Fabric Reinforced Vinyl Ester Research Articles

Flexural and Flammability Characteristics of Woven Jute Fabric Reinforced Vinyl Ester Treated with Ammonium Polyphosphate

The work aims to determine the optimum fire-retardant treatment for the jute/vinyl ester composites on the composites' flexural and flammability characteristics. Ammonium polyphosphate deposition in composite samples increased the thickness and weight, which led to an increase in their sample densities. The deposition of 10% ammonium polyphosphate (APP) resulted in the highest flexural strength. However, APP significantly increased the flexural modulus of all samples to the untreated sample. In terms of flammability properties, the deposition of APP increased composites' performance against fire. Incorporating 10% of APP provides good flexural and fire-retardancy properties for the woven jute/vinyl ester composites

Effect of MWCNT Anchoring to Para-Aramid Fiber Surface on the Thermal, Mechanical, and Impact Properties of Para-Aramid Fabric-Reinforced Vinyl Ester Composites

In the present work, para-aramid fabrics (p-AF) were physically modified via an anchoring process of 0.05 wt% MWCNT to the aramid fiber surfaces by coating the MWCNT/phenolic/methanol mixture on p-AF, and then by thermally curing phenolic resin of 0.01 wt%. Para-aramid fabric-reinforced vinyl ester (p-AF/VE) composites were fabricated using p-AF/VE prepregs by compression molding. The effect of MWCNT anchoring on the thermo-dimensional, thermal deflection resistant, dynamic mechanical, mechanical, and impact properties and the energy absorption behavior of p-AF/VE composites was extensively investigated in terms of coefficient of linear thermal expansion, heat deflection temperature, storage modulus, tan δ, tensile, flexural, and Izod impact properties and a drop-weight impact response. The results well agreed with each other, supporting the improved properties of p-AF/VE composites, which were attributed to the effect of MWCNT anchoring performed on the aramid fiber surfaces.

Mechanical and drilling process characterisation of herringbone sisal fabric reinforced vinyl ester sandwich composites

ABSTRACT In the modern trend of industrial progress and technological development a natural fibre polymer composite plays a great demand in many of the structural applications. However, the problems associated with the machining of these composites lead to slowdown the consummations. Out of many machining methods, drilling is one among most repetitively used in the field of composites while joining. This work focused on drilling process optimisation using three different parameters, such as feed rate (mm/min), speed of spindle (rpm), drill diameter (mm). The sisal fibre herringbone pattern reinforced with vinyl ester polymer composite prepared using a conventional compression moulding technique. The results reveal that delamination factor at entry increases at lower (450rpm) and higher (1860,2700) spindle speed for 4 and 12 mm bit diameter, but feed rate various. The delamination factor at exit can be controlled at higher spindle speed (2700 rpm) with lower feed rate (30 mm/min) for 12 mm bit diameter. The drill diameter is having a significant effect on the delamination factor, both the entry and exit of the hole. Result reveals that for 2700 rpm spindle speed, 70 mm/min feed and 10 mm diameter exhibit minimum effort based on grey regression analysis.

Performance of composite materials under high-speed impact in extreme environments

High-speed impact performance of composites of naval relevance is an important issue for analysing the reliability of components of battle ships produced with composite materials that may be subjected to impulsive loads in extreme conditions of temperature and aggressive environments. This paper presents preliminary results of a wide experimental research programme aiming to determine the response and failure of fibre-reinforced polymer composites of naval relevance under high-speed impact in extreme environments. Six different materials have been produced, namely S-2 glass, carbon, mate glass and hybrid glass/carbon woven fabric-reinforced vinyl ester matrix composites. The production method is by infusion of the resin into a vacuum mould. Impact tests have been carried out by shooting steel balls at speeds in the range of 200–600 m/s, approximately, by means of a compressed-gas gun. Impact velocities and residual velocities were measured by a high-speed camera and the corresponding software. Impact tests have been performed at room temperature 25 °C, as well as at low temperature − 50 °C, and high temperature + 50 °C. The whole experimental programme has been repeated by testing specimens previously conditioned by immersion in seawater up to saturation, aiming to analyse the influence of the aggressive environment on the performance of composites under high-speed impact. The experimental results, residual-velocity vs. impact-velocity curves and ballistic limits (impact velocity for 50% probability of target perforation), show no significant differences in the performance of all materials tested, although the best behaviour is observed in non-mixed hybrid glass/carbon reinforcement. On the other hand, saturated specimens show a slightly better behaviour except for low temperatures. Experimental results are compared with predictions of a new analytical model, previously developed by the authors. A good concordance is observed, showing that the analytical model may be a useful tool for predicting the response and failure of fibre-reinforced polymer composites under impact of different threats (fragments, bullets, etc.).

