Magnetically aligning multilayer graphene to enhance thermal conductivity of silicone rubber composites

Feng

J of Applied Polymer Sci

et al. 2020

A scalable strategy to fabricate thermally conductive but electrically insulating polymer composites was urgently required in various applications including heat exchangers and electronic packages. In this work, multilayered ultrahigh molecular weight polyethylene (UHMWPE)/natural graphite (NG)/boron nitride (BN) composites were prepared by hot compressing the UHMWPE/NG layers and UHMWPE/BN layers alternately. Taking advantage of the internal properties of NG and BN fillers, the UHMWPE/NG layers played a decisive role in enhancing thermal conductivity (TC), while the UHMWPE/BN layers effectively blocked the electrically conductive pathways without affecting the thermal conductive pathways. The in-plane TC, electrical insulation, and heat spreading ability of multilayered UHMWPE/NG/BN composites increased with the increasing layer numbers. At the total fillers loading of 40 wt%, the in-plane TC of multilayered UHMWPE/NG/BN composites with nine layers was markedly improved to 6.319 Wm −1 K −1 , outperforming UHMWPE/BN (4.735 Wm −1 K −1) and pure UHMWPE (0.305 Wm −1 K −1) by 33.45% and 1971.80%, respectively. Meanwhile, the UHMWPE/NG/BN composites still maintained an excellent electrically insulating property (volume resis-tance~5.40×10 14 Ω cm; breakdown voltage~1.52 kV/mm). Moreover, the multilayered UHMWPE/NG/BN composites also exhibited surpassing heat dissipation capability and mechanical properties. Our results provided an effective method to fabricate highly thermal conductive and electrical insulating composites. K E Y W O R D S applications, composites, thermal properties, molding 1 | INTRODUCTION Owing to the rapidly escalation of power densities and integration in electronic components, heat dissipation has become a critical issue to protect electronics from overheating. Polymer-based composites are widely used in many fields for their excellent processability, lightweight, low cost, and outstanding chemical stability. 1-3

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Multilayered ultrahigh molecular weight polyethylene/natural graphite/boron nitride composites with enhanced thermal conductivity and electrical insulation by hot compression

Feng

J of Applied Polymer Sci

et al. 2020

“…By introducing highly thermal conductive nano‐fillers, such as Al 2 O 3 , aluminum nitride, silicon carbide, and BN, [ 4–6 ] into the polymer is the most common method to enhance the thermal conductivity of the material. [ 7 ] Theoretically, the small size of the filler is beneficial to achieve the specific arrangement of the fillers in the matrix under the external action, [ 8–10 ] which has a significant value for the thermal conductivity of the composite. In virtue of some methods, small‐sized thermal conductive fillers can be interconnected into network, in which heat can be effectively transferred along the direction of the filler connection.…”

Section: Introductionmentioning

confidence: 99%

High‐thermal‐conduction and low‐cost composite originated from the tight packing structure of boron nitride sheets and binary alumina balls

Zhang

2021

Polymer Composites

In this work, a novel low‐cost and thermal conductive composite consisting of boron nitride (BN)/aluminum oxide (Al2O3) heat transfer network was constructed by the high packing volume fraction of two sizes Al2O3 spheres at the optimal weight ratio. The dense packing of 5 μm Al2O3 and 20 μm Al2O3 supports the BN sheets scattering around Al2O3 to interconnect into main three‐dimensional BN network, and acts as thermal conductive bridges forming secondary BN‐Al2O3 heat transfer networks. The maximum thermal conductivity of the composite reached 3.61 Wm−1 K−1, which was 20.1 times more than that of pure epoxy resin. Moreover, the excellent capacity of heat dissipation and the dielectric properties denoted that the composite can be used commendably in electronic components. This article is expected to provide a novel idea for the preparation of economical and high‐performance thermal conductive composites applied in new generation of microelectronic devices.

J of Applied Polymer Sci

Section: Introductionmentioning

confidence: 99%

“…Since the commercialization in 1940s', silicone rubber (SR) has been recognized as highly valuable elastomers in the fields of electronic and electrical industries due to its high and low temperature resistance, non-toxicity, superior hydrophobicity and excellent insulation property. [1][2][3][4] Unfortunately, the intrinsic flammability of SR restricts its wider industrial applications especially in the areas with high flame-retardant requirements. [5][6][7] To minimize the fire hazards and achieve satisfactory flame resistance of SR, a wide variety of flame retardants such as halogenated organic compounds, 8 inorganic mineral nanofillers, 9 and intumescent flame retardants (IFRs) were designed and incorporated in SR matrix by physical blending.…”

Section: Introductionmentioning

confidence: 99%

Facile preparation and flame retardancy mechanism of cyclophosphazene derivatives for highly flame‐retardant silicone rubber composites

Yang

et al. 2020

Self Cite

A novel and efficient flame retardant cyclophosphazene derivative Hexa (p‐acetamidophenoxy) cyclotriphosphazene (HACP) was successfully prepared via a facile one‐step reaction. The chemical structure of HACP was characterized and confirmed by FT‐IR, 1H and 13C NMR. Then the as‐prepared HACP was incorporated into addition‐cure liquid silicone rubber (ALSR) matrix to prepare highly flame‐retardant rubber composites. It was found that the incorporation of HACP can significantly enhance the flame resistance of ALSR. Typically, the ALSR composites filled with 30 phr HACP achieved UL‐94 V‐0 rating and meanwhile the total heat release and total smoke release were decreased by 26.9% and 41.5%, respectively. Moreover, the flame‐retardant mechanism of ALSR/HACP composites was investigated by TGA, Py‐GCMS, FT‐IR, SEM and EDX, confirming that HACP plays a significant role in capturing free‐radicals and forming protective layers. This work designed a novel cyclophosphazene‐based flame retardant to significantly enhance the flame retardancy of ALSR, which may offer some valuable inspiration for the fabrication of highly flame‐retardant polymer composites.