Size Of Graphene Nanoplatelets Research Articles

Impact of graphene nanoplatelet size and hybridisation on the properties of natural rubber nanocomposites

Impact of graphene nanoplatelet size and hybridisation on the properties of natural rubber nanocomposites

A novel prediction method for nanoplatelets content dependent yield strength of graphene nanoplatelets reinforced metal matrix composites at different temperatures

Especially, the quantitative relationship between the thickness and volume fraction of graphene and the grain size of graphene nanoplatelets reinforced metal matrix composites was revealed, based on which the influence of grain refinement, load transfer and dislocation strengthening on the yield strength of composites and their evolution with temperature was quantitatively characterized. Furthermore, by introducing the weakening effect of graphene agglomeration on associated control mechanism of yield strength, a prediction model of temperature dependent yield strength of graphene nanoplatelets reinforced metal matrix composites was established. The proposed prediction approach is verified by comparing the predictions with the experimental data in other literature. Moreover, using the established model, the quantitative effects of length and thickness of nanoplatelets on the yield strength of composites and their evolution with temperature were carried out. This research also provides an effective method for investigating the optimal volume fraction and failure volume fraction of added graphene.

Comprehensive 3-D homogenization approach for predicting mechanical properties and creep behavior of polymer nanocomposites reinforced with graphene nanoplatelets

The aim of this study is to provide a comprehensive 3-D homogenization approach based on the high-fidelity generalized method of cells method to predict the mechanical properties and creep behavior of polymer nanocomposite reinforced with graphene nanoplatelets. Several fundamental experimental aspects including the volume fraction, size, and random orientation of graphene nanoplatelets, the interphase region, and the aggregation state of nanofillers of graphene are taken into account. The present study introduces two novel perspectives. At first, the aggregation of graphene nanoplatelets is formulated as dependent on volume fraction. Then the size of graphene is formulated as an important factor affecting the interphase region and the mechanical properties of polymer nanocomposite. Micromechanical tests conducted using the proposed method illustrate the good agreement with experimental data. The results of the parametric study on different experimental aspects revealed important findings. (i) For a specific value of graphene nanoplatelet volume fraction, the mechanical properties of polymer nanocomposite are at the best state. By increasing the graphene content beyond the specified graphene content value, the effective properties of graphene are decreased. (ii) The size of graphene nanoplatelets and the characteristics of the graphene/polymer interphase region have a direct effect on the properties of the nanocomposite.

Evaluation and Analysis of Elastic Properties for Banana and Graphite Fiber Blended with Graphene Nano-Platelets Based Hybrid Green Composite Using Micromechanical and Semi-Empirical Models

This paper evaluates the isotropic elastic properties of a hybrid composite made of banana fiber and unidirectional graphite fiber reinforced with graphene nano-platelets (GNPs) embedded in polyimide resin. Three different micromechanical models, namely Mori-Tanaka (M-T), Paul’s model (PM), and Maxwell’s model (MM), and one semi-empirical model, namely Modified Halpin-Tsai (Mod. H-T), are used for evaluating and analyzing the elastic properties for the proposed novel hybrid composite. The impact of the size of GNPs on the proposed composite material in the fully dispersed and agglomerated state, impact of different volume fractions of banana and graphite fiber on the axial Young’s modulus (AYm), transverse Young’s modulus (TYm), axial Poisson’s ratio (APr) and axial shear moduli (ASm) of the proposed composite material are analytically evaluated and analyzed. The analysis shows that with the addition of graphite fiber in the GNP-reinforced banana fiber, the elastic features of the proposed composites are improved. It is also observed that the agglomeration of GNPs substantially reduces the hardening effect of GNPs in the proposed composite material. A low volume fraction of graphene (till 1.5 volume%) is observed to strengthen the mechanical features of the proposed composite material. Additionally, the hybridization effect for the composite is evaluated to examine the tensile failure strain features of banana and graphite fiber in the proposed hybrid composite material.

