The effect of filler localization on morphology and thermal conductivity of the polyamide/cyclic olefin copolymer blends filled with boron nitride

Ghahramani, Nikoo; Esfahani, Seyed Armin Seyed; Mehranpour, Milad; Nazockdast, Hossein

doi:10.1007/s10853-018-2746-x

Cited by 21 publications

(13 citation statements)

References 50 publications

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“…In general, thermal conduction in the multi-phase friction composite happens through the transfer of phonon particles across the phase boundary. However, the scattering of phonon particles at the filler-matrix interphase reduces thermal conductivity of the friction composite [36]. Presence of conductive fillers such as metal, graphite in friction composite can reduce scattering of phonon and increase thermal conductivity of the composite by lowering impedance mismatch at the filler-matrix interphase.…”

Section: Thermal Conductivitymentioning

confidence: 99%

Enhancement of tribological and thermo-mechanical properties of phenolic resin friction composites by improving interactions between elastomeric phase and matrix resin

2020

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New elastomer-modified brake friction composites with the identical composition, but differing in the type of rubber, were developed by altering polar/non-polar elastomeric phases into the phenolic resin matrix. Effect of dispersion and interaction of the polar/non-polar rubbers with the matrix resin on dry sliding wear characteristics of the friction composites was investigated using a laboratory-scale pin-on-disc tribometer. The composites were prepared by hot mixing followed by compression molding and post-curing at a high temperature. Coefficient of friction (COF) and specific wear rate of the composites sliding against a cast-iron disc were measured and analyzed. Polar acrylonitrile-butadiene rubber (NBR, both powder, and bale rubber), and non-polar styrene-butadiene rubber (SBR) and ethylene-propylene-diene monomer (EPDM) were used with the phenolic resin where rubber islands and its polarity played the key role in delayed stress dissipation, while the hard matrix phase contributed to the intrinsic strength of the composites. This work describes how the distribution and interaction of polar and non-polar rubbers with the matrix resin influence the performance of brake friction composites. NBR (powder)-phenolic composite showed the highest stable average COF of 0.52 as compared to 0.36 for EPDM-based composite. NBR (powder)-based composite also exhibited ~1.5 times better specific wear rate (4.9 × 10 −3 mm 3 N −1 m −1) than EPDM-based composite (7.2 × 10 −3 mm 3 N −1 m −1). However, EPDM rubber-based composite showed a significant enhancement in thermal conductivity (0.43 W/m K). Morphological analyses revealed that the dispersion of rubber phase in phenolic matrix played a significant role in transforming the wear mechanism from abrasive to adhesive.

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Section: Thermal Conductivitymentioning

confidence: 99%

Enhancement of tribological and thermo-mechanical properties of phenolic resin friction composites by improving interactions between elastomeric phase and matrix resin

2020

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“…When the fillers are dispersed into the polymer, the physical properties of the blends are strongly influenced by various factors, including crystallization behavior, 24 dispersion and loading level of fillers, shape and size, polarity. 22 Xue Liang et al 25 incorporated silane coupling agent KH550 modified BN into in situ polymerization of styrene (BN@PS), to improve the dispersion of BN in a polystyrene (PS) matrix. Simultaneously, enhancement of interfacial interaction between the fillers and PS matrix inhibited the migration of BN to PP, resulting in the selective localization of BN in the PS phase.…”

Section: Introductionmentioning

confidence: 99%

Phase morphology evolution and thermally conductive networks of immiscible polymer blends

Zhang

Xie

Zhang

et al. 2020

J of Applied Polymer Sci

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The selective distribution of fillers in multi-phase polymer blends was dramatically studied to deal with thermal management fields issues. Concerning thermodynamic and kinetic effects of fillers on immiscible polymer blends, the compatibilization of fillers on phase morphology evolution and final construction of thermal conductive pathways were rarely discussed. In this work, BN fillers and polar dispersed phase were introduced into PE through various processing methods. The result showed that filler-coated shell was formed around the larger-sized dispersed phase, thereby forming more thermal conductivity network with other fillers in the two-step processing composites. When the BN content was 20 phr, the thermal conductivity was 0.8271 W/(mÁK) for PE/PA6/BN-two steps composites, which was 95.48% higher than that of PE/PA6 composites. From the perspective of the regulation of the morphological structure of the dispersed phase, this study can provide methods and basic data for improving the thermal conductivity of incompatible polymer blends.

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“…Research has been conducted to evaluate the properties of the polymer/TC composites, and strategies have been proposed to improve the thermal conductivity of the polymer/TC composites by improving the dispersion of TC fillers in a polymer matrix. For example, Nikoo G. et al [34] used the relationship between normalized storage modulus and angular frequency as a method to compare the degree of dispersion of BN particles in a PA6 and cyclic olefin copolymer (COC) matrix; they found that BN particles had a better dispersion in the PA6 matrix than in the COC matrix due to better compatibility between PA6 and BN. Tang D. et al [35] studied the dispersion of KH550-modified BN in an epoxy matrix and its effect on the thermal conductivity and mechanical properties of the composite; it was found that KH550-BN could be more uniformly dispersed in the matrix than pristine BN, and the epoxy/KH550-BN composite had a relatively higher thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

Effect of Thermal Conductive Fillers on the Flame Retardancy, Thermal Conductivity, and Thermal Behavior of Flame-Retardant and Thermal Conductive Polyamide 6

et al. 2019

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In this work, polyamide 6 (PA6) composites with improved flame retardancy and thermal conductivity were prepared with different thermal conductive fillers (TC fillers) such as aluminum nitride (AlN) and boron nitride (BN) in a PA6 matrix with aluminum diethylphosphinate (AlPi) as a fire retardant. The resultant halogen-free flame retardant (HFFR) and thermal conductive (TC) PA6 (HFFR-TC-PA6) were investigated in detail with a mechanical property test, a limiting oxygen index (LOI), the vertical burning test (UL-94), a cone calorimeter, a thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The morphology of the impact fracture surface and char residue of the composites were analyzed by scanning electron microscopy (SEM). It was found that the thermal conductivity of the HFFR-TC-PA6 composite increased with the amount of TC fillers. The TC fillers exerted a positive effect for flame retardant PA6. For example, the HFFR-TC-PA6 composites with the thickness of 1.6 mm successfully passed the UL-94 V-0 rating with an LOI of more than 29% when the loading amount of AlN-550RFS, BN-SW08 and BN-NW04 was 30 wt%. The morphological structures of the char residues revealed that TC fillers formed a highly integrated char layer surface (without holes) during the combustion process, as compared to that of flame retardant PA6/AlPi composites. In addition, the thermal stability and crystallization behavior of the composites were studied.

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The effect of filler localization on morphology and thermal conductivity of the polyamide/cyclic olefin copolymer blends filled with boron nitride

Cited by 21 publications

References 50 publications

Enhancement of tribological and thermo-mechanical properties of phenolic resin friction composites by improving interactions between elastomeric phase and matrix resin

Enhancement of tribological and thermo-mechanical properties of phenolic resin friction composites by improving interactions between elastomeric phase and matrix resin

Phase morphology evolution and thermally conductive networks of immiscible polymer blends

Effect of Thermal Conductive Fillers on the Flame Retardancy, Thermal Conductivity, and Thermal Behavior of Flame-Retardant and Thermal Conductive Polyamide 6

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