Acrylonitrile-styrene-acrylate terpolymer and poly(α-methylstyrene-acrylonitrile) (ASA/α-MSAN, 25/75) with different loadings of chlorosulfonated polyethylene (CSM) were prepared via melt blending, with goals of toughening modification of ASA/α-MSAN blends and maintaining the heat resistance simultaneously. The results revealed CSM had excellent toughening effect at room temperature. At 0 °C, impact strength increased linearly with CSM content. However, toughening effect of CSM was undesirable at −30 °C. The temperature-dependent toughening efficiency of CSM was significantly related to its glass transition behavior. Scanning electron microscope analysis on cryo-fractured surfaces revealed the toughening mechanism was the formation of CSM toughening network in matrix, which was further confirmed by selective extraction tests. The formation of CSM network could lead to increased glass transition temperature of the blends at the low temperature region according to dynamic mechanical thermal analysis. Different from other toughening agents, CSM network uncompromised the heat resistance of ASA/α-MSAN blends.
Solar Energy Materials and Solar Cells 2017 Volume 172(Volume 172) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.solmat.2017.07.017
•The cool roofing materials show high NIR and solar reflectance.•The cool roofing materials perform excellent heat-insulation property.•The fabricated ASA/TiO2 hybrid materials have excellent weather resistance.•A hydrophobic surface was achieved by adding hydrophobic modified TiO2.•The materials all perform good mechanical properties to some extent.The cool roofing materials were fabricated to solve overheating concerns from absorbed solar energy (Ultraviolet-Visible-Near infrared) and infrared thermal energy absorbed from the ambient. In this study, four types of titanium dioxide (TiO2), namely hydrophobic rutile nano-TiO2, hydrophilic anatase nano-TiO2, unmodified rutile TiO2 and unmodified anatase TiO2, were chosen to fabricate cool roofing materials due to their high solar reflectance and excellent actual heat-insulation properties. Matrix is poly (acrylonitrile-styrene-acrylate) (ASA) resin for its excellent weather resistance. The reflectance was measured by an Ultraviolet-Visible-Near infrared (UV–vis–NIR) spectrophotometer and actual heat-insulation properties by a self-designed device. Contact angle analysis was conducted by a contact angle meter. When hydrophobic rutile nano-TiO2 particles (5 wt%) introduced, the ASA/TiO2 hybrid material possesses a reflectance of 45.2% throughout NIR and 59.4% throughout the whole solar spectrum. The thermal emissivity in the region of 8–13 µm is 0.87, as well as 0.86 in the region of 2.5–15 µm. The high solar reflectance and high thermal emissivity lead to cool materials with excellent cooling property. Simultaneously, significant drop in temperature shows excellent cooling property in comparison with unloaded ASA resin. Specifically, a maximum decrease of 34 °C can be observed in the indoor temperature test using a solar simulator, and a decrease of 10 °C can be achieved when tested outdoors under natural solar radiation. In particular, the contact angle of the sample added with hydrophobic rutile nano-TiO2 particles is 103°, which forms a hydrophobic surface. In addition, the cool roofing materials fabricated in this study demonstrate excellent weather resistance, meeting the strict requirements for outdoor use.
Composites Science and Technology 2017 Volume 145(Volume 145) pp:
Publication Date(Web):16 June 2017
DOI:10.1016/j.compscitech.2017.04.007
Nowadays, the undesirable heat generated from solar energy troubles people a lot in various aspects, including the energy consumption for cooling purposes, the potential safety hazards of the outdoor devices used in high-temperature environment and so on. Therefore, many cool materials emerge as the times require, which can mitigate these serious situation. In this study, a concept of solar reflective ASA (acrylonitrile-styrene-acrylate terpolymer) for cool material was proposed. To achieve this purpose, several inorganic particles with high solar reflectance were chosen to mix with ASA via melt blending to improve the cooling property of ASA. Ultraviolet-visible-near infrared (UV-Vis-NIR) spectral and temperature test were carried out to evaluate the cooling properties of ASA and its hybrid composites. The results of the solar spectral test showed that the addition of only 1% volume fraction of inorganic particles could effectively improve the solar reflectance of ASA. And ASA/barium titanate (BaTiO3) hybrid composite possessed the highest reflectance value of 67.66%, nearly 2 times that of neat ASA. The results of the indoor temperature test were in highly consistent with those of the solar reflectance, which showed that all the hybrid composites presented better cooling effect compared with neat ASA. Also, ASA/BaTiO3 hybrid composite exhibited the best cooling effect, nearly 10 °C lower than neat ASA. Besides, the outdoor temperature test showed the same trend with the indoor temperature test. Furthermore, the results of the mechanic test indicated that the improvement of the cooling properties was based on no sacrifice of the mechanical properties.
