Fiber Reinforced Vinyl Ester Resin Research Articles

Integrated design of flame retardancy, smoke suppression and structure of carbon fiber reinforced vinyl ester resin composites through intercalation of nanofiber membranes

A novel flame-retardant method based on the intercalation of nanofiber flame-retardant membrane has been studied for composite laminates. Compared to traditional additive flame-retardant method, this method is more efficient, does not affect the composite forming process, and can improve the mechanical properties of composite. Nanofiber flame-retardant membranes (FPm) are prepared from polyether sulfone (PES) and pentaerythritol phosphate ester (PEPA) by electrospinning technique and inserted in the interlayer of carbon fiber reinforced vinyl ester resin (CF/VER) composites. The FPm can improve the flame-retardancy and smoke suppression of the CF/VER composites by promoting the charring of interlayer structure and form a barrier layer. The thickness of the FPm and the flame-retardant performance of the composites are positive correlation. At a FPm’s thickness of 50 μm, the limiting oxygen index (LOI) and UL-94 ratings of the CF/VER composites reached 33.5 % and V-1, respectively. The total heat release (THR) and total smoke release (TSP) are reduced by 26.4 % and 30.4 %, respectively. Due to the interlayer enhancement effect of FPm, the mechanical strength and interlaminar fracture toughness of CF/VER composites are also improved. Especially, when the thickness of FPm is 30 μm, the mode I interlaminar fracture toughness (GIC) of the CF/VER composite increased by 17.4 %. while the flexural strength, interlayer shear strength (ILSS), mode II interlaminar fracture toughness (GIIC) and storage modulus (E’) are all enhanced.

Phosphorus-containing reactive compounds to prepare fire-resistant vinyl resin for composites: Effects of flame retardant structures on properties and mechanisms

The traditional flame-retardant method for carbon fiber reinforced vinyl ester resin composites is to add a large amount of solid flame retardants, which not only leads to the deterioration of the material's mechanical properties, but also increases the resin viscosity and affects the molding process of composites. In addressing this issue, this work adopts a liquid reactive flame retardant strategy and synthesizes six novel liquid phosphorus-containing reactive compounds as flame retardants. A comparative study is conducted on the effects of the structure of compounds (valence and group of phosphorus and number of reaction groups) on the properties of materials. The results demonstrate significantly improved flame retardancy and toughness, as well as unaffected viscosity and strength of the resin. When the phosphorus content does not exceed 3 wt%, the limiting oxygen index (LOI) of the resin can reach over 30% and UL-94 passes the V-0 rating. The structure of compounds significantly affects their flame retardancy mechanism. Especially, compounds rich in P-O-C structure have more outstanding condensed phase flame retardancy (promoting charring) and are more favorable for improving the LOI; Compounds rich in P-Ph and P-C structures have higher thermal stability and mainly exert gas phase flame retardancy, which is more beneficial for improving the self-extinguishing properties of materials. Furthermore, a synergistic flame retardant effect is observed between carbon fiber and compounds rich in P-Ph.

Effect of volume fraction of cashew nut de-oiled husk biosilica on load-bearing properties of ramie fiber–reinforced vinyl ester resin composite

Effect of volume fraction of cashew nut de-oiled husk biosilica on load-bearing properties of ramie fiber–reinforced vinyl ester resin composite

Effect of AA6061 on Mechanical Properties of Basalt Fiber Reinforced Vinyl Ester Resin by Using Hand Layup Process

Abstract: In this research work, thermo-set polymer hybrid compound was manufactured by using vinyl ester resin. In this study, vinyl ester resin is utilized as a matrix material. Introduce to study, an AA 6061 particulate filler is added with weight ratio of (0, 5, 10, 15) and basalt fiber (330 gsm) is arranged one on other, hand layup procedure is used to prepare a composite objects. These composite materials are cut in to the test specimen’s as per the ASTM standards. The mechanical properties like tensile, impact, and flexural strength are calculated according to the ASTM standards. In this work, composite with filler materials shows superior mechanical properties than the material without filler materials. The effects of AA6061 on mechanical properties of basalt fiber reinforced vinyl ester resin are studied from the experiment results. It has considerable effect on the mechanical properties of the composite material. In particular, a comprehensive SEM examination of the damaged sample surfaces has been undertaken to find out bonding between AA6061 filler, matrix and reinforcement

