Vinyl Ester Composites Research Articles

Synthesis and characterization of randomly oriented silane-grafted novel bio-cellulosic fish tail palm fiber–reinforced vinyl ester composite

Synthesis and characterization of randomly oriented silane-grafted novel bio-cellulosic fish tail palm fiber–reinforced vinyl ester composite

Experimental investigation of physical properties of homogenous and functionally graded glass fiber reinforced vinyl-ester composites

Experimental investigation of physical properties of homogenous and functionally graded glass fiber reinforced vinyl-ester composites

Erosion performance of natural fiber reinforced vinyl ester hybrid composites: Effect of layering sequences

The purpose of this study is to investigate on erosion performance of hybrid polymer composites under various parameters such as impingement angle and time. The vinyl ester composites used for the erosion tests were prepared by layering sequences of Jute (J), Kenaf (K), and Banana (B) fibres. Three composites with single fibres and three hybrid composites were prepared to understand the influence of layering sequence. The erosion performance of the composites was carried out by an Air jet erosion analyzer. In this study, different impingement angles of 90° and 60° for a period of 2, 4, and 6 min were exploited. Alumina particles were used as the erodent material at an erodent discharge rate of 3.3 g/m and the impact velocity of 72 m/s. The eroded samples were examined using the optical microscope to analyze the effect of erosion in the J/K/B vinyl ester composites. Finally, the erosion performance of the J/K/B reinforced vinyl ester hybrid composites was analyzed by comparing the reduction in weight of composites after erosion to initial weight of the composite materials.

Çeşitli Matris Malzemelerinin Bazalt/Jüt/Cam Elyaf Takviyeli Hibrit Kompozitlerin Mekanik Özelliklerine Etkisi

In this research, the effect of different matrix materials (epoxy and vinylester) on the mechanical properties of Basalt, Jute, and Glass fiber-based hybrid composites were analyzed mechanically and morphologically. The mechanical test results were achieved by the Tensile test and Vickers hardness test, while morphologic images were obtained by Scanning Electron Microscopy. Basalt fiber fabric, Jute fiber fabric, and Glass fiber fabrics of 86 gr/m² and 100 gr/m² were used as reinforcement elements, while epoxy and vinylester were utilized as matrix materials. A vacuum assisted resin transfer molding method was used as the production technique. In the results, it is given how the use of different reinforcement element types and different matrix materials affects the mechanical properties of the produced composite samples. Results show that the tensile strength of basalt fiber/glass fiber (100 gr/m²) reinforced with epoxy is the highest in all of the produced composites. In terms of microhardness, the hardness value of basalt fiber/glass fiber (100 gr/m²) reinforced epoxy composites have 1.39 times higher than basalt/glass fiber (100 gr/m²) reinforced vinylester composites. Scanning electron microscopy (SEM) analysis was utilized to examine the fiber rupture and fracture mode in hybrid composites. As a result of the analysis, also it was observed SEM results support the mechanical test results.

Microbond testing of the interface in glass fibre vinylester composites

ABSTRACT The microbond test was used to investigate the interface strength (IFSS) in various glass fibre-vinylester (VE) composite systems and a number of issues related to the sample preparation were identified. Cure schedules that produce well-reacted VE polymers on the macroscale did not result in cured microdroplets. Hence, the microbond test could not be carried out on samples with the same cure history as macroscale composites. Testable microdroplet samples could only be obtained when resin cure was carried out under an inert atmosphere. Higher IFSS values were obtained by raising the final temperature of the cure schedule. Glass fibres with a full sizing gave significantly higher apparent IFSS values comparedf to bare fibres or fibre coated with only silane coupling agent. It was discovered that the measured IFSS of VE compatible glass fibres was approximately doubled when fibres were mounted using epoxy glue instead of cyanoacrylate glue. This phenomenon appears to be related to the deposition of cyanoacrylate vapours onto the surface of the fibres during sample preparation. It is concluded that great care must be taken in ensuring that effects observed using the microbond test are evidence of real material characteristics and not artefacts of sample preparation.

Influence of Twin-Screw Extrusion on The Dispersion of Nanoclay in Vinylester Composites

This paper reports the dispersion of nanoclay in vinylester using co-rotating twin screw extrusion and ultrasonication for preparing nanoclay/vinylester gel coat. Two sets MMT/vinylester specimens, namely Type 1 and Type 2 were prepared for comparative studies. While Type 1 specimens were prepared using ultrasonication only, Type 2 specimens were prepared using both ultrasonication and twin-screw extrusion. Type 2 specimens showed lower levels of nanoclay intercalation and higher levels of exfoliation. By using the MMT/vinylester gel coat so prepared by the two different routes, MMT/vinylester/glass specimens were fabricated and tested for mechanical properties. Type 2 based nanocomposite specimens showed greater values of ultimate tensile strength, flexural strength, interlaminar shear strength and impact strength. Scanning Electron Micrographs (SEM) of tensile fractured Type 2 based specimens showed less agglomeration of nanoclay than that of Type 1 based specimens.