•A hydrophobic surface is achieved with the assistance of silane coupling agent.•The composited cool materials show high NIR and solar reflectance.•The composited cool materials perform excellent cooling property.•Excellent mechanical properties are achieved due to the surface modification.•Building the reaction model between silane coupling agent and TiO2.Hydrophobic surface modification of TiO2 was conducted for production of acrylonitrile-styrene-acrylate (ASA) terpolymer/titanium dioxide (TiO2) composited cool materials. Different amount of 3-methacryloxypropyl-trimethoxysilane (MPS) was employed to change hydrophilic surface of TiO2 into hydrophobic surface. The hydrophobic organosilane chains were successfully grafted onto TiO2 through SiOTi bonds, which were verified by Fourier transformed infrared spectra and X-ray photoelectron spectroscopy. The water contact angle of the sample added with TiO2 modified by 5 wt% MPS increased from 86° to 113°. Besides, all the ASA/TiO2 composites showed significant improvement in both solar reflectance and cooling property. The reflectance of the composites throughout the near infrared (NIR) region and the whole solar wavelength is increased by 113.92% and 43.35% compared with pristine ASA resin. Simultaneously, significant drop in temperature demonstrates excellent cooling property. A maximum decrease approach to 27 °C was observed in indoor temperature test, while a decrease around 9 °C tested outdoors is achieved.Download high-res image (101KB)Download full-size image
Journal of Materials Science: Materials in Electronics 2017 Volume 28( Issue 7) pp:5250-5261
Publication Date(Web):2017 April
DOI:10.1007/s10854-016-6182-x
The aim of the study was to use carbon fibers and carbon blacks to improve the thermal conductivity, mechanical and dielectric properties of ethylene propylene diene monomer (EPDM)/barium titanate (BaTiO3) composites. It was found that 7.5 vol% carbon blacks, with high specific surface area, can make complex viscosity of EPDM/BaTiO3 compound to become non-sensitive to varying shear. Due to the sulfuric atom and C=C groups on surface of carbon blacks, 10 vol% carbon blacks can enhance the tensile strength and tear strength of EPDM/BaTiO3 (70/30) from 9.00 MPa and 21.06 kN m−1 to 14.32 MPa (59% increase) and 30.02 kN m−1 (43% increase). It was found that the 10 vol% spherical carbon blacks with high specific area can partially contact BaTiO3 and fill the gap between BaTiO3 particles to increase thermal conductivity and dielectric constant of EPDM/BaTiO3(70/30) from 0.323 W m−1 K−1and 7 at 5 MHz to 0.632 W m−1 K−1 (95% increase) and 746 (106 times increase) at 5 MHz, respectively. When the filler content was 10 vol%, carbon blacks and carbon fibers can decrease the volume resistivity of EPDM/BaTiO3 (70/30) from 2.23 × 1013 to 6.37 × 105 Ω m (eight order of magnitude drop) and 4.25 × 1011 Ω m (two order of magnitude drop), respectively.
Acrylonitrile–butadiene rubber (NBR), a synthetic rubber having C≡N dipoles, was chosen as a polymer matrix with a higher dielectric constant than other non-polar rubber like silicone rubber or ethylene–propylene–diene monomer. Barium titanate (BaTiO3), as a ferroelectric material, with a high dielectric constant and low dielectric loss was selected as a main filler to further enhance the dielectric constant of NBR. An effective silane coupling agent (KH845-4), selected from five types of silane coupling agents with different characteristic functional groups, was used to modify the surface of BaTiO3 particles to enhance its interfacial adhesion to the matrix. Fourier transform infrared spectroscopy (FTIR) was used to verify the successful modification. The addition of BaTiO3 obviously enhanced the dielectric constants. In particular, an uncommon pattern of dielectric loss has been displayed and analyzed in this paper. Nevertheless, the reinforcing effect of mechanical strength of the NBR/treated BaTiO3 composites is limited. On this basis, the addition of nanosilica (SiO2), replacing part of NBR, improved the mechanical strength. Confirmed by scanning electron microscopy (SEM), the SiO2 and treated BaTiO3 particles were dispersed well in the NBR matrix. The tensile strength was increased from 4.33 to 6.12 MPa when SiO2 accounted for 4%. Moreover, the curing characterizations, crosslinking density, resistivity, and oil resistance were evaluated. This composite material can be used in manufacturing electronic devices, which are subjected to oily environments for a long time.
