Hybrid Filler Loading Research Articles

Paving thermally conductive highway by 3D interconnected framework of carbon nanotube and graphene oxide in poly(vinylidene fluoride)

Polymer-based materials with high thermal conductivity are highly desirable for thermal management applications. In this work, a new hierarchical three-dimensional (3D) framework is built by electrostatic self-assembly between positively charged carbon nanotube (CNT) and negatively charged graphene oxide (GO) in poly(vinylidene fluoride) (PVDF). The obtained composites possess an enhanced thermal conductivity and outstanding mechanical properties simultaneously. Thermal conductivity enhancement of 628% and tensile strength enhancement of 120% are achieved at 10 wt% GO-A-CNT hybrid filler loading compared with that of pure PVDF. Moreover, the GO-A-CNT/PVDF composites exhibit mainly polar γ-form crystallites and sharply decreased crystallinity compared with pure PVDF and CNT/PVDF composites. The theoretical simulation of the effective medium theory is well fitted with experimental observation, which elucidates the significance of 3D framework for more efficient phonon transmit. These GO-A-CNT/PVDF composites may have great potential application as heat exchanger materials.

Study on thermal conductive epoxy adhesive based on adopting hexagonal boron nitride/graphite hybrids

The effect of hybrid filler on newly developed thermal conductive epoxy adhesive has been reported in this paper. The hybrid filler containing hexagonal boron nitride (h-BN) and graphite (Gr) with the mass ratio of 1:1 was loaded in to the epoxy resin with different wt% ratio (10:90, 20:80, 30:70, 40:60, 50:50 and 60:40). The corresponding thermal conductivity of adhesives was measured using guarded heat flow meter technique which enhanced up to 2.025 W/mK with the loading of 60 wt% of hybrid filler. Lap shear strength of the adhesive containing 40 wt% of hybrid filler was higher than the pristine epoxy resin thereby confirming reinforcing effect of hybrid filler into the epoxy matrix. Afterward, the shear viscosity of uncured epoxy resin filled with hybrid fillers were analyzed by using parallel plate rheometry. Strong shear thinning behavior was exhibited at higher hybrid filler loading. Further, lower loss factor and higher Tg values were observed with increase in the hybrid filler (h-BN/Gr) loading thereby confirming the higher cross linking density and lower mobility of epoxy chain. Thermal stability of hybrid Gr/BN–epoxy composite adhesives was studied using thermo gravimetric analyzer. Scanning electron microscopy confirmed the uniform deposition of hybrid filler on to the surface of epoxy resin.

Improved thermal properties by controlling selective distribution of AlN and MWCNT in immiscible polycarbonate (PC)/Polyamide 66 (PA66) composites

A stable co-continuous morphology was achieved in immiscible polycarbonate (PC)/polyamide 66 (PA66) blend by controlling the selective distribution of multi-walled carbon nanotubes (MWCNT) and aluminum nitride (AlN) nanoparticles. SEM and TEM tests proved that hybrid fillers were both located in PA66 phase. Selective etching process was applied to confirm the gradual variation of morphologies. It indicated that the compatibilities between PC and PA66 were gradually enhanced since the phase size reduced significantly and the interface of two phases blurred after the fillers were incorporated. DMA confirmed that the glass transition temperature of PC and PA66 appeared a trend to merge, besides, the tensile properties were enhanced. TGA indicated that the in-situ generated PC-b-PA66 copolymer played an important role in the compatibilization effect. Besides, the raised interconnectivities were proved by theoretical models and the maximum thermal conductivity of 1.3 W/mK at hybrid fillers loading of 24.78 vol% was obtained.

Nitrile butadiene rubber composites reinforced with reduced graphene oxide and carbon nanotubes show superior mechanical, electrical and icephobic properties

In this article, we examine the effects of two different nanostructured carbons when they are incorporated in a rubber matrix in terms of mechanical and electrical properties as well as the icephobic behaviour of the nanocomposites when swollen. Nitrile butadiene rubber composites reinforced with thermally reduced graphene oxide or multiwalled carbon nanotubes or both of them were prepared and characterized. At a particular hybrid filler loading, tensile and electrical tests showed a significant improvement of the composite. From the swelling studies, after the immersion, the nanocomposites experienced a reduction of the cross-link density that promotes weakening of ice adhesion, being this effect more evident for those samples prepared with hybrid fillers. In view of the composite formulations, that utilize commercially available elastomers and fillers, these findings would be applicable to the automotive and aviation sectors, where the demand for multifunctional rubbers is increasing.

