Vinyl Ester Research Articles

Enhancing sustainable composites: isolation of nanocellulose from Selenicereus undatus (dragon fruit) and kenaf fiber reinforcement in vinyl ester matrix—a study on mechanical, wear, fatigue, creep, and dynamic mechanical properties

Enhancing sustainable composites: isolation of nanocellulose from Selenicereus undatus (dragon fruit) and kenaf fiber reinforcement in vinyl ester matrix—a study on mechanical, wear, fatigue, creep, and dynamic mechanical properties

Mechanical investigation for enhancing jute fibre vinyl ester composite performance through garnet waste utilization

This study explores the potential utilization of garnet waste, a byproduct of the Abrasive Water Jet Machining process, as a promising filler material in composite manufacturing. The disposal of garnet waste presents significant environmental and economic challenges, underscoring the need for sustainable waste management strategies. To tackle these challenges, this research investigates the incorporation of garnet waste into composites to create value-added materials. Consequently, the study focused on developing garnet-filled jute fibre-reinforced vinyl ester composites using the hand layup method. Various mechanical properties including flexural strength, tensile strength, hardness, and impact strength were assessed. The findings demonstrate that the inclusion of garnet filler enhances the mechanical strength of the composites. Particularly, composites containing 10 wt% garnet exhibit notable improvements in tensile, flexural, impact, and hardness strengths, with increases of 40%, 124%, 26%, and 15%, respectively. This research has the potential to advance the development of advanced materials across diverse industries, marking a significant stride towards sustainable and value-driven composite manufacturing practices.

The effect of span length on the flexural properties of glass and basalt fiber reinforced sandwich structures with balsa wood core for sustainable shipbuilding

The current research aims to analyze the mechanical characterization of sandwich materials through a three-point flexural test. The sandwich structures in question composed of balsa wood as a core and four different types of fiber reinforced vinyl ester composite facesheets, namely Glass, Basalt, Glass/Carbon, and Basalt/Carbon. The sandwich panels were prepared using the vacuum infused processing method. The primary objective of this investigation is to explore the feasibility of utilizing basalt fibers for the production of structural parts in shipbuilding and replacing the already existed glass fibers. The flexural test was carried out with using three-point flexural test with varying the span length from 120 mm, 180 mm, 220 mm. Additionally, an analysis of variance (ANOVA) was then carried out to compare the mean values of properties deduced from these tests. The results showed that using basalt fibers instead of glass fiber reinforced enhanced the flexural stiffness of the sandwich structure. The flexural strength and modulus are shown to depend on span length and fiber type. The flexural modulus increases with an increase in span length. Similarly, flexural strength increases in glass fiber-based structures, while a slight reduction is observed in basalt fiber-reinforced structures the larger span length. The findings of this research suggest that basalt fibers hold potential as a replacement for glass fibers in producing structural components in shipbuilding. These results offer valuable information that can aid in the design and optimization of sandwich materials in shipbuilding.

Characterization of vinyl ester–based biocomposites using grape stalk lignin biopolymer and Celosia cristata stem fibers: a characterization study

Characterization of vinyl ester–based biocomposites using grape stalk lignin biopolymer and Celosia cristata stem fibers: a characterization study

A study on: Design and fabrication of E-glass fiber reinforced IPN composite chain plates for low duty chain drives

Chains are used in mechanical drives to carry away a large amount of load from one drive to another drive. Therefore the material of the chain should be able to withstand tensile loads and have high stiffness. Usually the chains are made up of iron. But the disadvantage is that iron consumes more weight and it is more expensive. In order overcome the difficulties, the chain plates are fabricated with the help of Interpenetrating Polymer Networks (IPNs) resins (with vinyl ester and polyurethane) and reinforced E-glass fiber composite material. The main aim of the project is to study and analyze the physical properties and structural properties of the plate material varying proportions of IPN resin such as 100% vinyl ester (VEU) with 0% polyurethane (PU), 90% VEU and 10% PU, 80% VEU and 20% PU, 70% VEU and 30% PU, 60% VEU and 40% PU. Finally a fatigue tests is conducted for different plates for different resin proportion and comparison is made between the characteristics of fabricated chain plate with that of iron material. Because of their dependability and durability, glass fibre reinforced composite link plates are used in material handling equipment, agricultural machinery, manufacturing conveyors, and automobile manufacture.

