Vinyl Ester Resin Composites Research Articles

Wetting properties and performance test of modified rigid collector in wet electrostatic precipitators

ABSTRACTThe fine particles are considered a significant pollution problem. The wet electrostatic precipitators (ESPs) have advantages of efficient collection of the fine particles with lower pressure drop and eliminating reentrainment. The wetting properties of the collector surfaces have significantly important effect on wet ESPs’ stable and secure operation. The modified rigid collector (MRC) was modified by coating specific vinyl ester resin composites and loose glass fiber cloth over the conventional carbon steel in a certain way. The rigid collector surfaces before and after modification had been characterized by scanning electron microscopy (SEM) and interface tensiometer. The effect of operating temperatures on the wetting properties of the rigid collector surfaces before and after modification was investigated. The temperature range was 40~90 °C, and the wetting properties contained liquid holdup, surface flow rate, film rate, average film thickness, and critical saturation time. The modified rigid collector surface exhibited excellent wetting properties at the operating temperatures. The fine particles collection performance compared among the MRC, the conventional rigid collector (CRC), and the flexible collector (FC) in the wet ESPs was investigated. The effects of the applied voltage, the water film, corona power, and the specific collecting area on the fine particles collection were evaluated. The modified rigid collector provided high fine particles collection effect with lower energy and water consumption.Implications: To improve the submicron particles collection efficiency and decrease energy and water consumption, the formation of uniform water film over the collector surfaces has been widely studied. The modified rigid collector was modified by coating specific vinyl ester resin composites and loose glass fiber cloth (ERGF) over the conventional carbon steel (CCS) in a certain way. The modified rigid collector surface exhibited excellent wetting properties. The wet ESPs by the modified rigid collector exhibited significantly higher particles collection efficiency than by the conventional rigid collector.

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.

Characterization of aerosols and fibers emitted from composite materials combustion

This work investigates the aerosols emitted during combustion of aircraft and naval structural composite materials (epoxy resin/carbon fibers and vinyl ester/glass fibers and carbon nanotubes). Combustion tests were performed at lab-scale using a modified cone calorimeter. The aerosols emitted have been characterized using various metrological devices devoted to the analysis of aerosols. The influence of the nature of polymer matrices, the incorporation of fibers and carbon nanotubes as well as glass reinforcements on the number concentration and the size distribution of airborne particles produced, was studied in the 5nm–10μm range. Incorporation of carbon fibers into epoxy resin significantly reduced the total particle number concentration. In addition, the interlaced orientation of carbon fibers limited the particles production compared to the composites with unidirectional one.The carbon nanotubes loading in vinyl ester resin composites influenced the total particles production during the flaming combustion with changes during kinetics emission. Predominant populations of airborne particles generated during combustion of all tested composites were characterized by a PN50 following by PN100–500.

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.

Synthesis and Characterization of Mineral Wollastonite Particulate Filled Vinyl-Ester Resin Composites

In the present research presents influence of coupling agent 1 % triethoxymethyl silane sprayed on to the wollastonite particulate powder before it dispersed into the vinylester/composites. Firstly two different composites were developed in which wollastonite is filled with vinylester resin and same wollastonite was sprayed with coupling agent 1 % triethoxymethyl silane then filled with vinylester resin. The particle functionalization with a bi-functional coupling agent 1 % triethoxymethyl silane was observed to have a significant effect on the curing process and subsequent physical properties of the composites. Wollastonite functionalization favors the composite fabrication with a lower curing temperature as compared to the as-received particle filled vinyl ester resin composites. Thermogravimetric analysis showed an increased thermo-stability in the particles functionalized filled vinyl ester resin composites as compared to the unmodified particle filled counterparts. The uniform particle dispersion and the chemical bonding between filler and vinyl ester resin matrix were found to contribute to the increased thermal stability and enhanced tensile strength and modulus.

Synthesis and Characterization of Mineral Wollastonite Particulate Filled Vinyl-Ester Resin Composites

In the present research presents influence of coupling agent 1 % triethoxymethyl silane sprayed on to the wollastonite particulate powder before it dispersed into the vinylester/composites. Firstly two different composites were developed in which wollastonite is filled with vinylester resin and same wollastonite was sprayed with coupling agent 1 % triethoxymethyl silane then filled with vinylester resin. The particle functionalization with a bi-functional coupling agent 1 % triethoxymethyl silane was observed to have a significant effect on the curing process and subsequent physical properties of the composites. Wollastonite functionalization favors the composite fabrication with a lower curing temperature as compared to the as-received particle filled vinyl ester resin composites. Thermogravimetric analysis showed an increased thermo-stability in the particles functionalized filled vinyl ester resin composites as compared to the unmodified particle filled counterparts. The uniform particle dispersion and the chemical bonding between filler and vinyl ester resin matrix were found to contribute to the increased thermal stability and enhanced tensile strength and modulus.