The combined effect of temperature and seawater on the compression properties of carbon fiber vinyl ester composites for sandwich structures

For naval applications, composite sandwich structures are of significant interest, and are often manufactured using thin (2 to 4 mm) composite facings made from carbon or glass fiber reinforcement, attached to a thick (25 to 50 mm) section of PVC cellular foam or balsa wood-based core materials using a suitable polymeric resin. In the present study, we focus on the hygrothermal effect on the fiber-dominated compression properties of carbon fiber reinforced vinyl ester resin based polymeric composite (CF/VE), used as “skin” for a polymeric composite sandwich material. Hygrothermal conditioning is achieved by saturating samples in simulated seawater at 40°C. Compression properties are evaluated for coupons extracted along warp and fill undergoing- no conditioning, conditioning till saturation (up to 6 months), and long-term conditioning (2 years). Sea-water saturation yields in up to 12% drop in compression strength with a further 3–4% drop resulting from long-term conditioning. No statistically significant modulus degradation is noticed due to short or long-term hygrothermal exposure. The failure mechanism of the warp extracted coupon, which fails in a splitting failure mode originating due to the delamination between the 0/90 interface, or the fill extracted coupon, which fails due to the instability caused by tow micro-buckling, remains unchanged due to combined exposure (short or long-term) of seawater and temperature. The loss in strength is attributed to the degradation of the fiber-matrix interface, which is validated via conducting single fiber push-in tests with a nominal diameter of 7 micron for conditioned and unconditioned coupons.

Characteristics of Pinewood Dust Combined with Vinyl Ester Composites Through Material Testing and Machining

Natural fibre-reinforced polymer (NFRP) composites can be environmentally friendly and cost-effective alter-natives to synthetic fibre-reinforced composites. Major industries have expressed significant interest in the advancement of new natural fibre-reinforced composite materials. However, these materials perform poorly on their own and require further analysis since accessible information is lacking in the literature. This paper presents the results of previously reported works on natural fibre reinforced polymer composites, with strong attention to the types of fibres employed, the polymers used in the matrix, the treatment of fibres as well as the test parameters. The best proportion of composites is consequently selected. Composite materials are tested using a CNC router machine. Pinewood dust is combined with vinyl ester resin. A hand layup tech-nique is used to prepare the samples. The availability of relevant pinewood dust and the volume of pine wood dust to be used are first determined to continue with the experiment. According to the findings, the impact of machining performance is successfully evaluated by employing the tensile strength test, Charpy impact test, flexural strength test and surface roughness measurement. The findings are derived from the microscopic assessment of the surface roughness of pinewood dust (PWD) fibre reinforced vinyl ester resin.

Experimental Investigation on Hygroscopic Aging of Glass Fiber Reinforced Vinylester Resin Composites.

The hygroscopic behavior of vinylester resin and high strength glass fiber reinforced vinylester resin composites were examined here, including weight change and the resulting degradation of mechanical properties. The prepared resin and composites specimens were immersed in deionized water and artificial seawater with an applied temperature of 70 °C, and then the specimens were weighed at specified time intervals in combination with the observation of surface morphologies using a scanning electron microscope. Identification of variations of functional groups was also carried out using Fourier-transform infrared spectroscopy. Meanwhile, the mechanical properties for resin and the composite specimens were tested periodically. The observations on surficial morphologies and the test on weight change display that the vinylester resin hydrolyzes seriously after immersion in deionized water, and that the embedment of glass fiber effectively inhibits the moisture absorption and hydrolysis for resin matrix in composites. The results from the mechanical properties test reveal that the tensile strength of pure resin decreases by 35.3% after 7 days’ immersion and keeps small fluctuation in the sequent immersion duration. However, the compressive strength of pure resin consistently dwells at 100 ± 2 MPa during immersion. After immersion for 90 days, the tensile strength decreases by 28.5% and 38.4%, the compressive strength reduces by 7.2% and 16.6%, and the in-plane shear strength reduces by 16.6% and 15.2% for the composites immersed into deionized water and artificial seawater, respectively. The main highlights of this paper are that it provides a more comprehensive mechanical properties test in combination with the microscopic characterization on a matrix and its composites to reveal the aging behavior of composites under a hygroscopic environment.