Effect of Geometry and Size of Fiber Reinforced Plastic Deck Profile on Behavior of Bridges

Due to the important role that bridges play in rescue operations after an earthquake, it is necessary that these structures have a higher level of protection against seismic attacks. Earthquake identifies the weak points of the structure and causes the most damage there. Bridges are very vulnerable to these attacks due to their low degree of uncertainty. All bridges built before 1971 were designed with the elastic design method (permissible stress). In this method, the effects of plasticity, section cracking, and plastic deformation are not taken into account. The change of seismic locations based on the principles of elastic design is much less. It is because the structure experiences in a real earthquake, one of the consequences of which is the falling of the decks due to the loss of the support surface. The decision to strengthen the bridge was made when there were many bending and shear cracks on the king beams. The bridge was created. The use of FRP profiles can significantly prevent the damage caused by corrosion and is a good alternative to the traditional methods of strengthening the structure. In this study, a design for the deck of a steel bridge with I beams is presented. The shape of reinforcement using FRP fibers with vinyl ester resins has also been investigated, the effect of the geometry of FRP profiles has been investigated. The presented specifications are optimized to obtain a lasting shape and section, especially for the pultrusion process. FRP materials are light, resistant to corrosion and have high tensile strength. These materials come in different forms and range from multi-layer factory sheets to dry sheets that can be twisted on various structural forms before adding resin, is available. The durability and high tensile strength of FRP materials are among the advantages of these materials. The durability and long-term performance of FRP requires more research, which is ongoing and continues.

Flame-retardant vinyl ester resins enabled by phosphorus-containing 1-vinylimidazole salts with different phosphorus oxidation states

Different reactive flame retardants have been extensively developed for vinyl ester resins (VERs), but very few of them can yield a flame-retardant resin that meets defined standards (e.g. UL-94 V-0 rating). In this work, phosphorous-containing 1-vinylimidazole salts (called VIDHP and VIDPP) were synthesized through the facile neutralization of the acid and 1-vinylimidazole. VIDHP and VIDPP were then applied as flame-retardant crosslinking agents of VERs, by which phosphorus-containing groups could be incorporated into the resin chain via ionic bonds. VIDHP/VER and VIDPP/VER showed a high curing activity and can be well cured in moderate temperatures. With 20 wt.% additions of VIDHP and VIDPP, VIDHP20/VER, and VIDPP20/VER presented a limiting oxygen index value of 29.7 % and 28.4 %, respectively, with the latter achieving a UL 94 V0 rating. In the cone calorimetric test, compared to the unmodified VERs, VIDPP20/VER exhibited large reductions in the peak heat release rate, total heat release rate, and total smoke release rate while VIDHP20/VER demonstrated comparatively inferior performance in terms of the heat release. VIDHP20/VER and VIDPP20/VER showed good thermal stability and presented a little lower glass transition temperature than the control sample. VIDPP with a low phosphorus oxidation state (+1) demonstrated high flame-retardant activities in the gaseous phase, whereas VIDHP with a high phosphorus oxidation state (+5) primarily exhibited efficacy in the condensed phase.

