Functionalization of LDH through ATMP intercalation and decoration with PDA-Fe3+ complexes for fire-retardant and smoke-suppressed epoxy composites

Hybrid nanofillers loaded epoxy resin; Synthesis, characterizations, and dielectric spectroscopy

Low velocity impact of Kevlar and ultra high molecular weight polyethylene (UHMWPE) reinforced epoxy composites

Comparison of carbon nanofiller-based polymer composite adhesives and pastes for thermal interface applications

Core–shell structured silicon carbide (SiC)/epoxy (EP) composites exhibit superior non–linear DC conductivity. However, the high voltage alternative current dielectric properties of the composites are rarely reported. In this paper, the time–domain measurement was employed to obtain the basic dielectric characteristics, AC conductivity, and relative permittivity of the SiC/EP and SiC@Al2O3/EP composites under less than the breakdown strength of the SiC/EP (i.e. the amplitude of 1–5 kV mm−1). In addition, in the high AC electric field (i.e. the amplitude of 6–20 kV mm−1), the non–linear AC dielectric properties of the SiC@Al2O3/EP composite are also investigated. The experimental results suggest that the SiC@Al2O3/EP composite shows more obvious non–linear AC dielectric properties than the SiC/EP composite. In the high AC electric field, the AC conductivity of the SiC@Al2O3/EP composite presents the relaxation phenomenon, which is attributed to the excitation field and its derivative. This work lays a foundation for further research on the AC steady–state and transient dielectric properties of the field grading materials, which are widely used to homogenize the nonuniform electric field distribution in many electrical and electronic equipment.

ABSTRACTThermally reduced graphene oxide–polyamide (TrGO‐PA) hybrids were fabricated by self‐assembly between TrGO nanosheets and PA microparticles, and the dispersibility, interphase extension, and thermal conduction mechanism of TrGO‐PA/epoxy (EP) composites were investigated. Most of the oxygen‐containing functional groups of TrGO were removed, and a conjugated structure of graphene was recovered. TrGO was distributed evenly on the PA surface via electrostatic adsorption between TrGO and PA, which resulted in the inhibition of TrGO aggregation in the epoxy matrix. Compared with that of TrGO/EP and PA/EP composites, the thermal interface resistance (RTIM) of TrGO‐PA/EP composites was greatly decreased to 38.3 mm2 kW−1 and the thermal conductivity was improved to 0.268 W/(m K), which was attributed to the enhanced dispersibility of TrGO‐PA and the enlarged interphase in TrGO‐PA/EP composites. A schematic model of thermal conduction mechanisms was proposed based on the formation of contiguous thermal transfer pathways by bridged TrGO adsorbed on well‐dispersed PA microparticles in TrGO‐PA/EP composites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47826.

The aim of this paper is to replace the traditional fiber composites with a natural-fiber composite in perception of tribological and mechanical accepts. A systematic study has been carried out to investigate jute fiber properties when incorporated into epoxy matrix. Thermogravimetric analysis has also been carried out for jute and epoxy for thermal property analysis. For a comparison purpose epoxy and glass fiber composites are prepared. The investigation reveals that, due to incorporation of jute into polymer epoxy shows better properties than the resins alone; but the properties are inferior to those of glass reinforced in terms of mechanical. When considering the tribological application, the jute fiber shows superior properties than neat and glass-reinforced epoxy composites. The worn out samples were studied using scanning electron microscope.

Development of the ZnO:Ga microrods - epoxy composite as a scintillation screen for ultrafast X-ray detection

Due to their high specific stiffness, carbon-filled epoxy composites can be used in structural components in aircraft. Graphene nanoplatelets are short stacks of individual layers of graphite that are a newly developed, lower cost material that often increases the composite tensile modulus. In this work, researchers fabricated neat aerospace epoxy (EPON 862 with Curing Agent W) and 1 to 6 wt% of two different types of graphene nanoplatelets (XG Sciences xGnP®-M-5 and xGnP®-C-300) in epoxy composites. These materials were tested for tensile properties using typical macroscopic measurements. In addition, nanoindentation was used to determine modulus and creep compliance. The macroscopic measurements showed that the tensile modulus increased from 2.72 GPa for the neat epoxy to 3.35 GPa for 6 wt% (3.7 vol%) xGnP®-M-5/epoxy composite and 3.10 GPa for 6 wt% (3.7 vol%) xGnP®-C-300/epoxy composite. The modulus results from nanoindentation followed this same trend. xGnP®-C-300/epoxy composites had higher tensile strength and ductility compared to similar loading levels of xGnP®-M-5/epoxy composites. The creep compliance for the neat epoxy, 1 to 6 wt% xGnP®-M-5/epoxy composites, and 1 to 6 wt% xGnP®-C-300/epoxy composites were similar. The two dimensional randomly oriented filler Halpin-Tsai model adjusted for platelet filler shape predicts the tensile modulus well for the xGnP®-M-5/epoxy composites and the three-dimensional randomly oriented filler Halpin-Tsai model works well for the xGnP®-C-300/epoxy composites. Per the authors’ knowledge, mechanical properties and modeling for xGnP®-M-5 and xGnP®-C-300 in this epoxy system has never been reported in the open literature.

