Thermal Properties Of Epoxy Resin Research Articles

Thermal properties of epoxy resin based thermal interfacial materials by filling Ag nanoparticle-decorated graphene nanosheets

Epoxy resin based thermal interfacial materials (TIMs) with high thermal conductivity have been obtained by filling Ag nanoparticle-decorated graphene nanosheets (GNSs) as thermal conductive fillers. The thermal conductivity (k) enhancement of epoxy resin based TIMs increases with the thermal filler loading. The more decoration of Ag nanoparticles on the GNS surfaces, the higher thermal conductivity enhancement of epoxy resin based TIM is. It is proposed that the bigger Ag nanoparticles acting as “spacers” increase the distance between the graphene sheets more than the smaller ones. It is not easy for graphene sheets to form stacked graphitic structures and the high specific surface area as well as other unique properties exhibited by 2D graphene are retained. Furthermore, the larger particle size is desired to minimize the scattering of phonons because of low interfacial thermal barrier. The obvious enhancement of thermal properties should be also attributed to the high intrinsic k of graphene and the effective thermal conductive networks forming by graphene and Ag nanoparticles. The synergistic effects including the stronger phonon Umklapp scattering, better phonon transmission trough the interfaces, decreasing Kapitza resistance, and decreasing ability of heat transfer by electrons result in the slight variation of k with the temperature. The weak temperature dependence of k is beneficial for TIM applications and can be obtained by controlling the addition of hybrid thermal fillers and quantity of decorated silver nanoparticles.

Effect of styrene addition on thermal properties of epoxy resin doped with carbon nanotubes

The paper concerns thermal properties of epoxy resin doped with carbon nanotubes (CNTs) used as a matrix for Carbon Fiber Reinforced Polymer (CFRP) composites. The aim of this work was to determine the influence of styrene addition on thermal properties of epoxy resin/CNT nanocomposites. CNTs, supplied by Nanocyl, were dispersed in epoxy matrix using three roll millings. In order to dilute epoxy/CNT mixture, to make it useful for hand lay‐up method of CFRP fabrication, three different weight amounts of styrene were tested. Scanning electron microscopy was used for both CNT dispersion control and epoxy/CNT laminates structure evaluation. Glass transition temperature and thermal stability were determined. Fourier transform infrared spectroscopy (FTIR) was used for chemical structure verification. Thermal diffusivity of epoxy doped with carbon nanotubes, as well as CFRP doped with carbon nanotubes, was measured at four temperatures. Rheological tests were performed, and viscosity and storage and loss modulus were measured. From a modulus crossover point, gel time was determined. Scanning electron microscopy observations proved uniform dispersion of CNTs and reduction of voids and/or air bubbles amount as an effect of styrene addition. Decrease of thermal stability in the first stage of degradation is observed, and a decrease of glass transition temperature with an increase of styrene amount is noticed. For a small amount of styrene, thermal conductivity increases, while it starts to decrease when measured for a higher temperature. Viscosity decreases and gel time increases with the increase of styrene amount. Copyright © 2015 John Wiley & Sons, Ltd.

Dynamics and thermal properties of epoxy resin cured by new diamino disiloxanes

ABSTRACTTwo disiloxane compounds, 3,3′‐(1,3‐dimethyl‐1,3‐diphenyl‐1,3‐disiloxanediyl)bis(benzenamine) (C1) and 4,4′‐(1,3‐dimethyl‐1,3‐diphenyl‐1,3‐disiloxanediyl)bis(benzenamine) (C2) were synthesized and used as new curing agents of DGEBA epoxy resin with an epoxy value of 0.51 (E‐51). The curing kinetics of E‐51/C1 and E‐51/C2 systems was investigated by non‐isothermal differential scanning calorimetry (DSC) analyses. The activation energy (ΔE) and the characteristic cure temperatures of the two systems were determined. The two systems have the similar activation energy. The reactivity of E‐51/C1 is higher than that of E‐51/C2. The reaction orders of E‐51/C1 and E‐51/C2 are 0.88 and 0.87, respectively, illustrating that curing reaction between the epoxy resin and curing agent (C1 or C2) is complicated. The DSC result shows that E51 cured by C2 has higher Tg; whereas thermogravimetric analysis results indicate that E51 cured by C1 has higher thermal stability. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42385.