Flammability characteristics of chemical treated woven hemp fabric reinforced vinyl ester composites

In the present work, the treatments using sodium hydroxide, flame retardant chemical and combination of both sodium hydroxide and flame retardant changed the physical properties thus reduced the mechanical properties of woven hemp fabric and fabricated composites. However, the treatments increased the fire retardant properties of fabricated composites as indicated by the burning tests, thermogravimetry analyses and limiting oxygen index tests. An assessment based on woods and engineered wood products have shown that the fabricated composites are suitable to be used for building infrastructure materials as an alternative to wood products.

Static and Dynamic Mechanical Behavior of Hybrid Fibers Composites

Fiber reinforced polymer composites demonstrate essentially better execution over many regular metallic materials in light of their prevalent quality than weight proportion and greaterstiffness. Improvement of properties of FRP composites can be conceivable by the alteration of matrix properties.After the construction work, The static mechanical properties like Inter laminar shear strength and impact strength and dynamic mechanical properties arethe viscoelastic properties such as storage modulus, loss modulus, and tan delta (Damping Behavior) of the materials were deliberated by the Dynamic Mechanical Analysis as a part of temperature of these laminates were experimentally estimated as per ASTM standards for investigate the mechanical behavior of the hybrid fabric reinforced vinyl ester composites are behaved differently on different combination of hybrid fibers and described in detail.

Effect of physical modification of matrix by nano(polyvinyl alcohol) fibers on fatigue performance of carbon fiber fabric-reinforced vinylester composites

The vinylester resins were physically modified by 0.05 and 0.1 wt% nano polyvinyl alcohol fibers with about 80 nm in diameter prepared by electrospinning. Addition of nano polyvinyl alcohol fiber with 0.05–0.1 wt% improved the fracture toughness of vinylester resin slightly by ∼14.3%, while the carbon fiber/vinylester resin adhesion was almost unchanged. Then, carbon fiber/vinylester resin composites were fabricated by using modified vinylester resin as matrix and carbon fiber plain-woven fabrics as reinforcement. Low and high-cycle fatigue tests were conducted under the laboratory condition as well as static tensile tests. The tensile strength of carbon fiber/vinylester resin/polyvinyl alcohol composites increased slightly due to increased resistance to damage propagation at transverse bundles and resin-rich region. The fatigue properties of carbon fiber/vinylester resin composites were improved significantly by 3–50 times with the addition of no more than 0.1 wt% nano polyvinyl alcohol fibers. Due to the incorporation of nano filler, damage degree in carbon fiber/vinylester resin/polyvinyl alcohol composite was reduced at the fatigue initial stage based on thermoelastic stress damage analysis. Furthermore, a delay of delamination growth was found as well at the fatigue middle stage according to CT-scan and scanning electron microscopy investigation. The resistance to fatigue damage accumulation due to energy absorption by the addition of nano fiber contributed to fatigue life extension.