A thermally conductive epoxy polymer composites with hybrid fillers of copper nanowires and reduced graphene oxide

A thermally conductive epoxy polymer composite comprising copper nanowires and reduced graphene oxide as hybrid fillers was prepared. The synthesized one-dimensional copper nanowires (CuNWs) with excellent thermal conductivity and easy dispersity performed a thermal bridge to connect different layers of dimensional graphene oxide (GO), which benefited the thermal conductivity of epoxy composite conductor with increasing hybrid filler loading. The microstructure and morphology of hybrid fillers as well as the thermal properties, volume resistivity and dielectric constant of epoxy polymer composite were investigated. The TEM of hybrid fillers confirmed that CuNWs were loaded on the NH2-rGO uniformly and the CuNWs/NH2-rGO/epoxy possessed higher thermal conductivity and lower volume resistivity (the thermal conductivity and volume resistivity were about 0.43 W/(m · K) and 2.69 × 1011 Ω · cm, respectively) compared to CuNWs/epoxy polymer composite and NH2-rGO/epoxy polymer composite. Moreover, the CuNWs/NH2-rGO/epoxy composites presented better dielectric constant. These were all contributed to the synergetic effect between CuNWs and rGO.

Edible bio-nano-hybrid coatings for food protection based on pectins and LDH-salicylate: Preparation and analysis of physical properties

Abstract Novel active coatings from renewable sources were developed using a pectin matrix and a modified layered double hydroxyde (LDH), as filler. The active molecule, ionically bonded to the LDH, was sodium salicylate. The hybrid filler loading was 5 wt% of LDH-salicylate, with a total content of active molecule into the composites of 1.6 wt%. The degree of plasticization of the composites varied in the range 4–16 vol % of glycerol. Morphological, thermal and barrier properties of the composites were analyzed. The x-ray analysis showed a complete delamination of the hybrid filler at any glycerol loading. The thermal degradation behavior and mechanical properties resulted strictly influenced by the glycerol content. Barrier properties (sorption, diffusion and permeability) to water vapor indicated that composite plasticized with 4 vol% of glycerol showed the best improvement of barrier properties. This suggested that the interaction pectin-active filler-degree of glycerol plays a significant role in determining the transport phenomena. Fresh apricots were coated with the active composite plasticized with 4 vol % of glycerol, demonstrating the efficiency of this formulation in extending the preservation of such fruits.

Preparation, processing and analysis of physical properties of calcium ferrite-CNTs/PET nano-composite

The present work is focused on the preparation of composites based on Poly(ethylene terephthalate) (PET) and novel nano-hybrid filler composed of Calcium Ferrite (CF)-Carbon Nanotubes (CNTs), obtained by direct growth of CNTs on CF based iron catalysts. The carbon content in the hybrid filler was 76 wt%. Composites loaded with 1.0, 1.5, 2.0, 3.0 wt% of filler were obtained by melt compounding and processed by thin-wall injection molding. Unfilled Poly(ethylene terephthalate) was processed using the same techniques. Structural characterization and physical properties (thermal, mechanical and electrical) were analyzed and correlated to the hybrid filler loading, and to the percentage of carbon nanotubes.

Improved thermal conductivity of polycarbonate composites filled with hybrid exfoliated graphite/multi-walled carbon nanotube fillers

The thermal conductivities of polycarbonate (PC) composites filled with carbon fillers, including carbon black (CB), multi-walled carbon nanotubes (MWCNTs) and exfoliated graphite (EG), were studied. EG filler provided substantially greater thermal conductivity enhancement when embedded into PC matrix compared with CB and MWCNTs at the same loading. To further improve the thermal conductivity of PC composite, a hybrid EG/MWCNTs filler was used. When the hybrid filler loading was 10 mass%, the radio of EG: MWCNTs was 9:1, and the thermal conductivity of PC composite showed a maximum value of 1.19 W m−1 K−1 higher than that filled with EG or MWCNTs alone, indicating that the combination of EG and MWCNTs demonstrated a synergistic effect for the thermal conductivity enhancement of PC. EG/MWCNTs/PC composite with thermal conductivity >5 W m−1 K−1 was fabricated when the filler content was 40 mass%, which would widen its field of applications in electrons, LED lamps and aerospace.

