Type Epoxy Research Articles

Pull‐off capacity of FRP–concrete composite bonded with epoxy/geopolymer at elevated temperature

AbstractExternally bonded strengthening technique to the concrete has been widely used with epoxy adhesive. However, the adhesive is considerably weak against high temperatures, which has been regarded as the critical point in the loss of integrity of the strengthened system. Alternatively, geopolymer materials have shown an excellent performance at high temperatures, thus, their potential to be used as adhesive material has been investigated in this work. In experimentation, the composite specimens were developed using both types of adhesives, epoxy and geopolymer, and their performance was evaluated at three temperature levels (20, 60, and 120°C) by conducting pull‐off strength tests and classifying their failure modes. It was observed that the strength of concrete and epoxy was reduced with temperature. In contrast, the strength of geopolymer‐based adhesives strength was increased due to the reactivity of the precursor at high temperatures. Also, bond strength was reduced for both composite specimens at elevated temperatures. The highest bond strength was observed for the epoxy‐based adhesive system at 20°C, and about 70% loss in bond strength was observed when exposed to 120°C. The failure mode was also shifted from concrete to adhesive interface failure, that is, failure between the adhesive and the fiber fabric layer. The geopolymer‐based adhesive system has lower strength than its counterpart at all temperature levels, and the failure mode was adhesive interface failure. To enhance the bonding capacity at high temperatures, efforts are being made by adding different minerals has been employed. From the experimental results, it was found that there were some improvements, however, it was still less than that of epoxy‐based system. Further optimization of the geopolymer adhesive using minerals is required and then high‐thermal resistance geopolymer adhesive can be established.

Contribution of surface roughness and oxygen-containing groups to the interfacial shear strength of carbon fiber/epoxy resin composites

The interfacial shear strength (IFSS) between carbon fibers (CFs) and the matrix is crucial to the performance of CF-reinforced polymer composites. To evaluate the contribution of mechanical interlocking and chemical anchoring at the interfaces of a polyacrylonitrile-based CF (TORAYCA T800SC-12000-10E)-reinforced epoxy resin (EP: bisphenol A type epoxy resin and tetrafunctional epoxy resin) composites, the surface roughness and content of oxygen-containing functional groups of the CFs were respectively altered by ammonia treatment and electrochemical oxidation. The results showed that ammonia treatment increased the surface roughness without much change to the surface elemental composition, while electrochemical oxidation increased the number of surface oxygen groups without changing the surface roughness. The IFSS of CF/EP composites was tested by the micro-droplet method. The relationships between IFSS, and surface roughness and oxygen content were obtained by linear fitting. The results showed that in the interfacial bonding of CF to epoxy resin, the contribution of chemical anchoring to the IFSS is larger than that of mechanical interlocking.

Novel Low Df Thermosetting Film and Photo Imageable Film

There are various demands for interlayer insulation film. One typical demand is to interlayer insulation film with low Df for substrate to decrease transmission loss, and another typical demand is to low warpage, fine via type photo imageable interlayer insulation film for RDL. We have developed two types of the novel interlayer insulation films, one was low Dk/Df thermosetting film and another was fine via type photo imageable film. Epoxy based interlayer insulation film, which was mainly used for substrate, showed high transmission loss at mm wavelength due to its high Df, especially at high temperature. But it showed good processability and reliability due to its thermosetting property. PPE was known as low Df resin, but it had poor processability and reliability due to its thermoplastic property. Thus we have synthesized the novel curable PPE resin, and by using the resin, we have developed the novel thermosetting PPE based interlayer insulation film for substrate. It showed far lower Df and far lower transmission loss compared to the low Df type epoxy based interlayer insulation film. We have developed the novel photo imageable interlayer insulation film for RDL. Ordinally photo imageable PI solution was used for RDL, but it showed high CTE, which caused warpage and reliability issue, high surface roughness, which required post processing process, and high curing temperature. We have used the novel epoxy acrylate and developed the novel photo imageable film, which showed low CTE, low surface roughness and low curing temperature.

