Enhanced Thermal Conductivity of Epoxy Composites with MWCNTs/AlN Hybrid Filler

To further improve the thermal conductivity of epoxy resin, the multi-walled carbon nanotube/aluminum nitride (MWCNTs/AlN) hybrid filler was employed to prepare thermal conductivity MWCNTs/AlN/epoxy composite by casting process, and the silane coupling reagent of γ-glycidoxy propyl trimethoxy silane(KH-560) was also used to functionalize the surface of MWCNTs and/or AlN. Results revealed that, the thermal conductivity of epoxy resin was improved remarkably with the addition of MWCNTs/AlN hybrid filler, a higher thermal conductivity of 1.04 W/mK could be achieved with 29 wt% MWCNTs/AlN hybrid filler (4 wt% MWCNTs +25 wt% AlN), about 5 times higher than that of native epoxy resin. And the epoxy composite with 29 wt% MWCNTs/AlN hybrid filler possessed better thermal conductivity and mechanical properties than those of single 5 wt% MWCNTs or 40 wt% AlN. The thermal decomposition temperature of MWCNTs/AlN/epoxy composite was increased with the addition of MWCNTs/AlN hybrid filler. For given filler loading, surface treatment of MWCNTs and/or AlN by KH-560 exhibited a positive effect on the thermal conductivity of epoxy composite.     

Mechanical,thermal and electrical properties of multi‐walled carbon nanotube/aluminium nitride/polyetherimide nanocomposites

A series of polyimide‐based nanocomposites containing polyimide‐grafted multi‐walled carbon nanotubes (PI‐g MWCNTs) and silane‐modified ceramic (aluminium nitride (AlN)) were prepared. The mechanical, thermal and electrical properties of hybrid PI‐g MWCNT/AlN/polyetherimide nanocomposites were investigated. After polyimide grafting modification, the PI‐g MWCNTs showed good dispersion and wettability in the polyetherimide matrix and imparted excellent mechanical, electrical and thermal properties. The utilization of the hybrid filler was found to be effective in increasing the thermal conductivity of the composites due to the enhanced connectivity due to the high‐aspect‐ratio MWCNT filler. The use of spherical AlN filler and PI‐g MWCNT filler resulted in composite materials with enhanced thermal conductivity and low coefficient of thermal expansion. Results indicated that the hybrid PI‐g MWCNT and AlN fillers incorporated into the polyetherimide matrix enhanced significantly the thermal stability, thermal conductivity and mechanical properties of the matrix. Copyright © 2012 Society of Chemical Industry     

Effect of surface modification of aluminum nitride on electrical and thermal characterizations of thermosetting polymeric nanocomposites

Thermally conductive composites and nanocomposites composed of epoxy resin as base matrix and aluminum nitride (AlN) as micro and nanofiller have been studied at variable temperatures and loading of AlN. To improve the dispersion of the filler within the polymer matrix, AlN was surface modified with silane‐coupling agent. Thermogravimetric analysis confirmed the interfacial bonding of epoxy‐ and silane‐modified AlN. The dielectric properties of epoxy/AlN composites and nanocomposites have been studied at variable percentage of filler. Test result indicated an increase of thermal conductivity of the composites at 20 wt% of AlN. Also, silane‐treated composites exhibited improved electrical conductivity properties, whereas the electrical insulation property decreased in terms of dielectric strength and resistivity. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers     

New composites with high thermal conductivity and low dielectric constant for microelectronic packaging

Three composites based on cyanate (CE) resin, aluminum nitride (AlN), surface‐treated aluminum nitride [AlN(KH560)], and silicon dioxide (SiO₂) for microelectronic packaging, coded as AlN/CE, AlN(KH560)‐SiO₂(KH560)/CE, and AlN‐SiO₂/CE composite, respectively, were developed for the first time. The thermal conductivity and dielectric constant of all composites were investigated in detail. Results show that properties of fillers in composites have great influence on the thermal conductivity and dielectric constant of composites. Surface treatment of fillers is beneficial to increase the thermal conductivity or reduce dielectric constant of the composites. Comparing with binary composite, when the filler content is high, ternary composites possess lower thermal conductivity and dielectric constant. The reasons leading to these outcomes are discussed intensively. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Mechanical,thermal, and dielectric properties of aluminum nitride/glass fiber/epoxy resin composites

