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Thermal conductivity of copper powder filled polyamide composites are investigated experimentally in the range of filler content 0-30% by volume for particle shape of short fibers and 0-60% by volume for particle shapes of plates and spheres. The thermal conductivity of polymer composites is measured by the Hot-Disk method. It is seen that the expe...
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The work studied the effect of fine silicon carbide (SiC) powder with (0,3,5 ,7) wt % on the thermal conductivity and mechanical properties of unsaturated polyester composite in the presence of a fixed amount of chopped glass fiber. The hand lay-up technique was employed to prepare the required samples. Results showed that tensile, impact strength...
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... Table 1 lists some studies of metal particles filling polymer matrix materials. Tekce et al. (2007) studied the thermal conductivity of polyamide composite materials filled with copper powder with different morphologies, and found that the thermal conductivity of composite materials filled with copper powder with different morphologies was similar at low filling rate, but with the increase of filling rate, the thermal conductivity of composite materials filled with fibrous copper powder would increase rapidly. Yaman and Taga (2018) studied the thermal conductivity of unsaturated polyester resin (UPR) matrix composite materials with dendrite copper particles as fillers. ...
An experimental investigation was conducted to prepare and study the thermal conductivity performance of copper and diamond composite materials. Copper powder and diamond particles were used as fillers, epoxy resin was used as matrix, and composite materials were prepared by vacuum-assisted mechanical stirring. The thermal expansion coefficient of different composite materials was measured by a laser flash method, which can be used to calculate the thermal conductivity. The effect of the filling rate of copper powder, the morphology of copper powder, the filling rate of diamond, and the thermal conductivity of the particles on the thermal conductivity of composite materials was studied. The results showed that thermal conductivity of copper powder and diamond particles composite materials were 874% and 535% higher than that of the epoxy resin when their filling rates were 50.3 vol.% and 40.0 vol.%, respectively. For two-dimensional flake copper powder materials, the thermal conductivity could be effectively improved at a lower filling rate. However, the flake particles were easy to aggregate at a high filling rate, which maybe cause the composite materials to pulverize.
... of fillers, either particles or fibres simply with conductivity greater than that of polymers, aimed at improving mechanical characteristics combined with light weight, can also impart distinct thermal, electrical, optical or magnetic properties to the material [5,7,12,13]. The effects of a number of conductive fillers on the properties of different polymer materials have been investigated, with particular emphasis on copper and aluminium powders, and various experimental approaches and numerical models have been employed to assess the thermal conductivity of such composites [14][15][16][17][18][19][20]. For instance, Rahmati and Dickens (2007) [21] and Pontes et al. (2008) [22] carried out studies on aluminium-filled 3D-printed epoxy inserts for hybrid moulds, evaluating the thermal and mechanical properties and reporting promising outcomes relative to enhancing the thermal performance of the moulds. ...
Metal-reinforced polymer composites are suitable materials for applications requiring special thermal, electrical or magnetic properties. Three-dimensional printing technologies enable these materials to be quickly shaped in any design directly and without the need for expensive moulds. However, processing data correlating specific information on how the metal particles influence the rheological behaviour of such composites is lacking, which has a direct effect on the processability of these composites through melt processing additive manufacturing. This study reports the compounding and characterisation of ABS composites filled with aluminium and copper particulates. Experimental results demonstrated that the tensile modulus increased with the incorporation of metal particles; however, there was also an intense embrittling effect. Mechanical testing and rheological analysis indicated poor affinity between the fillers and matrix, and the volume fraction proved to be a crucial factor for complex viscosity, storage modulus and thermal conductivity. However, a promising set of properties was achieved, paving the way for polymer–metal composites with optimised processability, microstructure and properties in melt processing additive manufacturing.
... Tekce et al. [12] studied the thermal conductivity of polyamide composite materials lled with copper powder with different morphologies, and found that the thermal conductivity of composite materials lled with copper powder with different morphologies was similar at low lling rate, but with the increase of lling rate, the thermal conductivity of composite materials lled with brous copper powder would increase rapidly. Kemal et al. [13] studied the thermal conductivity of unsaturated polyester resin (UPR) matrix composite materials with dendrite copper particles as llers. ...