Synthesis And Applications of Bisphenol-A Epoxide Resins - A Review

Epoxy resin is a widely used substance for coatings, adhesives, composites, electrical components, LEDs, paintbrush manufacturing, fiber-reinforced plastic materials, and consumer product manufacturing (such as cases, kits, and snowboards). Epoxy resin is highly versatile due to its properties. One of the most commonly used types of epoxy resin is Bisphenol-A Epoxy resin, which is excellent for high-temperature applications, the adhesion of a variety of substrates, compression, bends, electrical insulation, mortar, grouts, adhesion, and high-tensile-strength applications. There are several types and applications of Bisphenol-A epoxy resin. This paper aims to review the types, synthesis, and applications of Bisphenol-A epoxy resin.

Investigating the efficiency of bisphenol-A diglycidyl ether/resole phenol formaldehyde/polyamine blends as Cerium adsorbent from aqueous solution

The blending process of epoxy resin types of bisphenol-A diglycidyl ether (DGEBPA) with resole phenol-formaldehyde (RPF) and polyamine (PA) materials is investigated for Cerium (Ce+3) desorption. Two different blend weight ratios of EPR2 (DGEBPA/PA/RPF; 2:1:1) and EPR3 (DGEBPA/PA/RPF; 2:1:3) are used for the evaluation and compared with the epoxy blank sample EPR1 (DGEBPA/PA; 2:1), under the same preparation conditions of the thermal curing reaction for 1 h at 80 °C. SEM/EDX, XRF, and FTIR are used to illustrate the obtained sorbents. Since cerium is utilized in many industries, this research examines the prospect of extracting it from aqueous solutions that include it using sorbent materials that are affordable, simple to use, and easy to apply. Balance equilibrium is determined by; 40 ppm, solid-to-liquid ratio: 0.1:10 g/mL, room temperature, time: 4 h, and pH 4. Cerium is extracted almost completely without significant solution changes in the chemical composition. Sorption isotherm models are used to analyze the investigative findings. Kinetic, isotherms, and thermodynamics analysis for the obtained data have been performed followed by Langmuir models and pseudo-second-order. The adsorption capacity of Cerium is obtained near; 1.8, 3.9, and 11.7 mg/g for EPR1, EPR2, and EPR3, respectively. The detected results of Ce+3 adsorption; EPR3 is the most effective Cerium adsorbent from solutions and for application on real samples from Nuclear Materials Authority.

Interfacial Bond Properties of Underwater Concrete Coated with Bisphenol A Epoxy Resins.

This study investigated changes in the interfacial properties of epoxy-coated concrete exposed to various conditions, regarding the epoxy type, coating equipment, and exposure environment and period. The measured coating thickness and pull-off bond strength exhibited diverse trends, depending on the exposure period and conditions. In the real sea (RS) environment, the average bond strengths for bisphenol A (BPA) (E1), BPA with zinc powder (E2), and BPA with cresyl glycidyl ether (E3) were 1.26, 1.93, and 1.92 MPa, respectively. The coating method did not significantly affect the measured coating thickness and strength values. The conventional roller (D1) exhibited the highest thickness variation, with a value of 214.45 μm. The RS condition significantly increased the coating thickness (34% to 158%) compared to the tap water (TW) condition. The exposure conditions had little impact on bond strength except for E3, which showed an increased strength (2.71 MPa) over 7-91 days, especially under RS conditions, while E2 remained constant at approximately 1.82 MPa. This study offers insights into factors influencing marine concrete coating performance and discusses limitations and future work.