Solar Energy Materials and Solar Cells 2016 Volume 151() pp:30-35
Publication Date(Web):July 2016
DOI:10.1016/j.solmat.2016.02.016
•The addition of UV absorber and pigment yellow could block UV and blue light.•The films added with ITO or ATO perform efficient NIR-shielding property.•The films fabricated maintain a high light transmittance in visible light region.•The transparent films achieved perform excellent heat-insulation property.•The plasticized PVC films are reinforced by ITO or ATO to some extent.In this work, we present the development and assessment of transparent and heat-insulation thin films that represent a new class of polyvinyl chloride (PVC) polymers. The addition of ultraviolet (UV) absorber, yellow pigment and indium tin oxide (ITO) or antimony tin oxide (ATO) showed significant improvement upon shielding effect against UV light, blue light and near-infrared (NIR) light, respectively. Particularly, environmentally friendly polyester plasticizer was applied. The optical and actual heat insulation properties were investigated by an Ultraviolet–Visible–Near infrared (UV–vis–NIR) spectrometer and a self-designed device, respectively. It was found that low transmittance (21.09% and 24.46% respectively) in NIR region (800–2600 nm) can be achieved with the addition of 2.0 phr ITO or ATO particles, and a decrease of 3 °C or 5 °C can also be observed in temperature test. Meanwhile, the thin films possessed a low UV transmittance performance (200–400 nm), accompanied with low transmittance in blue light range (400–500 nm) while maintained a high light transmittance in visible light range (400–800 nm). The shielding effectiveness provided by the materials fabricated in this study offer specificity and potency in next-generation transparent and heat-insulation thin film, with applications in protection of valuable antique, glasses, display screen and windows of automobiles.
Poly(butyl-acrylate)-g-poly(styrene-co-acrylonitrile)/α-methyl-styrene-acrylonitrile/thermoplastic polyurethane elastomer (PBA-g-SAN/α-MSAN/TPU) ternary blends were prepared with different composition ratios via melt blending. This work is mainly focused on improving the toughness of PBA-g-SAN/α-MSAN blends at room temperature (25 °C) and low temperature (0 °C and −30 °C). The results of notched Izod impact strength tests revealed that TPU had good toughening efficiency at 25 °C and 0 °C. With addition of 30 phr TPU, the impact strength of the blends increased from 5.3 kJ m−2 to 26.5 kJ m−2 at 25 °C, and increased from 2.9 kJ m−2 to 18.7 kJ m−2 at 0 °C. Obvious brittle-tough transition of the ternary blends was observed with increasing TPU content at 25 °C and 0 °C. The toughening efficiency of TPU was not notable when the impact temperature dropped to −30 °C, but the impact strength of the blends still increased with increasing TPU content. The glass transition temperature (Tg) of the blends was mainly responsible for the temperature dependence of toughening efficiency, which was proved by dynamic mechanical thermal analysis. It was also found the addition of TPU could lead to the slightly decreased Tg of the blends in the low temperature region. The probable reason for this is the unique structure formed in ternary blends, which was proved by attenuated total reflection infrared analysis and contact angle tests. The impact-fracture surfaces of blends were observed by scanning electron microscopy. The introduction of TPU brought with it a slight decrease of tensile strength, but the elongation at break of the blends increased greatly. Flexural strength, flexural modulus and heat resistance showed a decreasing tendency with increasing TPU content.
