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Thermoset Polymer Matrix–Based Natural Fiber Composites
Published in Shishir Sinha, G. L. Devnani, Natural Fiber Composites, 2022
Vinyl ester resin is an excellent type of thermoset that shows the associated characteristics of unsaturated polyesters and epoxy resin. The thermal properties and the curing process of vinyl ester resin can be measured employing MEKP (methyl ethyl ketone peroxide) catalyst and a cocatalyst, cobalt octoate. The resin has been mixed with more polymers to review their impact on the thermal properties of vinyl ester resin. The nano- and micro-composites have been prepared to increase the flame-retardant characteristic and thermal property of vinyl ester resin.
Experimental study of two-way FRP composite slab
Published in Peter J. Moss, Rajesh P. Dhakal, Progress in Mechanics of Structures and Materials, 2020
D. Huang, G.M. Van Erp, T.J. Heldt, C.L. Cattell
A prototype of the composite slab (2020 mm × 1620 mm) was constructed for the experimental study. A total of eight layers of unidirectional laminates with stacking sequence [0°/90°]4 were laminated on both sides of the 120 mm core resulting in an overall thickness of 129 mm. In this study, E-glass and vinyl ester resin were used to construct the prototype testing slab. Vinyl ester resin has advantages such as excellent chemical resistance, low viscosity, fast curing, and a good balance between mechanical properties and cost. However, the volumetric shrinkage of vinyl ester resin is in the range of 5–10%, which can cause cracking during the manufacturing process if the volume of PFR core is large. A modular manufacturing approach was adopted to overcome this exotherm problem (Huang et al. 2002). In this manufacturing approach, the shrinkage is controlled by first fabricating small element (modules) which are later combined into large assemblies. Due to the smaller volume of material involved in the modules, shrinkage is restricted to an acceptable level and does not result in cracking. In addition to the efficient control of the exotherm and shrinkage, the advantages of this modular approach also include cost effectiveness, flexibility of section shapes and suitability for both small and large structures (Huang 2004).
Hydrolysis and Fermentation Technologies for Alcohols
Published in Yatish T. Shah, Water for Energy and Fuel Production, 2014
The Tennessee Valley Authority (TVA) developed a two-stage, low-temperature, atmospheric pressure process that utilizes the separate unit operations to convert hemicellulose and cellulose to sugars [32]. An experimental pilot plant was designed and built in 1984. The process showed a very low level of inhibitor concentration. The results of this study are briefly summarized as follows: The size of ground corn stover of 2.5 cm was adequate for the hydrolysis of hemicellulose.The time required for optimum hydrolysis in 10% acid at 100°C was 2 h.For 1 and 3 h reaction times, the overall xylose yields were 86% and 93%, respectively.Recycle leachate, dilute acid, and prehydrolysis acid solutions were stable during the storage for several days.Vacuum drying was adequate in the acid concentration step.Cellulose hydrolysis by cooking stover containing 66%-78% acid for 6 h at 100°C resulted in 75%-99% cellulose conversion to glucose.Fiberglass-reinforced plastics of vinyl ester resin were used for the construction of process vessels and piping.
Weibull distribution analysis of roselle and coconut-shell reinforced vinylester composites
Published in Australian Journal of Mechanical Engineering, 2021
S. Navaneethakrishnan, V. Sivabharathi, S. Ashokraj
Vinyl ester resin (bisphenol A epoxy vinyl ester) was used as matrix material. It was obtained from GVR Chemicals Pvt. Ltd., Tamilnadu, India, under the trade name of Satyan Polymer. Methyl ethyl ketone peroxide (MEKP) (C8H18O6), cobalt 6% naphthenate (C20H34CoO4) and N–N dimethylaniline (C8H11N) were used as accelerator, catalyst and promoter, respectively. Vinyl ester resins are somewhere between polyesters and epoxies in terms of mechanical properties. One of their major advantages is that they offer better resistance to moisture absorption and hydrolytic attack than polyester. It has excellent physical and mechanical properties and is familiar for its versatility as a composite matrix. The cast resin has a tensile strength of 29.1 MPa and tensile modulus of 1097.4 MPa.
Crashworthiness characterization of jute fiber woven mat reinforced epoxy composite tube for structural application using Taguchi’s method
Published in International Journal of Crashworthiness, 2022
T. P. Sathishkumar, S. Satheeshkumar, K. Bhuvaneshkumar, M. R. Sanjay, Suchart Siengchin
Figure 1 shows the commercial-grade bi-directional jute yarn woven mat and it was purchased in the form of long mat of 600 mm width with 1200 mm length from Krishna Net Weaving industry, Coimbatore, Tamilnadu, India. The thickness of mat is 1 ± 0.15 mm and the linear density of jute yarn on warp and weft direction is 8 yarns/cm. The long jute yarn mat was cut into 300 mm width and 210 mm length for preparing hollow tube. The commercial grade epoxy resin with hardener was purchased from Covai Sennu Industry, Coimbatore, Tamilnadu, India. Table 1 shows the physico-mechanical properties of epoxy resin. It is good chemical resistance and also heat resistance. This resin has high durability, no wet-ability, and low shrinkage compared to polyester and vinyl ester resin.
Evaluation of the mechanical properties of carbon fiber/polymer resin interfaces by molecular simulation
Published in Advanced Composite Materials, 2019
Jun Koyanagi, Norie Itano, Michihiro Yamamoto, Kazuki Mori, Yuichi Ishida, Timur Bazhirov
Epoxy resin was prepared with epoxy molecules (bisphenol-A diglycidyl ether) attached to curing agents (triethylenetetramine) at both ends (105 atoms per molecule). The vinyl ester resin was used along with bisphenol-A and the polymerization degree was set to 1 (75 atoms per molecule). The triA-X polyimide resin was composed of 4 monomer-oligomers (301 atoms per molecule) and 7 monomer-oligomers (428 atoms per molecule). It should be noted that the 4 monomer-oligomers were investigated experimentally. Carbon-fiber was used represented by a graphene sheet (1728 atoms per molecule) and all molecular structures used in the simulations are shown in Figure 3. PolyPargen [35] was used for resin modeling and the OPLS-AA potential was used.