Fractographic Investigation of Cryogenic Temperature Mode-II Delamination Behavior of Filament Wound CFRP Laminates with Varied Resin Systems

This study investigates the mode-II delamination performance of filament-wound unidirectional composites with different types of epoxies as their matrix phase under room and cryogenic temperatures. A typical vacuum infusion resin, an aerospace-grade cold-curing resin and crack-resistant toughened resin systems were wet-wound with 12K carbon fiber tows to manufacture the composite samples. Test samples with a (0)16 ply sequence were tested according to ASTM D7905-19. The tested samples were investigated via microscopic analysis to assess the failure mechanisms associated with varying the matrix material and temperature. ENF tests at room temperature were found to be susceptible to the inherent variance in the fiber architectures along with resin-viscosity-driven fiber wetting. Cryogenic conditions induce a shift in the mode-II delamination behavior from a rather complex failure mechanism to a consistent fiber/matrix debonding mode with diminishing GIIc values except for the toughened resin system. The provided comprehensive fractographic analysis enables an understanding of the various causes of fracture, which determines the laminate performance. The combined evaluation of the distinctive damage modes reported in this study provides guidance on the conventional wet-winding process, which still remains a volumetrically dominant and viable option for cryogenic applications, particularly for vessels with limited operational durations like sounding rockets.

Prediction of Thermal Conductivity of Litz Winding by Least Square Method and GA-BP Neural Network Based on Numerical Simulations

This paper proposes a Litz winding numerical-simulation model considering the transposition effect, and uses the transient-plane-source method to verify the numerical-simulation method. In addition, numerical methods were adopted to further investigate the impact of filling rate and epoxy-resin type, and their combined effects, on thermal conductivity. To facilitate engineering design, the discrete data points were fitted using the least square method to obtain a straightforward and application-friendly polynomial empirical formula. On this basis, the GA-BP neural network was used to analyze the data in order to seek out more accurate prediction results for the entire data set. As a result, compared with the least square method, the error between the prediction result and the target value in the x direction was reduced by 87.04%, and the error in the z direction was reduced by 84.97%.

Preparation, Curing and Properties of Hydantoin Based Epoxy Resins with Different Structures

AbstractHydantoin based epoxy resins are a kind of special epoxy resin with nitrogen‐containing five‐membered heterocycle structure but less intensively studied than the common bisphenol A type epoxy resins. Besides, only 5,5‐dimethylhydantoin epoxy resin (DMHR) was paid enough attention among hydantoin based epoxy resins. To understand the reasons behind the above background, in this work, three hydantoin based epoxy resins with different structures but similar epoxy values (0.37–0.40 mol/100 g), including hydantoin epoxy resin (HR), 5,5‐dimethylhydantoin epoxy resin (DMHR), 1,3‐dihydroxymethyl‐5,5‐dimethylhydantoin epoxy resin (DHMDMHR), were synthesized first, their non‐isothermal curing kinetics, thermal and mechanical properties and adhesion performance of the cured products were then investigated and compared with bisphenol A epoxy resin E44. The apparent activation energies of the three hydantoin based epoxy resin/diaminodiphenylmethane (DDM) systems were in the range of 55–59 kJ/mol, slightly higher than that of E44/DDM system (47.1 kJ/mol). The properties of the three cured hydantoin based epoxy resins, such as glass transition temperature, thermal stability, tensile strength and storage modulus, declined with decreasing content of the hydantoin cycles. 5,5‐dimethylhydantoin epoxy resin (DMHR) had the highest adhesion strength (5.6 MPa) among the three hydantoin based epoxy resins, but nearly 60 % lower than that of bisphenol A type E44 epoxy resin (13.2 MPa) when a polyether amine was used as the curing agent. The cured product of E44 epoxy resin was stronger, tougher and thermally more stable than the cured products of the three hydantoin based epoxy resins. While, hydantoin based epoxy resins exhibited superior damping performance than E44 epoxy resin.

Low velocity impact behaviors and highly residual compressive strength of epoxy foam‐filled 3D woven composites

AbstractIn this work, a new type of epoxy foam‐filled 3D woven spacer composites (FF‐3DWSCs) was designed and manufactured by self‐made 3D loom and foaming technology. The low velocity impact behaviors, residual compressive properties and strengthening mechanisms of epoxy foam were systemically investigated. As the results, the FF‐3DWSCs showed higher impact load of 4000–5200 N than that of 3D woven spacer composites (3DWSCs) (2800–4300 N) at the energy from 10 to 40 J. The residual compressive strength of FF‐3DWSCs (23.85 MPa) was maintained at about 80% after 30 J energy impact. Due to the good compatibility of the epoxy foam and the epoxy resin and the synergistic effect between the pile yarn and the epoxy foam, the interface between epoxy foam and fiber/epoxy was strong. Therefore, the novel FF‐3DWSCs proposed here exhibited excellent impact properties and energy absorption capacity and can be used as a candidate material in the field of high‐performance composites.