Effect of stirring on characteristics of electrochemically exfoliated graphene

Electrochemical exfoliation of graphite is a promising technique for the synthesis of graphene at a commercial scale. Electrochemical synthesis of graphene at high voltage (∼10 V) is widely reported. However, at high voltage, multilayer graphene platelets with high defect concentration are produced. In this study, high quality graphene nanoplatelets consisting of 1–5 layers were produced at low voltage (3–4 V) using KOH solution as electrolyte. The effect of electrolyte stirring on the characteristics of graphene was studied. The stirring of electrolyte during electrolysis showed profound effect on the characteristics of graphene. The scanning electron microscopic (SEM) analysis showed that the stirring of electrolyte increased the average size of graphene nanoplatelets to 360 nm from 253 nm (without stirring). Raman spectroscopy indicated the presence of 1–5 layers of carbon atoms and the same was confirmed by transmission electron microscopy (TEM). A decrease in the defect concentration was noted with the increase in number of layers of carbon atoms in graphene produced with stirring.

Free vibration analysis of functionally graded composite rectangular plates reinforced with graphene nanoplatelets (GPLs) using full layerwise finite element method

The current investigation is the first endeavor to apply the full layerwise finite element method (FEM) in free vibration analysis of functionally graded (FG) composite plates reinforced with graphene nanoplatelets (GPLs). Unlike the equivalent single-layer (ESL) theories, the layerwise FEM focuses on all three-dimensional (3D) effects. Therefore, it can compute interlaminar stresses and other local effects with the same accuracy as 3D FEM, requiring a lower computational cost. The GPLs weight fraction is presumed invariable in each layer but varies through the plate thickness in a layerwise model. The modified Halpin-Tsai model is employed to acquire the effective Young’s modulus. The rule of mixtures is applied to specify the effective Poisson’s ratio and mass density. First, the current method is validated by comparing the numerical results with those stated in the available works. Next, a thorough numerical study is performed to examine how various factors involving the pattern of distribution, weight fraction, geometry, and size of GPLs, together with the thickness-to-span ratio and boundary conditions of the plate, affect its free vibration behaviors. Numerical results demonstrate that employing a small percentage of GPL as reinforcement considerably grows the natural frequencies of the pure epoxy. Also, distributing more square-shaped GPLs, involving a smaller amount of graphene layers, and vicinity to the upper and lower surfaces make it the most efficient method to enhance the free vibration behaviors of the plate.

Calculation of the degree of crystallinity of HDPE/GNPs nanocomposites by using various experimental techniques: a comparative study

This work is a comparative study of four different techniques to determine the crystallinity of high-density polyethylene (HDPE) nanocomposites filled with different diameter sizes (5, 15 and 25 μm) of graphene nanoplatelets (GNPs) at various amounts (0.5–5 wt%). The structure of HDPE/GNPs nanocomposites was extensively studied by using different experimental methods, such as X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. To further provide a complete comparison, differential scanning calorimetry measurements were utilized to calculate the crystallinity values, while temperature-modulated DSC was employed to investigate the possible mechanism of the different crystalline structures. It was found that these methods can be used to estimate the crystallinity, but the sample parameters and experimental conditions must be taken into consideration. All the techniques showed that the crystallinity depends on GNPs size and content. The distance between dispersed platelets was substantial at low concentrations of GNPs, making it comparatively easy for additional nucleation sites to incorporate the polymer matrix, and the crystal nucleus was simply formed. However, at high concentrations of GNPs, the diffusion of polymer chains to the growing crystallites was hindered by large GNPs particles, despite the formation of additional nucleation sites.

Effect of the Addition of Graphene Nanoplatelets on the Thermal Conductivity of Rocket Kerosene: A Molecular Dynamics Study.

Rocket kerosene plays an important role in the regenerative cooling process of rocket thrust chambers. Its thermal conductivity determines the cooling efficiency and the tendency to coke in rocket kerosene engines. In this paper, graphene nanoplatelets (GNPs) were introduced into rocket kerosene to improve its thermal conductivity. Molecular dynamics simulation was used to investigate the thermal conductivity of the composite system and its underlying thermal conductivity mechanism. Firstly, by studying the effect of the mass fraction of GNPs, it was found that, when the graphene mass fraction increases from 1.14% to 6.49%, the thermal conductivity of the composite system increases from 4.26% to 17.83%, which can be explained by the percolation theory. Secondly, the influence of the size of GNPs on the thermal conductivity of the composite system was studied. Basically, the thermal conductivity was found to increase by increasing the aspect ratio of GNPs, indicating that GNPs with a higher aspect ratio are more conducive to improving the thermal conductivity of rocket kerosene. By carefully analyzing the effect of the size of GNPs on thermal conductivity, it was concluded that the thermal conduction enhancement by adding GNPs is determined by the combined effect of the percolation theory and the Brownian motion. The results of the temperature effect study showed that the ratio of thermal conductivity to rocket kerosene increased from 1.16 to 1.26 and from 1.07 to 1.11 for the composite systems, with graphene sizes of 41.18 Å × 64.00 Å and 24.14 Å × 17.22 Å in the temperature range of 293 K to 343 K, respectively. It is further proved that the Brownian motion of GNPs has a non-negligible effect on the thermal conductivity of the composite system. This work provides microscopic insights into the thermal conduction mechanism of GNPs in nanofluids and will offer practical guidance for improving the thermal conductivity of rocket kerosene.