Mechanical properties of Nomex honeycombs filled with tubes of carbon fibre reinforced vinyl ester resin composites

The Nomex honeycomb structures filled with carbon fibre reinforced vinyl ester resin composite tubes (NHFCT) were proposed to improve the energy absorption capacity of Nomex honeycombs. Thereafter, the mechanical properties of the NHFCT structures were explored based on the quasi-static pressure test, finite element simulation, and a theoretical model. The test result showed that the NHFCT structures enable increased SEA while retaining the energy absorption performance of Nomex honeycombs. When applying a certain load on the NHFCT structures, the Nomex honeycombs are folded; the CFRP tubes are torn and expanded, and the embedded cells bulge. The established finite element simulation model was used to simulate the deformation of NHFCT structures and the theoretical model was employed to predict their energy absorption performance. Tests applicable to the practical application revealed that NHFCT structures of a large area present more stable performance and the superimposed NHFCT structures are subjected to step-wise gradient deformation. The CFRP tubes suffer slight indentation on the panel between layers and they are torn in a funnel shape under the effect of the panel stiffness. The research provides reference for improving the mechanical properties of Nomex honeycomb structures and broadening their range of application.

A closed-loop recycling process for carbon fiber reinforced vinyl ester resin composite

Carbon fiber reinforced thermosetting polymer composites have been widely used in industrial fields, such as wind blades, aerospace and automobiles. However, it is extremely hard to degrade their waste due to the insoluble and infusible crosslinked networks. A solvothermal method is proposed to degrade carbon fiber reinforced vinyl ester resin composite (CF/VER) in this paper. The degradation reaction was conducted in a teflon-lined autoclave at 160 ℃ to 240 ℃ for 60 min to 180 min using isopropanol and acetone as solvents. NaOH or KOH were added to efficiently accelerate degradation process. Degradation ratio up to 99.96% was achieved. Furthermore, a multi-step degradation mechanism was put forward based on FT-IR and GC/MS analysis of degradation products. SEM, FT-IR, and XPS analysis of recycled carbon fibers (RFs) revealed that resin was nearly completely removed. Furthermore, contact angle measurement showed surface wettability of RFs was enhanced. XRD and Raman spectra further verified microstructure of RFs was not damaged drastically. Besides, reusing of degradation products and RFs was explored. Epoxy resin cured with degradation products exhibited excellent performances. Meanwhile, flexural strength tests and SEM images of fracture surfaces showed RFs reinforced epoxy resin composites had superior mechanical strength due to stronger interfaces between fibers and resin. Therefore, an efficient and closed-loop recycling process demonstrated in this manuscript provides a new pathway for degradation and reuse of CF/VER.

Moisture Absorption and Diffusion of a Carbon Composite Structure

Composite materials are lightweight structures and have been wildly used in marine applications. A carbon composite structure usually absorbs moisture while in-service, which can significantly affect its properties, and detriments the overall performance. We perform a detailed study on moisture absorption and diffusion of a carbon fibre reinforced vinyl ester resin composite system. Composite samples are immersed directly in four different solutions at a temperature of 37±0.5℃ for 1444h. The moisture diffusion is analysed through the Fickian diffusion model; the diffusion parameters are subsequently determined from the gravimetric data. The moisture absorption and interaction with the composite constituents are then discussed. These indicate the fundamentals of the moisture absorption and diffusion within the carbon composite structure.

Molecular dynamics simulation of the influence of sizing agent on the interfacial properties of sized carbon fiber/vinyl ester resin composite modified by self-migration method

ABSTRACT The interfacial property of sized carbon fiber reinforced vinyl ester resin (SCF/VE) composite was improved by a self-migration method using acrylamide (AM) as a modifier. A molecular dynamics simulation was performed to study the influence of sizing agent on the interphase formation and the interfacial modification effect. After the system equilibrium, the analysis of monomer distribution shows that an interphase region with thickness of ~2.0–2.5 nm was formed surrounding the fiber surface and the interaction energy was increased obviously. The thickness of this interphase region is obviously larger than that of unsized carbon-reinforced composite (~0.5–1.0 nm). This is mainly due to the sizing agent diffusion to the resin and the strong polar interaction between the sizing agent and AM molecule. As a consequence, the interfacial strength and toughness of the composite were enhanced jointly, which was confirmed by the test of interface shear strength and interlaminar shear strength.