The treated hybrid fillers of aluminum nitride/glass fibers (AlN/GF) were performed to prepare the AlN/GF/epoxy composites by casting method. Results showed that the flexural and impact strength of the composites were increased firstly, but decreased with the excessive addition of AlN. The mechanical properties were optimal with 5 wt% treated AlN. The thermal conductivities of the composites were improved with the increasing content of AlN, and the thermal conductive coefficient λ was 1.412 W/mK with 70 wt% treated AlN, about seven times higher than that of pure epoxy resin. The dielectric constant and dielectric loss of the composites were increased with the increasing content of AlN. For a given AlN/GF hybrid fillers loading, the surface treatment of AlN/GF hybrid fillers exhibited a positive effect on the mechanical properties and thermal conductivities of the composites. POLYM. COMPOS., 35:381–385, 2014. © 2013 Society of Plastics Engineers     

Mineral filler reinforcement for commingled recycled‐plastic materials

Three types of mineral fillers, gypsum, wollastonite, and talc, were investigated for their ability to modify the mechanical properties of commingled recycled‐plastic composites containing 0.07–0.26 v/v of filler. Mechanical test results showed that the talc reinforced composites were significantly better in mechanical properties when compared with the gypsum and wollastonite composites. Scanning electron microscopy (SEM) showed that gypsum formed large agglomerates in the matrix. Interfacial adhesion between filler and matrix was evaluated using simple empirical models. To enhance the adhesion, talc, and wollastonite were pretreated with silane coupling agents, 3‐methacryloxypropyltrimethoxy silane (γ‐MPS) and 3‐aminopropyltriethoxy silane (γ‐APS). This did not result in any significant improvement to the material properties. The γ‐APS treatment, however, increased the tensile properties of the composites by ～ 5% when compared with the γ‐MPS treatment. The SEM investigations showed that the γ‐APS treatment provided better adhesion of filler particles and hence voids were less likely to form in the matrix when compared with the γ‐MPS composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and thermal effects of polyarylene ether nitrile aluminium nitride composites

Particulate‐filled polyarylene ether nitrile (PEN) composites were prepared using methyltriethoxy‐silane‐treated aluminium nitride (AlN) as the filler for thermal modification. The effects of AlN fraction, particle size and surface treatment on the thermal performance of PEN were investigated. The thermal conductivities of the composites increased when the AlN filler concentration was increased, as well as with decrement of the filler size. The thermal conductivity value of the composites increased up to 0.779 W m^?1 K^?1 when the AlN weight loading was 60 wt%. The trend of the thermal conductivities of the composites can be more efficiently predicted by theoretical models than empirical models. The composites exhibited stable performances of thermal decomposition and thermal expansion when AlN filler faction in the composites increased. © 2013 Society of Chemical Industry     

Surface morphology of styrene-butadiene rubber vulcanizate filled with novel electron beam modified dual phase filler by atomic force microscopy

Topographic and phase imaging in tapping mode atomic force microscopy (TMAFM) has been performed to investigate the effect of unmodified and modified dual phase fillers on the morphology of and the microdispersion of the filler particles in the rubber matrix. The above fillers were modified using acrylate monomer (trimethylol propane triacrylate, TMPTA) or a silane coupling agent (triethoxysilylpropyltetrasulphide, Si-69) followed by electron beam modification at room temperature. Both unmodified and surface treated fillers were incorporated in a styrene-butadiene rubber. The phase images of the above composites show three levels of contrasts that correspond to matrix, filler aggregates, and bound rubber around the filler aggregates. Also, the images further elucidate the aggregated nature of the filler due to modification, which is more pronounced in the case of electron beam modified acrylated filler loaded rubber. The corresponding topographic images have been characterized by various statistical quantities like roughness parameters and one- and two-dimensional power spectral densities (1D-PSD and 2D-PSD). As compared to the control, significant increase in surface roughness is observed in the case of the modified dual phase filler loaded composites. The higher fractal value of these vulcanizates confirms the above fact. AFM study also suggests that the electron beam modification of the above fillers significantly increases the filler-filler and filler-polymer interactions.     

