In the current study, the epoxy material was mixed with 10%, and 30% weight percent carbon material as filler in different thicknesses (1 cm, 1.5 cm, and 2 cm). Transmission electron microscope (TEM) measurements showed the average size of the nano-carbon was 20 nm with a standard deviation of 5 nm. The morphology of samples was examined using scanning electron microscopy (SEM), which showed the flatness of the epoxy surface, and when the content of carbon increases, the connection between the epoxy array and carbon increases. The compression test indicates the effect of nano-size on enhancing the mechanical properties of the studied samples. To survey the shielding properties of the epoxy/carbon composites using gamma-rays emitted from Am-241, Ba-133, Cs-137, Co-60, and Eu-152 sources, which covered a wide range of energies from 0.059 up to 1.408 MeV, the gamma intensity was measured using the NaI (Tl) detector. The linear and mass attenuation coefficients were calculated by obtaining the area under each peak of the energy spectrum observed from Genie 2000 software in the presence and absence of the sample. The experimental results obtained were compared theoretically with XCOM software. The comparison examined the validity of experimental results where the relative division rate ranged between 0.02 and 2%. Also, the measurement of the relative division rate between linear attenuation coefficients of microand nano-composites was found to range from 0.9 to 21% The other shielding parameters are calculated at the same range of energy, such as a half-value layer (HVL), mean free path (MFP), tenth-value layer (TVL), effective atomic number (Zeff), and the buildup factors (EBF and EABF). The data revealed a consistent reduction in the particle size of the shielding material across various weight percentages, resulting in enhanced radiation shielding capabilities. The sample that contains 30% nano-carbon has the lowest values of TVL (29.4 cm) and HVL (8.85 cm); moreover, it has the highest value of the linear attenuation coefficient (LAC), which makes it the best in its ability to attenuate radiation.

In this study, the aromatic carbon content of epoxy resin (EP) increased via carbon tar pitch (CTP) modification, and the CTP occurred self-polymerization reaction. The carboxyl and hydroxyl groups of CTP and the hydroxyl and carboxyl groups of EP occurred chemical cross-linking reaction. CTP and graphitization treatment promoted EP CF carbon crystal growth. The graphitization degree of pure EP CF and 40 wt% CTP modified EP CF are 8.42% and 44.21%, respectively. With the increase CTP content, the cell size, ligament junction and density of graphitization modified EP CF gradually increased, while the number of pores and cells gradually decreased. The cell size, ligament junction size and density of 40 wt% CTP modified graphitization EP CF increased to 1200 μm, 280 μm and 0.5033 g/cm3, respectively. EP CF exhibits entangling carbon ribbon and isotropic amorphous carbon. The 40 wt% CTP modified EP CF is composed of evenly distributed amorphous resin carbon and graphite domain CTP carbon. The graphitization modified EP CF improved electrical conductivity, and the electrical conductivity of 40 wt% CTP modified EP CF is 126.6 S/m. The compressive strength can be decided by EP carbon strength and its char yield, and graphitization 40 wt% CTP modified EP CF reached 4.9 MPa. This study provides some basis for preparation and application of CTP modified EP CF.

Composite laminates are used in a wide range of applications including defense, automotive, aviation and aerospace, marine, wind energy, and recreational sporting goods. These composite beams still exhibit problems such as buckling, local deformations, and interlaminar delamination. To overcome these drawbacks, a novel viscoelastic autoclave bonding with tapered epoxy reinforcement polyurethane films is proposed. In existing laminates, compression face wrinkling and interlaminar delamination is caused in the sandwich beam. The unique viscoelastic autoclave spunbond interlayer bonding is designed to prevent face wrinkling and absorb and distribute stresses induced by external loads, thereby eliminating interlaminar delamination in the sandwich beam. Also, the existing special reinforcement causes stress concentrations, and the core is not effectively connected, which directly affects the stiffness of the beam. To address this, a novel tapered epoxy polyurethane reinforcement adhesive film is proposed, whose reinforcement thickness gradually tapers as it enters the core material. This minimizes stress concentrations at the interface, preventing excessive adhesive squeeze-out during the bonding process, and improves the stiffness of the beam. Results indicate the proposed model avoids the formation of micro cracks, interlaminar delamination, buckling, and local deformations, and effectively improves the stiffness of the beam.

This study aimed to fabricate composites with high thermal conductivity using diglycidyl ether of bisphenol-A (DGEBA), incorporating carbon fiber cloth (CFC) and graphene as reinforcing agents. Notably, the dispersion of graphene within the DGEBA matrix was enhanced through surface modification via a silane coupling agent. The effects of CFC and graphene addition on the impact strength, thermal conductivity, and morphology of the composites were examined. The experimental results showed that the incorporation of 6 wt% CFC resulted in a substantial (16-fold) increase in impact strength. Furthermore, the introduction of 6 wt% CFCs along with 20 wt% graphene led to a remarkable enhancement in thermal conductivity to 5.7 W/(m K), which was approximately 22 and 4 times higher than the intrinsic thermal conductivities of pristine DGEBA and the CFC/DGEBA composite, respectively. The increased impact strength is ascribed to the incorporation of CFC and silane-modified graphene. Additionally, the gradual increase in thermal conductivity can be attributed to the enhanced interaction between the acidic silane-modified graphene and the basic epoxy–amine hardener within the system studied.

