Enhanced thermal conductivity of fluorinated epoxy resins by incorporating inorganic filler

Comparison of the Properties of Epoxy Resins Containing Various Trifluoromethyl Groups with Low Dielectric Constant

A series of epoxy resins containing various trifluoromethyl groups were synthesized and thermally cured with diaminodiphenylmethane (DDM) and aminophenyl sulfone (DDS). All epoxy resins exhibited excellent thermal stability with the glass transition temperatures of above 128 °C and 5% weight loss temperatures of above 300 °C. DDS-cured epoxy resins possessed higher thermal stability than that of DDM-cured epoxy resins, while DDM-cured epoxy resins showed better mechanical, dielectric, and hydrophobic properties. Additionally, DDM-cured epoxy resins with different locations and numbers of trifluoromethyl groups showed flexural strength in the range of 95.55~152.36 MPa, flexural modulus in the range of 1.71~2.65 GPa, dielectric constant in the range of 2.55~3.05, and water absorption in the range of 0.49~0.95%. These results indicate that the incorporation of trifluoromethyl pendant groups into epoxy resins can be a valid strategy to improve the dielectric and hydrophobic performance.

The preparation and evaluation mechanism of mesoporous spherical silica/porous carbon-filled polypropylene composites obtained from coal gasification fine slag

Coal gasification fine slag is a by-product of the entrained-flow gasifier, which has caused some environmental pollution. Through acid dissolution and calcination at different temperatures, mesoporous spherical silica/porous carbon composite filler was prepared using coal gasification fine slag. The particle size and specific surface area of the composite filler decreased with the decrease of unburned carbon content. The analysis of X-ray photoelectron spectroscopy (XPS) indicated the decrease of oxygen-containing functional groups and the increase of C-C groups with the decrease of the content of carbon. The effects of mesoporous spherical silica/porous carbon with different carbon content on the comprehensive properties of filled polypropylene (PP) were studied. The tensile strength and interface interaction increased at first and then decreased with the decrease of carbon content, due to the synergistic effect of mesoporous spherical silica and rough amorphous carbon. The scanning electron microscope showed that the composite filler with the carbon content of 14.47 wt.% at the calcination temperature of 450 °C had the best compatibility with the matrix. Thermodynamic analysis of the PP composites indicated that thermal insulation properties and thermal stability improved with the incorporation of the composite filler. Differential scanning calorimetry (DSC) testing indicated the highest crystallinity of the matrix corresponding to the best comprehensive performances of the composites. XRD patterns revealed that the cooperation of fillers brought characteristic peaks and did not change the primary crystal structure of PP. Simultaneously, heavy calcium powders (CC) were used as comparative fillers, and the overall properties of the PP composites filled with the composite filler were better compared to those of the CC-filled PP composite. The results illustrated that mesoporous spherical silica/porous carbon particles can completely replace CC used in the PP composites, which can be used in auto bumpers, plastic pipes, display cases, and car air deflectors. The CGFS can be processed into a plastic filler for substituting heavy calcium powder particles, which can solve the environmental pollution caused by the accumulation of solid waste.

Effect of perlite on the thermal conductivity, thermal degradation and mechanical properties of epoxy materials

In this study, the thermal conductivity, thermal degradation and mechanical properties of the perlite added epoxy materials were investigated. Perlite was added into the epoxy resin (EP) at the rate of 2%, 4%, 6%, 8% and 10% compared to the total mass. For the analysis of these epoxy materials, the thermal conductivity, density, hardness, X-ray diffraction (XRD), FTIR spectra, thermogravimetric analysis (TGA), tensile strength, flexural strength, limit oxygen index (LOI) and vertical burning tests were carried out. With the added perlite (PER10), a decrease of 24.03% occurred in the thermal conductivity coefficient compared to the pure EP material. A maximum decrease of 6.86% was detected in its density. It gained fire retardant feature as it increased from 6.15% to 28.71% in V-0 and carbon residue as inflammability class. Despite the decrease of tensile stress, tensile modulus increased. The maximum increase PER02 was 36.9%. It did not provide any improvement in terms of other mechanical properties.

Thermal Conductivity and Cure Kinetics of Epoxy-Boron Nitride Composites-A Review

Epoxy resin composites filled with thermally conductive but electrically insulating particles play an important role in the thermal management of modern electronic devices. Although many types of particles are used for this purpose, including oxides, carbides and nitrides, one of the most widely used fillers is boron nitride (BN). In this review we concentrate specifically on epoxy-BN composites for high thermal conductivity applications. First, the cure kinetics of epoxy composites in general, and of epoxy-BN composites in particular, are discussed separately in terms of the effects of the filler particles on cure parameters and the cured composite. Then, several fundamental aspects of epoxy-BN composites are discussed in terms of their effect on thermal conductivity. These aspects include the following: the filler content; the type of epoxy system used for the matrix; the morphology of the filler particles (platelets, agglomerates) and their size and concentration; the use of surface treatments of the filler particles or of coupling agents; and the composite preparation procedures, for example whether or not solvents are used for dispersion of the filler in the matrix. The dependence of thermal conductivity on filler content, obtained from over one hundred reports in the literature, is examined in detail, and an attempt is made to categorise the effects of the variables and to compare the results obtained by different procedures.

Preparation and Corrosion Resistance of ETEO Modified Graphene Oxide/Epoxy Resin Coating

Improving the corrosion resistance of epoxy resin coatings has become the focus of current research. This study focuses on synthesizing a functionalized silane coupling agent (2-(3,4-epoxycyclohexyl)ethyl triethoxysilane) to modify the surface of graphene oxide to address nanomaterial agglomeration and enhance the coating resistance of the epoxy resin coating to corrosion by filling the coating with functionalized graphene oxide. Functionalized graphene oxide and coatings filled with functionalized graphene oxide were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The corrosion performance of each coating was studied by electrochemical impedance spectroscopy and a salt spray test. Results showed that the incorporation of functionalized graphene oxide enhances the corrosion protection performance of the epoxy composite coating, and the composite coating exhibited the best anticorrosion performance when the amount of functionalized graphene oxide was 0.7 wt %.