High-frequency optimally windowed chirp rheometry for rapidly evolving viscoelastic materials: Application to a crosslinking thermoset

Knowledge of the evolution in the mechanical properties of a curing polymer matrix is of great importance in composite parts or structure fabrication. Conventional rheometry, based on small amplitude oscillatory shear, is limited by long interrogation times. In rapidly evolving materials, time sweeps can provide a meaningful measurement albeit at a single frequency. To overcome this constraint, we utilize a combined frequency- and amplitude-modulated chirped strain waveform in conjunction with a homemade sliding plate piezo-operated rheometer (PZR) and a dual-head commercial rotational rheometer (Anton Paar MCR 702) to probe the linear viscoelasticity of these time-evolving materials. The direct controllability of the PZR, resulting from the absence of any kind of firmware and the microsecond actuator-sensor response renders this device ideal for exploring the advantages of this technique. The high frequency capability allows us to extend the upper limits of the accessible linear viscoelastic spectrum and, most importantly, to shorten the length of the interrogating strain signal (OWCh-PZR) to subsecond scales, while retaining a high time-bandwidth product. This short duration ensures that the mutation number (NMu) is kept sufficiently low, even in fast-curing resins. The method is validated via calibration tests in both instruments, and the corresponding limitations are discussed. As a proof of concept, the technique is applied to a curing vinylester resin. The linear viscoelastic (LVE) spectrum is assessed every 20 s to monitor the rapid evolution in the time and frequency dependence of the complex modulus. Comparison of the chirp implementation, based on parameters such as duration of the experiment, sampling frequency, and frequency range, in a commercial rotational rheometer with the PZR provides further information on the applicability of this technique and its limitations. Finally, FTIR spectroscopy is utilized to gain insights into the evolution of the chemical network, and the gap dependence of the evolving material properties in these heterogeneous systems is also investigated.

Effect of adding Urtica dioica–chopped fiber on load bearing, wear, fatigue, thermal stability, flammability, and water absorption behavior of rock dust dispersed vinyl ester composite

Effect of adding Urtica dioica–chopped fiber on load bearing, wear, fatigue, thermal stability, flammability, and water absorption behavior of rock dust dispersed vinyl ester composite

Method of Increasing the Fracture Toughness of Unsaturated Polyester with the Addition of Vinyl Ester as a Material for Automotive Body

Unsaturated polyester is the polymer material most widely used for matrix composites in the field of construction engineering, including for ships, automotive components and other engineering fields. The weakness of this polymer is that it is brittle and brittle and is unable to withstand cracking loads due to having cross-linked molecules that easily link together. The study to improve it was mixing with vinyl ester which succeeded in making the polyester crack resistant which was tested using a CTM machine and the fracture was observed using an SEM microscope. The test results showed that the polyester polymer mixed with 30% vinyl ester showed the highest increase in fracture strength, which was equal to K<sub>1c</sub> = 1.67 N.mm<sup>0.5</sup> compared to pure polyester, only K<sub>1c</sub> = 0.77 N.mm<sup>0.5</sup> can increase (216 %). Increasing the mixture content of 30% vinyl ester in polyester will change the brittle nature of unsaturated polyester to become more resilient because the vinyl ester molecules break the bonds of the polyester molecular chains.

Theoretical study of the effect of orientations and fibre volume on the thermal insulation capability of reinforced polymer composites

Abstract In industry, synthetic fibre reinforcements are popular due to their cost-effectiveness and lightweight nature. However, the non-reusability and non-degradability have raised environmental concerns and prompted scientists to explore more environmentally friendly alternatives. Natural fibres are being investigated as potential replacements to address these issues and promote sustainability. This study investigated the effect of fibre loading and orientation on the heat conductivity of polymer resins using a finite element-based numerical model developed in our previous research. The numerical analysis was conducted in ANSYS® modelling and simulation using glass and sisal fibres in combination with three distinct matrix materials (epoxy, polyester, and vinyl ester). Different orientations (parallel, perpendicular, 45°, and normal) and volume of fibre fractions (20–35%) were used for the analysis. The properties of the materials were incorporated into the ANSYS Engineering database, and the composite model was divided into five segments to analyse the heat transfer. The thermal boundary condition was implemented by keeping one side of the cylinder at 120°C. The results showed that the thermal conductivity of the composites decreased as the volume fraction of natural fibres increased. Epoxy-based composites exhibited better insulation performance than polyester and vinyl ester-based composites. This study demonstrated the potential of using natural fibres to improve the thermal insulation properties of composites.