A strategy and mechanism of fabricating flame retarding glass fiber fabric reinforced vinyl ester composites with simultaneously improved thermal stability, impact and interlaminar shear strengths

Poor flame retardancy, even worse than that of their matrix, is the common bottleneck for glass fiber (GF) reinforced polymeric composites (GFRPs), however, overcoming this problem generally degrades other performances of GFRPs. Herein, new GF fabric (PHSi-g-GF) grafted with phosphorus-containing hyperbranched polysiloxane (PHSi) through grafting-from technique, and new matrix (PSiVE) consisting of vinyl ester matrix (VE) and PHSi were prepared to develop new composites; meanwhile other three kinds of composites (GF/VE, PHSi-g-GF/VE, GF/PSiVE), of which at least one composition (matrix or fabric) is the original one, were also fabricated. The flame retardancy, thermal and mechanical performances of these composites were intensively studied and compared. Results show that PHSi-g-GF/VE and GF/PSiVE composites have much better integrated performances than GF/VE composite. Interestingly, the PHSi-g-GF/PSiVE composite has the best flame retardancy, for example, compared with GF/VE composite, PHSi-g-GF/PSiVE composite has 7 s longer time to ignition and 34% lower peak of heat release rate as well as 13% higher limited oxygen index and much higher UL-94 grade. This is originated from the unique dual flame retarding mechanisms in both gaseous and condensed phases. In addition, PHSi-g-GF/PSiVE composite has significantly improved thermal stability, 14% higher interlaminar shear and 60% higher impact strengths than GF/VE composite, completely overcoming the common problems of GFRPs. The presence of PHSi provides good interaction between GF and matrix as well as toughening effect on VE resin due to the flexible Si–O–Si chain and cavity structure of PHSi. These attractive improvements in the performances of PHSi-g-GF/PSiVE composite demonstrate that the method and mechanism provided herein are effective to develop high performance GFRPs.

Mode‐I intralaminar fracture toughness of silica particles‐filled glass woven fabric‐reinforced vinyl ester composites

AbstractGlass woven fabric reinforced vinyl ester (GV) composites filled with different weight proportions of silica particles were fabricated by hand lay up technique followed by oven curing. The plane strain Mode‐I Intralaminar fracture toughness, KIC of the silica filled GV composites has been studied and the experimental results were compared with those of unfilled GV composites. The findings of the experiments showed that the fracture toughness has improved by the addition of silica particles up to 6 weight % with marginal increase of tensile properties. The silica filled and unfilled GV composites showed brittle fracture, with maximum toughness for 6 weight % silica particles. The morphology of fracture surfaces was examined by using SEM. Pulled and fractured fibers are observed on the fracture surface of GV composites evidencing fiber bridging but not in the silica filled GV composites. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

Relation between Impact Properties and Interfacial Strength of UHMWPE/VE Composites

This study presents impact properties and interfacial strength of Ultra-high molecular weight polyethylene fiber plain woven fabric reinforced vinyl ester composites with different matrix volume fraction. The interfacial strength was found to be decreased by reducing the matrix volume fraction. Stress, strain and energy absorption per thickness in the impact process were evaluated and the relation between these impact parameters and interfacial strength of the laminates were investigated. The maximum stress was decreased and the maximum strain was increased with the drop of interfacial bonding strength. The experiment results also revealed that the sample with a matrix volume fraction 23% showed higher energy absorption than other ones.

Performance analysis of waste silk fabric-reinforced vinyl ester resin laminates

Laminates of vinyl ester resin system with different weight fractions of waste silk fabrics ‘as reinforcement’ are developed and their physico-mechanical properties are studied, using standard procedure. Both, tensile strength and modulus of laminates were found to increase with the increase in weight fraction of silk fabric loading. Properties such as density, void content, hardness, and water absorption of the developed composite laminates are studied. Chemical resistance test is also carried out. Attempts to explain these differing trends are made in this study by analyzing the features observed on the cross-section of tensile fractured specimen using fractography employing scanning electron microscopy.