An experiment investigation was conducted to prepare and study the thermal conductivity performance of copper and diamond composite materials. Copper powder and diamond particles were used as fillers, epoxy resin was used as matrix, and composite materials were prepared by vacuum-assisted mechanical stirring. The thermal expansion coefficient of different composite materials was measured by a laser flash method, which can be used to calculate the thermal conductivity. The effect of the filling rate of copper powder, the morphology of copper powder, the filling rate of diamond, and the thermal conductivity of the particles on the thermal conductivity of composite materials was studied. The results showed that thermal conductivity of copper powder and diamond particles composite materials are 874% and 535% higher than that of the epoxy resin when their filling rates were 50.3 vol.% and 40.0 vol.%, respectively. For two-dimensional flake copper powder materials, the thermal conductivity could be effectively improved at a lower filling rate. However, the flake particles were easy to aggregate at a high filling rate, which is not conducive to the thermal conductivity of the composite materials.
... As thermal interface materials (TIMs), they improve the thermal transition between solid surfaces, as a potting they protect electronic components and conduct excessive heat to the environment and as a case for electronic devices they help with minimizing operating temperatures. Various theoretical and experimental studies have investigated the effective thermal conductivity of the filled polymer, and the effects of filler loading [1][2][3][4], filler materials [1,[4][5][6][7][8], particle shapes [1,9], and sizes [10,11]. Thermal conductivity measurements were performed using laser flash analysis (LFA) (calculated from thermal diffusivity, heat capacity and density) [1,3,10], transient hot-bridge, -wire or -disc methods [4,6,7,9], or the steady-state cylinder method [2,8,11]. ...
... Various theoretical and experimental studies have investigated the effective thermal conductivity of the filled polymer, and the effects of filler loading [1][2][3][4], filler materials [1,[4][5][6][7][8], particle shapes [1,9], and sizes [10,11]. Thermal conductivity measurements were performed using laser flash analysis (LFA) (calculated from thermal diffusivity, heat capacity and density) [1,3,10], transient hot-bridge, -wire or -disc methods [4,6,7,9], or the steady-state cylinder method [2,8,11]. The latter can be referred to as the industrial standard for TIMs, and is described in ASTM D5470-17. ...
... 1-6) and alumina (Sample no. [8][9][10][11][12] and different filler contents were used. Sample no. ...
This article reports the use of a new measurement technique based on micro thermography for determining the thermal contact resistances between filled polymers and solids. The thermal conductivity of polymers can be significantly increased by using thermally conductive fillers. For numerous applications, not only is a high intrinsic thermal conductivity required but also a good thermal transfer between the filled polymer and an adjacent solid surface. The physical principles of thermal transport when considering this type of contact have not yet been investigated in detail, and only a few experimental results are available. The most common measurement techniques determine a macroscopic resistance and project it onto the contacting surface. However, the heterogeneous microstructure of a filled polymer causes the thermal contact resistance to be a volumetric phenomenon in the overall boundary region. The utilized IR camera system takes thermal images with a spatial resolution of less than 15 μm per pixel. The new method resolves the thermal contact resistances spatially and gives new insights into the microscale effects on the particle level. In addition to the common zero-gap extrapolation for the extraction of thermal contact resistances, we propose another evaluation method that considers all microscale effects of the boundary layers and evaluates thermal contact resistance as a volumetric phenomenon. For the first systematic study, samples consisting of two aluminum substrates and a filled epoxy polymer were prepared and investigated. We studied the effects of filler size, filler material, filler volume fraction, and surface structure, focusing on monomodally filled polymers with filler amounts between 30 and 60 v%. The obtained results and the uncertainties of the new method are discussed within this paper.
... Hafieng Zhang et al. [29] experimentally obtained TC values of different polymer filler combination at room temperature and showed a significant rise in TC value for the synthesized polymer composite on high filler concentration. H.S. Tacke et al. [30] showed that the TD Value of fiber filler is higher than that of the spherical filler or plate shape filler for the low filler concentration. At higher concentration the TD Value of plate shaped fillers were found to be higher than spherical shaped fillers. ...