Free vibration analysis of jute/kenaf/banana hybrid biocomposites: effects of various stacking sequences

This work provides an insight of the free vibration behaviour based on experimental modal analysis of hybrid natural fibre reinforced polymer composites fabricated via compression moulding method. This study aims to study the impact of different polymer matrices (vinyl ester and epoxy) and stacking order of different natural fibres (Jute, Kenaf and Banana) on the composite’s free vibration characteristics. Jute-Kenaf-Banana-Epoxy (JKBE) matrix composites exhibited enhanced free vibration properties compared to single fiber reinforcements, except the banana/epoxy composites. Additionally, Jute-Kenaf-Banana-Vinyl ester (JKBV) composites demonstrated improved free vibration properties in comparison to single fiber reinforcements, with the exception of kenaf/vinyl ester composites. Kenaf-Banana-Jute-Jute-Banana-Kenaf-Epoxy (KBJJBKE) and Kenaf-Banana-Jute-Jute-Banana-Kenaf-Vinyl ester (KBJJBKV) hybrid composites showed the highest natural frequencies of 68.36 Hz and 97.66 Hz, respectively. However, there was no significant improvements in the natural frequencies of Jute-Kenaf-Banana-Kenaf-Banana-Jute-Epoxy (JKBKBJE) and Jute-Kenaf-Banana-Kenaf-Banana-Jute-Vinyl ester (JKBKBJV) hybrid composites. The highest damping factor was observed for JKBKBJE (0.153) and JKBKBJV (0.224) hybrid composites. These hybrid composites with better free vibration properties shall be a potential candidate in the automobile interior applications.

Investigation of moisture absorption and long-term properties of carbon nanotube-reinforced vinyl-ester composites

Vinyl-ester resin (VE) is a polymer matrix frequently used in several civil applications, but its long-term properties in humid and harsh environments can be a concern. Carbon nanotubes (CNTs) have remarkable mechanical, physical, and thermal properties. Adding them to the resin is a promising solution and makes it possible to manufacture cost-effective products with enhanced engineering properties. Our study investigated the chemical functionalization of multi-wall carbon nanotubes (MWCNTs) through acid oxidation to evaluate the durability-related properties of vinyl-ester-based nanocomposites. Samples containing 0.1 wt% of as-received CNTs and functionalized CNTs were characterized by scanning electron microscopy (SEM), elemental analysis, and X-ray photoelectron spectroscopy (XPS). A small amount of two dispersing agents (BYK 104S and BYK 9076) was added to the mixtures to produce high particle stability in the nanocomposites. Barrier properties and moisture diffusivity were determined by immersing samples in a water bath at 50°C. Aging was conducted by fully immersing samples in NaOH solution at 50°C. Matrix degradation was assessed with tensile tests, dynamic mechanical analysis (DMA), and differential scanning calorimetry (DSC) before and after conditioning. The results indicate that the addition of oxidized CNTs significantly improved the mechanical, physical, and durability properties of the composites. Additionally, unlike nanoclay-based nanocomposites, oxidized CNTs do not increase water absorption at saturation.

Characterization of Low- and High-Velocity Responses of Basalt-Epoxy and Basalt-Elium Composites.

Currently, fiber-reinforced polymer composites (FRPs) used for demanding structural applications predominantly utilize carbon, glass, and aramid fibers embedded in epoxy resin, albeit occasionally polyester and vinyl ester resins are also used. This study investigates the feasibility of employing recyclable and sustainable materials to formulate a composite suitable for load-bearing structural applications, particularly in scenarios involving low-velocity and high-velocity impacts (LVIs and HVIs, respectively). The paper presents a comparative analysis of the performance of basalt-Elium, a fully recyclable, sustainable, and environmentally friendly composite, with an epoxy-based counterpart. Moreover, an accurate and reliable numerical model has been developed and introduced through which the response of these composites can be examined efficiently and accurately under various loading states. The results of this investigation demonstrate the viability of the basalt-elium composite as a fully recyclable and sustainable material for crafting efficient and lightweight composites. Additionally, the accurately developed finite element model presented here can be used to assess the influence of several parameters on the composite, thereby optimizing it for a given situation.