Experimental study on interfacial shear strength between date palm fibers and thermoset resins

Date palm fibers (DPFs) can be potentially used in novel applications including composites. In this study, the Microbond technique was used to measure the interfacial shear strength (IFSS) between DPFs extracted from the mesh (ME), the midrib (MI), and the Spadix stem (SS) and three types of thermoset resins, i.e., unsaturated polyester (P), epoxy (E), and phenolic Resol (R). The fibers’ tensile strength was measured and the aspect ratio of the fibers (critical length/diameter) for different fiber-resin systems was determined. It was shown that there is a clear relationship between resin droplet contact angle and IFSS. SS fibers provided the highest and ME fibers the lowest IFSS values among the fibers. Among the resins, E provided the highest and R the lowest adhesion to all fibers. The IFSS values of the E with MI, SS, and ME fibers were 7.62, 8.89, and 5.88 MPa, for the R matrix were 2.94, 3.02, and 2.33 MPa, and for the P matrix were 5.59, 5.97 and 5.17 MPa, respectively. It was shown that there is a clear relationship between IFSS values and contact angles of different fiber/matrix systems.

Structural design strategy of biobased propargyl ether-functionalized epoxy monomer to access low viscosity resin with excellent heat resistance and mechanical properties for advanced composite via VARTM

High performance biobased epoxy resin with low viscosity is important for preparing fiber-reinforced polymer composites via vacuum-assisted resin transfer molding (VARTM). Herein, a novel biobased propargyl ether-functionalized epoxy monomer (BPBO) with low viscosity (0.07 Pa·s) was designed and synthesized from renewable eugenol, and then it was combined with methyl nadic anhydride (MNA) to produce a new epoxy system (BPBO/MNA) with excellent properties. The curing behaviors and integrated performances were systematically researched and compared with those of petrochemical-based commercial diglycidyl ether of bisphenol A (DGEBA) type epoxy resin (DGEBA/MNA). BPBO/MNA shows better thermal and mechanical properties than DGEBA/MNA. Specifically, the glass transition temperature (Tg) and the flexural strength of BPBO/MNA resin are as high as 242 °C and 176.2 MPa, about 47 °C and 16.8 % higher than those of DGEBA/MNA resin, respectively, and both of them are the highest among those of eugenol-derived epoxy resins reported so far. The nature behind these outstanding integrated performances is attributed to the unique cross-linked structure of BPBO/MNA that originated from the ring opening polymerization of epoxy with anhydride and the polymerization of aryl propargyl ether groups. Moreover, carbon fiber reinforced composite with attractive performance was developed by taking BPBO/MNA as the resin matrix via VARTM process. This work presents a simple and unique strategy to prepare high performance biobased epoxy resin with low viscosity for advanced composites.

Flame retardant, strong and tough, low dielectric epoxy thermoset enabled by a novel bi-DOPO type epoxy with aggregation-induced emission

