Resin Mixture Research Articles

Composite Anion Exchange Membranes Fabricated by Coating and UV Crosslinking of Low-Cost Precursors Tested in a Redox Flow Battery.

This paper presents a novel, cost-effective approach to the fabrication of composite anion exchange membranes (AEMs). Hierarchical AEMs have been fabricated by coating a porous substrate with an interpenetrating polymer network (IPN) layer where poly(vinylpyrrolidone) (PVP) is immobilized in a crosslinked matrix. The IPN matrix was formed by UV initiated radical crosslinking of a mixture of acrylamide-based monomers and acrylic resins. The fabricated membranes have been compared with a commercial material (Fumatech FAP 450) in terms of ionic transport properties and performance in a vanadium redox flow battery (VRFB). Measures of area-specific resistance (ASR) and vanadium permeability for the proposed membranes demonstrated properties approaching the commercial benchmark. These properties could be tuned by changing the content of PVP in the IPN coating. Higher PVP/matrix ratios facilitate a higher water uptake of the coating layer and thus lower ASR (as low as 0.58 Ω.cm2). On the contrary, lower PVP/matrix ratios allow to reduce the water uptake of the coating and hence decrease the vanadium permeability at the cost of a higher ASR (as high as 1.99 Ω.cm2). In VRFB testing the hierarchical membranes enabled to reach energy efficiency comparable with the commercial AEM (PVP_14—74.7%, FAP 450—72.7% at 80 mA.cm−2).

Evaluation of dose received by workers while repairing a failed spent resin mixture treatment device

Intermediate-level radioactive waste (ILW) is not subject to legal approval for cave disposal in Korea. To solve this problem, a spent resin treatment device that separates 14C-containing resin from zeolite/activated carbon and desorbs 14C through a microwave device has been developed. In this study, we evaluated the radiological safety of the operators performing repair work in the event of a failure in such a device treating 1 ton of spent resin mixture per day. Based on the safety evaluation results, it is possible to formulate a design plan that can ensure the safety of workers while developing a commercialized device. When each component of the resin treatment device can be repaired from the outside, the maximum and minimum allowable repair times are calculated as 263.2 h and 27.7 h for the 14C-detached resin storage tank and zeolite/activated carbon storage tank, respectively. For at least 6 h per quarter, the worker's annual dose limit remains within 50 mSv/year; further, over 5 years, it remained within 100 mSv. At least 6 h of repair time per quarter is considered, under conservative conditions, to verify the radiological safety of the worker during repair work within that time.

Analytical Behaviour of Coconut Coir Roofing Sheet

In world wide the ever increasing population in most developing countries and the corresponding increase in demands and need for infrastructural development, there is an urgent need to focus attention on low-cost alternative construction materials. Lignocellulosic fibers from green coconut fruit were dried under suitable conditions. After this, mixture of phenol cardanol formaldehyde resin and hardener are added to the fiber for binding purpose. Then it is impacted and compressed between two corrugated sheets, in order to obtain the shape of the roofing sheets, for 12 hours. After 12 hours of drying, it is then subjected to various tests such as tensile test, flexural test, impact test, compression test, and hardness test. The results are tabulated in order to compare it with GI sheet and asbestos cement sheet. This coconut coir roof sheet can be replace the former roofing sheets because of its durability, high strength, heat resistivity and low cost which i have been collected data from literature survey. The choose of this alternative is based on economic interest because it is very cheap, available with good mechanical properties, and also based on environmental interest because it is eco friendly. Thus this review paper addresses the characterization and performance of the coconut coir roofing sheet.

Properties of epoxy-thiokol materials based on the products of the preliminary reaction of thioetherification

In order to improve the adhesive and physical-mechanical properties of epoxy-thiocol compositions cured without heat treatment, we propose to carry out the reaction of interaction between thiokol mercaptan groups and oxirane cycles of epoxy resin at an elevated temperature before introducing a curing agent, and then use the product of this thioetherification reaction for curing at room temperature. The temperature range of the thioetherification reaction (90–1800С) was determined by the method of differential scanning calorimetry. The optimal temperature (1600С) and duration of the preliminary thioetherification reaction (2 hours) were determined, which ensure the maximum level of adhesive strength and physical-mechanical properties. It was shown that composite materials based on the products of the thioetherification reaction significantly outperform analogs based on mechanical mixtures of epoxy resin and thiokol in terms of cohesive and adhesive strength, deformation capacity, fracture work and specific impact strength. The impact resistance and shear strength of adhesive joints are especially significantly increased during the curing of the compositions without external heat supply.