Tensile properties of LDPE + Boehmite composites

Effect of interfacial interactions on mechanical properties of composites of low-density polyethylene reinforced with micrometric Boehmite powders were studied in combination with two silane coupling agents vinyltri(2-methoxyethoxy)-silane (VTMES)-SCA 972 and 3-(trimethoxysilyl)-propylmethacrylate (3MPS)-SCA 989. Samples were prepared via melt mixing followed by compression or injection molding. Morphology and mechanical behavior of the composites were investigated as a function of the filler loading. The modulus of the composites increases with increasing contents of micrometric Boehmite particles. Environmental scanning electron microscopy (ESEM) examination reveals formation of fibrous structures upon addition of the treated micro fillers. We presume the fibrillation of the LDPE phase is related to changes of the matrix viscosity. Improvements in mechanical properties are attributed to homogeneous dispersion and good interfacial adhesion between the filler and the matrix, as evidenced by ESEM. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Improvement in thermal conductivity and mechanical properties of ethylene‐propylene–diene monomer rubber by expanded graphite

Thermally conductive fillers are usually employed in the preparation of rubber composites to enhance thermal conductivity. In this work, ethylene‐propylene‐diene monomer rubber (EPDM)/expanded graphite (EG) and EPDM/graphite composites with up to 100 phr filler loading were prepared. Compared to EPDM/graphite compounds with the same filler loading, stronger filler network was demonstrated for EPDM/EG compounds. Thermal conductivity and mechanical properties of EPDM/graphite and EPDM/EG composites were compared and systematically investigated as a function of the filler loading. The thermal conductivity of both EPDM/graphite and EPDM/EG composites increased with increasing volume fraction of fillers, and could be well fitted by Geometric Mean Model. The thermal conductivity as high as 0.910 W · m⁻¹ · K⁻¹ was achieved for the EPDM/EG composite with 25.8 vol% EG, which was ∼4.5 times that of unfilled EPDM. Compared to EPDM/graphite composites, EPDM/EG composites exhibited much more significant improvement in thermal conductivity and mechanical properties, which could be well correlated with the better filler‐matrix interfacial compatibility and denser structure in EPDM/EG composites, as revealed in the SEM images of tensile fracture surfaces. POLYM. COMPOS., 38:870–876, 2017. © 2015 Society of Plastics Engineers     

紫外光固化涂料配方设计

以Hypomer AC-7435热塑性丙烯酸树脂、氯醋树脂和CAB 381-2醋酸纤维素为成膜物,合成了铝粉底漆:以Hypomer UA-M6丙烯酸酯聚合物、Hypomer UR-61聚氨酯丙烯酸酯、二缩三丙二醇二丙烯酸酯(TPGDA)、三羟甲基丙烷三丙烯酸酯(TMPTA)、异冰片丙烯酸酯(IBOA)为成膜物,1-羟基环己基苯基甲酮为光引发剂,合成了适用于各种基材的紫外光固化清漆.介绍了紫外光固化涂料及其底漆配方,讨论了影响配方设计的各种因素以及光引发剂用量对涂料固化速率的影响.     

Mechanical,thermal, and burning properties of viscose fabric composites: Influence of epoxy resin modification

The influence of epoxy resin modification by 3‐aminopropyltriethoxysilane (APTES) on various properties of warp knitted viscose fabric is reported in this study. Dynamic mechanical, impact resistance, flexural, thermal properties, and burning behavior of the epoxy/viscose fabric composites are studied with respect to varying content of silane coupling agent. The results obtained for APTES‐modified epoxy resin based composites reinforced with unmodified viscose fabric composites are compared to unmodified epoxy resin based composites reinforced with APTES‐modified viscose fabric. The dynamic mechanical behavior of the APTES‐modified resin based composites indicates improved interfacial adhesion. The composites prepared from modified epoxy resin exhibited a twofold increase in impact resistance. The improved adhesion between the fiber and modified resin was also visible from the scanning electron microscope analysis of the impact fracture surface. There was less influence of resin modification on the flexural properties of the composites. The 5% APTES modification induced early degradation of composites compared to all other composites. The burning rate of all the composites under study is rated to be satisfactory for use in automotive interior applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46673.     

Effects of a liquid metal co-filler on the properties of epoxy/binary filler composites

Liquid metals (LMs) with high fluidity and high thermal conductivity (TC) are receiving considerable attention in the research on thermal management polymer composites as alternatives to conventional rigid solid fillers or as co-fillers to overcome the trade-off between TC and composite processability at high filler loads. While most previous studies have investigated the effects of LM fillers in soft elastomeric matrices, their effects on the composite properties with rigid matrices, such as epoxy-based polymers, have not been discussed extensively. Herein, we investigated the effects of LM eutectic Ga-In (EGaIn) as a co-filler on the properties of rigid epoxy-based composites with a binary filler (Al₂O₃/EGaIn) system. The increase in the volume fraction of LM fillers significantly improves the processability of uncured precursor composites but markedly decreases the mechanical strength of the cured composites at their high loads—the latter effects have rarely been examined in previous studies. However, with adequate LM loads, the composites exhibited superior mechanical properties compared with the all-solid-filler system, withstanding a surprisingly high compressive load (~100 kN) under which the all-solid-filler system fractured. Furthermore, the epoxy/binary filler composites exhibited reasonably high TC values (~1 W/mK) comparable to that of commercial epoxy molding compounds, suggesting their potential applicability for electronic packaging.     