Assessment of morphological, thermal, and viscoelastic properties of epoxy vinyl ester coating composites: Role of glass flake and mixing method

In this work, glass flake (GF)/epoxy vinyl ester resin composites were fabricated with various compositions and mixing methods. The effect of GF on thermal and mechanical behavior of these composites was investigated using different techniques such as differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and thermogravimetric analysis (TGA). The results showed that the presence of GF in epoxy vinyl ester formulation could obviously affect the cure temperature, reaction enthalpy value, and degradation temperature. DMTA results also exhibited that the tanδ peak area decreased and storage modulus increased with increasing GF content and this effect seemed to be different depending on the initial epoxy vinyl ester compositions. The scanning electron microscopy (SEM) images showed that mixing method had a strong effect on the surface morphology, size, and distribution of glass flake. The effect of mixing method on properties of produced composite was also studied.

Effect of nano silica fillers on mechanical and abrasive wear behaviour of vinyl ester resin

In this paper, influence of different nano particles such as ……….. on the wear behavior of a vinyl ester resin composites is reported. Nano silica particles, functionalized with a bi-functional coupling agent, methacyloxypropyl-trimethoxysilane (MPS) is found to improve the wear resistance as well as the tensile strength of the fabricated vinyl ester resin nano composite. The uniform particle dispersion and chemical bond between nano particle and vinyl ester resin was observed. Wear behavior of the resin with silica, zinc oxide and alumina nano particles were studied using taber abrasive wear tester. Wear test was conducted for different load conditions and distances. Experimental result showed that vinyl ester resin with nanosilica particles had significantly improved the wear resistance than alumina and zinc oxide nancomposites.

The Mechanical Properties of Jute Fiber Mats Reinforced Vinyl Ester Resin Composites

Surfaces of jute fiber needled mats were treated by alkali, potassium permanganate and A-151 silane coupling respectively, and those reinforced vinyl resin composites were made by VARTM method . The changes of the surface energy of the jute fiber mats were analyzed basing on the dynamic contact angle, and the surface of the jute fiber and the interface morphology of the composites were observed by SEM. The results showed that interface compatibility and the comprehensive properties of the composites were improved evidently, because the surface energy of the jute fiber was lowered and the surface micro-structures of the fiber were changed. Especially, the tensile strength and flexural strength of the composites treated by A-151 silane coupling increased by 63.08% and 94.79% respectively.

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.

Influence of temperature on styrene emission from a vinyl ester resin thermoset composite material

Composite materials made with vinyl ester resins are lighter, stronger and corrosion resistant compared to most metals, and are increasingly being used as building materials and in public transportation. Styrene monomer is used as both a diluent and strengthener in the production of vinyl ester resin (VER) composites. Some researchers contend that free styrene in VER composites is available to diffuse out of the material into air, perhaps leading to adverse health effects via inhalation exposures in humans, yet there is no known data on styrene emissions from these materials in the literature. In this study, a typical VER composite made with resin containing 38% by weight styrene, reinforced with E-glass fiber and formed using a vacuum assisted resin transfer method was characterized for styrene emissions by environmental test chamber (ETC) methodology. Styrene concentrations in the ETC were measured over a temperature range of 10 to 50°C. Initial evaporative styrene emissions increase with increasing temperature. There is a nearly linear relationship in the total mass of styrene emitted and emission factor as emissions increase with increasing temperature. Styrene emission factors appear to vary for different materials, which could indicate more complex processes or the influence of material physical properties on emission rates. These results can be used to validate and improve mass transfer emission models for the prediction of volatile organic compound concentrations in indoor environments.

Influence of Carbon Nanotubes on Mechanical and Thermal Properties of Glass Fiber Reinforced Vinyl Ester Resin Composites

Carbon nanotubes (CNTs) were incorporated into glass fiber/ vinyl ester resins composites to improve their mechanical and thermal properties, especially the interlaminar shear and longitudinal compressive strengths which are belong to the matrix-dominanted properties and much weaker than the fiber-dominated properties. In this study, a higher temperature initiator was added to improve the polymerization degree and raise the transition temperature (Tg). Mechanical testing indicated that by adding 0.4 wt% CNTs, the nano-filled composites attributed to 21%, 16%, 10%, and 8% improvement in interlaminar shear strength, compressive strength, tensile strength and flexural strength with respect to their counterparts without CNTs, respectively. Moreover, Thermogravimetric analysis (TGA) also exhibits approximately 14°C higher decomposition temperature than those of conventional composites.

