Production and properties of thermally and electrically conductive polymeric composites containing conductive micro and nano fillers are investigated. Mechanical, electrical, and thermal properties of the produced nano and hybrid Polyamide 6–based composites filled with graphene nanoplatelets and metal microfibers are studied. The influence of nanofiller content and geometrical characteristics on the thermal conductivity of the composites are studied through experiments and finite element modeling. The results show the influence of nanoplatelets aspect ratio and lateral dimension on the thermal conductivity of the composites. Furthermore, combination of graphene nanoplatelets and metallic micro-scale fillers leads to significant improvements in thermal and electrical conductivities. In fact, graphene nanoplatelets act as conductive bridges in minuscule gaps to increase the number of contacts in the constructed network. The combination of the two different fillers increased the mechanical properties up to 120% compared to the metal reinforced composites, indicating stronger interfaces between the fillers and polymeric matrix. Rheological investigations also confirm the effectiveness of hybridization. Furthermore, the influence of annealing on the conductivities of the specimens are studied. Adding an annealing step following the nanofiller inclusion within the composites resulted in 151 and 72% enhancement in the thermal and electrical conductivities, respectively. Stress relaxation and reorientation of metal fibers in combination with additionally constructed nanofiller networks have been attributed to the observed enhancements. The involved mechanisms in the observed behaviors are studied using optical and electron microscopies.
MamunyaYPDavydenkoVVPissisP, et al.Electrical and thermal conductivity of polymers filled with metal powders. Eur Polym J2002; 38: 1887–1897.
2.
BauhoferWKovacsJZ. A review and analysis of electrical percolation in carbon nanotube polymer composites. Compos Sci Technol2009; 69: 1486–1498.
3.
SenguptaRBhattacharyaMBandyopadhyayS, et al.A review on the mechanical and electrical properties of graphite and modified graphite reinforced polymer composites. Prog Polym Sci2011; 36: 638–670.
4.
LuxF. Models proposed to explain the electrical conductivity of mixtures made of conductive and insulating materials. J Mater Sci1993; 28: 285–301.
5.
WeberMKamalMR. Estimation of the volume resistivity of electrically conductive composites. Polym Compos1997; 18: 711–725.
6.
DengHLinLJiM, et al.Progress on the morphological control of conductive network in conductive polymer composites and the use as electroactive multifunctional materials. Prog Polym Sci2014; 39: 627–655.
7.
ChenHGinzburgVVYangJ, et al.Thermal conductivity of polymer-based composites: Fundamentals and applications. Prog Polym Sci2016; 59: 41–85.
8.
IslamAHansenHNTangPT. Direct electroplating of plastic for advanced electrical applications. CIRP Ann2017; 66: 209–212.
9.
Sarvar F, Whalley DC and Conway PP. Thermal interface materials–a review of the state of the art. In: 2006 1st Electronics systemintegration technology conference, Dresden, 2006, pp.1292–1302. DOI: 10.1109/ESTC.2006.280178.
10.
GoyalVBalandinAA. Thermal properties of the hybrid graphene-metal nano-micro-composites: applications in thermal interface materials. Appl Phys Lett2012; 100: 73113.
11.
Doagou-RadSIslamASøndergaard JensenJ. Correlation of mechanical and electrical properties with processing variables in MWCNT reinforced thermoplastic nanocomposites. J Compos Mater2018; 52: 3681–3697.
12.
Doagou-Rad S, Islam A, Jensen JS, et al. Interaction of nanofillers in injection-molded graphene/carbon nanotube reinforced PA66 hybrid nanocomposites. J Polym Eng. Epub ahead of print 20 June 2018. DOI: 10.1515/polyeng-2018-0060.
13.
HopmannChFragnerJHaaseS. Development of electrically conductive plastic compounds based on filler combinations. J Plast Technol2014; 10: 49–67.
14.
MichaeliWHopmannCFragnerJ, et al.Injection molding of conductor paths: integration of functionality by the use of a metal/thermoplastic hybrid material. J Polym Eng2011; 31: 479–487.
15.
Lin Y, Jia Y, Alva G, et al. Review on thermal conductivity enhancement, thermal properties and applications of phase change materials in thermal energy storage. Renew Sustain Energy Rev 2018; 82: 2730–2742.
16.
CiprianoBHKotaAKGershonAL, et al.Conductivity enhancement of carbon nanotube and nanofiber-based polymer nanocomposites by melt annealing. Polymer2008; 49: 4846–4851.
17.
VerdejoRBernalMMRomasantaLJ, et al.Graphene filled polymer nanocomposites. J Mater Chem2011; 21: 3301–3310.
18.
BilottiEZhangHDengH, et al.Controlling the dynamic percolation of carbon nanotube based conductive polymer composites by addition of secondary nanofillers: the effect on electrical conductivity and tuneable sensing behaviour. Compos Sci Technol2013; 74: 85–90.
19.
SocherRKrauseBHermaschS, et al.Electrical and thermal properties of polyamide 12 composites with hybrid fillers systems of multiwalled carbon nanotubes and carbon black. Compos Sci Technol2011; 71: 1053–1059.