UV固化丙烯酸酯胶粘剂的合成及性能研究

以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、甲基丙烯酸缩水甘油酯(GMA)和丙烯酸羟乙酯(HEA)为共聚单体,并以二缩三丙二醇二丙烯酸酯(TPGDA)为交联剂、十二烷基硫醇(NDM)为链转移剂和乙酸乙酯为极性溶剂,采用核/壳溶液聚合法合成了侧链含C=C的丙烯酸酯预聚体;然后以此为基体树脂、丙烯酸异冰片酯(IBOA)和三羟甲基丙烷二丙烯酸酯(TMPTA)为活性稀释剂、651为自由基光引发剂和碘鎓盐为阳离子光引发剂,制备了UV固化胶粘剂。研究结果表明:合成丙烯酸酯预聚体的最佳工艺条件是m(BA)∶m(MMA)∶m(GMA)∶m(TPGDA)∶m(HEA)=20∶60∶10∶4∶6、n(TPGDA)∶n(NDM)=2∶2、w(热引发剂)=3%和w(乙酸乙酯)≥70%(均相对于共聚单体总质量而言);自由基/阳离子混杂双重UV固化胶粘剂比单一自由基UV固化胶粘剂具有更大的附着力和耐酸碱性,此时前者的最佳配方中w(预聚体)=55%、w(651或碘鎓盐)=5%、w(IBOA)=15%、w(TMPTA)=12%和w(GMA)=8%(均相对于胶粘剂总物料质量而言)。     

Correlated electrical conductivity and mechanical property analysis of high-density polyethylene filled with graphite and carbon fiber

The development of conductive polymer composites remains an important endeavor in light of growing energy concerns. In the present work, graphite (G), carbon fiber (CF) and G/CF mixtures are added to high-density polyethylene (HDPE) to discern if mixed fillers afford appreciable advantages over single fillers. The effects of filler type and composition on electrical conductivity, composite morphology and mechanical properties have been examined and correlated to establish structure-property relationships. The threshold loading levels required for G and CF to achieve measurable conductivity in HDPE have been identified. Addition of CF to HDPE/G composites is found to increase the conductivity relative to that of HDPE/G composites at the same filler concentration. This observed increase depends on CF length and becomes more pronounced at and beyond the threshold loading of the HDPE/G composite. Scanning electron microscopy is employed to elucidate the morphology of these multicomponent composites, whereas dynamic mechanical analysis reveals that filler concentration, composition and CF length impact both the magnitude and temperature dependence of the dynamic storage modulus.     

Novel electron beam‐modified surface‐coated silica fillers: Physical and chemical characteristics

A novel process of surface modification of silica fillers has been performed by coating with an acrylate monomer, trimethylol propane triacrylate (TMPTA) and with a silane coupling agent, triethoxy vinyl silane (TEVS), followed by electron beam irradiation of these coated fillers. The surface‐modified fillers have been characterized by Fourier‐Transform Infrared Analysis (FTIR), Electron Spectroscopy for Chemical Analysis (ESCA), Contact angle measurements by dynamic wicking method, Scanning Electron Microscopy (SEM), Energy dispersive X‐ray spectroscopy (EDX), Transmission Electron Microscopy (TEM), Fractal studies, Thermogravimetric analysis (TGA), and X‐ray diffraction (XRD) studies. Presence of the acrylate and the silane coupling agent on the modified fillers is confirmed from the above studies. The contact angle measurements suggest a significant improvement in hydrophobicity of the treated fillers, which is supported by water flotation test. After irradiation and acrylate treatment an increase in filler aggregation is observed, which is not as significant in the case of silanized silica filler. However, XRD studies demonstrate that the entire modification process does not alter the bulk properties of the fillers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2255–2268, 2002     

Magnetite‐functionalized graphene/poly(styrene‐butadiene‐styrene) composites: thermal and mechanical properties

