Table 2.
A brief record of epoxy-based nanocomposites studied for improvement in thermal conductivity values.
| Sr. | Authors | Year | Reinforcement (wt %) | Dispersion method | % Increase in thermal conductivity | Remarks | Ref. |
|---|---|---|---|---|---|---|---|
| 1 | Kandre et al. | 2015 | GnP (1.9 wt %) | Sn | 9 | The simultaneous inclusion of GnPs and SnP/SnW at a combined loading of 1 vol % resulted in about 40% enhancement in the through-thickness thermal conductivity, while the inclusion of GnP at the same loading resulted in only 9% improvement. A higher increment with simultaneous addition of GnP and SnP/SnW can be attributed to synergistic effects. | [202] |
| SnP/(0.09 wt %) | 18 | ||||||
| SnW/(0.09 wt %) | 8 | ||||||
| GnP (1.9 wt %), SnP (0.09 wt %) | 38 | ||||||
| GnP (1.9 wt %), SnW (0.09 wt %) | 40 | ||||||
| 2 | Tang et al. | 2015 | Three-dimensional graphene network (3DGNs) (30 wt %) | None | 1,900 | (Composites produced using layer-by-layer dropping method.) The filler with large size is more effective in increasing the thermal conductivity of epoxy because of continuous transmission of acoustic phonons and minimum scattering at the interface due to reduced interfacial area. High intrinsic thermal conductivity of graphene is the major reason for the obtained high thermal conductivity of nanocomposites. | [203] |
| Chemically reduced graphene oxide (RGO) (30 wt %) | Sn + MS | 1,650 | |||||
| Natural graphite powder (NG) (30 wt %) | 1,400 | ||||||
| 3 | Burger et al. | 2015 | Graphite flakes (12 wt %) (GRA-12) | Sn + MgSr | 237.5 | As the filler/matrix interfaces increase, the thermal resistance increases due to phonon scattering. In order to improve the thermal conductivity of a composite, it is better to structure a sample with an adapted morphology than trying to have the best dispersion. A 3D-network was first prepared with graphite foils oriented through the thickness of the sample and then stabilized with DGEBA/DDS resin. The produced composite sample was called as “Network”. In “fibers”, all the graphite flakes were aligned through the thickness of sample. When a DGEBA interface layer was applied in “fiber”, the sample was called “Fiber + 1 interface”. When two DGEBA interface layers was applied in “fiber” the sample was called as “Fiber + 2 interfaces”. | [204] |
| Graphite flakes (15 wt %) (GRA-15) | 325 | ||||||
| Graphite flakes (14–15 wt %) (Network) | 775 | ||||||
| Graphite flakes (11–12 wt %) (Fibers) | 666.7 | ||||||
| Graphite flakes (11–12 wt %) (Fiber + 1 interface) | 608.3 | ||||||
| Graphite flakes (11–12 wt %) (Fiber + 2 interface) | 237.5 | ||||||
| 4 | Zeng et al. | 2015 | Liquid crystal perylene bisimides polyurethane (LCPU) modified reduced graphene oxide (RGO) (1 wt %) | Sn | 44.4 | Along with the increase in thermal conductivity, the impact and flexural strengths increased up to 68.8% and 48.5%, respectively, at 0.7 wt % LCPU/RGO. | [205] |
| 5 | Wang et al. | 2015 | GnPs, 1 µm, (GnP-C750) | Sn + MgSr + 3RM | 9.1 | The increase in thermal conductivity is higher in the case of larger particle size than smaller particle size. | [206] |
| GnPs, 5 µm | 115 | ||||||
| 6 | Zhou et al. | 2015 | Multi-layer graphene oxide (MGO) (2 wt %) | Sn | 95.5 | The thermal conductivity decreases after 2 wt % MGO. | [207] |
| 7 | Zeng et al. | 2015 | Al2O3 nanoparticles (30 wt %) | Sn | 50 | The thermal conductivity can be improved by using hybrid fillers. | [208] |
| Aminopropyltriethoxy-silane modified Al2O3 nanoparticles (Al2O3-APS) (30 wt %) | 68.8 | ||||||
| Liquid-crystal perylene-bisimide polyurethane (LCPBI) functionalized reduced graphene oxide (RGO) and Al2O3-APS (LCPBI/RGO/Al2O3-APS) | 106.2 | ||||||
| 8 | Tang et al. | 2015 | Al2O3 (18.4 wt %) | Sn + MS | 59.1 | The increase in thermal conductivity decreases with Al2O3 coating of graphite. | [209] |
| Graphite (18.4 wt %) | 254.6 | ||||||
| Al2O3-coated graphite (Al2O3-graphite) (18.4 wt %) | 195.5 | ||||||