A combination of a series of epoxy coatings filled with octadecylamine (ODA)-modified graphene oxide (mGO) or commercial exfoliated graphite nanoplatelets (xGnP) was developed to boost the anticorrosion performances of mild steel substrates in acidic and NaCl aqueous solutions. The xGnP and mGO were applied successfully as fillers for the preparation of layer by layer (LBL) xGnP or mGO/epoxy coatings, respectively, which were coated on the clean steel surfaces to form LBLassembled layers. The LBL-assembled xGnP or mGO/epoxy coating-coated steel substrates exhibit excellent anticorrosion performances. The corrosion potentials (Ecorr) of xGnP-1/xGnP-2/3 and mGO-1/mGO-2/3 display at − 193 and − 150 mV, respectively, while Ecorr of the bare steel shows at − 871 mV of immersion in the 3.5 wt% NaCl solution. The most positive Ecorr values are obtained for xGnP-1/2/3 (− 117 mV) and mGO-1/2/3 (− 66 mV), showing the best anticorrosion performances compared to the bare steel (− 404 mV) in 17 wt% HCl solution.

Curing agents are critical components of aqueous epoxy resin systems. Unfortunately, its uses and applications are restricted because of its low emulsifying yields. Epoxy resins are frequently used in electrical devices, castings, packaging, adhesive, corrosion resistance, and dip coating. In the presence of curing agents, epoxy resins become rigid and infusible. Eco-friendliness and mechanical functionality have emerged as vulcanization properties. Curing agents are used for surface modification, thermodynamic properties, functional approaches to therapeutic procedures, and recent advances in a variety of fields such as commercial and industrial levels. The curing agent has superior construction and mechanical properties when compared to the commercial one, which suggests that it has the potential for use as the architectural and industrial coatings. The thermal stability of cured products is good due to the presence of the imide group and the hydrogenated phenanthrene ring structure. Over the course of the projection period, it is anticipated that the global market for curing agents will continue to expand at a steady rate. The growth of the market is mainly driven by its expanding range in future applications such as adhesives, composites, construction, electrical, electronics, and wind energy. This review focused on the most recent advancements in curing techniques, emphasizing their thermal and mechanical properties. The review also presents a critical discussion of key aspects and bottleneck or research gap of the application of curing agents in the industrial areas.

In this work, the trend in the performance of carbon fiber (CF) and its composite during self-polymerization of polydopamine (PDA) at carbon fiber surface was investigated by varying the self-polymerization time of dopamine in an aqueous solution. Research has shown that the PDA coating elevated the surface roughness and polarity of the inert fiber. The tensile strength of single carbon fiber was significantly improved, especially after 9 h of polydopamine self-polymerization, increasing by 18.64% compared with that of desized carbon fiber. Moreover, the interlaminar shear strength (ILSS) of CF-PDA9-based composites was 35.06% higher than that of desized CF-based composites. This research will provide a deep insight into the thickness and activated ingredients of dopamine oxidation and self-polymerization on interfacial compatibility of carbon fiber/epoxy resin composites.

This comprehensive study delves into the intricate process of exfoliating and functionalizing boron nitride nanosheets (BNNSs) extracted from hexagonal boron nitride (h-BN), and meticulously explores their potential application within epoxy composites. The extensive research methodology encompasses a sequence of treatments involving hydrothermal and sonication processes aimed at augmenting the dispersion of BNNSs in solvents. Leveraging advanced analytical techniques such as Raman spectroscopy, X-ray diffraction, and FTIR spectroscopy, the study rigorously analyzes a spectrum of changes in the BNNS’s properties, including layer count variations, interlayer interactions, crystal structure modifications, and the introduction of functional groups. The research also rigorously evaluates the impact of integrating BNNSs, specifically glycidyl methacrylate (GMA)-functionalized BNNSs, on the thermal conductivity of epoxy composites. The conclusive findings exhibit notable enhancements in thermal properties, predominantly attributed to the enhanced dispersion of fillers and enhanced interactions within the epoxy matrix. This pioneering work illuminates the wide potential of functionalized BNNSs for significantly enhancing the thermal conductivity of epoxy composites, paving the way for advanced materials engineering and practical applications.