Effect of graphene size variation on mechanical properties of aluminium graphene nanocomposites: A modeling analysis

Graphene, as a nano-filler in aluminium (Al) matrix, improves the mechanical, thermal, electrical, and functional properties of Aluminium matrix Graphene nanocomposites (AGNCs). The present work aims to estimate the effect of varying the size of graphene nanoplatelets (GNPs) in AGNCs on mechanical properties. The analysis has been performed for an optimal Gr reinforcement of 1% weight fraction in AGNCs. The size effect of GNPs on the mechanical properties of AGNCs is investigated by dispersing randomly inclined GNPs of diameters 15 nm, 20 nm, 30 nm, and 40 nm inside the Al matrix. These formations are normally difficult to synthesize in experimental studies and remained unexplored. To overcome this difficulty, here-in we are using the Finite Element (FE) technique to investigate the effect. The effective mechanical properties of AGNC have been determined by applying load uniaxially on the representative volume element and by using material properties such as young’s modulus, mass density, poisons ratio, etc. It has been found, that the largest size of GNPs shows a good balance of strength and ductility in NC. Larger sizes GNP AGNC have shown a decrement in strength from 702 MPa to 475 MPa and a significant increase in ductility. The analytical results obtained have been validated with the experimental measurements available in the existing literature and generated AGNC have shown a 50 % increment in yield strength compared to experimental. These NCs are prominent materials to develop lightweight structures for aircraft, automobiles, etc. without compromising strength.

Graphene Based Wideband Electromagnetic Absorbing Textiles at Microwave Bands

The design and realization of graphene based wideband electromagnetic (EM) absorbing textiles are becoming of primary interest. Hence, the development of new conductive coatings to be cast onto commercial textiles is crucial. In this article, we propose new graphene based absorbing textiles that conjugate outstanding EM absorbing properties at radiofrequency with low-weight, flexibility, cost-effectiveness, and washability. With this purpose, an innovative production process of polyvinylidene fluoride (PVDF) coatings filled with graphene nanoplatelets (GNPs) is developed for the production of radar-absorbing coated textiles, which are fully characterized in terms of morphological, electrical, and EM absorbing properties. In particular, the complex dielectric permittivity of the coated textiles including different amounts of GNPs is assessed through the measurement of the complex permittivity of a benchmark sample, the consequent estimation of the average GNP size and the prediction by simulations of the effective complex permittivity of graphene based coatings loaded with different GNP amounts. Such predicted data are crucial to design radar absorbing textiles with minimum bandwidths at −10 dB of 5 GHz and reflection coefficients below −5 dB over all the frequency range from 8 up to 18 GHz. These textiles are then produced and characterized in terms of reflection coefficient in free space against a plane wave with normal incidence. The obtained results demonstrate the full satisfaction of the design requirements. In fact, the produced samples show a reflection coefficient with a bandwidth at −10 dB up to 77% of the resonant frequency.

Influence of graphene nanoplatelets geometrical characteristics on the properties of polylactic acid composites

The influence of graphene nanoplatelets (GNP) surface area and size on the dispersion, electrical percolation behavior, electrical conductivity, thermal conductivity, electromagnetic interference (EMI) attenuation, and EMI attenuation mechanisms of GNP/polylactic acid (PLA) were investigated. The GNP/PLA composite's electrical percolation threshold decreased with the increase in GNP surface area and decrease in GNP size. The higher number of GNP particles associated with the decrease in GNP size and increase in GNP surface area facilitated the creation of a conductive network at a lower GNP content. However, at a GNP loading of 30 wt%, the GNP/PLA composites' electrical, EMI SE, and thermal conductivity decreased with the increase in GNP surface area and decrease in GNP size. At high nanofiller loading, the contact resistance between the nanofiller particles is more important than the nanofiller aspect ratio or size. The smaller filler size means more particles and more filler/filler resistance points. The most exciting finding is the dependence of EMI attenuation mechanisms on the GNP surface area. EMI attenuation by absorption was found to increase with the increase in GNP surface area.

