of polyethylene with BNNPs, the tensile strength of the composite film reaches 1.82 MPa, an increase of 173.58% compared to that of pure polyethylene film (0.66 MPa). The fracture stress was also highly enhanced, with an increase of 148.44% compared to pure polyethylene film. Moreover, the addition of BNNPs in PE does not highly reduce its good transmittance, which is preferred for thermal management in devices like light-emitting diodes. This work gives an insight into the preparation strategy of transparent and flexible thermal management materials with high thermal conductivity.

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Highly thermally conductive UHMWPE/NG composites with the segregated structure and their application for heat spreader

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705720965649 ◽

2020 ◽

pp. 089270572096564

Author(s):

Xiao Wang ◽

Hui Lu ◽

Jun Chen

Keyword(s):

Thermal Conductivity ◽

Laser Flash ◽

Heating Process ◽

X Ray Diffraction ◽

Heat Spreader ◽

Conductive Composites ◽

Compression Direction ◽

Thermal Analyzer ◽

Thermally Conductive ◽

Plane Direction

In this work, ultra-high molecular weight polyethylene (UHMWPE)/natural flake graphite (NG) polymer composites with the extraordinary high thermal conductivity were prepared by a facile mixed-heating powder method. Morphology observation and X-ray diffraction (XRD) tests revealed that the NG flakes could be more tightly coated on the surface of UHMWPE granules by mixed-heating process and align horizontally (perpendicular to the hot compression direction of composites). Laser flash thermal analyzer (LFA) demonstrated that the thermal conductivity (TC) of composites with 21.6 vol% of NG reached 19.87 W/(m·K) and 10.67 W/(m·K) in the in-plane and through-plane direction, respectively. Application experiment further demonstrated that UHMWPE/NG composites had strong capability to dissipate the heat as heat spreader. The obtained results provided a valuable basis for fabricating high thermal conductive composites which can act as advanced thermal management materials.

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