Epoxy-based composites find extensive application in electronic packaging due to their excellent processability and insulation properties. However, conventional epoxy-based polymers exhibit limitations in terms of thermal properties and insulation performance. In this study, we develop epoxy-based siloxane/silica composites that enhance the thermal, mechanical, and insulating properties of epoxy resins. This is achieved by employing a sol–gelsynthesized siloxane hybrid and spherical fused silica particles. Herein, we fabricate two types of epoxy-based siloxane/ silica composites with different siloxane molecular structures (branched and linear siloxane networks) and investigate the changes in their properties for different compositions (with or without silica particles) and siloxane structures. The presence of a branched siloxane structure results in hardness and low insulating properties, while a linear siloxane structure yields softness and highly insulating properties. Both types of epoxy-based siloxane/silica composites exhibit high thermal stability and low thermal expansion. These properties are considerably improved by incorporating silica particles. We expect that our developed epoxy-based composites to hold significant potential as advanced electronic packaging materials, offering high-performance and robustness.

Epoxy resin (EP) is a thermosetting resin with excellent properties, but its application is limited due to its high brittleness and poor flame retardancy. Therefore, to solve this problem, a dispersion system of imidazole-containing ionic liquid ([Dmim]Es) and graphene in epoxy resin is designed based on the π–π stacking effect between imidazole and graphite layers. The study on the thermal and flame-retardant properties of the composites show that the modified [Dmim]Es–graphene nanosheets improved the flame retardancy, smoke suppression and thermal stability of epoxy resin. With the addition of 5wt% [Dmim]Es and 1% Gra, the exothermic rate (HRR) and total exothermic (THR) of the composites decrease by 35% and 30.2% compared with the untreated epoxy cross-linking, respectively. The limiting oxygen index reaches 33.4%, the UL-94 test rating reaches V-0. The characterization of mechanical properties shows that the tensile properties and impact properties increased by 13% and 30%, respectively. Through SEM observation, the addition of [Dmim]Es improves the dispersion of graphene in the EP collective and changes the mechanical fracture behavior. The results show that ionic liquid [Dmim]Es-modified graphene nanosheets are well dispersed in the matrix, which not only improves the mechanical properties of epoxy resin (EP), but also has a synergistic effect on flame retardancy. This work provides novel flame-retardant and graphene dispersion methods that broaden the range of applications of epoxy resins.

Doping graphene to epoxy resins can improve the protective ability of the coating, but the lack of active anticorrosion function greatly limits its application in the field of anticorrosion. Herein, N/S-rich few-layer-graphene (N/S-FLG) was prepared and adopted to endow epoxy coating with dual passive/active corrosion protection. The obtained amphiphilic N/S-FLG is highly dispersed in the epoxy coating, giving rise to the enhanced hosting effect for graphene defects, avoiding the interface corrosion and blocking the penetration of corrosive species. Furthermore, the doping of N and S endows graphene sheets favourable catalytic ability for corrosive oxygen, actively eliminating its contribution to metal corrosion. Under this dual effect, the passive and active anticorrosion properties of epoxy coating are simultaneously enhanced. The coating with 1 wt% N/S-FLG reduces the corrosion rate of metal to 6.5 × 10– 5 mm/a, exhibiting almost no corrosion. The proposed concept of introducing nanocatalytic N/S-FLG is facile and eco-friendly, and will undoubtedly promote the practical application of anticorrosion coatings.

Thermal management is significant to maintain the reliability and durability of electronic devices. Heat can be dissipated using thermal interface materials (TIMs) comprised of thermally conductive polymers and fillers. Furthermore, it is important to enhance the thermal conductivity of TIMs through the formation of a heat transfer pathway. This paper reports a polymer composite containing vertically aligned electrochemically exfoliated graphite (EEG). We modify the EEG via edge selective oxidation to decorate the surface with iron oxides and enhance the dispersibility of EEG in polymer resin. During the heat treatment and curing process, a magnetic field is applied to the polymer composites to align the iron oxide decorated EEG. The resulting polymer composite containing 25 wt% of filler has a remarkable thermal conductivity of 1.10 W m− 1 K− 1 after magnetic orientation. These results demonstrate that TIM can be designed with a small amount of filler by magnetic alignment to form an efficient heat transfer pathway.

이 논문에서는 교량받침 교체를 위한 에폭시 주입 공법을 제시하였다. 에폭시 주입 공법의 성능 평가를 위하여, 에 폭시 주입성 실험 및 통공앵커의 인발실험을 수행하였다. 에폭시 주입성 실험은 빈 공간을 갖고 있는 콘크리트 블록 내에 통공 앵커를 이용하여 에폭시를 주입하고, 콘크리트 블록을 절단한 후, 주입성능을 육안으로 관찰하였다. 또한, 인발실험은 2가지 형태의 통공앵커를 콘크리트 블록 내에 삽입하여 수행하였으며, 2가지 형태의 통공앵커에 대한 인발실험 결과를 비교하고, 케 미컬 앵커의 인발강도와도 비교하였다. 실험 결과 통공앵커는 교량받침 교체공사를 위한 에폭시 주입성과 인발성능이 우수한 것으로 나타났다.