Polymer composite materials attract researchers as polymers can be filled with different fillers to get desired properties. Thermophysical properties of HDPE-silicon composite is reported in the present study. HDPE-Si composite was synthesized by hot compression and molding technique for different silicon volumetric ratio. Thermal conductivity as well as thermal diffusivity was found to be enhanced significantly on increasing the filler volumetric ratio. Thermal conductivity value for 20 volume % composite was more than twice of the pure HDPE (0.364 W/m-K for pure HDPE and 0.733 W/m-K for 20 volume % composite). Thermal diffusivity value of 20 volume % composite (0.518 mm 2 /s) was also more than double than that of the pure HDPE (0.224 mm 2 /s). TGA analysis of composite showed a substantial increase in thermal stability from 414°C (for pure HDPE) to 454°C (for 20 volume % silicon). Thermophysical properties were also measured at elevated temperature from 30°C to 80°C for different volumetric ratio of filler. Both thermal conductivity and thermal diffusivity showed a gradual decrement on increasing the temperature. Adding more silicon to the HDPE caused a better adhesion between HDPE and silicon which improved the hardness of the synthesized composite.
... Regarding the shape of the filler, experimental results have been reported that the thermal conductivity of the composite material varies significantly due to the subtle differences in the shape of the filler [14] [15] [16]. Regarding the anisotropy of fillers, there are some fillers whose properties are anisotropic, depending on their structure resulting from the manufacturing method of fillers. ...
... About Eqs. (12) and (13), if and are eliminated using the relation of Eq. (14), then the relation between and can be obtained as follows: ...
... =1 ( ) holds for the volume fraction. From Eqs. (31), (32), and(14), the relation between and can be obtained.Equating this relation with Eq.(16), the effective permittivity is finally obtained as is the solution for multiphase composites. In the case of polycrystalline materials, since and are zero or = 1 in Eqs. ...
In this study, micromechanical modeling will be performed for composite materials containing fillers oriented randomly in the matrix. The purpose of this study is to derive more general and explicit solutions for the effective thermal and electromagnetic properties of such composite materials without restricting the properties and shapes of the fillers. For this purpose, it is assumed that the physical properties of the filler are the same anisotropic properties as orthorhombic materials, and the shape of the fillers is ellipsoidal. This model is analyzed by micromechanics combining the Eshelby's equivalent inclusion method with the self-consistent method or the Mori-Tanaka's theory. Solutions of the effective thermal and electromagnetic properties both for composite materials containing many kinds of fillers with different shapes and physical properties and for polycrystalline materials can be also derived. Using the obtained solutions, the effect of the shape, the anisotropy, and the volume fraction of the filler on the effective thermal conductivity is examined for the carbon filler / polyethylene and the two types of quartz particles (and voids) / polyethylene. As a result, for the carbon filler / polyethylene, it is found that the effective thermal conductivity of the material when the shape of the filler is flat is about 20% higher than that when the shape of the filler is fibrous. Furthermore, when the shape of the carbon filler is flat, the result when the carbon filler is assumed to be isotropic is significantly different from that when the filler is assumed to be anisotropic. From the above, when the filler is oriented randomly in the material, it is found that simultaneously considering not only the shape of the filler but also its anisotropic properties is important to accurately evaluate the effective physical properties of the composite material. For two types of quartz particles (and voids) / polyethylene materials, the experimental result agrees better with the result of the Mori-Tanaka's theory than that of the self-consistent method, even if the volume fraction of the filler is more than 50%. From the above results, it is found that the analytical solutions of this study can generally explain the experimental results and can be applied to actual materials.
... Diğer yandan, bakır [15] ve nikel [16] metal tozlarının polimer matrisli kompozitlerin yapısına eklenerek, sırasıyla elektriksel/ısıl iletkenlik ve mekanik özelliklerde artışı sağlama üzerine çalışmalar gerçekleştirilmektedir. Bu bağlamda, dentritik bakır tozlarının kullanımı ile hem dentrit kollarının devasa yüzey alanı sağlaması ile yapısına eklenebilecek matrisler içerisinde de yüksek tutunma sağlayarak arayüzeyi gelişmiş kompozit eldesinin sağlanabileceği, hem de yüksek mekanik özellik sunan nikel katmanın dentritik bakır tozları üzerinde biriktirilmesi ile yüksek mekanik özellik gösteren fonksiyonel bimetalik tozların eldesinin sağlanabileceği açıktır [8]. ...
