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Auxiliary methods technology
Published in Emilio Bilotta, Renato Casale, Claudio Giulio di Prisco, Salvatore Miliziano, Daniele Peila, Andrea Pigorini, Enrico Maria Pizzarotti, Handbook on Tunnels and Underground Works, 2023
G. Cassani, M. Gatti, C.L. Zenti, V. Manassero, S. Pelizza, A. Pigorini
Pure solutions include various types of resins, such as acrylic, phenol, polyurethane and epoxy. Resins are solutions of organic products in water, or a non-aqueous solvent, capable of causing the formation of a gel with specific mechanical properties under normal temperature conditions and in a closed environment. Resins are used for both strengthening and waterproofing where durability is essential and specific characteristics have to be provided. Their typical field of applicability is shown in Table 4.1.
Manufacturing Techniques
Published in Sumit Sharma, Composite Materials, 2021
In the resin film infusion (RFI) process, a precatalyzed resin film placed under the dry fiber preform provides the liquid resin that flows through the preform and on curing, becomes the matrix. The process starts by covering the mold surface with the resin film and then placing the dry fiber preform on top of the resin film (Figure 3.29). The thickness of the resin film depends on the quantity of resin needed to completely infiltrate the preform. RFI can be carried out using the bag-molding technique described earlier. In that case, the assembly of resin film and dry fiber preform is covered with a vacuum bag and placed inside an autoclave. The full vacuum is applied at the beginning to remove the trapped air from the preform. As the temperature is increased in the autoclave, the resin viscosity decreases and the resin starts to flow through the dry fiber preform. Pressure is applied to force the liquid resin to infiltrate the preform and wet out the fibers. With the temperature now raised to the prescribed curing temperature, the curing reaction begins and the liquid resin starts to gel. If an epoxy film is used, the curing cycle may take several minutes to several hours depending on the resin type and the curing conditions used.
Reinforced composite materials
Published in Andrew Livesey, Motorcycle Engineering, 2021
The main types of resins are polyesters, vinylesters, epoxies, phenolics, cyanate esters, silicones, polyurethanes, bismaleides (BMIs), and polyamides. The first three are the ones mainly used for manufacturing work, as they are reasonably priced. Cyanates, BMI, and polyamides cost about ten times the price of the others.
Effects of drying conditions on the solvent diffusion process during coated fabrics curing
Published in Drying Technology, 2022
Zhenrong Zheng, Yuejiao Bi, Xiaoming Zhao, Jiawei Wang, Jianjian Nie
Coated fabric refers to the composite fabric formed by coating a polymer or other materials on a fabric substrate. Many kinds of polymer solutions, such as silicone resin, acrylic resin, epoxy resin and polyurethane are commonly used. Among them, the acrylic resin film is transparent and does not susceptible yellow. It is chemically stable, weather resistant, flame retardant, low cost and has good adhesion to glass fiber. It has been widely used in construction, decoration, transportation and military fields.[1–4] In the curing process of coated fabrics, drying is the key process step and solvent diffusion is the key factor to control the drying rate, which determines the content of residual solvent in the film and affects the performance of the film.[5] During the development of coated textile materials, experimental methods are often used as a way to optimize important parameters such as solvent content, drying temperature, drying air speed and so on.[6,7] However, this approach requires repeated experiments with high costs and longer experimental times, and the solvent in the coating solution releases a large amount of smoke into the air. Therefore, it is desirable to predict the change of solvent concentration in coated fabric under certain condition by means of numerical calculation.
Bio-binders for the improvement of the performance of natural fibers as reinforcements in composites to increase the sustainability in the transport sector
Published in Mechanics of Advanced Materials and Structures, 2021
Julio Vidal, David Ponce, Antonio Miravete, Jesús Cuartero, Pere Castell
Epoxies are one of the most commonly used resin systems in the composites industry for high performance applications. Their dimensional stability, chemical resistance, and thermo-mechanical properties allow the composites with epoxy resin to outperform current thermoplastic composites. The epoxy monomers with two or more functional groups react with the hardener’s molecules, whose terminal group is usually an amine to form a thermoset structure [2, 3]. Besides, it is possible to modify the epoxy resins in order to control its final properties, even if it is necessary to generate brittle or ductile materials [4]. The epoxy resins are materials that can be used in many different technologies, such as liquid resin infusion (LRI), resin transference mold, prepregging, and even new technologies, in which thermoplastics were the main material used. Epoxy resins are starting to be used in technologies like additive manufacturing [5]. Currently, these resins are used in many different sectors and applications such as aeronautics, wind turbine blades, naval, railways, construction, and so forth.
Using Mechanistic Modeling for Understanding Antibiotics Purification with Ion Exchange Chromatography
Published in Solvent Extraction and Ion Exchange, 2020
Lucrèce Nicoud, Karen-Vanessa Gonzalez, Aude Portier, Roger-Marc Nicoud
The ionic capacity of the resin was determined by injecting an ammonia solution on a resin initially in the H+ form. To do so, in a first step, the resin was cleaned with a sulfuric acid solution at 2 mol/L during 2.6 h and then rinsed with water. In a second step, an ammonia solution at 1.7 mol/L was loaded during 3.1 h, and then the column was rinsed with water. The experiment was performed at 1 bed volume per hour (8 mL/min) and was monitored by online pH and conductivity. Ammonium ions were titrated with HCl both in the feed solution and in the solution collected during the second step (i.e., during the load of the ammonia solution and rinse with water). The titration was performed with 20 mL solution. The pH was recorded as a function of the volume of HCl 1 mol/L added.