The Effect of Chitosan Addition in Acrylic Resin Matrix towards the Residual Monomers and Impact Strength

Background: A residual monomer might have impact on the quality of acrylic resin since its caused allergic reactions and inflammation. Chitosan is a biocompatible material and potential to reduce residual monomers and ameliorate the impact strength of acrylic resin Objective of the study: To examine the effect of an acrylic resin matrix mixed with chitosan together with 1% and 2% acrylic acid as denture base and orthodontic material on residual monomers and impact strength. Methodology: There were 30 samples for the test analysis. The impact strength test sample formed with a plate size of 55 × 10 × 10mm, whereas the residual monomer test sample was prepared into powder. The test samples were divided into 3 groups, of 10 samples. Group 1 acrylic resin only, group 2 acrylic resin matrix mixed with chitosan and 1% acrylic acid, group 3 is the same as group 2 but with a concentration of 2% acrylic acid. Gas chromatography was used for measuring the residual monomers. The impact strength was tested by the Charpy impact. The data was evaluated using the ANOVA and correlation test. Results: There were significant differences (p < 0.05) in acrylic resin without addition with the matrix of acrylic resin with chitosan and acrylic acid 1% and 2% to the number of monomers and impact strength. Conclusion: The mixture of acrylic resin with chitosan and acrylic acid 1% and 2% can reduce the amount of residual monomer and increase the impact strength.

Microstructural, mechanical and tribological performances of copper foam modified CFRP composite for pantograph strip

AbstractA novel pantograph strip of copper mesh modified carbon fiber reinforced polymer (CFRP) composite was fabricated by impregnating copper foam with the resin mixture of carbon fiber and flaky graphite, following by mold hot‐pressing technology. Microstructure, mechanical strength, electric conductivity, friction, and wear behaviors of the composite were investigated and analyzed to explore the fracture failure and wear mechanisms. The results show that the composite obtains much lower electric resistance than that of the pure carbon strip used in China's high‐speed railway. Adding carbon fiber can improve impact strength and wear resistance considerably, but has little effect on anti‐friction performance. The electric resistance and tribological performances are graphite dependent, reduced electric resistance and friction coefficient can be obtained with the increase of flaky graphite from 0 to 15 wt% while negligible changes of impact strength and wear rate are found. However, further increasing the flaky graphite to 20 wt%, the wear rate reveals a dramatic rise. High content of flaky graphite contributes to the formation of thick tribolayer with unconsolidated structure. And the tribolayer is easy to curl and worn off from the wear surface, leading to severe wear of the composite during the current carrying friction tests.

Preparation of hierarchically porous carbon nanosheets by carbonizing resol resin for supercapacitors

Hierarchically porous carbon nanosheets were synthesized by using homogeneous mixture of soluble phenolic resin and KOH activator, which was carbonized and activated through one step. Structural characterization revealed that the as-prepared carbon materials consisted of abundant macropores, mesopores and micropores from the carbonization of the resin and activation of KOH. With the appropriate ratio of KOH to resol resin, hierarchically porous carbon nanosheets with specific surface area beyond 3000 m2g−1 and average pore size of up to 3.44 nm were achieved, which exhibited a high specific capacitance of 365.6 F g−1 at 0.5 A g−1, excellent cycle life with 98.7% specific capacitance retained after 10,000 cycles, and high energy density of 12.7 Wh Kg−1 when measured as an electrode in a coin type symmetric supercapacitor in 6 M KOH electrolyte, indicating a promising electrode material for real energy storage in supercapacitors.

Modelling and experimental validation of thermoset resin curing during pultrusion

Mathematical modelling of the pultrusion manufacturing process involves many parameters of the resin mixture. In this article thermo-chemical behavior of resin used for pultrusion of glass fiber/epoxy-vinyl L-shaped profiles was characterized. Profiles were manufactured at pulling speeds of 200, 400, and 600 mm·min-1. Dependency of resin specific heat from temperature was determined by differential scanning calorimetry (DSC); the influence of temperature on resin’s thermal conductivity was found; parameters of resin cure kinetics were described. Subsequently, the gained parameters were used for numerical simulation of the pultrusion thermo-chemical problem in ABAQUS software. The temperature and cure degree evolutions obtained from the experiments run at different pulling speeds, and those from the numerical model were shown to be correlated.

Research on Steel Slag Resin Mixture Used in Rapid Repair of Pavement Damage

In order to explore the pavement performance of steel slag for pavement damage repair, steel slag, river sand and resin binder are mixed in proportion to prepare steel slag mixture. The test results show that the steel slag mixture has excellent high temperature stability, water stability, low water absorption and low expansibility. The engineering application shows that the steel slag resin mixture has no quality problem after being used to repair the pavement damage for half a year. At the same time, it can also solve the problem of environmental pollution caused by the solid waste of steel slag, which has good social benefits.