In this work, some additives were added into plasticized poly(vinyl chloride) (PVC) matrix for the purpose of shielding ultraviolet light (UV), high-energy visible light (HEV) and near-infrared light (NIR). Furthermore, the flame retardance of the plasticized PVC films were also enhanced by adding organo-phosphorus flame retardant plasticizer such as tris(1-chloropropan-2-yl) phosphate (TCPP). The properties of PVC films were investigated by the limiting oxygen index (LOI) test and ultraviolet-visible-near-infrared (UV-vis-NIR) spectrophotoscopy. With the incorporation of Sb2O3 and polyester plasticizer (PEP) into the PVC films, the resultant LOI was increased from 26% (LOI value of PVC with PEP) to 32% (LOI value of PVC with PEP/Sb2O3), while the transmittance of visible light decreased from 84.84% to 0.18%. The replacement of PEP in PVC films by TCPP resulted in a significant improvement in flame retardancy. The LOI increased from 26% (LOI value of PVC with PEP) to 35% (LOI value of PVC with TCPP), and the transmittance increased from 84.84% to 91.79%, respectively. Hence, a flame retardant functional PVC film was achieved by the combination of a UV absorber, pigment yellow, TCPP and indium tin oxide (ITO), which possesses a high LOI value (35%), high transmittance in the visible region (81.56%) and low transmittance in the UV region (0.40%), HEV region (62.79%) and NIR region (39.04%).
Co-reporter:Zhen Zhang, Shichao Wang, Jun Zhang, Wenqiang Zhu, Tingsheng Tian
Polymer Testing 2016 Volume 51() pp:1-5
Publication Date(Web):May 2016
DOI:10.1016/j.polymertesting.2016.02.003
The key drawback of impact modifier-toughened polymer is that the improved toughness is accompanied by loss in stiffness. Surprisingly, poly (vinyl chloride) (PVC)/poly (α-methylstyrene-acrylonitrile) (α-MSAN) blend was toughened without loss in stiffness by simply combining two impact modifiers-chlorinated polyethylene (CPE) and acrylic resin (ACR). The prepared blend's impact strength was 3.0 times higher than PVC/α-MSAN/CPE blend and 18.6 times higher than pure PVC/α-MSAN blend. An impressive thermal stabilizing effect was also achieved when CPE and ACR were combined. The improved toughness could be attributed to the overlap of the stress field between different impact modifiers, which help to form the continuum percolation of stress volume under impact loading.
Composites Part B: Engineering 2016 Volume 99() pp:196-202
Publication Date(Web):15 August 2016
DOI:10.1016/j.compositesb.2016.06.012
In this study, TiO2/acrylonitrile-styrene-acrylate (ASA) nanocomposites with different loading content of TiO2 were prepared via in situ emulsion polymerization. Before the polymerization, TiO2 nanoparticles were dispersed in the reaction monomer by ultrasonic to reduce the agglomeration of TiO2. A series of characterization were taken to study the properties of the nanocomposites. The result of Wide angle X-ray diffraction (WAXD) analysis indicated that the crystal form of TiO2 remained unchanged after the in situ emulsion polymerization. Interestingly, the introduction of TiO2 induced a significant improvement in the impact toughness of TiO2/ASA nanocomposites, which increased dramatically by about 10 kJ/m2 compared with neat ASA. And we attributed this improvement to the better dispersibility of TiO2 in ASA matrix which is proved by Transmission Electron Microscopy (TEM) analysis. In addition, the solar reflectance of the nanocomposites was related to the addition of TiO2 nanoparticles. The more the TiO2 nanoparticle was added, the higher the solar reflectance of the nanocomposite was. Moreover, the outdoor temperature test just proved the result of the solar reflectance.
Co-reporter:Shichao Wang, Jun Zhang, Li Liu, Fan Yang, Yuhao Zhang
Solar Energy Materials and Solar Cells 2015 Volume 143() pp:120-127
Publication Date(Web):December 2015
DOI:10.1016/j.solmat.2015.06.032
•The advantage of high solar reflectance of specimen remained after UV irradiation.•Structure changes are discussed to be related the final reflectance after UV aging.•Anatase TiO2 could slightly increase the reflectance in NIR region after UV aging.•A self-designed device is used to evaluate the actual cool property of the samples.Cool materials targeted to minimize temperature are employed to lower energy consumption and the heat island effect. UV damage of cool materials appears to be inevitable when they serve as outdoor applications. Among researches into cool materials, the effect of UV irradiation on cooling property and stability of materials have been barely considered. In this work, UV irradiation of high density polyethylene (HDPE)/titanium dioxide (TiO2) composites were performed via the artificial accelerated xenon lamp UV irradiation process. Structural changes were studied by wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR). A spectrometer was applied to measure solar reflectance before and after UV irradiation. The advantage of the high solar reflectance of the specimen remained after UV irradiation. The relationship between UV irradiation and solar reflectance was discussed. The solar reflectance after UV irradiation depended on changes of the crystallinity, surface roughness of composite and the structure of TiO2. It was interesting to find that the anatase TiO2 particle could slightly increase the solar reflectance in the near infrared region after UV irradiation, which may provide an approach to achieve high reflectance of polymeric materials in the near infrared region. Finally, the temperature test was conducted to evaluate the effect of UV irradiation on the actual cooling property by a self-designed device, of which, the result was in accordance with the result of solar reflectance.