The properties of vinyl ester composites reinforced with different types of woven fabric and hollow phenolic microspheres

This study compares the effects of hollow polymeric microspheres (PHMS) on specific mechanical properties and thermal properties of glass, basalt, and carbon woven fabric reinforced vinyl ester composites. The specific flexural and specific impact strengths of the composites were marginally increased with the addition of PHMS; however, it was at the expense of reduced specific flexural modulus. The thermal stability of the neat vinyl ester was improved with the addition of woven glass and carbon, but was consequently reduced with the further inclusion of PHMS. SEM observations identified the presence of the combined failure mechanism of fibers and PHMS. In short, the major reinforcing effect of the woven fiber-reinforced vinyl ester composites is governed by the type of fiber used, while the addition of PHMS enhanced the ductility of the composites.

Evaluation of the friction and wear properties of PTFE composites filled with glass and carbon fiber

AbstractThe aim of the research article is to study the mechanical and two‐body abrasive wear behaviour of glass/carbon fiber reinforced PTFE composites. The measured wear volume loss increases with increase in abrading distance. The results showed that the highest specific wear rate is for glass fiber reinforced PTFE composite with a value of 8.1×10–6 mm3/Nm and the lowest wear rate is for carbon fabric reinforced vinyl ester composite with a value of 7.2×10–6 mm3/Nm. Mechanical properties were evaluated and obtained values are compared with the wear behaviour. The worn surface features have been examined using scanning electron microscope (SEM). Photomicrographs of the worn surfaces revealed higher percentage of broken glass fiber as compared to carbon fiber.

Friction and dry sliding wear behavior of carbon and glass fabric reinforced vinyl ester composites

Friction and dry sliding wear behavior of glass and carbon fabric reinforced vinyl ester composites have been presented. The results show that the coefficient of friction and wear rate increased with increase in load/sliding velocity and depends on type of fabric reinforcement and temperature at the interphase. The excellent tribological characteristics were obtained with carbon fiber in vinyl ester. It is believed that a thin film formed on counterface was seems to be effective in improving the tribological characteristics. The worn surfaces examined through SEM, showed higher levels of broken glass fiber in vinyl ester compared to carbon–vinyl ester composites.

Investigations on mechanical and two-body abrasive wear behaviour of glass/carbon fabric reinforced vinyl ester composites

The aim of the research article is to study the mechanical and two-body abrasive wear behaviour of glass/carbon fabric reinforced vinyl ester composites. The measured wear volume loss increases with increase in abrading distance/abrasive particle size. However, the specific wear rate decreases with increase in abrading distance and decrease in abrasive particle size. The results showed that the highest specific wear rate is for glass fabric reinforced vinyl ester composite with a value of 10.89 × 10 −11 m 3/Nm and the lowest wear rate is for carbon fabric reinforced vinyl ester composite with a value of 4.02 × 10 −11 m 3/Nm. Mechanical properties were evaluated and obtained values are compared with the wear behaviour. The worn surface features have been examined using scanning electron microscope (SEM). Photomicrographs of the worn surfaces revealed higher percentage of broken glass fiber as compared to carbon fiber. Also better interfacial adhesion between carbon and vinyl ester in carbon reinforced vinyl ester composite was observed.

Three-Body Abrasive Wear Behaviour of Fiber Reinforced Vinyl Ester Composites

Fiber reinforced polymer composites are generally known to possess high strength and attractive wear resistance in dry sliding conditions. The behaviour of such composites performing in abrasive wear situations needs a proper understanding. Hence, in the present work of the three-body abrasive wear behaviour of two dimensional stitched carbon fabric, E-glass woven fabric and three dimensional E-glass woven fabric reinforced vinyl ester composites was investigated. Three-body abrasive wear tests were conducted using rubber wheel abrasion tester (RWAT) under different abrading distances at two loads, wherein the wear volume loss were found to increase and that of specific wear rate decrease. The results indicate that the type of fabric in vinyl ester have a significant influence on wear under varied abrading distance/loads. Further, it was found that carbon fabric reinforced vinyl ester composite exhibited lower wear rate compared to E-glass woven fabric reinforced vinyl ester composites. The worn surface features, as examined through scanning electron microscope (SEM), show higher levels of broken glass fiber in two dimensional glass woven fabric reinforced vinyl ester composite compared to carbon fabric and three dimensional glass fabric reinforced vinyl ester composites.