Mechanical and anticorrosive properties of graphene/epoxy resin composites coating prepared by in-situ method.

The graphene nanosheets-based epoxy resin coating (0, 0.1, 0.4 and 0.7 wt %) was prepared by a situ-synthesis method. The effect of polyvinylpyrrolidone/reduced graphene oxide (PVP-rGO) on mechanical and thermal properties of epoxy resin coating was investigated using nanoindentation technique and thermogravimetric analysis, respectively. A significant enhancement (ca. 213% and 73 °C) in the Young modulus and thermal stability of epoxy resin coating was obtained at a loading of 0.7 wt %, respectively. Furthermore, the erosion resistance of graphene nanosheets-based epoxy resin coating was investigated by electrochemical measurement. The results showed also that the Rrcco (ca. 0.3 mm/year) of graphene nanosheets-based epoxy resin coating was far lower than neat epoxy resin (1.3 mm/year). Thus, this approach provides a novel route for improving erosion resistance and mechanical-thermal stability of polymers coating, which is expected to be used in mechanical-thermal-corrosion coupling environments.

Enhanced mechanical and thermal properties of epoxy with hyperbranched polyester grafted perylene diimide

The mechanical and thermal properties of epoxy were significantly enhanced modified by H20-g-PDI.

The effect of electron beam on the mechanical and thermal properties of hybrid epoxy/clay/TiO2 nanocomposites

In this research, the effects of electron beam on the mechanical and thermal properties of epoxy resin/clay/TiO2 nanocomposite were studied. The epoxy/clay/TiO2 nanocomposite was prepared by dispersing clay and TiO2 nanoparticles in epoxy matrix. The dispersion of the clay/TiO2 in the epoxy matrix was characterized by X-ray diffraction and transmission electron microscopy analyses. The obtained results confirm the structure of exfoliate and intercalate in the prepared samples. Mechanical properties and thermal stability of nanocomposites were studied by tensile test and simultaneous thermo-gravimetric–differential thermal analysis. In order to study electron beam irradiation effects, nanocomposites were exposed to electron beam irradiation in 100, 500, and 1000 kGy doses. The results show that mechanical characteristics and thermal stability of epoxy resin/clay/TiO2 decreased with irradiation.

Curing behaviour and thermal properties of epoxy resin cured by aromatic diamine with carborane

A new kind of carborane-containing aromatic diamine, 1,2-bis (4-aminophenyl)-1,2-dicarba-closo-dodecaborane (HPPA), as a curing agent for epoxy resins was synthesized and confirmed by proton, carbon and boron nuclear magnetic resonance imaging, Fourier transform infrared spectroscopy and elemental analysis. The compatibility, thermal curing behaviour and thermal properties of HPPA/epoxy resin E51 system were investigated. HPPA exhibited good compatibility with E51. Compared with 4,4′-diaminodiphenylsulphone (DDS)/E51, HPPA/E51 system had higher reaction activity and lower curing temperature. When the ratio of amine protons versus epoxy groups was 1:1 in resin systems, the epoxy resin cured by HPPA exhibited the highest glass transition temperature of 207°C. The residual weight ratios of cured HPPA/E51 at 800°C under argon and in air atmospheres were 43.7% and 50.5%, respectively, which were 28.6% and 47.2% higher than that of DDS/E51, respectively, indicating that the HPPA/E51 system had good heat resistance.