Enhanced Thermal Conductivity of Nanofluid by Synergistic Effect of Multi-Walled Carbon Nanotubes and Fe<sub>2</sub>O<sub>3</sub> Nanoparticles

This study investigates the synergistic effect of combining multi-walled carbon nanotubes (MWNTs) and Fe2O3nanoparticles on thermal conductivity of nanofluid. Results show that low percentage hybrid fillers loading improve thermal conductivity of water based nanofluid, due to the good dispersion and interfacial adhesion, which is confirmed by scanning electron microscope. Furthermore, the hybrid fillers provide synergistic effect on heat conductive networks. The thermal conductivity enhancement of water based nanofluid containing 0.05 wt % MWNTs and 0.02 wt % Fe2O3nanoparticles is 27.75%, which is higher than that of nanofluid containing 0.2 wt % single MWNTs or Fe2O3nanoparticles.

Hybrid clay‐carbon nanotube/PET composites: Preparation, processing, and analysis of physical properties

ABSTRACTThe aim of this work was the preparation of novel composites of poly(ethylene terephthalate) (PET) and nano‐hybrid systems based on clay used as catalyst for the growth of multi walled carbon nanotubes (Clay‐CNTs), through catalytic chemical vapor deposition (CCVD). The carbon content into the hybrid filler was 58.1 wt %. Composites with 1.0, 1.5, 2.0, 3.0 wt % of Clay–CNTs were obtained by melt compounding and processed using a microinjection molding press. Unfilled PET was processed in the same composites conditions. Structural characterization and physical properties (thermal, degradation, mechanical, and electrical) were analyzed and correlated to the hybrid filler loading, and carbon nanotubes amount. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40441.

Preparation and properties of multi‐walled carbon nanotubes/carbon fiber/epoxy composites

Multi‐walled carbon nanotubes/carbon fiber (MWCNTs/CF) hybrid fillers are employed to prepare MWCNTs/CF/epoxy composites. Results reveal that a great improvement of the thermal conductivities of the epoxy composites with the addition of MWCNTs/CF hybrid fillers, and the thermal conductivity of the MWCNTs/CF/epoxy composites is 1.426 W/mK with 8 vol% treated MWCNTs/CF hybrid fillers (5 vol% MWCNTs + 3 vol% CF). Both the flexural and impact strength of the MWCNTs/CF/epoxy composites are increased firstly, but decreased with the excessive addition of MWCNTs. The flexural and impact strength of the MWCNTs/epoxy composites are optimal with 2 vol% MWCNTs. For a given MWCNTs/CF hybrid fillers loading, the surface treatment of MWCNTs/CF hybrid fillers can further increase the thermal conductivities and mechanical properties of the MWCNTs/CF/epoxy composites. POLYM. COMPOS., 35:2150–2153, 2014. © 2014 Society of Plastics Engineers

Mechanical and Thermal Conductivities of MWCNTs/Si3N4/Epoxy Composites

The treated multiwalled carbon nanotube/silicon nitride (MWCNTs/Si3N4) hybrid fillers were employed to fabricate thermal conductive MWCNTs/Si3N4/epoxy composites. The thermal conductive coefficient of the composites with 45 wt.% treated MWCNTs/Si3N4 hybrid fillers (5 wt.% MWCNTs + 40 wt.% Si3N4) was 2.42 W/mK. The mechanical properties of the composites were optimal with 7 wt.% MWCNTs/Si3N4 hybrid fillers (2 wt.% MWCNTs + 5 wt.% Si3N4). The composites possessed better thermal stabilities than that of native epoxy composites. For the same hybrid fillers loading, the surface treatment of MWCNTs/Si3N4 hybrid fillers exhibited a positive effect on the thermal conductivities of MWCNTs/Si3N4/epoxy composites.

Preparation and properties of silicon nitride/glass fiber/epoxy composites

Silicon nitride/glass fiber (Si3N4/GF) hybrid fillers are performed to prepare the Si3N4/GF/epoxy composites. Results showed the thermal conductivities of the Si3N4/GF/epoxy composites that are improved with the addition of Si3N4, and the thermal conductive coefficient λ is 1.412 W/mK with 38 vol% modified Si3N4/GF hybrid fillers (30 vol% Si3N4 + 8 vol% GF), seven times higher than that of pure epoxy resin. The flexural strength and impact strength of the composites are optimal with 13 vol% modified Si3N4/GF hybrid fillers (5 vol% Si3N4 + 8 vol% GF). The dielectric constant and dielectric loss of the composites are increased with the increasing addition of Si3N4. For a given Si3N4/GF hybrid fillers loading, the surface modification can further improve the thermal conductivities of the Si3N4/GF/epoxy composites. POLYM. COMPOS., 35:1338–1342, 2014. © 2013 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