Mechanical and three-body abrasive wear behaviour of three-dimensional glass fabric reinforced vinyl ester composite

The mechanical and three-body abrasive wear behaviour of two- and three-dimensional E-glass woven fabric reinforced vinyl ester composites were studied in this article. The mechanical properties were evaluated using universal testing machine as per ASTM D-638. Three-body abrasive wear tests were conducted using rubber wheel abrasion tester (RWAT) under different abrading distances at two loads, wherein the wear volume loss were found to increase and that of specific wear rate decrease. The results indicate that the three-dimensional glass woven fabrics in vinyl ester (G 3D–V) have significant influence on wear under varied abrading distance/loads. Further, it was found that G 3D–V composite exhibited lower wear rate compared to two-dimensional glass woven fabric reinforced vinyl ester (G 2D–V) composite. The worn surface features, as examined through scanning electron microscope (SEM), show ruptured glass fiber in G 2D–V composite compared to G 3D–V composites.

Compressive behavior of biaxial spacer weft knitted fabric reinforced composite at various strain rates

AbstractThe in‐plane and out‐of‐plane compressive properties of biaxial weft knitted E‐glass fabric reinforced vinyl ester composite at quasi‐static strain rate of 0.001/s and high strain rates from 700/s to 2200/s were tested to investigate the strain rate effect on the compressive behavior. The compressive tests were conducted on split Hopkinson pressure bar at high strain rate and on MTS 810.23 system at quasi‐static state. The experimental results indicated the strain rate sensitivity of compressive stiffness, failure stress, and strain of the composite in both out‐of‐plane and in‐plane compressive direction. The compressive stiffness and failure stress linearly increased with the increase of strain rate. The failure strain linearly decreased with the increase of strain rate. As the strain rate increased, the main failure mode at out‐of‐plane compression is the interlaminar shear failure and at in‐plane direction is the delamination. At the high strain rate of 2200/s, the composite coupon was compressed into debris with the shear or delamination failure. POLYM. COMPOS., 28:224–232, 2007. © 2007 Society of Plastics Engineers

Effects of Fibre Surface Treatment on Dynamic Tensile Properties of Glass Woven Fabric Reinforced Vinylester Composites

Glass fibre has been recognized as a strain rate dependent material. Its failure behaviour changes from brittle to ductile as the strain rate increases. As a consequence, the strength of the glass fibre increases, but the fibres within a composite become more prone to debond from the matrix because of the brittleness of the matrix material, promoted by the high strain rate. In the present study, the tensile responses of glass woven fabric reinforced vinyl ester composites with various fibre surface treatments are examined under static and dynamic loading conditions. The results show that both the ductility and the strength of the composites increased with increasing strain rate. The tensile strength was lower and the failure strain was higher in the weft direction than in the warp direction, because of excessive crimping in the former direction. The tensile strength in general increased with increasing silane concentration, for the majority of strain rates studied. The influence of fibre surface treatment on the impact tensile strength and modulus of composites were functionally similar, confirming the influence of fibre-matrix interphase properties on composite fracture behaviour at high strain rates.

Micromechanical Models for Damping in Woven Fabric-Reinforced Polymer Matrix Composites

This paper describes the development of a finite element model and a closed-form model for studying viscoelastic damping in woven fabric-reinforced polymer matrix composites. The finite element model was based on the actual geometric configuration of a plain weave fabric-reinforced composite unit cell, and the damping loss factors were determined from a strain energy formulation. The closed-form model was developed by first deriving an approximate elastic solution based on the mechanics of materials theory, then applying the Elastic-Viscoelastic Correspondence Principle to the elastic solution. The damping loss factors were then determined from the viscoelastic solution. Experiments were conducted using an impulse-frequency response technique to measure damping in beam samples made of plain weave E-glass fabric-reinforced vinyl ester resin matrix composite. The predictions from both analytical models show reasonably good agreement with experimental data.