Multifunctional epoxy resins with excellent flame retardancy, high strength, high toughness, low dielectric loss and strong fluorescence show great potentials in electrical/electronic applications; however, simultaneously achieving those goals are difficult. To address those challenges, an epoxy resin with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) pendant group and flexible aliphatic spacer (DOPOEP) was developed. V-0 rating in UL-94 test and LOI of 33.1% are achieved at only 0.45 wt% phosphorus loading, benefitting from the flame retardant mechanism in gas and condensed phase. Compared with neat DGEBA, the cured epoxy with 10 wt% DOPOEP shows 13.4% and 37.6% improvements in tensile strength and impact strength, respectively; in addition, the tensile strength of the cured epoxy with 20 wt% DOPOEP is as high as 102.2 MPa, a 35.3% increase, without compromising toughness. The strengthening effects of DOPOEP derive from π-π stacking and hydrogen bonding, and the improved toughness is due to the flexible aliphatic spacer and reduced crosslinking density. Meanwhile, free volume reduction was observed after introducing DOPOEP, which is responsible for the improved modulus. DOPOEP addition also lowers the hydroxyl group concentration, leading to lower dielectric constant and dielectric loss tangent. Moreover, the aggregation-induced emission behavior of DOPOEP was reported, and its application in anti-counterfeiting field was explored. In air, the fluorescence of DOPOEP-containing thermoset steadily diminishes with increasing temperature, however the fluorescence changing trend is complex in vacuum. Besides, the fluorescence of DOPOEP is effective in the visual detection of defects and flaws in cured products. This work provides a new direction for developing high-performance epoxy with multifunction.

A Comprehensive Review on the Thermal Stability Assessment of Polymers and Composites for Aeronautics and Space Applications.

This review article provides an exhaustive survey on experimental investigations regarding the thermal stability assessment of polymers and polymer-based composites intended for applications in the aeronautical and space fields. This review aims to: (1) come up with a systematic and critical overview of the state-of-the-art knowledge and research on the thermal stability of various polymers and composites, such as polyimides, epoxy composites, and carbon-filled composites; (2) identify the key factors, mechanisms, methods, and challenges that affect the thermal stability of polymers and composites, such as the temperature, radiation, oxygen, and degradation; (3) highlight the current and potential applications, benefits, limitations, and opportunities of polymers and composites with high thermal stability, such as thermal control, structural reinforcement, protection, and energy conversion; (4) give a glimpse of future research directions by providing indications for improving the thermal stability of polymers and composites, such as novel materials, hybrid composites, smart materials, and advanced processing methods. In this context, thermal analysis plays a crucial role in the development of polyimide-based materials for the radiation shielding of space solar cells or spacecraft components. The main strategies that have been explored to improve the processability, optical transparency, and radiation resistance of polyimide-based materials without compromising their thermal stability are highlighted. The combination of different types of polyimides, such as linear and hyperbranched, as well as the incorporation of bulky pendant groups, are reported as routes for improving the mechanical behavior and optical transparency while retaining the thermal stability and radiation shielding properties. Furthermore, the thermal stability of polymer/carbon nanocomposites is discussed with particular reference to the role of the filler in radiation monitoring systems and electromagnetic interference shielding in the space environment. Finally, the thermal stability of epoxy-based composites and how it is influenced by the type and content of epoxy resin, curing agent, degree of cross-linking, and the addition of fillers or modifiers are critically reviewed. Some studies have reported that incorporating mesoporous silica micro-filler or microencapsulated phase change materials (MPCM) into epoxy resin can enhance its thermal stability and mechanical properties. The mesoporous silica composite exhibited the highest glass transition temperature and activation energy for thermal degradation among all the epoxy-silica nano/micro-composites. Indeed, an average activation energy value of 148.86 kJ/mol was recorded for the thermal degradation of unfilled epoxy resin. The maximum activation energy range was instead recorded for composites loaded with mesoporous microsilica. The EMC-5p50 sample showed the highest mean value of 217.6 kJ/mol. This remarkable enhancement was ascribed to the polymer invading the silica pores and forging formidable interfacial bonds.

Study on copolymerization modification and properties of bio-based trifunctional diphenolic acid epoxy resin by CE and DPR

Diphenolic acid epoxy resin (DPAE), a new type of bio-based epoxy, exhibits many attractive performances, such as high reactivity, low expansion coefficient (CTE), high glass transition temperature (Tg) and high storage modulus. However, the dielectric constant of DPAE is not satisfied for the requirements of high frequency circuit field, which need to be further improved to expand its application in emerging area of electronic information. In this work, both dicyclopentadiene phenol epoxy resin (DPR) and cyanate ester (CE) were used to modify DPAE in order to improve its dielectric property, while keeping good heat resistance and low dimensional stability. Furthermore, the influence of curing agent types on properties of DPAE/DPR system was studied. Compared with DPAE resin, both DPAE/DPR and DPAE/CE composites exhibited higher glass transition temperature (Tg), lower dielectric constant, lower loss tangent with good compatibility between DPAE and those two resins. Moreover, CE resin exhibited better modified effect than DPR on thermal and dielectric properties of DPAE with the same addition. For example, the dielectric constant and loss tangent of DPAE/CE with 50 wt% CE were as low as 3.4 and 0.018 at 1 MHz, respectively.