The fabrication of superhydrophobic GF/PEEK composites with integrated structure and function by prepreg modifying and hot-pressing process

ABSTRACT The superhydrophobic surface presents great application potential in self-cleaning, anti-icing, and other efficient filed of surface engineering. In this work, we suggested introducing superhydrophobic property to glass fiber/polyetheretherketone composite surface. The developed route involves preparation of functional prepregs using hydrophobic particles and subsequent thermal pressing of modified composite sheets. The results show that depending on the hydrophobic polytetrafluoroethylene contents in the resin mixture, it is possible to obtain the functional prepreg with tunable surface wetting, and ulteriorly control the interlaminar bonding of laminates. The optimized procedure of hot-pressing temperature indicates that the hierarchical microstructure played a crucial role in governing the super-hydrophobicity of the rough composite surfaces. As the sandblasted mold temperature increases from 300°C to 360°C, the water contact angle of pressed composite surfaces ranges from 98° to 152°. Furthermore, the surface exhibits excellent environmental durability. The main advantages of the proposed procedure are its environmental friendliness and expandability, which makes it very potential for driving the superhydrophobic surface to practical applications.

Preparation and photochemical properties of PEG based alpha-hydroxyalkylphenone photoinitiator

A novel emulsified photoinitiator (named as OP10-IPDI-2959) was prepared by the reaction of isophorone diisocyanate (IPDI) with 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (Ir-2959) and nonylphenol polyoxyethylene ether (OP-10). The structure of OP10-IPDI-2959 was characterized by FT-IR, 1H NMR, UV–vis and high-resolution mass spectrometry. The photochemical behavior of OP10-IPDI-2959 was investigated through the photolysis and polymerization of neopentyl glycol diacrylate (NPGDA), mixture of epoxy acrylate resin and 1,6-hexanediol diacrylate (HDDA). Under irradiation of UV light, the OP10-IPDI-2959 has similar photochemical properties with the Ir-2959. Combined with benzophenone, the photoinitiated rate of OP10-IPDI-2959 is higher than that of Ir-2959. The polyoxyethylene fragment of OP10-IPDI-2959 is not only an alternative to toxic amine as hydrogen donor, but also a hydrophilic unit for interface between oil and water. The OP10-IPDI-2959 can effectively emulsify the epoxy acrylate resin and 1,6-hexanediol diacrylate mixture to form low viscosity emulsion. Compared with Ir-2959, OP10-IPDI-2959 has good photoinitiation activity, lower migration and good water emulsification performance.

Digital light processing 3D printing Kevlar composites based on dual curing resin

Abstract Adding fiber filler is a classic strategy for plastic reinforcement, which is well worth applying to Digital Light Processing (DLP) 3D printing technology. Herein, this study evaluated the application of micro-size poly(p-benzoyl-p-phenylenediamine) (Kevlar) fiber in resin for stereolithography. The mixture of Kevlar fiber and resin has an acceptable viscosity. In the mentioned process, the resin was solidified by the projector beam (405 nm) in the Z-axis direction layer by layer. The results showed that the object could still be printed after the content of Kevlar reached 7 wt%. After UV light irradiation and thermal curing, the strength and Young's modulus of the composite are 1.79 times and 11.2 times higher than those of the pure resin. The wear resistance of the composite material is improved. In the single-layer exposure test, the addition of Kevlar makes the resin have a better resolution. Compared with other strategies using Kevlar fiber, it is shown that Kevlar fiber has potential application prospects in DLP 3D printing.

Experimental and numerical study of optimum functionally graded Aluminum/GFRP adhesive lap shear joints using Epoxy/CTBN

Abstract Failure in adhesive joints is usually the result of a non-uniform distribution of stress, which is observed with maximum values near the two ends of the overlap, and the central parts have a minor overall load-bearing contribution. In the joint of two dissimilar materials, the stress fields are asymmetric and the optimum grading of the adhesive properties will not be symmetric. The main objective of this work was to study the performance of optimum functionally graded joints (OFGJ) to maximize the ultimate loading capacity of a lap shear joint. The adherends were aluminum 7075-T6 and unidirectional glass-epoxy composite. The study has been performed considering a grading strategy based on mixtures of an epoxy resin with different values of liquid rubber to obtain the properties variations. First, the mono-adhesive joints with homogeneous bond-line and then symmetrical graded joints with equal bands were investigated. A compliance-based optimization method with the normalized shear stress distribution was used to obtain the best properties along the bond-line. The elastic-plastic model and mixed-mode cohesive damage model were used to obtain the stress distribution and failure prediction, respectively. By grading the overlap symmetrically, the stress distribution has become more uniform and the failure load compared to the base specimen (with a shear strength of 6 kN), increased by 206%. Optimization of adhesive properties using normalized shear stress distribution has positive effects on modifying stress distribution, non-shear forces elimination, improvement of the load-bearing contribution, failure mode alteration, and delay on adhesive joints failure. Therefore, there is a high increase in shear load strength of optimum graded specimen by a significant amount of 299%.