Effect of the double bond content of sizing agents on the mechanical properties of carbon fibre reinforced vinyl ester composites

Unsaturated polyester sizing agents with various double bond contents have a significant influence on the interface between carbon fibers (CF) and vinyl ester resins (VER). This paper aims to study the effect of the double bond content of sizing agents on the surface properties of CF and thermo mechanical properties of the sized CF/VER composites. We synthesized five types of self-emulsifying cationic sizing agents with various double bond contents and characterized the samples by FTIR, dynamic light scattering (DLS), cryo-scanning electron microscopy (Cryo-SEM) and thermal gravimetric analysis (TGA). The double bond content of the sizing agents on the cross-linking extent of the CF surface were investigated on factors such as the wettability of VER, the interlaminar shear strength (ILSS) and flexural strength and modulus of CF/VER composites. It was identified that the distribution of the sizing agent emulsions had a mono-dispersion of around 50 nm and were thermally stable below 300 °C. Additionally, it was identified that the double bond content of the sizing agents enhanced the grafting reactions and cross-linking extent between the sizing agent and CF surface. The CF had the best wettability for vinyl ester resin when the double bond content was 10% in the sizing agent. In addition, the ILSS, the flexural strength and the modulus reached maxima.

Effect of Moisture on the Resistance of Sansevieria Cylindrica–Reinforced Vinyl Ester Composites

Abstract The research is intended to determine the absorption behavior of a newly fabricated, sansevieria cylindrica–reinforced vinyl ester composite (SCVEC) under a different immersion medium. For this purpose, seawater, distilled water, and groundwater was taken. The samples of untreated and sodium hydroxide (NaOH)-treated SCVEC with varying fiber content and fiber length was subjected to water absorption studies. The diffusion coefficient, permeability coefficient, and sorption coefficient were determined to study the kinetics of water molecules penetrating the SCVEC. The results show that SCVEC can resist seawater effectively compared to other medium. This is because of the salt molecule, which disables the secure transport of water molecules into the composite. NaOH-treated composites showed better results compared to the untreated composites irrespective of immersion medium. Scanning electron microscopic studies reveal the water absorption mechanism of SCVEC materials.

Enhanced creep resistance of GFRP composites through interpenetrating polymer network

Fiber reinforced polymer (FRP) composites have become promising materials of modern times and find numerous applications in critical engineering fields including aerospace, marine and automobile sector. Due to their increasing demand, it becomes apparently essential to employ advanced techniques, which can predict the long-term behavior of such materials in various in-service conditions. Epoxy and vinyl ester based composites are most commonly used in structural FRP composites. As each polymer has its own advantages and disadvantages, hybridization or blending of different polymers is a trending technology to improve the performance of resulting FRP composite. The present article aims at comparing the performance of glass fiber reinforced epoxy-vinyl ester interpenetrating polymer network (GEVIPN) composite with that of the base materials, i.e. glass fiber reinforced epoxy (GE) and glass fiber reinforced vinyl ester (GVE) composites. Flexural testing has been conducted at various in-situ temperatures (30 °C, 60 °C and 90 °C) where GEVIPN composite showed highest properties at 30 °C. The lifetime prediction of the composite materials has been carried out using accelerated deformation and time-temperature superposition (TTSP) principle. It was observed that GEVIPN composite showed highest creep resistance as compared to the other two composites at lower temperature, whereas opposite trend was observed at elevated temperature. At 30 °C, GEVIPN composite showed positive reinforcement efficiency for ∼385 days with respect to GE and ∼46.27 years with respect to GVE. Similar studies were done for the other reference temperatures. Following this, fractography analysis of the fractured surface was done under FESEM to identify the failure mechanisms and draw a comparison between the composites.

Monte Carlo simulations study on gamma ray–neutron shielding characteristics for vinyl ester composites

AbstractThe current study aims to report the gamma ray–neutron attenuation parameters of eight types of vinyl ester pumice (V‐P) composites for wide energy ranges of 511–2140 keV via MCNPX and FLUKA codes. The radiation shielding properties of these composites were presented graphically and are discussed in detail in this study. From the obtained results, it can be concluded that the MCNPX and FLUKA outcomes are in agreement with each other, and also the FLUKA code can be used as an alternative technique to determine the attenuation features of vinyl ester composites. Besides, the linear attenuation coefficient and total macroscopic cross sections' (∑t) dependencies on the density and also mass attenuation coefficient were found for all selected samples. To sum up, findings show that composite coded as V‐P50 can be a good competitive candidate in terms of gamma rays and neutron shielding.