Bu çalışmada, elektroliz yöntemi ile hurda bakır plakadan elde edilen dentritik bakır tozları üzerine akımsız nikel kaplama işlemi uygulanmıştır. 30 dk, 60 dk ve 90 dk sürelerinde akımsız nikel kaplama işlemleri uygulanarak elde edilen dentritik bakır-nikel bimetalik tozların morfolojik ve oksidasyon incelemeleri gerçekleştirilmiştir. Morfoloji incelemeleri taramalı elektron mikroskobu (SEM) ile yapılırken, oksidasyon direnci incelemeleri termogravimetrik analiz (TGA) yöntemi ile yapılmıştır. Elde edilen sonuçlara göre, akımsız nikel kaplama süresinin artması ile elektrolitik bakır parçacıklar üzerinde indirgenen nikel miktarı artmıştır. İndirgenen nikel tabaka nano boyutta parçacıklardan oluşmuştur. Akımsız nikel kaplama süresinin artışı ile parçacıkların oksidasyon direnci değerlerinde artış sağlanırken, oksitlenmeye başlama sıcaklıkları da arttırılmıştır. Ayrıca, nano nikel parçacıkların parçacık yüzeylerinde oluşturduğu tabaka ve birikintiler, elektrolitik bakır parçacıklarının yüzey alanı değerlerini yaklaşık %20 oranında arttırmıştır. Parçacık boyutu analizi sonuçlarına göre, akımsız nikel kaplama tabakası sayesinde ortalama parçacık boyutu değerleri artarak 1 µ’ye kadar bir kaplama tabakasının elde edildiği tespit edilmiştir.
... Thermal conductivity enhancement has been observed in various polymer composites using highly thermally and electrically conductive metallic fillers such as aluminum (Al; k = 247 W m −1 K −1 ), [16][17][18] copper (Cu; k = 398 W m −1 K −1 ), 16,[18][19][20][21][22] nickel (Ni; k = 100 W m −1 K −1 ), 23,24 and silver (Ag; k = 427 W m −1 K −1 ) 9,18,25 with filler size ranging from 20 nm to 300 μm. A comparative analysis of thermal and electrical properties of composites prepared with polypropylene (PP) matrix (k = 0.24 W m −1 K −1 ) filled with Cu particles by Boudenne et al. showed thermal conductivity increased with increasing the volume fractions of Cu particles with a maximum value of 2.14 W m −1 K −1 at 35% volume filler concentration. ...
... % loading. 21 Similarly, dendritic Cu particles in the silicon matrix showed k ∼ 0.75 W m −1 K −1 at 15 vol. %, an enhancement of about 300% compared to the matrix. ...
The development of electrical insulators that are thermally conducting is critical for thermal management applications in many advanced electronics and electrical devices. Here, we synthesized polymer nanocomposite (PNC) films composed of polymers [polyethylenimine, poly(vinylamine), poly(acrylic acid), and poly(ethylene oxide)] and dielectric fillers (montmorillonite clay and hexagonal boron nitride) by layer-by-layer technique. The cross-plane thermal conductivity [Formula: see text] of the film was measured by the 3ω method. The effect of various factors such as film growth, filler type, filler volume fraction, polymer chemical structures, and temperature on the thermal conductivity is reported. The [Formula: see text] of PNCs with thickness from 37 nm to 1.34 μm was found to be in the range of 0.11 to 0.21 ± 0.02 W m −1 K ⁻¹ . The [Formula: see text] values were found to be lower than the constituent polymer matrix. The experimental result is compared with existing theoretical models of nanocomposite systems to get insight into heat transfer behavior in such layered films composed of dielectrics and polymers.