UAV-Mounted Tank for Processing Agricultural Land with Liquid Agrochemicals

To process agricultural crops, unmanned aerial vehicles carrying tanks with liquid chemicals are used. The paper highlights that containers made of polypropylene and polyethylene exhibit inferior qualities compared to those made of fiberglass, specifically, in terms of strength, thermal stability, resistance to ultraviolet rays, and service life. (Research purpose) To design and manufacture a tank made of composite fiberglass material with a water hammer damper. (Materials and methods) S-glass and epoxy vinyl ester resin were selected for the tank, as they exhibit superior resistance to chemical influences. To construct the tank elements, spray application, impregnation of glass fiber filler in a closed form, and winding were used. (Results and discussion) A comparative analysis was conducted on tank models, assessing their performance with and without a water hammer damper. The effectiveness of the suggested solution has been substantiated through the utilization of KOMPAS-3D software in the KompasFlow application, Within this software, the hydraulic shock is simulated to propagate inside the tank, reflecting off the walls, and gradually diminishing. Load and strength calculations for the fiberglass tank were performed by considering fiberglass parameters using the APM FEM application. (Conclusions) A tank model designed for application of liquid chemical substances in crop spraying from unmanned aerial vehicles has been developed. Innovative methods were employed in the manufacturing of the tank components. Additionally, careful consideration was given to the feasibility of maintenance and reparability. The tank’s volume (experimental sample) measures 0.0158 cubic meters, with a length of 480 millimeters, a width of 216 millimeters, a thickness of 3.6 millimeters, and a weight of approximately 4 kilograms. The design for mounting the composite tank on the unmanned aerial vehicle ensures that the weight of the unmanned aerial vehicle does not impact the tank.

Development and characterization of kevlar and glass fibers reinforced epoxy/vinyl ester hybrid resin composites

AbstractThis research investigates the influence of kevlar and glass fiber reinforcements on the mechanical and thermal properties of epoxy/vinyl ester (hybrid resin) composite. The hybrid resin was synthesized by achieving an interpenetrating network between epoxy and vinyl ester. The composites were characterized using tensile, flexural, impact, and thermo‐gravimetric analysis (TGA). Scanning electron microscopy was employed to analyze surface morphology whereas Fourier‐Transformation Infrared Spectroscopy (FT‐IR) was used to investigate the possible interaction between the constituents of the composites. The findings have shown a notable improvement in the mechanical properties after the hybridization of the resin. For reference, the tensile strength of glass/hybrid resin and kevlar/hybrid resin composites were observed to increase by 8.33% and 23.65%, as compared to glass/epoxy and kevlar epoxy composites respectively, whereas, the bending strength of these composites was improved by 8.36% and 30.61%, respectively. TGA also showed an enhanced thermal stability of the hybrid resin‐based composites. Such improvements are noticed due to multi‐resin incorporation (the oxirane group of epoxy reacts with the hydroxyl group of vinyl ester), confirmed by the FTIR, TGA, and morphological analysis. This study signifies that the proposed hybrid composites are better in terms of strength and modulus relative to conventional metallic materials.Highlights The paper presents the development of novel hybrid resin, reinforced with synthetic fibers. Hybrid resin is imparted positively and is highly favorable in improving the mechanical properties of composites. The tensile strength of novel composites is increased by 8.33% and 23.65% relative to their base specimens, and a similar trend is observed in flexural and impact analysis. Fractured analysis showed that composite laminates deteriorated more intensely due to cohesive matrix fracture; adhesion failure was not observed at all, as evidenced by the emergence of micro‐cracks in resin. Developed novel composites exhibited maximum thermal stability; residual char in glass/epoxy/vinyl‐ester composite attained 17.81% higher, whereas kevlar/epoxy/vinyl‐ester achieved 3.56% relative to glass/epoxy and kevlar/epoxy base samples.