Flexural and Inter-laminar shear stress properties of glass fiber reinforced Iso-polyester, Epoxy & vinyl ester composites

In this study the glass fiber is reinforced in Iso-polyester, Epoxy & vinyl ester resin with different percent fiber and resin combination. The composites were prepared with the hand lay-up technique followed by compression. After preparing specimens as per ASTM standard these specimens are tested on the computerized universal testing machine for flexural strength and inter-laminar shear stress (ILSS). The experimental data is used to compare and find the best percentage combination of resin and fiber for different applications of composite.

Study of Mechanical Properties of Roselle Fiber Reinforced Vinyl Ester Biocomposite Based on the length and content of Fiber

Mechanical properties of Roselle fiber reinforced vinyl ester biocomposite were studied based on the fiber content and length in the present communication. Usually, natural fiber reinforced polymer composites depend on some aspects such as fiber content, fiber length and orientation, the fiber-matrix adhesion. Composite plates were prepared by a simple hand lay-up technique for two different fiber lengths (3 and 13 mm) and five different fiber content (10, 20, 30, 40 and 50 wt%). Composite specimens were tested according to ASTM standards and their results were recorded. Experimental results showed that mechanical properties such as tensile, flexural and impact, increases with increase of fiber content up to 40 wt% after which it is decreases at both the fiber length. However, modulus values were increased linearly with fiber content of 10 to 50 wt%. Composites with the fiber length of 13 mm show the high level of mechanical properties compared to composites with the fiber length of 3 mm at all combinations of fiber contents. It is observed that the optimal fiber content is 40 wt%, which can be used to obtain the maximum property level in the Roselle fiber reinforced vinyl ester composites

Interlaminar fracture toughness of low curing temperature vinylester composites exposed to severe service conditions

The effects of high temperature environmental exposition and of soft curing treatment on the interlaminar shear strength for vinylester glass fibre multilayer composites have been studied. The degradation effects on the matrix and fibre–matrix interface are due to scissions of polymer chains, the oxidation process, the weakening of fibre–matrix bonding. Possibility of stabilization of Glassfiber – Vinylester-Bisphenol-A composite for prolonged high temperature service by low temperature curing is established.

Evaluation of mechanical properties of coconut shell particle/vinyl ester composite based on the untreated and treated conditions

The aim of the present communication is to study the effects of the addition of the untreated and treated coconut shell particles on the mechanical properties of vinyl ester composites. Composite plates were prepared by hand lay-up technique with the six different content (5, 15, 25, 35, 45, and 55 wt%) of the coconut shell particles. Mechanical properties such as, tensile, flexural, and impact, of the coconut shell particle/vinyl ester composites were determined and compared at both the untreated and treated conditions based on the content of the coconut shell particles. The results revealed that the mechanical properties of the composites have increased with the addition of the coconut shell particles up to 35 wt% and then dropped at both the conditions. The treated composites show the high level of mechanical property values compared to the untreated composites. The optimum particle content to get the best combination of mechanical properties is 35 wt% in this composite. The fractographic studies were carried out to understand the failure of the composites. To understand the chemical compatibility between the particle and the matrix in the composite at both the untreated and treated conditions, the Pukanszky’s model was used and correlated with the experimental results.

Effect of Stacking Sequences, Fabric Orientations, and Chemical Treatment on the Mechanical Properties of Hybrid Woven Jute–Ramie Composites

Natural fibres have been widely used in advanced applications, especially in the automotive industry. These fibres are inexpensive, non-abrasive, environmentally friendly, biodegradable, and possess low density with good mechanical properties. The main issue in using natural fibres is their incompatibility with a polymer matrix that lowers the mechanical properties. Therefore, this research analyses the effect of stacking sequences, fibre orientations, and alkali treatment on the mechanical properties of hybrid jute (J) and ramie (R) reinforced vinyl ester (VE) composites. Initially, woven fibres were fabricated based on the 3 and 4—layer stacking sequence with 0° orientation. The characterisation was done to analyse its properties. It was found that the RJJR stacking sequence possessed a tensile strength higher value of 28.90 MPa. The results for the RJJR sequence were fabricated with various fibre orientations such as 0°, 30°, 45°, and 90° to understand the effect of fibre orientation towards the tensile and flexural properties. The tensile and flexural strength with 0° fibre orientation is significantly higher than the other orientations with values of 28.90 MPa and 66.81 MPa, respectively. Besides, alkali treatment with 5 wt.% and 10 wt.% was used to enhance the mechanical properties, where 0° RJJR with 5 wt.% indicated maximum flexural strength with 34.50% increment compared to untreated RJJR. In conclusion, the combination of fibre orientation and lower alkali treatment concentration (5 wt.%) is highly beneficial in improving fibre hybrid composites' mechanical properties.