Ball milling: An effective technique for the preparation of exfoliated clay filled unsaturated polyester toughened epoxy nanocomposite

This paper investigates the possibility of improving the mechanical and thermal properties of epoxy and unsaturated polyester toughened epoxy resins through the dispersion of octadecyl ammonium ion-exchanged montmorillonite (organoclay) through exfoliated mechanism. The nanocomposites prepared are characterized for their structural change and studied for their crystallite size, mechanical, thermal and water absorption (hydrophilicity) properties. The mechanical data indicates significant improvement in the flexural and tensile properties over the neat epoxy and UP-epoxy matrix according to the percentage content of organoclay. The thermal behavior too shows noticeable enhancement in glass transition temperature T g and high thermal stability. Hydrophilicity of all the composites decreases irrespective of the concentration of organoclay on the epoxy and UP-epoxy matrices. The homogeneous morphology of epoxy and UP toughened epoxy nanocomposite hybrid systems is ascertained using scanning electron microscope (SEM). X-ray results point out that the cetyl ammonium modified clay filled composites exhibited the exfoliated structure.

Study on Electrical and Thermal Properties of Epoxy Resin/Inorganic Filler Composites for the Fully Enclosed Casting Bus Bar and its Calculation of the Temperature Field

This paper focused on the epoxy resin/inorganic filler composites. The electrical and thermal properties of the composites were tested and analyzed at room temperature. The influence of temperature on the thermal conductivity and thermal expansion coefficient was studied. Based on the electrical and thermal properties of the composites, the simulation model of the fully enclosed epoxy resin casting bus bar (FEERCB) was built, and the temperature field distribution of the FEERCB was calculated. T The study results showed that the volume resistivity, dielectric constant, dielectric loss factor and breakdown strength of the epoxy resin/inorganic filler composites were 1.74×1014Ω·cm, 3.44, 3.75 and 22.31 kV/mm respectively at room temperature. The thermal conductivity and thermal expansion coefficient of the composites were 2.55 W/m·K and 21.73×10-6 /°C, achieved the insulation requirements for FEERCB. In the temperature range of the test, with increasing temperature, the thermal conductivity reduced gradually, while the thermal expansion coefficient increased gradually. The simulation results showed that the FEERCB has remarkable performance on the heat dissipation and current carrying capability.

The curing kinetics and thermal properties of epoxy resins cured by aromatic diamine with hetero-cyclic side chain structure

The use of novel aromatic diamine containing phthalide structure (BAPP) as curing agent of diglycidylether of bisphenol A (DGEBA) epoxy resin has been studied. BAPP can react with epoxy monomers by an epoxy-amine condensation mechanism, which renders phthalide cardo incorporate into the network structure of the thermoset. The curing behavior and kinetics have been investigated by differential scanning calorimetry (DSC) and the kinetic analysis of non-isothermal cure shows that autocatalytic model is suitable to describe the cure mechanism. The thermal–mechanical properties have been determined with dynamic mechanical analysis (DMA) and the activation energies for relaxation were calculated according to the Arrhenius law. Thermogravimetric analysis exhibits a lower initial decomposition temperature, decreased rate of decomposition and higher char yield compared with DGEBA cured with commercially available 4,4′-diaminodiphenylsulfone (DDS).

Effect of Filler Materials on the Mechanical and Thermal Properties of Epoxy Resin

In this present work the influence of Cenosphere filler material in thermal and mechanical properties of Epoxy resin is discussed. For comparative study, pure resin and composites made with different compositions (1, 3 and 5 wt% of Cenosphere) were prepared. The specimens were submitted to thermal analysis (DMA) and mechanical test (Tensile and Flexural) as well. Dynamic mechanical analysis (DMA) revealed an enhancement in the energy dissipation ability of the composite with 1wt%, wt3%, wt5% of Cenosphere and an increase in stiffness relative to the pure matrix phase. It was generally observed that the tensile strength found to increase with the inclusion of Cenosphere as filler material. Maximum value of tensile stress and strain of resin is not sensitively increased by filler material.