Intrinsically Noncombustible Thermosets from Sulfur-Containing Epoxy Resin and Benzoxazines: Evaluation of Thermal and Mechanical Properties

Benzoxazine (BZ)-epoxy copolymers exhibit favorable mechanical properties, but their thermal and flame-retardant characteristics are impaired at high epoxy fractions. Here, we report a new type of sulfur-containing epoxy resin (EPS), which we synthesized using 4,4’-thiobisphenol (TBP) instead of bisphenol A (BA) and then blended with three sulfur-containing BZs (TBP-a, TBP-fa, and TBP-tma). The polymerization behavior of the resins was analyzed using Fourier transform infrared spectroscopy and differential scanning calorimetry for determining the optimal curing procedure. This analysis revealed that the oxazine and epoxy rings undergo ring-opening and cross-linking reactions at the same time and that double-substituted structures originating from the furan and thiophene rings appeared during the curing process. Thermogravimetric analysis showed that the addition of EPS increased the initial decomposition temperature by hindering the formation of double-substituted structures. The char yield at 800°C decreased owing to the unstable C–O–C–C–O groups derived from the ring-opening of EPS. To prepare the self-extinguishing copolymers with a char yield of 24%, a smaller quantity of BZ was needed for the EPS-based blends than for the BA-based ones. The heat release capacities—measured using micro-combustion calorimetry—of all copolymers except TBP-a/EPS were less than 300 J/g·K, demonstrating that the presence of thioether bonds and double-substituted structures resulted in excellent flame retardancy. The TBP-fa/EPS copolymer also exhibited excellent flame retardancy in cone calorimeter measurement. Finally, the glass transition temperature of the TBP-fa/EPS copolymer at a ratio of 5 : 5 (w/w) reached as high as 289°C. A TBP-fa/EPS copolymer with an epoxy content of 70% had nearly the same storage modulus (2,206 MPa) at 50°C as poly(BA-a) and thus similar mechanical properties. In summary, BZ-epoxy copolymers prepared from sulfur-containing epoxy combine the advantages of the constituent components and extend their areas of application.

Study of the behaviour of FRP materials and epoxy adhesives under elevated temperature

Strengthening using externally bonded FRP is widely adopted to enhance load carrying capacity of structural elements and overall safety of the structures. However, the performance of FRP materials and epoxy adhesives under elevated temperature needs to be addressed. This study mainly focuses on evaluation of tensile performance of Glass Fiber Reinforced Polymer (GFRP) and Carbon Fiber Reinforced Polymer (CFRP) strips as well as behaviour of two different types of epoxy adhesives i.e. Sikadur 30 LP and Sikadur 330 under elevated temperatures. The performance of FRP materials is compared with Stainless Steel Wire Mesh (SSWM), which is a cost-effective alternative for strengthening. A total of 54 number of coupon specimens (strips of size 300 mm × 25 mm) of GFRP, CFRP and SSWM are prepared and tested under uniaxial tension as per ASTM standard. Coupon specimens are exposed to different elevated temperatures i.e. 100℃, 200℃, 300℃, 400℃ and 500℃ for 2 h. For epoxy material, 50 mm long strips of 25 mm width and 5 mm thickness are prepared. From the results, superior performance of SSWM is observed as compared to GFRP and CFRP material at elevated temperature. A complete disintegration of fibers is observed beyond 200℃ for FRP specimens. However, SSWM maintains both the integrity and strength even up to 500℃. Further, from the comparison of integrity and weight loss, it is observed that Sikadur 30 LP performs better as compared to Sikadur 330 at elevated temperature. From the results, it is concluded that SSWM along with Sikadur 30 LP epoxy can be used for the strengthening of concrete structures exposed to elevated temperature. Based on study, it is suggested to further create diverse hybrid composites by combining CFRP, GFRP, and SSWM with appropriate bonding materials for applications in various industries and environmental conditions having exposure to high temperatures.