... Epoxies filled with aluminum, brass, copper, etc., in spherical shapes have been used for a long time in indirect rapid tooling, and have especially been applied as mold insert materials [4,15,17,22]. The type and amount of filler composition on the MEC material are critical in ensuring good performance, which can be assessed by conducting various types of tests such as physical, thermal, and mechanical tests to examine the properties of the material [4,15,16,22,[27][28][29]. Most manufacturers of epoxy resin for tooling use mixtures in the range of 20-30% because, at this condition, it has the highest compressive strength, saves money on filler, and is easy to pour into more complex pouring blocks [22,[30][31][32][33][34][35]. ...
... However, regarding density and compressive strength, brass fillers are proven to be more effective than copper fillers. There is also research on the use of irregularly shaped filler particles and fibers, in addition to spherical shapes, but they have not been comprehensively reported for use as mold insert material [29,47]. Therefore, with regard to the contribution to knowledge in MEC mold inserts, this study was initiated to investigate the cooling performance of the MEC mold by investigating the effect of the mold material in the mixture using brass and copper filler particles of irregular shapes. ...
... Miracast 1516A with Miracast 1516B is a low viscosity epoxy system suitable for the production of molds, tools, and fixtures that are subjected to heat. Most manufacturers of epoxy resin for tooling use aluminum filler at a composition of 20-30% to ensure that the material properties are at an optimal level [29,[33][34][35]. From the literature study [49], it can be seen that the aluminum filler in a spherical shape and size is in the range of 20-65 microns. ...
Due to their low shrinkage and easy moldability, metal epoxy composites (MEC) are recognized as an alternative material that can be applied as hybrid mold inserts manufactured with rapid tooling (RT) technologies. Although many studies have been conducted on MEC or reinforced composite, research on the material properties, especially on thermal conductivity and compressive strength, that contribute to the overall mold insert performance and molded part quality are still lacking. The purpose of this research is to investigate the effect of the cooling efficiency using MEC materials. Thus, this research aims to appraise a new formulation of MEC materials as mold inserts by further improving the mold insert performance. The effects of the thermal, physical, and mechanical properties of MEC mold inserts were examined using particles of brass (EB), copper (EC), and a combination of brass + copper (EBC) in irregular shapes. These particles were weighed at percentages ranging from 10% to 60% when mixed with epoxy resin to produce specimens according to related ASTM standards. A microstructure analysis was made using a scanning electron microscope (SEM) to investigate brass and copper particle distribution. When filler composition was increased from 10% to 60%, the values of density (g/cm3), hardness (Hv), and thermal conductivity (W/mK) showed a linear upward trend, with the highest value occurring at the highest filler composition percentage. The addition of filler composition increased the compressive strength, with the highest average compressive strength value occurring between 20% and 30% filler composition. Compressive strength indicated a nonlinear uptrend and decreased with increasing composition by more than 30%. The maximum value of compressive strength for EB, EC, and EBC was within the range of 90–104 MPa, with EB having the highest value (104 MPa). The ANSYS simulation software was used to conduct a transient thermal analysis in order to evaluate the cooling performance of the mold inserts. EC outperformed the EB and EBC in terms of cooling efficiency based on the results of thermal transient analysis at high compressive strength and high thermal conductivity conditions.
... Thermal conductivity plays a role in evaluating the thermal performance of a composite material. Many studies have investigated the effects of filler type, shape and size on the thermal performance of composites [17][18][19][20][21]. However, there is a scarcity of data on the influence of fillers in the polymer blend. ...
We have demonstrated the use of XRD and thermal measurements to diligently probe the location of nano-scaled boron carbide (B4C-type compounds) fillers. Herein, the XRD diffraction Bragg and amorphous peaks were successfully fitted from the parameters determined by a deconvolution process using the Pearson VII function, with a fitting error of less than 4%. Thermal measurement was achieved by measuring the thermal conductivity of the composite. A filler loading of 4%wt was found as a threshold. Beyond this value, a significant increase in the thermal conductivity was observed. There was no further decrease in the HDPE crystallinity above the threshold, but rather a considerable increase. Below the threshold value, the addition of fillers disturbed the HDPE crystal arrangement, leading to a reduction of both the HDPE crystallinity and the thermal conductivity. The influence on the ordered structure, intrinsic thermal conductivity and radius of gyration of the fillers, together with their interactions, elucidated the trend of the thermal conductivity.