Thermal properties of epoxy resins crosslinked by an aminated lignin

Aminated lignin possessing significant amount of reactive amino groups was studied as a curing agent of epoxy resin. Fourier transform infrared spectroscopy results proved the reactivity of the aminated lignin with the epoxy resin. Both appearance features and scanning electron microscopy images indicated that the transparent and homogeneous epoxy resin films could be formed with the aminated lignin less than 40% in the hardener mixture. In addition, thermogravimetric analysis and dynamic thermomechanical analysis results revealed that the epoxy resin cured by aminated lignin had better thermal stability compared with ones cured by a common hardener. The mass loss of the epoxy resin cured by the aminated lignin before 300°C was small around only 2.5%. The Tg (the glass transition temperature) of epoxy resin sample after cured by mixed hardener increased from 79°C to 93°C. The obvious difference (70–84°C) of Td (the thermal deformation temperature) was also observed from the samples with and without the aminated lignin after cured at a high temperature. POLYM. ENG. SCI., 55:924–932, 2015. © 2014 Society of Plastics Engineers

Studies on the synthesis and reaction of silicone oxirane dendrimer and their thermal and rheological properties

A series of silicone core dendrimers bearing SiH terminal group was synthesized by the reaction of tetraethoxysilane and diorganochlorosilane in high yields, which on reacting with allylglycidylether in presence of Speier’s catalyst yielded oxirane terminated dendrimers. These dendrimers were characterized using physico-chemical techniques viz; elemental analysis, Fourier transforms infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H NMR spectroscopy). Molecular weight was determined by vapour pressure osmometry (VPO). The rheological studies were performed to study the curing behavior of oxirane dendrimer with triethylenetetraamine. Thermal properties of cured dendrimers were evaluated using thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC). Change in thermal properties of epoxy resin (LY556) on addition of dendrimers was also studied by TGA and DSC.

The Thermal Properties of Unsaturated Polyester Resin Treated with Intumescent Flame Retardants

A novel cheap macromolecular intumescent flame retardant (IFR), was synthesized. Unsaturated polyester resin (UPR) was modified with IFR to get the flame retardant UPR, whose flammability and burning behavior were characterized by limiting oxygen index (LOI). 22.7% of weight of IFR was doped into UPR to get 28.5 of LOI. The thermal properties of epoxy resins containing IFR were investigated with thermogravimetry (TG). Activation energy for the decomposition of samples was obtained using Kissinger equation. The resultant data show that for UPR containing IFR, compared with UPR, IFR decreased weight loss, thermal stability, increased the char yield, which shows that IFR can catalyze decomposition and carbonization of UPR.

Synthesis and characterization of phosphorus- and silicon-containing flame-retardant curing agents and a study of their effect on thermal properties of epoxy resins

Two amines, one phosphoric acid tris-(5-amino-naphthalene-1-yl) ester and another bis-(5-amino-naphthalene-1-yl) dimethyl silane, were synthesized and their structures were characterized with the help of elemental analysis, FTIR, 1H NMR, 13C NMR, and 31P NMR spectroscopic techniques. These amines are used as reactive flame retardants as well as curing agents to blend with commercial epoxy resin diglycidyl ether of bisphenol A (DGEBA). The thermal properties of these epoxy thermosets (EPs) were investigated by thermogravimetric analysis and the flame retardancy was tested according to the LOI and UL 94 tests. The results indicate that all epoxy thermosets exhibit excellent flame retardancy, moderate changes in T g, and 5% decomposition temperature in the range of 344–435°C.

Preparation of epoxy resin using n-hexadecane based shape stabilized PCM for applying wood-based flooring

Epoxy resin has excellent characteristics of moisture, low toughness, solvent and chemical resistance, low shrinkage on cure, superior electrical and mechanical resistance properties, and good adhesion to many substrates. In this experiment, we prepared epoxy resin with shape stabilized phase change material (SSPCM) to enhance the thermal properties of epoxy resin. The SSPCM was prepared through the vacuum impregnation method, and the SSPCM/epoxy resin composites were prepared through the shear stirring process and curing process. In the preparation process, the epoxy resin and hardener were mixed in a beaker at a one-to-one ratio. Then, 5, 10, 15, and 20 wt.% of the SSPCM was added to the mixture. The thermal properties and chemical properties of epoxy resin with SSPCM were analyzed from scanning electron microscopy, differential scanning calorimetry, thermal gravimetric analysis, and universal testing machine analyzer. From the analysis, we determined that the prepared epoxy resin with SSPCM has heat storage capacity and high thermal conductivity, compared with the epoxy resin.