Thermal properties of sawdust reinforced vinyl ester composites post-cured in microwaves: A pilot study

The mechanical properties of sawdust reinforced vinyl ester resin composites post-cured in microwaves have been measured and evaluated in earlier studies. This basic but critical and important data have caused interests in the relevant industry in Australia. This study is therefore carried out to measure and evaluate the thermal properties of the composites with a view to benefit the civil and construction industry as the materials are used in the industry. The original contributions of this paper are that samples post-cured in microwaves, irrespective of the percentage by weight and particle size of sawdust, have higher glass transition temperatures than their counterparts post-cured in an oven; these imply that the stiffness of the samples post-cured in microwaves are higher than their peers. From previous study, it was discovered that the fracture toughness increased with increasing particulate loading. These properties are vital in civil engineering applications because civil structures need composites with high rigidity and fracture toughness. It is hoped that the discussions and results in this work would not only contribute towards the development of sawdust reinforced vinyl ester composites with better material properties, but also useful for the investigations of thermal and mechanical properties in other composites.

Thermo-mechanical correlations to erosion performance of short carbon fibre reinforced vinyl ester resin composites

Thermo-mechanical properties and erosion performance of short carbon fibre reinforced vinyl ester resin based isotropic polymer composites with four different fibre weight fractions have been investigated. The storage, loss and damping characteristics were analysed to assess the energy absorption/viscous recoverable energy dissipation and reinforcement efficiency of the composites as a function of fibre content in the temperature range of 0–140°C. The composite with 30wt.% of short carbon fibres has been observed to exhibit superior thermo-mechanical response with highest energy dissipation/damping ability accompanied with a constant storage modulus without any substantial decay till 60°C. The erosion rates (Er) of these composites are evaluated at different impingement angles (30–90°), fibre loadings (20–50wt.%), impact velocities (43–76m/s), stand-off distances (55–85mm) and erodent sizes (250–600μm) following the erosion test schedule in an air jet type test rig. An optimal parameter combination is determined and subsequently validated for erosion rate minimization following Taguchi method and by conducting confirmation experiments. A correlation between the loss-modulus inverse and the erosion rate has been observed which conceptually establishes a possible mechanistic equivalence between erosion and dynamic mechanical loading modes. The morphologies of eroded surface are examined by the scanning electron microscopy to investigate the nature of wear-craters, material damage mode and other qualitative attributes responsible for promoting erosion.

Mechanical and Wear Characterization of GF Reinforced Vinyl Ester Resin Composites with Different Co-Monomers

This article reports the mechanical characterization and sliding wear behavior of glass fiber-reinforced vinyl ester resins of varying acid values, based on epoxy-novalocs in the presence of three different comonomers (styrene, methyl acrylate and butyl acrylate) as reactive diluents. It presents a special account of the optimization of fabrication techniques of glass fiber-reinforced vinyl ester resin composites. It outlines optimum reaction conditions such as temperature, time, monomer type and initiator concentration. The experimental plan consisted of preparation of vinyl ester resin followed by the composite samples. Mechanical characterization was done and a comparison was made between the different samples. It was found that these composites have fairly good tensile and flexural properties. The composites with styrene and butyl acrylate as co-monomers had similar tensile strength which was higher than that of the composite with methyl acrylate. Hardness values of the three composites were almost the same without any significant effect of the comonomer type. Volumetric wear rate was estimated for these samples under various test conditions. A steady wear rate regime after certain amount of sliding was observed all the three cases.

Properties and performance of fire resistant eco-composites using polyhedral oligomeric silsesquioxane (POSS) fire retardants

Fire retardants are combined with polymer resins to reduce their flammability, decrease production of volatiles and inhibit pyrolysis. The goal of this work is to develop environmentally friendly fire retardant vinyl ester resin composites by blending fatty acid vinyl ester (FAVE) resins with environmentally friendly particulate fire retardants: polyhedral oligomeric silesquioxanes (POSS), while comparing them to similar composites with talc, a standard inorganic filler. Various concentrations of POSS or talc filler were blended into commercial and FAVE brominated vinyl ester resins, Derakane 510A-40 and FAVE-Br, respectively, and commercial and FAVE non-brominated vinyl ester resins, Derakane 441-400 and FAVE-L, respectively. Thermo-mechanical characterization of the new eco-composites was conducted using dynamic mechanical analysis and thermo-gravimetric analysis. Most POSS additives performed no better than talc in improving the composite performance relative to that of the neat resin. Yet, composites reinforced with methacryl POSS (MA0735) slightly outperformed the other POSS additives and talc. This POSS additive maintained resin viscosity, improved T g , increased cross-link density, and increased flame retardance. However, the flame retardance of even this relatively high performing POSS-filled composite was very poor compared to that of brominated resins and the thermo-mechanical improvements relative to talc were small.