Molecular dynamics simulations of the effect of sizing agent on the interface property in carbon fiber reinforced vinyl ester resin composite

The role of sizing agent in the formation of interphase and the effect on the interfacial properties of carbon fiber (CF) reinforced vinyl ester resin (VE) composite were studied by molecular dynamics (MD) simulations. A novel unsaturated sizing agent N-(4′4-diaminodiphenyl methane)-2-hydroxypropyl methacrylate (DMHM) was used in this study. Epoxy sizing agent (E44) and modified epoxy sizing agent (ME44) were used for comparison. Simulation results showed that DMHM exhibited the highest interfacial bonding strength with CF surface due to the strong polarity of the sizing agent molecule. This result was confirmed by the interfacial shear strength test. The swelling effect of sizing agent in liquid VE was evaluated by solubility in styrene and compatibility with VE component. All three sizing agents had good solubility in styrene according to the calculation of total solvation free energy, while E44 and DMHM exhibited good compatibility with VE molecule based on the mixing energy calculation. The swelling property of sizing agent was confirmed by nano-indentation test. The results of this study explain the higher interfacial shear strength (62.25 MPa) between VE and CF sized by DMHM.

Enhancement of interface performance between shape memory alloy fiber and polymer matrix using silane coupling agent KH550 and Al2O3 nanoparticles

The interface performance of nickel‐titanium (Ni‐Ti) shape memory alloy (SMA) fiber reinforced vinyl ester resin composites was investigated in this work. All the SMA fibers were pre‐treated with H2SO4 and NaOH solution. The fiber surfaces were coated with Al2O3 nanoparticles and silane coupling agent KH550. For comparison, two groups of SMA fibers were coated only with the silane coupling agent or the nanoparticles. Furthermore, the effect of the nanoparticle content on the interface performance of the composites was investigated for Al2O3 nanoparticle contents ranging from 1 wt% to 4 wt%. Scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy (EDX) were used to study the effect of the surface modifications. The results demonstrate that all the modified methods enhance the interface strength of the SMA/vinyl ester resin, but samples with SMA fibers coated with both the silane coupling agent and 3 wt% Al2O3 nanoparticles have the best interface performance. SEM observations show that the dispersion of nanoparticles increases when the silane coupling agent is added to the composites. POLYM. COMPOS., 39:3040–3047, 2018. © 2017 Society of Plastics Engineers

Wear Performance Forecasting of Chopped Fiber–Reinforced Polymer Composites: A New Approach Using Dimensional Analysis

ABSTRACTSolid particle erosion of polymer matrix composites is a complex process in which wear occurs from the target surface by impingement of rigid sand particles in an air medium. The rate of material removal (RMR), also referred to as the erosion rate, mainly depends on target material parameters and the erosion conditions such as impact angle, impact velocity, and erodent size. A new semi-empirical model for prediction of the erosion rate of polymer matrix composites has been developed using a dimensional analysis technique based on Buckingham's π theorem. The predictive model analytically rests upon parameters related to chopped glass fiber composites, erodent (target material properties), and operating variables that mainly affect the erosion process of chopped glass fiber–vinyl ester resin composites. The forecasting ability of the predictive model has been assessed and verified by experimental investigations for chopped glass fiber–reinforced vinyl ester resin (VGF) composites. Validation of the theoretical erosion rates obtained from the predictive model showed that they were in good agreement with the experimentally determined erosion rates, where the average error range was estimated to be ∼10 to ∼20%.

Improving the interfacial properties of carbon fibers/vinyl ester composites by vinyl functionalization on the carbon fiber surface

APMA functionalized CFs can significantly improve the interfacial adhesion properties of the carbon fiber reinforced vinyl ester resin composites.

PROCESSING AND CHARACTERIZATION OF GLASS FIBER AND CARBON FIBER REINFORCED VINYL ESTER BASED COMPOSITES

Composites materials are used in almost all aspects of the industrial and commercial fields in aircraft, ships, common vehicles, etc. Their most attractive properties are the high strength-to-weight ratio.Polymer composites are used because overall properties of the composites are superior to those of the individual polymers. The aim of this experimental study has targeted to investigate the mechanical strength of glass fiber & carbon fiber reinforced vinyl ester resin composites. The laminated specimens were fabricate using Hand lay-up technique. and the specimens are subjected to the investigated as per the ASTM standards. The tensile tests, compression tests, flexural tests were carried out on the laminated specimen for the determination of its mechanical properties.