| 9 | Pan et al. | 2015 | Perylene bisimide (PBI)-hyper-branched polyglycerol (HPG) modified reduced graphene oxide (RGO), (PBI-HPG/RGO) (1 wt %) | Sn | 37.5 | The filler was observed to be uniformly dispersed, resulting in strong interfacial thermal resistance. | [210] |
| 10 | Wang et al. | 2015 | SiO2, 15 nm, (1 wt %) | Sn | 14.3 | SiO2 nanoparticles are more effective in increasing thermal conductivity than GO. The maximum improvement in thermal conductivity was observed in the case of hybrid filler. | [211] |
| GO (1 wt %) | 4.8 | ||||||
| As-prepared nanosilica/graphene oxide hybrid (m-SGO) (1 wt %) | 28.6 | ||||||
| 11 | Zha et al. | 2015 | GNPs (3.7 wt %), Al2O3 nanoparticles (ANPs), (65 wt %) | Sn + MS | 550.4 | Al2O3 nanofibers are more effective in improving thermal conductivity than Al2O3 nanoparticles. | [212] |
| GNPs (3.7 wt %), Al2O3 fibers (Afs) (65 wt %) | 756.7 | ||||||
| 12 | Zhou et al. | 2015 | Multi-layer graphene oxide (MGO) (2 wt %) | Sn | 104.8 | The thermal conductivity decreases after 2 wt % MGO. | [213] |
| 13 | Wang et al. | 2015 | GNPs (8 wt %) | MS | 627 | The thermal conductivity increases with GNPs at the loss of Vickers microhardness after 1 wt % of GNP. | [214] |
| 14 | Pu et al. | 2014 | RGO (1 wt %) | Sn + MgSr | 21.8 | The thermal conductivity decreases after 1 wt % RGO. The silica layer on S-graphene makes electrically conducting graphene insulating, reduces the modulus mismatch between the filler and matrix, and improves the interfacial interactions of the nanocomposites, which results in enhanced thermal conductivity. | [215] |
| 3-aminopropyl triethoxysilane (APTES) functionalized graphene oxide (A-graphene) (8 wt %) | 47.1 | ||||||
| Silica-coated A-graphene (S-graphene) (8 wt %) | 76.5 | ||||||
| 15 | Fu et al. | 2014 | Graphite (44.30 wt %) | MS | 888.2 | The maximum improvement in thermal conductivity was observed in the case of graphene sheets with thickness of 1.5 nm. | [216] |
| Graphite nanoflakes (16.81 wt %) | 982.3 | ||||||
| Graphene sheets (10.10 wt %) | 2258.8 | ||||||
| 16 | Li et al. | 2014 | Aligned MLG (AG) (11.8 wt %) | Sn | 16670 | The alignment of MLG causes an exceptional improvement in thermal conductivity and exceeds other filler-based epoxy nanocomposites. | [193] |
| 17 | Guo and Chen | 2014 | GNPs (25 wt %) | Sn | 780 | Ball milling is more effective in improving the thermal conductivity of GNP/epoxy than sonication. The thermal conductivity decreases when ball milling is carried out for more than 30 h. | [126] |
| GNPs (25 wt %) | BM | 1420 | |||||
| 18 | Corcione and Maffezzoli | 2013 | Natural graphite (NG) (1 wt %) | Sn | 24.1 | The thermal conductivity decreases with increasing wt % of NG after 1 wt %. The thermal conductivity decreases after 2 wt % of GNPs. The maximum improvement in thermal conductivity was observed with expanded graphite. | [217] |
| GNPs (2 wt %) | 89.8 | ||||||
| Expanded graphite (EGS) (3 wt %) | 232.1 | ||||||
| 19 | Chandrasekaran et al. | 2013 | GNP (2 wt %) | 3RM | 14 | The thermal conductivity increases with increasing temperature. | [73] |
| 20 | Min et al. | 2013 | GNPs (5 wt %) | Sn | 240 | High aspect ratio of GNPs and oxygen functional groups play a significant role in improving thermal conductivity of nanocomposites. | [218] |
| 21 | Hsiao et al. | 2013 | Silica (1 wt %) | Sn + ShM | 19 | The existence of the intermediate silica layer enhances the interfacial attractions between TRGO and epoxy and improved dispersion state, which caused a significant increase in thermal conductivity. | [219] |
| Thermally reduced graphene oxide (TRGO) (1 wt %) | 26.5 | ||||||
| Silica nanosheets (Silica-NS) (1 wt %) | 37.5 | ||||||
| TRGO-silica-NS (1 wt %) | 61.5 | ||||||
| 22 | Zhou et al. | 2013 | Untreated GNPs (12 wt %) | Sn + MgSr | 139.3 | Silane functionalization can significantly improve thermal conductivity of GNP/epoxy. | [220] |
| Silane-treated COOH-MWCNTs (6 wt %) | 192.9 | ||||||
| Silane-treated GNPs (6 wt %) | 525 | ||||||