Influence factors on CO2 solubility in cycloalkanes and cycloalkane volume expansion: Temperature, pressure and molecular structure

In CO2 enhanced oil recovery process, the interactions between CO2 and oil components are complex since crude oil is a mixture of n-alkanes, cycloalkanes, aromatics, resin, asphaltene and other compounds. To investigate the effects of temperature, pressure and molecular structure on CO2 solubility in cycloalkanes and the resulting cycloalkane volume expansion, the solubility of near critical and supercritical CO2 in cyclopentane (CP), cyclohexane (CH), methylcyclohexane (MCH), methylcyclopentane (MCP) and ethylcyclohexane (ECH) and the volume expansion factor of cycloalkanes at diverse temperature and pressure were measured. It was observed that increasing temperature decreases CO2 solubility, while CO2 solubility increases with pressure increasing. Compared with CP and CH, it's harder for CO2 to dissolve in their methyl or ethyl substituents. For homologues, CO2 solubility decreases with carbon number increasing. The volume expansion factor and solubility have a same variation tendency with temperature, pressure and molecular structure. The experimental results of solubility were correlated with Fornari's model and PR equation of state with the maximum average absolute relative deviation (AARD) of 2.8% and 6.8%, respectively. The excess molar volume of CO2 + cycloalkane mixtures was calculated to be negative and increases with pressure.

Synthesis and characterization of polymer concrete withpumice aggregate and singkut leaf fiber as filler

Polymer concretehave been made based sand, pumice, epoxy resin, and singkut leaf fiber as fillers. The manufacture of polymer concrete uses block-shaped molds with a size of 100 mm x 20 mm x 10 mm with the press molding method using a hotpress. Variations in the composition polymer concrete of sand, pumice stone, singkut leaf fiber, and epoxy resin, namely 60:20:0:20 g, 60:18:2:20 g, 60:16:4:20 g, 60:14:6:20 g, 60:12:8:20 g, and 60:10:10:20 g. The variation in the composition was made into 2 groups of variations based on the concentration of NaOH used to singkut the leaves, namely the leaves with immersion of 5% NaOH and 13% NaOH. The polymer concrete then characterizes its physical properties (density and water absorption), mechanical properties (flexural strength, compressive strength, tensile strength), and SEM-EDX. The results of characterization carried out on concrete samples, show that the best composition is (60:18:2:20) g (5% NaOH content) with a density value of 1.74 g/cm3, water absorption of 0.34%, flexural strength. amounted to 37.07 MPa, compressive strength of 60.18 MPa, tensile strength of 8.33 MPa. The results of microstructure testing showed that the polymer concrete samples with a mixture of sand, pumice, epoxy resin, and singkut leaf fiber were mostly dominated by the element C (carbon).

CaAlSiN3:Eu/glass composite film in reflective configuration: A thermally robust and efficient red-emitting color converter with high saturation threshold for high-power high color rendering laser lighting

To achieve high color rendering and proper color temperature, a red color converter is essential for phosphor-converted white lighting devices. CaAlSiN3:Eu2+ (CASN) is a highly suitable red phosphor for white light-emitting diodes. However, it can be hardly used in high-power laser lighting due to poor thermal/chemical performance of the phosphor/silicone resin mixture. A series of all-inorganic CASN-based phosphors (e.g., composite ceramic and phosphor-in-glass) were developed to avoid the use of resin. However, new challenges emerged: none of them showed sufficient luminous efficacy (i.e., >50 lm/W) and adequate saturation-threshold (i.e., >30 W or 10 W/mm2). Here, we report a facile fabrication of CASN/glass composite films using a simple and efficient blade-coating method. Upon 450 nm excitation, the resultant composite film presents a high internal quantum efficiency of ~83%, comparable to that of pristine CASN powder (~90%). When irradiated with a blue laser, the composite film shows a record high luminous efficacy of 82 lm/W. Furthermore, its saturation threshold was investigated in high power and high power density mode, respectively. When measured in high power mode, it shows a high saturation threshold over 29.7 W (1.75 W/mm2), thus achieving a high luminous flux of 1576 lm; when measured in high power density mode, it shows a saturation threshold of ~10.2 W/mm2 (1.13 W). With abovementioned excellent properties, the CASN/glass composite film has great potential for use in high-power and high color rendering laser lighting.