In this study, three types of coupling agent, titanium tris(dodecylbenzenesulfonate) isopropoxide (NDZ 109), γ-methacryloxypropyltrimethoxysilane (KH570) and vinyltrim + ethoxysiloxane homopolymer (SG-Si6490), were utilized to reduce the polar surface energy of barium titanate (BaTiO3) particles from 37.53 mJ m−2 to 0.77 mJ m−2, 16.52 mJ m−2 and 5.46 mJ m−2, respectively. At 30 vol% filler loading, NDZ 109 treated BaTiO3 with the lowest polar surface tension exhibited a remarkable compatibility with ethylene propylene diene monomer (EPDM) gum shown by the bound rubber content. It is found that just 1% (by weight of BaTiO3 amount) coupling agents SG-Si6490 can raise the tensile strength of EPDM with untreated BaTiO3 composite from 1.94 MPa to 9.00 MPa, due to the CC bonds from vinyl groups. In terms of electrical properties, when untreated BaTiO3 loading was 30 vol%, the dielectric constant of EPDM control can increase from about 2 to 7. Moreover, the SG-Si6490 treated BaTiO3 further improved the dielectric constant of EPDM with untreated BaTiO3 composite from 7 to around 8. EPDM with NDZ109 treated BaTiO3 composite exhibited the lowest volume resistivity among EPDM composites.
Co-reporter:Tingting Chen, Guodong Jiang, Guoyu Li, Zhipeng Wu and Jun Zhang
RSC Advances 2015 vol. 5(Issue 74) pp:60570-60580
Publication Date(Web):08 Jul 2015
DOI:10.1039/C5RA09252C
A series of poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG) random copolymers were synthesized and characterized using 1H and 13C nuclear magnetic resonance, infrared spectroscopy and viscometry. Differential scanning calorimetry, wide-angle X-ray diffraction, and thermogravimetric analysis were used to probe the effects of copolymer composition and microstructure on the thermal properties, crystallization behavior, and thermal stability of the PETG copolymers, respectively. The mechanical properties were evaluated by tensile testing and dynamic mechanical measurements. The partial replacement in the polymerization feed of ethylene glycol by 1,4-cyclohexanedimethanol led to statistically random PETG copolymers with adjustable compositions and suitable molecular weights, which were thermally stable above 380 °C. The number-average sequence length of ethylene glycol terephthalate decreased with the increasing 1,4-cyclohexanedimethanol terephthalate (CT) content. In contrast, the number-average sequence length of CT increased gradually with the increasing CT content. The crystalline structure of the PETG copolymers changed from a PET-type lattice to a PCT-type lattice at a lower CT content. The crystallinity decreased at first, and then increased remarkably with the increasing CT content. It was interesting to notice that the rigid structure of the CT unit controlled the crystallization. The incorporation of CT in the PET chain, significantly altered the thermal transitions of the polyester. The glass transition temperature increased linearly with the increasing CT content. The melting temperature of the segments in crystalline domains strongly depended on the corresponding average sequence length. An increase in the average sequence length resulted in a higher melting temperature and an increase in the melting enthalpy.
In this work, the non-isothermal crystallization kinetics of poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG) random copolyesters with different compositions was first investigated from the glassy state. Regardless of the composition, the value of the Avrami exponent determined from Jeziorny theory was 2.1–2.4, depending on the heating rate, whereas the value of α (the ratio of the Avrami exponent to the Ozawa exponent) obtained from Mo's method was 1.3–1.6, depending on the relative crystallinity. These results indicated that the nucleation and growth mechanism of the PETG copolyesters were apparently identical to those of the poly(ethylene terephthalate) (PET) homopolymer. However, the cold crystallization rate was accelerated by increasing the heating rate, but retarded by incorporating the 1,4-cyclohexanedimethanol (CHDM) unit into the polymer backbone. Based on the crystallization rate coefficient (CRC) and the crystallization rate parameter (CRP) approaches, the cold crystallization rate was in the following order: PET > PETG(30/70) > PETG(85/15) > PETG(50/50) > PETG(70/30).