| 23 | Raza et al. | 2012 | GNPs, 5 µm, 30 wt %, in rubbery epoxy | MS | 818.6 | The thermal conductivity increases with increasing particle size. The particle size distribution significantly influences the thermal conductivity. GNPs with a broad particle size distribution gave higher thermal conductivity than the particles with a narrow particle size distribution, due to the availability of smaller particles that can bridge gaps between larger particles. | [221] |
| GNPs, 5 µm, 20 wt %, in rubbery epoxy | ShM | 332.6 | |||||
| GNPs, 15 µm, 25 wt %, in rubbery epoxy | MS | 1228.4 | |||||
| GNPs, 15 µm, 25 wt %, in rubbery epoxy | ShM | 1118.2 | |||||
| GNPs, 20 µm, 20 wt %, in rubbery epoxy | ShM | 684.6 | |||||
| GNPs, 20 µm, 12 wt %, in glassy epoxy | ShM | 567.6 | |||||
| GNPs, 15 µm, 20 wt %, in glassy epoxy | MS | 683 | |||||
| 24 | Kim et al. | 2012 | GO (3 wt %) | Sn | 90.4 | The increase in thermal conductivity decreases with Al(OH)3 coating on GO. | [222] |
| Al(OH)3-coated graphene oxide (Al-GO) (3 wt %) | 35.1 | ||||||
| 25 | Chatterjee et al. | 2012 | Amine functionalized expanded graphene nanoplatelets (EGNPs) (2 wt %) | Sn + 3RM | 36 | The EGNPs form a conductive network in the epoxy matrix allowing for increased thermal conductivity. | [83] |
| 26 | Im and Kim | 2012 | Thermally conductive graphene oxide (GO) (50 wt %) | Sn | 111 | The thermal conductivity decreases after 50 wt %, which can be attributed to residual epoxy that forms an insulting layer on reinforcement. MWCNT helps the formation of 3D network structure. | [223] |
| Thermally conductive graphene oxide (GO) (50 wt %), MWCNTs (0.36 wt %) | 203.4 | ||||||
| 27 | Heo et al. | 2012 | Al2O3 (80 wt %), GO (5 wt %) | 3RM | 1,650 | The increase in thermal conductivity decreases with Al(OH)3 coating of GO. | [224] |
| Al(OH)3-coated GO (5 wt %) | 1,450 | ||||||
| 28 | Huang et al. | 2012 | MWNTs (65 wt %) | MS | 1,100 | GNPs are more effective in improving thermal conductivity than MWNTs. The maximum improvement in thermal conductivity was observed in the case of hybrid fillers. | [225] |
| GNPs (65 wt %) | 2,750 | ||||||
| MWNTs (38 wt %), GNPs (38 wt %) | 3,600 | ||||||
| 29 | Teng et al. | 2011 | MWNT (4 wt %) | Sn | 160 | GNPs showed a significantly greater increase in thermal conductivity than MWNTs. The maximum improvement in thermal conductivity is shown by non-covalent functionalized GNS, which can be attributed to high surface area and uniform dispersion of GNS. | [114] |
| GNPs(4 wt %) | 700 | ||||||
| Poly(glycidyl methacrylate containing localized pyrene groups (Py-PGMA) functionalized GNPs (Py-PGMA-GNS) | 860 | ||||||
| 30 | Gallego et al. | 2011 | MWNTs (1 wt %) in nanofluids | ShM | 66.7 | The layered structure of MWNTs enables an efficient phonon transport through the inner layers, while SWNTs present a higher resistance to heat flow at the interface, due to its higher surface area. The f-MWNTs have functional groups on their surface, acting as scattering points for the phonon transport. | [226] |
| f-MWNTs (0.6 wt %) in nanofluids | 20 | ||||||
| SWNTs (0.6 wt %) in nanofluids | 20 | ||||||
| Functionalized graphene sheet (FGS) (1 wt %) in nanofluids | 0 | ||||||
| GO (1 wt %) in nanofluids | 0 | ||||||
| MWNTs(1 wt %) in nanocomposites | 72.7 | ||||||
| Functionalized graphene sheet (FGS) (1 wt %) in nanocomposites | 63.6 | ||||||
| 31 | Tien et al. | 2011 | Graphene flakes (12 wt %) | Sn | 350 | The thermal conductivity increases exponentially with increasing wt % of graphene flakes. | [227] |
| 32 | Ganguli et al. | 2008 | Exfoliated graphite flakes (20 wt %) | SM | 2,087.2 | The thermal conductivity increases with chemical functionalization. | [177] |
| Chemically functionalized graphite flakes (20 wt %) | 2,907.2 | ||||||
| 33 | Yu et al. | 2008 | Carbon black (CB) (10 wt %) | Sn + ShM | 75 | The hybrid filler demonstrates a strong synergistic effect and surpasses the performance of the individual SWNT and GNP filler. | [228] |
| SWNTs (10 wt %) | 125 | ||||||
| GNPs (10 wt %) | 625 | ||||||
| GNPs (7.5 wt %), SWNTs (2.5 wt %) | 775 |