Thermal Percolation Behavior in Thermal Conductivity of Polymer Nanocomposite with Lateral Size of Graphene Nanoplatelet.

In this study, the thermal percolation behavior for the thermal conductivity of nanocomposites according to the lateral size of graphene nanoplatelets (GNPs) was studied. When the amount of GNPs reached the critical concentration, a rapid increase in thermal conductivity and thermal percolation behavior of the nanocomposites were induced by the GNP network. Interestingly, as the size of GNPs increased, higher thermal conductivity and a lower percolation threshold were observed. The in-plane thermal conductivity of the nanocomposite containing 30 wt.% M25 GNP (the largest size) was 8.094 W/m·K, and it was improved by 1518.8% compared to the polymer matrix. These experimentally obtained thermal conductivity results for below and above the critical content were theoretically explained by applying Nan’s model and the percolation model, respectively, in relation to the GNP size. The thermal percolation behavior according to the GNP size identified in this study can provide insight into the design of nanocomposite materials with excellent heat dissipation properties.

Thermo-responsive and electro-active shape memory poly(styrene-b-isoprene-b-styrene)/poly(ethylene-co-1-octene)/graphene composites: Effect of size of graphene nanoplatelets

Thermally and electrically triggered poly(styrene-b-isoprene-b-styrene) (SIS) and poly(ethylene-co-1-octene) (PEO) thermoplastic elastomer blend composites having a SIS/PEO weight ratio of 40/60 were prepared by melt blending method. Two different graphene nanoplatelets (GnPs) with different sizes (small size (SG) and big size (BG)) were used as conductive fillers at different amounts. The thermo-responsive and electro-active shape memory performances of the composites as well as their morphological, mechanical and thermal properties were investigated by paying attention to the effect of size and loading degree of the graphene nano-fillers. Both the BG and the SG improved elastic modulus with increase in amount of the fillers. The modulus values increased by 553 % and 507 % for the 50BG and 50SG composites having 50 phr GnPs respectively, as compared to the blend. Heat-triggered thermo-mechanical shape memory tests showed that the BG filler is more advantageous for shape fixing whereas the SG filler is favorable to shape recovery ability. The electrical percolation threshold was achieved at relatively lower content for the BG filler. The 50BG composite exhibited electro-active shape recovery under 25 V, while the SG composite recovered its shape under 65 V. The thermal stability of the blend significantly improved by the use of the both fillers. The degradation onset temperatures of the 50SG and the 50BG composites increased by 25 °C and 10 °C, respectively, compared to the blend.

Stability, rheology, and thermophysical properties of surfactant free aqueous single-walled carbon nanotubes and graphene nanoplatelets nanofluids: a comparative study

A comparative study, for the first time, was conducted on thermophysical and rheological properties of single-walled carbon nanotubes (SWCNT) and graphene nanoplatelets (GNP) nanofluids. Highly stable aqueous 0.5, 1.0, and 2.0 wt% SWCNT and GNP nanofluids were successfully prepared with no surfactant, through ultrasound technology. The preparation was explained in detail, adjusting pH to around 8 where nanofluids would be expected to be stable. The highest zeta potential of −60.5 mV was obtained for 2.0 wt% SWCNT nanofluids. Shear thinning was observed for all nanofluids at low shear rates. Unlike shear thickening of GNP, Newtonian behavior of SWCNT nanofluids was detected at high shear rate region. The effect of ultrasound technology was directly verified by scanning electron microscopy (SEM), resulting in GNP size reduction and separation of bundles for SWCNT. The results revealed that SWCNT nanofluids showed a remarkable zeta potential value for heat transfer systems compared to GNP nanofluids.