Co-reporter:Zhen Zhang, Wenqiang Zhu, Jun Zhang, Tingsheng Tian
Polymer Testing 2015 Volume 44() pp:23-29
Publication Date(Web):July 2015
DOI:10.1016/j.polymertesting.2015.03.017
The effect of chlorinated polyethylene (CPE) on the properties of poly (acrylonitrile-styrene-acrylic) (ASA) was investigated. As an impact modifier, CPE effectively toughened ASA. With the addition of 15 phr CPE, the impact strength increased from 25.1 kJ/m2 to 41.7 kJ/m2. The morphology of the blends exhibited heterogeneous structure and correlated well with the results of impact strength. The glass transition temperature corresponding with ASA remained constant, indicating that CPE did not change the dual-phase structure of ASA. In rheological tests, the enhancement of storage modulus and complex viscosity of ASA, together with Cole-Cole plots, indicated that certain changes in phase structure existed after CPE content exceeded 8 phr. Thermogravimetric analysis results suggested that CPE slightly decreased the onset degradation temperature. Our study showed that CPE, as an impact modifier, can effectively improve the toughness of ASA.
Crystal Research and Technology 2014 Volume 49( Issue 4) pp:232-243
Publication Date(Web):
DOI:10.1002/crat.201300369
Poly(ethylene terephthalate) (PET) and a series of poly(ethylene terephthalate-co-1,4-cyclohexylene dimethylene terephthalate) (P(ET/CT)) copolyesters with different molar ratios of ethylene glycol (EG) to 1,4-cyclohexanedimethanol (1,4-CHDM) were investigated by their isothermal crystallization behavior, transparency, crystal structure and morphology changes in different isothermal crystallization process using differential scanning calorimetry (DSC), digital photos, wide-angle X-ray diffraction (WAXD) and polarized optical microscopy (POM). The results revealed that P(ET/CT) copolyesters with ≤ 15 mol% 1,4-CHDM and ≥ 50 mol% 1,4-CHDM, such as P(ET/CT)(85/15), P(ET/CT)(50/50) and P(ET/CT)(30/70), were crystallizable, while that with 30 mol% 1,4-CHDM, namely P(ET/CT)(70/30), was amorphous. The crystallization rate, crystallinity and transparency of these copolyesters underwent the same isothermal crystallization process, i.e. it first decreased and then increased remarkably with the increase of 1,4-CHDM content. Accordingly, the crystal structure of these copolyesters changed from PET-type lattice to PCT-type lattice when the copolyester with around 30 mol% 1,4-cyclohexylene dimethylene terephthalate (CT) unit. Interestingly, the small incorporation of 1,4-CHDM into PET could lead to the formation of larger spherulite crystals than that of PET. But small and grainy crystallites appeared with further increase in the 1,4-CHDM content.
Composites Part B: Engineering (1 March 2017) Volume 112() pp:
Publication Date(Web):1 March 2017
DOI:10.1016/j.compositesb.2017.01.002
In this study, ethylene propylene diene monomer (EPDM)/barium titanate (BaTiO3)/mica (or graphite) composites with different volume fraction of mica (or graphite) were prepared by two-roll milling process. Thermal conductivity, crosslink density, cure, rheological, mechanical and dielectrical properties of composites were investigated. The results of rheological properties indicated that the 15 vol% mica made the complex viscosity of EPDM/BaTiO3 compound to become non-sensitive to varying shear. In terms of mechanical properties, only 5 vol% graphite flakes remarkably improved the tensile strength of EPDM/BaTiO3 (70/30) from 7.47 MPa to 13.20 MPa (76% increase). By comparison, the 20 vol% mica just increased the tensile strength of EPDM/BaTiO3 (70/30) to 12.10 MPa. In addition, 20 vol% graphite flakes boosted the thermal conductivity and dielectric constant of EPDM/BaTiO3 (70/30) from 0.323 W m−1 K−1 and 7.1 at 40 MHz to 2.421 W m−1 K−1 (749% increase) and 70 at 40 MHz (almost 1000% increase), respectively. The excellent electric and thermal performance was attributed to the mobile π electrons in graphite flakes.
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