Investigations on Mechanical Properties of Basalt Powder filled Vinyl Ester Composites

The current research work deals with the addition of basalt powder on the characteristics of vinyl ester resin composites. The vinyl ester was modified by basalt powder in the amount of 5%, 10% and 15% by weight. The impact of basalt powder on the performance, such as tensile strength and flexural strength was analyzed. The consequence of powder addition on the impact strength of the fabricated materials was also examined. From the results obtained the basalt powder has an encouraging outcome on the strength of the fabricated composites.

Investigation on the Mechanical and Morphological Properties of Red banana/Ramie Fiber vinyl ester composites

The need of green materials for various applications is in high demand. The bio fibers play a very important position to achieve eco friendliness and cost effectiveness. The aim is to analyse the effect of hybrid mat performance. In this work banana and ramie fibers were taken into consideration, With vinyl ester composites. Three different combinations have been developed in laminating the composites at 90 degree orientation. ASTM standards were used to examine the mechanical performances of the composites. The worn out analysis have been carried out by using scanning electronic microscopy. In this work two single layer fibers of ramie and banana have been taken into account and the third composite is developed with hybridisation of red banana and ramie fibers. On comparing all the results obtained the hybrid double layer of red banana and ramie fibers possessed good results in tensile/flexural property. The impact properties of ramie fiber were marginally higher than red banana fibers.

Influence of environmental factors on the processes of biodegradation of vinylester composites

Polymer composite materials based on various binders are widely used in the construction industry. Polymer composites are characterized by high performance. Of great interest is the study of more economical compared to other polymers vinylester composites. They are successfully used in the US and European countries. In Russia, the use of polyester resin as a binder is not as common as abroad. At the same time, the influence of environmental factors on the biodegradation of vinyl ester polymer composites has not been sufficiently studied to date. This study is devoted to the study of the biostability of vinyl-ether composites under the influence of environmental factors. The most significant are the processes of atmospheric aging of materials, which include a complex effect of climatic and environmental factors. The study of changes in the species composition of microflora and indicators of resistance of composites, depending on their composition and operating conditions in the conditions of the seacoast.

Mechanical behavior and dynamic damage constitutive model of glass fiber-reinforced Vinyl Ester with different fiber contents.

Glass fiber-reinforced plastics (GFRP) based on polymer materials are widely used in lightweight impac-resistant structure design. In the process of design and development, it is very important to clarify the mechanical behavior under dynamic load to improve the product performance. Therefore, in this paper, Quasi-stati and dynamic compression behaviors of unidirectional continuous glass fiber-reinforced vinyl ester (GF/VE) composites with five kinds of fiber contents in the fiber direction were measured by an electro-hydraulic servo experiment system and a split Hopkinson pressure bar, and damage evolution of the material is analyzed by observing the microstructure of the cross section of the material. Results show that: The content of glass fiber affects the wettability between fiber and matrix, and the failure mechanism of material at high strain rate; Under quasi-static conditions, higher glass fiber content yields greater failure strength; Under dynamic conditions, as glass fiber content increases, toughness decreases, and the peak stress first increases and then decreases. Finally, the nonlinear viscoelastic constitutive model with damage evolution is derived, which can be used to predict the impact resistance of new composite structures in the product development and design stage and reduce the development cycle.

The effect of chestnut wood flour size on the mechanical properties of vinyl ester composites

Green composites are a special class of composites in which at least one of the components is obtained from natural resources. They are an alternative to traditional composites because of their useful properties such as biodegradability, low cost, easy processability, sound insulation and recycling. Green composites, which emerge as environmentally friendly polymeric composite materials, offer techno-economic advantages in commercial and engineering applications and are among the widely dealt subjects due to the very high demand from the global market. The aim of this study is to investigate the effect of chestnut wood flour size on the mechanical properties of chestnut-wood-flour-filled vinyl ester composites. With this aim, composite specimens were produced by using vinyl ester polymer as the matrix material and chestnut wood flour in three different sizes (0–150, 150–315 and 315–400 μm) as the natural filler. In each size combination, four different matrix/filler ratios (5, 10, 15 and 20% by weight) were adopted. These mixtures were then poured into Teflon moulds to produce the test specimens. Izod impact, three-point bending, hardness and tensile strength tests were performed on the composite specimens. In addition, morphological investigations were performed on the fractured surfaces of the specimens by using scanning electron microscopy. It is concluded that composites with a small-sized chestnut wood flour as the filler have superior properties for composite applications.