20.
ZhouTWangXChengP, et al.Improving the thermal conductivity of epoxy resin by the addition of a mixture of graphite nanoplatelets and silicon carbide microparticles. Express Polym Lett2013; 7: 585–594.
21.
YooYLeeHLHaSM, et al.Effect of graphite and carbon fiber contents on the morphology and properties of thermally conductive composites based on polyamide 6. Polym Int2014; 63: 151–157.
22.
BalandinAA. Thermal properties of graphene and nanostructured carbon materials. Nat Mater2011; 10: 569–581.
23.
MarinhoBGhislandiMTkalyaE, et al.Electrical conductivity of compacts of graphene, multi-wall carbon nanotubes #carbon |black, and graphite powder. Powder Technol2012; 221: 351–358.
24.
HuKKulkarniDDChoiI, et al.Graphene-polymer nanocomposites for structural and functional applications. Prog Polym Sci2014; 39: 1934–1972.
25.
MayoralBHarkin-JonesEKhanamPN, et al.Melt processing and characterisation of polyamide 6/graphene nanoplatelet composites. RSC Adv2015; 5: 52395–52409.
26.
MittalGDhandVRheeKY, et al.A review on carbon nanotubes and graphene as fillers in reinforced polymer nanocomposites. J Ind Eng Chem2015; 21: 11–25.
27.
HuZTongGLinD, et al.Graphene-reinforced metal matrix nanocomposites–a review. Mater Sci Technol2016; 32: 930–953.
28.
WejrzanowskiTGrybczukMChmielewskiM, et al.Thermal conductivity of metal-graphene composites. Mater Des2016; 99: 163–173.
29.
PavithraCLPSaradaBVRajulapatiKV, et al.A new electrochemical approach for the synthesis of copper-graphene nanocomposite foils with high hardness. Sci Rep2014; 4: 4049.
30.
Doagou-RadSIslamAJensenJS. Influence of processing conditions on the mechanical behavior of MWCNT reinforced thermoplastic nanocomposites. Procedia CIRP2017; 66: 131–136.
31.
PontefissoAMishnaevskyL. Nanomorphology of graphene and CNT reinforced polymer and its effect on damage: micromechanical numerical study. Compos Part B Eng2016; 96: 338–349.
32.
MishnaevskyLDaiG. Hybrid and hierarchical nanoreinforced polymer composites: Computational modelling of structure–properties relationships. Compos Struct2014; 117: 156–168.
33.
DaiGMishnaevskyL. Fatigue of multiscale composites with secondary nanoplatelet reinforcement: 3D computational analysis. Compos Sci Technol2014; 91: 71–81.
34.
MishnaevskyLDaiG. Hybrid carbon/glass fiber composites: micromechanical analysis of structure–damage resistance relationships. Comput Mater Sci2014; 81: 630–640.
35.
GhoshSBaoWNikaDL, et al.Dimensional crossover of thermal transport in few-layer graphene. Nat Mater2010; 9: 555.
36.
UhlFMYaoQNakajimaH, et al.Expandable graphite/polyamide-6 nanocomposites. Polym Degrad Stab2005; 89: 70–84.
37.
ShteinMNadivRBuzagloM, et al.Thermally conductive graphene-polymer composites: size, percolation, and synergy effects. Chem Mater2015; 27: 2100–2106.
38.
DescampsPVan WassenhoveGTeixeiraS, et al.Using a Monte-Carlo model to identify best filler arrangement in thermally conductive materials. Microelectronics J2015; 46: 1179–1184.
39.
Wypych G. Physical properties of fillers and filled materials. In: Wypych G (ed.) Handbook of fillers. 4th ed. Toronto, Canada: ChemTec Publishing, pp.303–371.
40.
KonathamDBuiKNDPapavassiliouDV, et al.Simulation insights into thermally conductive graphene-based nanocomposites. Mol Phys2011; 109: 97–111.
41.
ShihW-HShihWYKimS-I, et al.Scaling behavior of the elastic properties of colloidal gels. Phys Rev A1990; 42: 4772.
42.
KotsilkovaRFragiadakisDPissisP. Reinforcement effect of carbon nanofillers in an epoxy resin system: rheology, molecular dynamics, and mechanical studies. J Polym Sci Part B Polym Phys2005; 43: 522–533.
43.
BurgerNLaachachiAFerriolM, et al.Review of thermal conductivity in composites: mechanisms, parameters and theory. Prog Polym Sci2016; 61: 1–28.
44.
RamaniKVaidyanathanA. Finite element analysis of effective thermal conductivity of filled polymeric composites. J Compos Mater1995; 29: 1725–1740.
45.
MortazaviBBaniassadiMBardonJ, et al.Modeling of two-phase random composite materials by finite element, Mori–Tanaka and strong contrast methods. Compos Part B Eng2013; 45: 1117–1125.
46.
PalzaHGarzónCAriasO. Modifying the electrical behaviour of polypropylene/carbon nanotube composites by adding a second nanoparticle and by annealing processes. Express Polym Lett2012; 6: 639–646.