Evaluation of the Effects of Fluids Upon the Flexural and Parallel-plate Loading Behavior of Glass Fiber Reinforced-vinyl Ester Resin Matrix Composite Pipes

Commercial glass fiber reinforced-vinyl ester resin composite pipes used in onshore and offshore utilities were exposed to the action of fluids that could normally come into contact with them during their service life, namely: salt water, biodiesel and a mixture of water and oil. The influence of these fluids upon the flexural properties and parallel-plate loading behavior of the composites was evaluated. The results of the mechanical tests point out that physical aging was the main phenomenon, and that it causes a reduction of stiffness of around 20-30% – at the parallel-plate test – and a decrease of toughness of up to 40% – at the flexural test. The results of the flexural tests were very dependent of the inhomogeneous microstructure of the commercial composite analyzed.

Desirability Fuzzy Multiple Criteria Optimization of Process Parameters in CNC Turning of GFRP/ Vinyl Ester Composites

Although, Glass fiber reinforced vinyl ester resin is used for the production of many electrical components, automotive structural parts, sporting goods and high performance marine equipments, very little is known about its machining aspects. In this study, a hybrid multiple criteria optimization algorithm involving desirability index and fuzzy inference system coupled with Taguchi methodology is used to evaluate the optimal cutting parameters setting, in order to satisfy contradictory requirements of quality and productivity. Woven fabric based GFRP/ Vinyl ester tubes are finish turned using PCD cutting tool. Four process parameters, each at three levels are selected for the study viz. cutting tool nose radius, cutting speed, feed rate and depth of cut. Individual desirability indices of the three performance measures, viz. surface roughness, tangential cutting force and material removal rate are converted into a single multi-performance characteristics index (MPCI) using fuzzy inference system, which is then optimized using Taguchi analysis.

Thermo-mechanical correlations to erosion performance of short glass/carbon fiber reinforced vinyl ester resin hybrid composites

Abstracts This paper focuses on the erosion of fibre reinforced hybrid composites consisting of vinyl ester resin and short E -glass/carbon fiber (1:1) at different fiber weight fractions (from 20 wt.% to 50 wt.%). A plan of experiments is carried out to investigate the optimal level of control factors using Taguchi orthogonal arrays design that lead to minimization of erosion rate. The steady state erosion responses of these composites are investigated with respect to impingement angle, impact velocity and erodent size by keeping other factors constant. The dynamic mechanical properties were evaluated to determine possible correlation with erosion rate of these composites. The storage modulus ( E ′) steadily increases up to 3927 MPa for 40 wt.% fiber, but on further increase in the fiber content, the E ′ value decrease to 3321 MPa at 0 °C. The maximum storage modulus was obtained at 40 wt.% of fiber contents which may be due to the maximum stress-transfer between the fibers and matrix. Cole–Cole plot of hybrid composites was made at different fiber contents to evaluate the heterogeneity of the system. Finally, a wicket plot is also studied to observe the material behavior, in terms of relaxation of materials. The worn surface of composites were analyzed by scanning electron microscopy (SEM) to observe the mechanism of erosion.

Viscoelastic interpretations of erosion performance of short aramid fibre reinforced vinyl ester resin composites

Short aramid fibre reinforced vinyl ester resin based isotropic composites are fabricated with varying fibre weight fractions (20–50 wt%). The composites were evaluated for their erosion performance under a dynamic set of variables such as impingement angle (30°–90°), impact velocity (43–76 m/s), erodent size (250–600 μm) and stand-off distance (55–85 mm) following design of experiments (DOE) based on Taguchi analysis approach. The thermo-mechanical attributes such as storage modulus, loss modulus and damping properties as viscoelastic responses of the composites were investigated in the temperature range of 0–180 °C for their possible interpretations regarding reinforcement efficiency and energy dissipation aspects relevant to erosion process. An interrelation between the full-width half-maxima (FWHM) of loss modulus peak and erosion rate has emerged indicating the erosion to be mainly controlled by the fibre–matrix interfacial characteristics. The eroded surface morphology investigation by scanning electron microscopy (SEM) revealed the nature of wear-craters, material damage mode and other qualitative attributes responsible in facilitating erosion of the composites.