Study on Blending Modification of Bisphenol A Epoxy.

Epoxy-resin-based composites in the field of current electrical materials often work in high temperature, high humidity or salt spray conditions. In order to improve the operation reliability of the composite insulator cross arm in a high temperature, high humidity and high salt spray environment, and analyze the aging mechanism and performance characteristics of resin, in this paper, wet heat aging and salt spray aging experiments were carried out on the blended resin system composed of bisphenol A type epoxy resin (E-51), aliphatic epoxy modified bisphenol A epoxy resin (2021P/E-51) and dimeric acid modified bisphenol A epoxy resin (EPD-172/E-51). Among them, 10 wt% and 20 wt% of 2021P blend resin and 10 wt% of EPD blend resin have superior thermo-mechanical properties. Under humid and hot conditions, the dielectric loss of 10 wt% EPD blend system before and after aging is 39.9% and 49.5% lower than that of pure E51 resin system, respectively. Under the condition of salt spray, the dielectric loss of 20 wt% and 10 wt% EPD blends decreased by 73.1% and 74.6% after aging. The leakage current of 10 wt% 2021P blend resin and 10 wt% EPD blend resin decreased by 7% and 3.8% before aging, respectively. After aging, they decreased by 3.7% and 2.2%, respectively. The bending strength of 2021P blend resin before and after aging reached 29.3 MPa and 26.6 MPa, respectively. The above three blending resin systems exhibit good electrical properties and good mechanical properties, their ageing resistance performance is strong and they are suitable as the matrix resin of compound cross arm mandrel material.

The Study of Some Mechanical Properties of Some Composite Materials with Different Types of Matrices and Reinforcement from Chromat-type Isophthalic Resin Granules NPG

Using the experimental determinations obtained on the basis of compressive stress, some mechanical properties were studied for composite materials with the matrix of three types of resin, epoxy, unsaturated polyester and hybrid based on Dammar natural resin, which was reinforced with isophthalic resin granules NPG (Neopentyl Glycol) Chromat Kayan / Javari / Payette type. The stress-strain diagrams, compressive yield strength, compressive strength and modulus of elasticity in uniaxial compression were obtained. With the EDS analysis, the graphical distribution of the atomic spectra of the elements identified in the hybrid resin was determined and the image of the fracture surface of a hybrid resin specimen was presented based on the stereomicroscopic analysis (SEM).

3D printed heterogeneous cation exchange membrane processed using stereolithography

AbstractMembrane chemistry belongs to the field in which 3D printing can advantageously also be used because of enabling the production of prototypes with precisely defined dimensions. The presented work aimed to develop new polymeric compositions for heterogeneous cation exchange membranes manufactured using stereolithography (SLA) from commercially available materials. Three types of photo‐curable thermoset resins (acrylic resin and two types of epoxy resins) were used as polymer matrixes in combination with strong acid cation exchange resin (CER) powder. The membrane production consisted of several stages, namely mixing the photo‐curable resin with finely ground CER powder, processing using SLA, and appropriate post‐curing using UV light and elevated temperature. The work aimed to monitor the influence of the photo‐curable resin type and post‐curing on the microstructural, electrochemical, and mechanical properties of resulting membrane objects. The results revealed that heterogeneous cation exchange membranes could be processed using SLA from the mixture of the acrylic photo‐curable resin and CER powder (weight ratio of 60/40) without the need for post‐curing. These products exhibited high permselectivity (93%), high ion exchange capacity (2.23 meq⋅g−1), and sufficiently low electrical resistance (2200 Ω⋅cm), which predetermines them for efficient electrophoretic separation.