This work outlines the characterization of epoxy resin [Bisphenol A-(epichlorhydrin): epoxy] and hardener [[Formula: see text](3-dimethylaminopropyl)-1,3-propylenediamine] with various inorganic nano-fillers. Dielectric characterizations of epoxy, hardener, neat epoxy (epoxy + hardener) and nano-epoxy (nano-filler + neat epoxy) composites loaded with 1 wt.% of inorganic nano-fillers (SiO2, Al2O3, TiO2 and ZnO) were carried out using precision LCR meter, over the frequency range of 1 kHz–2 MHz at a constant temperature of 300.15 K. The structural information of nano-fillers, neat epoxy and nano-epoxy composites was understood by Fourier transform infrared spectroscopy and by XRD. Moreover, hardness and shear strength (shear punch) were also determined in order to gain additional information about the mechanical properties of epoxy composite. Influence of inorganic nano-fillers on the dielectric properties, structural chemistry and mechanical properties of neat epoxy composite is discussed thoroughly in this study.

Fibre-reinforced epoxy composites are well established in regard to load-bearing applications in the aerospace, automotive and wind power industries, owing to their light weight and high durability. These composites are based on thermoset resins embedding glass or carbon fibres1. In lieu of viable recycling strategies, end-of-use composite-based structures such as wind turbine blades are commonly landfilled1–4. Because of the negative environmental impact of plastic waste5,6, the need for circular economies of plastics has become more pressing7,8. However, recycling thermoset plastics is no trivial matter1–4. Here we report a transition-metal-catalysed protocol for recovery of the polymer building block bisphenol A and intact fibres from epoxy composites. A Ru-catalysed, dehydrogenation/bond, cleavage/reduction cascade disconnects the C(alkyl)–O bonds of the most common linkages of the polymer. We showcase the application of this methodology to relevant unmodified amine-cured epoxy resins as well as commercial composites, including the shell of a wind turbine blade. Our results demonstrate that chemical recycling approaches for thermoset epoxy resins and composites are achievable.

The creation of a theoretical heat conduction model for polymers embedded with spherical inclusions is described in this study. It also contains the experimental confirmation of the suggested correlation for utilizing the model to estimate the effective thermal conductivity ( K ) of such composites. According to ASTM‐E‐1530, composites are made with varying amounts of aluminium oxide and pine wood dust reinforced in polyester resin. The effective thermal conductivities ( K eff ) of the composites are then determined using the Unitherm TM model 2022. Ansys 19.R2 software is used to evaluate the effective thermal conductivity of these composites with a uniform filler distribution, while Digimat‐FE software is used determine the thermal conductivity values of such particle filled polymer composites with a random filler distribution. After comparison and validation with experimental data, these values are shown to be fairly good agreement with the theoretical values from the suggested correlation. The investigation is further expanded to determine the thermal conductivities for epoxy composites using wood apple shell dust and coir dust particle. Also epoxy and polyester composites reinforced with SiO 2 and TiO 2 have been investigated in the similar manner. The main thrust of this report to validate the numerical results of composites by varying numerous polymers. The thermal conductivity all the composites grow monotonically with increase in filler content. The thermal conductivity of silicon dioxide, titanium oxide, and aluminium oxide filled epoxy composites is measured as 1.5, 7, and 35 W/m‐K respectively. Highlights In this study spherical fillers are successfully used as a potential filler material in polyester composites The thermal conductivity predicted by proposed mathematical model of polyester is validated with measured value and found better agreement. The Ansys 19.R2 and digimat software are used to predict the thermal conductivity values of these composites. The mathematical model is further used to predict thermal conductivity of epoxy composites to check the accuracy of the model.

High thermal conductive polymeric composites are extremely desired for the thermal management of electronic devices due to the rapid development of the modern microelectronic industry. Herein, the functionalized boron nitride (BN) and magnesium oxide (MgO) hybrid fillers (f‐BN@f‐MgO) were synthesized and used to prepare the enhanced thermal conductive epoxy (EP) composites through the hot‐pressing method. The results demonstrated that the covalent binding of BN and MgO in the hybrid fillers reduced the interface thermal resistance effectively between fillers and matrix and the hot‐pressing induced force facilitated the construction of the continuous thermal conduction paths. Consequently, the as‐prepared epoxy composite at 40 wt% hybrid fillers loading had high thermal conductivity (TC) (1.97 W/[m·K]), outstanding insulating performance (6.9 × 1015 Ω cm) and excellent thermal stability. Furthermore, a probable thermal conduction mechanism was proposed to illustrate the high TC of the epoxy composite. Therefore, this study provides a new approach to preparing epoxy composites with outstanding performances.

Investigation of tensile and flexural behavior of epoxy and SiO2 composite: An experimental study

The viscoelastic behaviour of glass fibre (GF)-epoxy composites was studied by flexural tests and dynamic mechanical measurements. In relation, the influence of surface treatment of GF on viscoelastic behaviour was also examined. Using the results of flexural tests under a variety of constant temperature and strain rate, master curves of flexural strength (σ) and flexural strain (ɛ) were obtained for matrix epoxy and GF composites. The magnitudes of the master curves were different between matrix epoxy and GF composites. The fracture mode was influenced by temperature, strain rate, and G F surface treatment. The magnitude of storage modulus and effectiveness of adhesion at the GF-matrix interface were also influenced by GF surface treatment. Relationship between the results of flexural strain and loss modulus were considered for GF composites.

Novel micro-nano epoxy composites for electronic packaging application: Balance of thermal conductivity and processability