Novel conductive wearing course using a graphite, carbon fiber, and epoxy resin mixture for active de-icing of asphalt concrete pavement

Ice and snow on road surfaces can affect driving safety severely and cause accidents. Numerous active snow and ice removal technologies, such as conductive asphalt concrete, heating cables and pipes, have been developed in recent years. However, they reduce the lifetime of the pavement and cannot be applied on the existing roads. In this study, a novel conductive ultra-thin anti-skidding wearing course (CUAWC) is firstly proposed, which consists of a lower conductive layer and an upper wearing course. The conductive layer consists of a mixture of graphite, carbon fiber, and an epoxy resin adhesive. The optimal proportion of each additive was determined using an electrical conductivity test. The mass percolation threshold of graphite and carbon fiber in the conductive mixture were 25 and 4%, respectively. Freeze–thaw cycle and cyclic loading tests were conducted to evaluate the long-term skid resistance and resistivity fluctuation rate of the CUAWC. Finally, a laboratory de-icing test and a field snow melting test were performed. The CUAWC specimens had good skid resistance, good durability and stable resistivity, even after multiple freezing–thawing cycles and a million load cycles. Furthermore, the proposed CUAWC has lower resistivity and higher conductivity than traditional conductive asphalt concrete and can be laid on top of existing road surfaces.

Unsteady Disposable Flow Tracking Using Discrete Phase Model

Thermosetting materials are commonly used as an insulative material in medium- and high-voltage applications. Production of large volume elements is causing several problems related to a mold filling or an exothermic polymerization reaction, which may lead to quality issues. To improve the quality, numerical simulations are commonly used for a production process prediction and optimization. One of most critical stage of production of thermosetting-based components is filling the mold with a fresh, uncured resin. Laminar flow has a tendency to create sharp transitions between resin’s layers with different curing degree, which may lead to local mechanical weakening of the material or degradation of its insulative properties. Another problem observed during the material injection is creation of voids, having great influence on mechanical and electrical properties of the final product. A novel approach to the resin residence time tracking has been proposed, where a volume of fluid and a discrete phase method has been coupled. It allows to connect injection time and place of residence of the resin, even if it is a mixture of resins injected in various moments of the filling process. These methodologies are also applicable for design of product made of a functional materials based on different resin compounds or a microencapsulation.

Reviewing Propolis with Multi-components in the Treatment of Oral Diseases through Multi-pathways and Multi-targets.

Propolis is a natural product made from the mixture of plant resin, saliva and wax collected by bees. It has been studied and concerned because of its high medicinal value and broad application prospects. Propolis has complex components, which can act on the body through multi-pathways and multi-targets to play the role of antibacterial, anti-inflammatory, anti-tumor and so on, and it can be used as an important resource for the prevention and treatment of oral diseases. In this review, we mainly reviewed components of propolis and its physiological activities against oral diseases, as well as the new dosage forms and applications of propolis in oral treatment. The purpose of this review is to explore the advantages of propolis in the treatment of oral diseases and the wide application of propolis in the field of oral health.

Facile preparation of robust dual MgO-loaded carbon foam as an efficient adsorbent for malachite green removal

This study developed a facile approach for the fabrication of dual MgO-loaded carbon foam (DMCF) via carbonization of a cured MgO/cyanate ester resin mixture, which underwent self-foaming of the resin followed by the carbothermal reduction of MgO. The features of the prepared DMCF prepared were characterized by FESEM, TEM, XRD, FTIR, XPS and so on, and the effects of adsorption conditions, adsorption isotherms, kinetics, and thermodynamics on malachite green (MG) removal using the DMCF as adsorbents were investigated through batch adsorption experiments. Results demonstrate that the DMCF possesses a unique dual loading of MgO particles which are not only loaded onto its foam walls but also filled within the walls with a graphene-wrapped core-shell structure. The experimental maximum adsorption capacity of MG reaches up to 1874.18 mg/g with a partition coefficient of 10.87 mg/g/μM. The adsorption process can be better described with Langmuir, pseudo-second-order, and intraparticle diffusion models. Moreover, the DMCF exhibits a removal percentage of 84.85% after five reuses, indicating that it is an efficient and promising adsorbent for MG adsorption.