Cyclic fatigue behavior of carbon fiber reinforced vinylester resin composites manufactured by RTM and VARI

The mechanical behavior of [0°] 8 unidirectional, [+45°/0°/−45°/90°] S quasi-isotropic and [+45°/−45°] 3S angle-ply laminates produced by pressure or vacuum assisted resin infusion from toughened vinylester resin systems with unidirectional carbon fiber fabric reinforcement was investigated. The study included the determination of ultimate in-plane tension, compression and shear properties as well as the characterization of the cyclic fatigue behavior under stepwise increasing and constant amplitude loading. The experimental results showed a better fatigue performance of an epoxy-terminated butadiene-nitrile rubber modified VE resin system. Furthermore, the cyclic strength of the composites produced by VARI was lower compared to RTM composites. From the S– N curves of the quasi-isotropic material for R = +0.1, −1 and +10 the fatigue life diagram was determined.

Effect of the defect concentration on the impact fatigue endurance of untreated and alkali treated jute–vinylester composites under normal and liquid nitrogen atmosphere

A comparative impact fatigue study has been made for the first time on the untreated and alkali treated, 35% jute fibres in the vinylester resin composites under normal room temperature and liquid nitrogen atmosphere respectively. The jute fibres were alkali treated in a 5% concentration for 4 and 8 h before preparing the longitudinally aligned pultruded composites. The calculated defect concentrations in the composites reinforced with the untreated, 4 and 8 h alkali treated jute fibres were 30%, 18.5%, and 28.5%, respectively. Under normal room temperature the presence of such defects proportionately improved the endurance of the composites acting as a damper to the shock waves produced by the repeated impacts. Whereas, under the liquid nitrogen atmosphere the defects with higher concentration in particular, displayed an inverse role having provided more sites for the adsorbed moisture to form ice facilitating the initiation of cracks, thus lowering its endured number of cycles. A relationship in the form of nlog E I = C−log N was established to describe the impact fatigue curves of the composites. From the relationship, the value of the material character ( C) was obtained. The value of the fatigue resistance parameter ( n) were found to vary considerably with the defect concentration between the samples tested under the normal and the liquid nitrogen environment.

Surface modification of ultrahigh‐molecular‐weight polyethylene fibers

AbstractTo prevent the loss of fiber strength, ultrahigh‐molecular‐weight polyethylene (UHMWPE) fibers were treated with an ultraviolet radiation technique combined with a corona‐discharge treatment. The physical and chemical changes in the fiber surface were examined with scanning electron microscopy and Fourier transform infrared/attenuated total reflectance. The gel contents of the fibers were measured by a standard device. The mechanical properties of the treated fibers and the interfacial adhesion properties of UHMWPE‐fiber‐reinforced vinyl ester resin composites were investigated with tensile testing. After 20 min or so of ultraviolet radiation based on 6‐kW corona treatment, the T‐peel strength of the treated UHMWPE‐fiber composite was one to two times greater than that of the as‐received UHMWPE‐fiber composite, whereas the tensile strength of the treated UHMWPE fibers was still up to 3.5 GPa. The integrated mechanical properties of the treated UHMWPE fibers were also optimum. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 463–472, 2004

Impact fatigue behaviour of carbon fibre-reinforced vinylester resin composites

Two types of unidirectional carbon fibre, one of high strength (DHMS) and another of medium strength (VLMS) reinforced vinylester resin composites have been examined for their impact fatigue behaviour over 104 impact cycles for the first time. The study was conducted using a pendulum type repeated impact apparatus specially designed and constructed for the purpose. A well-defined impact fatigue behaviour (S-N type curve) curve has been demonstrated. It showed a plateau region of 10–102 cycles immediately below the single cycle impact strength, followed by progressive endurance with decreasing impact loads, culminating in an endurance limit at about 71% and 85% of the single impact strength for DHMS-48 and VLMS-48, respectively. Analysis of the fractured surfaces revealed primary debonding, fibre breakage and pull-out at the tensile zone of the samples and a shear mode of fracture with breakage of fibre bundles at the compressive zone of the samples. The occurrence of a few major macrocracks in the matrix with fibre breakage at the high load-low endurance region and development of multiple microcracks in the matrix, coalescing and fibre breakage at the low-load-high endurance region have been inferred to explain the fatigue behaviour of the composites examined.