Construction of anticorrosive coatings with emergency response closure by introducing functionalized graphene oxide

Vinyl ester resins (VER) are commonly used in the field of anticorrosive coatings. During the preparation and application of the coatings, it is inevitable to produce defects such as micro-porosity, micro-cracks, and scratches, which will reduce the barrier capacity of the anticorrosive coatings against corrosive media. In this paper, 2-(chloromethyl) pyridine is used to functionalize the silane-decorated graphene oxide for obtaining the functionalized modified graphene oxide (TGO). The aggregation of TGO nanosheets under the influence of Fe2+ ions generated by corrosion, achieving the response closure of TGO/VER coatings to hinder the diffusion path of corrosive media, thereby strengthening the anticorrosion effect of the coating. The water vapor transmission rate of TGO/VER coatings decreases significantly after immersion in Fe2+ solution. Electrochemical impedance spectroscopy tests indicate that TGO/VER coatings have better corrosion resistance compared with VER coatings, in which the impedance modulus after immersion for 100 d of 0.3TGO/VER coatings (3.93 × 1010 Ω cm2) is about four orders of magnitude greater than that of the VER coatings (5.85 × 106 Ω cm2). The TGO/VER coatings provide the responsive closure function via complexation of TGO with Fe2+ to achieve the long-term corrosion resistance. These results suggest that TGO/VER system provides an effective strategy for the preparation and application of graphene-based long-term anticorrosive coatings.

Preparation of unsaturated self-emulsifying polyester sizing agents for improving interfacial and mechanical properties of carbon fiber/vinyl ester resin composites

In order to promote the interfacial adhesion between carbon fiber and vinyl ester matrix, a series of unsaturated self-emulsifying anionic polyester sizing agents were designed. The results indicated that the sizing agents exhibited a uniform particle size distribution at the nanometer level and demonstrated favorable thermal stability below 200 °C. As the content of double bonds of sizing agents increases, the glass transition temperature also increases, and the moisture absorption of sized carbon fiber decreases. The carbon fiber surface becomes smoother after sizing. Moreover, the interlaminar shear strength and interfacial shear strength increased by 18.8 % and 43.4 %, respectively, compared to the commercial carbon fiber. This is mainly due to the unsaturated bonds in the sizing agent react with the free radicals on the surface of the carbon fiber, which enhance the interface bonding strength between the sizing agent and the surface of the carbon fiber and the vinyl ester matrix.

İki Farklı Reçine Kullanılarak Oluşturulan Hibrit Kompozit Malzemelerin Araç Tamponlarında Kullanımının Araştırılması

As efforts to reduce vehicle weight in today's vehicles accelerate, efforts to find new types of materials that can replace traditional materials have accelerated. In this study, carbon fiber was used as a reinforcement element together with glass fiber for lightening in vehicle bumpers. While vinyl ester and polyester were chosen as the matrix material for the piece to be produced, production was made by the hand lay-up method. The produced samples were first subjected to tensile test and their mechanical values were determined. The mechanical test results were introduced to the ANSYS program, and separate analyzes were made for the materials produced on the same bumper design and the results were compared. According to the results of the analysis, there was 2.13 times decrease in total deformations in glass fiber/carbon fiber/Vinyl ester hybrid composites compared to glass fiber/vinyl ester homogeneous composites. In terms of equivalent stresses, 8% reduction was achieved in the carbon fiber /glass fiber/Vinyl ester hybrid composite compared to the carbon/Vinyl ester homogeneous composite. It was concluded that the choice of reinforcement and matrix is important for creating bumper material and improving the mechanical values of the bumper

Non-isocyanate epoxy vinyl ester urethane prepolymer based on diglycidyl ether of bisphenol-A

Non-isocyanate epoxy vinyl ester urethane prepolymer based on diglycidyl ether of bisphenol-A