Studies on Mechanical and Thermal Properties of Epoxy Resin Modified by Fluorine-Containing Silicone

The epoxy resin was modified with the mixture of α,ω-dihydroxy poly-(3,3,3-trifluoropropyl) siloxane (PTFPMS), KH560 and stannous octoate. KH560 can react with PTFPMS and also epoxy resin curing agent. The two reactions were characterized by FI-IR. The modified epoxy resin was characterized by FI-IR. The result showed that fluorine-containing silicone had been successfully introduced into the epoxy system. The mechanical and thermal properties of the modified epoxy resin were analyzed. The results showed that with the increase of PTFPMS the impact strength of epoxy resin increased, hardness and bending strength correspondingly reduced, slight decrease in the glass transition temperature.

The Thermal Properties of Rigid Polyurethane Foams Treated with Flame Retardant

A novel cheap macromolecular intumescent flame retardants (MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus characterized by IR. Rigid polyurethane foam (PUF) were modified with MIFR to get the flame retardant PUF, whose flammability and burning behavior were characterized by UL 94 and limiting oxygen index (LOI). 25% of weight of MIFR were doped into PUF to get 24.5 of LOI and UL 94 V-0. The thermal properties of epoxy resins containing MIFR were investigated with thermogravimetry (TG). Activation energy for the decomposition of samples was obtained using Kissinger equation. The resultant data show that for PUF containing MIFR, compared with PUF, MIFR decreased weight loss, thermal stability, increased the char yield. The activation energy for the decomposition of EP is 205 kJ/mol while it becomes 162 kJ/mol for PUF containing MIFR, decreased by 42 kJ/mol, which shows that IFR can catalyze decomposition and carbonization of PUF.

Hydrolytic degradation and thermal properties of epoxy resins derived from soybean oil

Vegetable oils are an attractive substitute for petroleum sources for the derivation of polymers. Epoxy resins have been synthesized containing epoxidized soybean oil (ESO) and traditional petroleum-derived epoxy resin components (the diglycidyl ether of bisphenol A [DGEBA] and methylene dianiline). The curing reaction was moni-tored with in situ differential scanning calorimetry, indicating that significantly higher curing temperatures are required for ESO as compared with DGEBA. Increasing the concentration of ESO in the resin sig-nificantly decreased the glass transition temperature. However, epoxy resins with high ESO content (60–100 wt% relative to the total epoxide-bearing molecules in the mixture) exhibited a second, higher-temperature peak in the derivative of the thermogravimetric analysis weight loss curve. Significant differ-ences were observed in the hydrolytic degradation characteristics of the polymers at 80°C in NaOH solutions. Polymers with 0–40 wt% ESO exhibited little measurable mass loss over 72 days (in both 3 and 10 wt% NaOH solutions), while polymers with 60–100 wt% ESO exhibited substantial mass loss within 2 weeks in a 3 wt% NaOH solution. The presence of degradable cleavage points throughout the network structure may provide a valuable route for recycling these materials after their useful lifetime. Supple-mentary information is available at http://www.icevirtuallibrary.com/upload/10.1680gmat.12.00023_SupplementaryInformation.pdf

Effect of functional nitrile groups on curing behaviors and thermal properties of epoxy resins as advanced matrix materials

AbstractThis paper reports the preparation of the amine/epoxy blends with various amines such as 4,4′-diaminodiphenylsulfone (DDS), one nitrile side chain-containing diamine (BDB), and phthalonitrile-containing amine (APN). Differential scanning calorimetry (DSC), rheological analysis, and thermal gravimetric analysis (TGA) were used to evaluate the curing behaviors and thermal properties of amine/epoxy blends with the effect of functional nitrile groups of amines. Interestingly, an amine/epoxy blend exhibited double curing reactions. The cured epoxy copolymers exhibited high glass transition temperatures (>220°C) and excellent thermal stabilities having 5% weight loss temperature in the range of 375°C to 383°C.