Fracture Toughness of Hybrid Carbon Fibre/Epoxy Enhanced by Graphene and Carbon Nanotubes

Carbon-based nanoparticles have attracted considerable attention in materials science and engineering fields as they can significantly improve the electro-thermo-mechanical properties of polymer-based materials. With the need of enhancing the mechanical property through the thickness direction of a carbon fibre reinforced polymer (CFRP) system, this study investigates the effect of graphene nanoplatelets (GNP), multi-walled carbon nanotubes (MWCNT) and their hybridisations on its Mode I interlaminar fracture toughness. Various nanoplatelet sizes and weight percentages are compared to prohibit their agglomeration in epoxy which can drastically reduce the mechanical properties of CFRP. The smallest GNP size, 1 μm, dispersed in the n-methyl-2-pyrrolidone solvent leads to an advanced 146% enhancement of Mode I interlaminar fracture toughness on the CFRP system. The acetone solvent is found less surface compatible with the nanoplatelets, but provides a simple and environmentally friendly manufacturing process. The hybrid GNP/MWCNT with 1wt% content dispersed in acetone solvent shows the synergistic effect and reaches a 120% enhancement of Mode I interlaminar fracture toughness of CFRP. Additionally, the application of the thin film hot press technique on nanoplatelets enhanced CFRP demonstrates an effective and promising solution to manufacture homogeneous multi-phase composites.

Effect of silicate sodium and graphene nanoplatelets on morphology and rheology characteristics of new synthesized preformed particle gel (PPG) for water shut-off treatment

Water flooding is one of the most common enhanced oil recovery (EOR) methods, however its application in naturally fractured reservoirs (NFR), suffers from the flow of water in high permeable channels and fractures which leads to low areal and volumetric sweep efficiency. Preformed Particle Gels (PPG), as a subset of gel treatments, can play a vital role in plugging super-permeable zones either near wellbore or deep in the reservoir. Nevertheless the mechanical strength and thermal stability of the designed PPGs, especially under harsh environmental conditions, are subject to further research and development. In spite of recent studies, the effects of nano-materials on the rheological and morphological properties of the PPGs are not systematically investigated and understood. In this study novel PPGs were designed and synthesized (using free radical polymerization process) for application at harsh environments in terms of temperature, pH and salinity. To investigate the effectiveness of the designed PPG samples static swelling bulk tests as well as dynamic Hele-Shaw tests are performed. The examined parameters in static tests include various pH of the environment, the type and concentration of ions in the brine, temperature, dehydration durability and presence of carbon dioxide. In addition, to enlighten the mechanisms behind the performance of the new designed PPGs, comprehensive set of rheological tests (evaluation of both storage and elastic modules) as well as SEM and ESEM image analysis of dry and swollen particles are performed. Taking advantages of silicate sodium gelation capacity and functionalization of graphene nano-platelets (GNP), novel monolithic gel samples (SNGP) with unique qualities are synthesized. Although the addition of sodium silicate and GNP reduced the swelling capacity of the gels, they have significantly improved the rheological properties of the PPG samples. Rheological tests, confirmed that by adding only 0.1 wt% graphene nano-platelets and 0.5 wt% sodium silicate, the storage module of the swollen gel increased three times. Additionally the main advantage of the samples SNGP sample is its stability at harsh conditions such as high salinity, high as well as low pH, high temperature and its dehydration durability. SEM images of dry particles shows that presence of both silicate sodium and GNP has improved the harmonization of the networked structure, with making it thicker and denser. This has increased the porous interrelated structure which in turn is responsible for strong and improved mechanical properties of the SNGP gels. ESEM images of the swollen samples shows that the uniformly porous network structure of hydrogels is led to the maximum water holding capacity, which contributes to good stability of the 3D network structure of swollen PPGs under dehydration and thermal tests. Additionally, this improved microstructure can explain the compressive strengths increment with adding up nano-graphene and silicate content. The two PPG samples with the most suitable specification in the bulk tests were selected for further performance analysis in dynamic tests through Hele-Shaw cell setup. The experimental results in this transparent fracture model showed that increasing salinity causes the increase of the residual resistance factor (Frr). The results showed that the plugging efficiency and the damage factor are directly related to the PPGs size, water salinity and concentration of both GNP and silicate sodium. It is demonstrated that SNGP sample containing 50% size of 1190–595 μm and 50% size of 297–177 μm (larger size distribution) has a higher plugging capability compared to the samples containing each of these particles sizes alone. Additionally both bulk tests and Hele-Shaw cell tests approved that synthesized PPGs are also applicable for CO 2 injection. • New PPG is synthesized to be applicable in harsh environments such as low/high pH, high salinity and high temperature. • Sodium silicate and graphene nano-platelets improved temperature resistance and dehydration durability properties. • Static swelling bulk tests and dynamic Hele-Shaw cell tests are performed to evaluate the water shut-off performance. • Different rheological tests are performed to evaluate the mechanical and rheological properties of the designed hydrogels. • SEM and ESEM are used to shed light on the morphology of the samples and the reason behind improved properties.