Carbon hybrid fillers composed of carbon nanotubes directly grown on graphene nanoplatelets for effective thermal conductivity in epoxy composites

Carbon nanomaterials are generally used to promote the thermal conductivity of polymer composites. However, individual graphene nanoplatelets (GNPs) or carbon nanotubes (CNTs) limit the realization of the desirable thermal conductivity of the composite in both through- and in-plane directions. In this work, we present the thermal conductivity enhancement of the epoxy composite with carbon hybrid fillers composed of CNTs directly grown on the GNP support. The composite with 20 wt% hybrid filler loading showed 300% and 50% through-plane thermal conductivity improvements in comparison with the individual CNTs and GNPs, respectively. Moreover, it showed an enhanced thermal conductivity of up to 12% higher than that of the simply mixed GNP and CNT fillers. In more detail, hybrid fillers, whose CNTs were synthesized on the GNP support (Support C, Fe/Mo–MgO:GNP=1:0.456) for 60 min via chemical vapor deposition process, presented the highest through-plane thermal conductivity of 2.41 W m−1 K−1 in an epoxy composite.

Improved Thermal Conductivity of Silicon Carbide/Carbon Fiber/Epoxy Resin Composites

The surface functionalized silicon carbide/carbon fiber (SiC/CF) hybrid fillers were introduced to improve the thermal conductivities and mechanical properties of the epoxy resin composites. Results revealed that, the thermal conductivities of epoxy resin composites were increased with the increasing volume fraction of SiC, and a higher thermal conductivity of 1.226 W/mK could be achieved with 28 vol% treated SiC/CF hybrid fillers (25 vol% treated SiC +3 vol% treated CF), about 6 times higher than that of native epoxy resin (0.202 W/mK). Both the flexural strength and impact strength of the epoxy resin composites increased up to 5 vol% incorporation, but decreased with the further addition of SiC. However, the electrical conductivity was decreased with the increasing volume fraction of SiC. For a given SiC/CF hybrid fillers loading, the surface functionalized SiC/CF hybrid fillers exhibited a positive effect on the thermal conductivities and mechanical properties of the epoxy resin composites.

Mechanical and morphological properties of waste Eurycoma longifolia fiber/montmorillonite reinforced poly(vinyl chloride) hybrid composites

AbstractHybrid composites are currently spearheading in polymer composites field with the promising ability in improving polymer properties. The influence of Eurycoma longifolia (EL)/montmorillonite (MMT) hybrid fillers loading on the mechanical properties of poly(vinyl chloride) (PVC) hybrid composites has been investigated. PVC resin and various additives were first dry‐blended using a laboratory blender before being milled into sheets using two‐roll mills at 165°C and hot pressed at 180°C and 120 kgm−2. The mechanical properties of PVC hybrid composites were determined using Izod impact, tensile, and flexural test. The incorporation of EL fiber into PVC matrix improved the flexural modulus, tensile modulus of PVC composites, whereas the tensile strength and impact strength decreased with increasing EL fiber content. The addition of MMT into EL‐filled PVC composites has significantly increased the flexural modulus, tensile modulus of PVC hybrid composite compared to PVC composites. However, MMT decreased the flexural strength and impact strength of PVC hybrid composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Effect of carbon black loading on curing characteristics and mechanical properties of waste tyre dust/carbon black hybrid filler filled natural rubber compounds

AbstractCuring characteristics, tensile properties, fatigue life, swelling behavior, and morphology of waste tire dust (WTD)/carbon black (CB) hybrid filler filled natural rubber (NR) compounds were studied. The WTD/CB hybrid filler filled NR compounds were compounded at 30 phr hybrid filler loading with increasing partial replacement of CB at 0, 10, 15, 20, and 30 phr. The curing characteristics such as scorch time, t2 and cure time, t90 decreased and increased with increment of CB loading in hybrid filler (30 phr content), respectively. Whereas maximum torque (MHR) and minimum torque (ML) increased with increasing CB loading. The tensile properties such as tensile strength, elongation at break, and tensile modulus of WTD/CB hybrid filler filled NR compounds showed steady increment as CB loading increased. The fatigue test showed that fatigue life increased with increment of CB loading. Rubber–filler interaction, Qf/Qg indicated that the NR compounds with the highest CB loading exhibited the highest rubber–filler interactions. Scanning electron microscopy (SEM) micrographs of tensile and fatigue fractured surfaces and rubber–filler interaction study supported the observed result on tensile properties and fatigue life. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011