Advanced polymer composites containing organic–inorganic fillers are gaining increasing attention due to their multifunctional applications. In this work, poly(styrene‐butadiene‐styrene) (SBS) composites containing magnetite‐functionalized graphene (FG) were prepared by a dissolution ? dispersion ? precipitation solution method. Evidently, through morphology studies, amounts of FG were well distributed in the SBS matrix. Improvements in neat SBS properties with respect to FG loading in terms of thermal stability, creep recovery and mechanical properties are presented. As expected, the addition of FG improved the thermal stability and mechanical properties of the composites. The yield strength and Young's modulus of the SBS increased by 66% and 146% at 5 wt% filler loading which can be attributed to the reinforcing nature of FG. Similarly, an increase in the storage and loss modulus of the composites showed a reinforcement effect of the filler even at low concentration. The results also showed the significant role of FG in improving the creep and recovery performance of the SBS copolymer. Creep deformation decreased with filler loading but increased with temperature. © 2017 Society of Chemical Industry     

High-Thermal-Conductivity AlN Filler for Polymer/Ceramics Composites

To increase the thermal conductivity of polymer/ceramic composites, aluminum nitride (AlN) granules were added as a ceramic filler. Granules, sintered at 1850°C for 24 h, showed a very high conductivity of 266±26 W (m·°C)⁻¹, as measured by a thermal microscope equipped with thermoreflectant and periodic heating techniques. This conductivity exceeds 80% of the theoretical value of AlN. Ceramic fillers consisting of the obtained AlN granules and commercially available hexagonal boron nitride particles (h-BN) powder plus polyimide resins were mixed and then molded at 100 MPa and 420°C in a vacuum. The resultant composite showed a high conductivity of 9.3 W (m·°C)⁻¹. This study demonstrates that a high-thermal-conductivity filler effectively enhances the conductivity of polymer/ceramic composites.     

Preparation of nano‐zinc oxide/EPDM composites with both good thermal conductivity and mechanical properties

In this article, nano‐zinc oxide (ZnO) filled ethylene propylene diene monomer (EPDM) composites are prepared, and the mechanical (static and dynamic) properties and thermal conductivity are investigated respectively, which are further compared with the traditional reinforcing fillers, such as carbon black and nano‐silica. Furthermore, influence of in‐situ modification (mixing operation assisted by silane at high temperature for a certain time) with the silane‐coupling agent Bis‐(3‐thiethoxy silylpropyl)‐tetrasufide (Si69) on the nano‐ZnO filled composites is as well investigated. The results indicate that this novel reinforcing filler nano‐ZnO can not only perform well in reinforcing EPDM but can also improve the thermal conductivity significantly. In‐situ modification with Si69 can enhance the interfacial interaction between nano‐ZnO particles and rubber matrix remarkably, and therefore contribute to the better dispersion of filler. As a result, the mechanical properties and the dynamic heat build‐up of the nano‐ZnO filled composites are improved obviously by in‐situ modification, without influencing the thermal conductivity. In comparison with traditioanl reinforcing fillers, in‐situ modified nano‐ZnO filled composites exhibit the excellent performance in both mechanical (static and dynamic) properties and better thermal conductivity. In general, our work indicates that nano‐ZnO, as the novel thermal conductive reinforcing filler, is suitable to prepare elastomer products serving in dynamic conditions, with the longer expected service life. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Influence of aminosilane‐functionalized carbon nanotubes on the rheometric,mechanical, electrical and thermal degradation properties of epoxidized natural rubber nanocomposites

We describe the preparation, characterization and physical properties of multiwalled carbon nanotube (MWCNT)‐filled epoxidized natural rubber (ENR) composites. To ensure better dispersion in the elastomer matrix, the MWCNTs were initially subjected to aminopropyltriethoxysilane (APS) treatment to bind amine functional groups (?NH₂) on the nanotube surface. Successful grafting of APS on the MWCNT surface through Si–O–C linkages was confirmed using Fourier transform infrared spectroscopy. Grafting of APS on the MWCNT surface was further corroborated using elemental analysis. ENR nanocomposites with various filler loadings were prepared by melt compounding to generate pristine and APS‐modified MWCNT‐filled elastomeric systems. Furthermore, we determined the effects of various filler loadings on the rheometric, mechanical, electrical and thermal degradation properties of the resultant composite materials. Rheometric cure characterization revealed that the torque difference increased with pristine MWCNT loading compared to the gum system, and this effect was more pronounced when silane‐functionalized MWCNTs were loaded, indicating that this effect was due to an increase in polymer–carbon nanotube interactions in the MWCNT‐loaded materials. Loading of silane‐functionalized MWCNTs in the ENR matrix resulted in a significant improvement in the mechanical, electrical and thermal degradation properties of the composite materials, when compared to gum or pristine MWCNT‐loaded materials.© 2013 Society of Chemical Industry