Electrodeposited nickel–graphene nanocomposite coating: influence of graphene nanoplatelet size on wear and corrosion resistance

In this paper, we broaden our previous work, which investigated the influence of graphene nanoplatelets (GNPs) size on microstructure and hardness of composite coatings, to determine the effect of GNP size on wear-resistance and anti-corrosion property of GNP-reinforced nickel coating (Ni/GNPs). The experimental results indicated that the small GNP material size could enhance the wear resistance for nickel composite coating with the wear rate of 13.2 × 10–4 mm3/Nm, the wear depth of 17.69 µm. Meanwhile, the anti-corrosion property is enhanced significantly, this is shown via the low corrosion current density (Icorr value of 1.16 × 10–7 A/cm2) and the high corrosion potential (Ecorr value of − 0.1661 V). In addition, the mass lost in salt fog testing is low with the weight of 12.3 mg, which decreased down to ~ 55.27% compared to pristine Ni coating. These results are attributed to the uniform distribution of the small GNP size inside Ni matrix as well as the grain refinement effect of composite coating when using the small GNP size.

Examining the contribution of factors affecting the electrical behavior of poly(methyl methacrylate)/graphene nanoplatelets composites

AbstractIn this study, poly(methyl methacrylate) (PMMA)/graphene nanoplatelets (GNPs) conductive composite films with different morphologies were fabricated from the same constituent materials using four fabrication techniques, solution casting (SC), SC followed by hot pressing (SCP), melt mixing followed by SC (MSC), and melt mixing followed by hot pressing (MP). Morphologies of dispersed GNPs and electrical properties in both in‐plane and perpendicular direction were investigated and compared systematically. The corresponding percolation thresholds (Φc) of the composites varied from 0.42 ± 0.13 vol% to 3.26 ± 0.48 vol%. The conductivities varied up to two orders of magnitude and decreased in the sequence of SC > MSC > SCP > MP. These variations were explained in terms of GNPs size, GNPs orientation, distribution and dispersion state of fillers. The contribution of the above factors in each procedure were discerned individually, the results were discussed and compared with other experimental studies and simulations as well.

Micromechanical modeling over two length-scales for elastic properties of graphene nanoplatelet/graphite fiber/polyimide composites

The transversely isotropic elastic properties of the multi-scale composites made of unidirectional T650-35 graphite fibers embedded in graphene nanoplatelets (GNPs)-enriched PMR-15 polyimide resin are evaluated. A multi-step micromechanical model consisted of generalized method of cells (GMC) and Halpin-Tsai approaches is hierarchically developed. The main advantage of this micromechanical methodology lies in its ability to consider the size and the agglomerated state of GNPs. The numerical results of the model are compared to the existing experimental data and a quite good agreement is found. The influences of amount, size, and agglomerated degree of GNPs, volume fraction of graphite fibers on the Young's moduli, Poisson's ratios, and shear moduli along the axial and transverse directions are investigated. The results clearly demonstrate an improvement in the elastic properties of the graphite fiber-reinforced multi-scale composites by the uniform dispersion of nano-graphene fillers in the polyimide resin. Furthermore, the change of GNP size can notably affect the multi-scale composite properties. Thinner GNPs would be preferable to improve the mechanical characteristics. However, the nano-graphene agglomeration drastically reduces the stiffening effect of the GNPs.

Enhanced thermal conductivity and electrically insulating of polymer composites

Highly thermally conductive but electrically insulating polymer composites play an increasingly important role in thermal management applications due to their features of easy processing and lightweight. Herein, a unique segregated network, which consists of graphene nanoplatelets (GNP) and boron nitride fibers (BNF), was constructed in polypropylene (PP)-based composites via two-screw extrusion. The thermal conductivity and electrical insulation characteristic of the composites could be well controlled by adjusting the content and size of GNP and BNF. When PP was filled with 9wt% GNP and 30wt% short BNF, the highest thermal conductivity of 1.32 W/(m·K) was achieved in this work, which is about six times higher than the value of neat PP, while remained a good electrical insulating (as low as 2.98 × 10−9 S/m). It proposed that the unique segregated network, where the BNF play as a bridge to connect the scattered GNP, could benefit for phonons transmission but effectively interrupt electron conduction. Our work provides a facile method to design and fabricate the highly thermally conductive but electrically insulating composites applied in thermal management materials.