Papers by Keyword: Vinyl Ester

Abstract: In terms of enhancing the mechanical properties of the com-posite material, we investigate the effect of different post-curing tem-peratures on the tensile strength, strain, and elastic modulus of carbon UD/Vinyl Ester composite. The performance of composite material can be developed by modifying the condition of manufacture to en-hance the bonding between resin and fibre. The best interlocking will occur upon the complete polymerization reactions of the resin. It was characterized by the formation of the polymer cross-link chain. These conditions are commonly called curing conditions. We did three dif-ferent post-curing treatments for this composite, they were conditioned at room temperature (approximately 25° C), 80° C, and 100 ° C, for 24 hrs, 4 hrs, and 4 hrs time respectively. The tensile properties have al-ready been tested for both composites that refer to ASTM D3039. The Ultimate Tensile Strength (UTS) of three different heat treatment composites was increased by increasing the heat temperature from 25° C to 80°C and 100° C, the increment is about 1.17% and 17.46% ap-proximately. Furthermore, still comparing with the 25° C post-curing treatment, the modulus of elasticity value with heat treatment in 80 ° C is a little bit decreased to 7.29% but it decreased significantly for 47.42% in 100° C heat treatment.

Abstract: This paper deals with the problematics of polymer repair and adhesive mortars. In this study, the vinyl ester and epoxy resins filled with siliceous filler are used. This paper studies physical-mechanical properties and chemical resistance of developed mortars. The compressive strength, flexural strength and visual evaluation of reaction and degradation of polymer mortars in presence of common acids, alkalis and other compounds are compared. The results show, the amine-based epoxy mortar can withstand against a large variety of solutions, but the overall chemical resistance of vinyl ester mortar is higher.

Abstract: In this study, vinyl ester –Jute fiber biocomposites were prepared using vacuum-assisted resin infusion (VARI) process. Woven Jute fibers were used with mass fraction 0.68. Multi-walled carbon nanotubes (MWCNTs) are added to the resin with weight ratio 0.5: 99.5 to investigate the thermo-mechanical properties of bio-composites. Storage and loss modulus of vinyl ester bio-composites were investigated in the presence MWCNTs over a range of temperature (25 to 160 ^oC) to measure the capacity of bio-composite to store and dissipate energy. Damping properties of vinyl ester bio-composites were studied in terms of tan (d). Viscoelastic test using dynamic mechanical analysis (DMA) showed that the glass transition temperature increases with the addition of MWCNTs up to 112.4 ^oC. Addition of jute fiber reinforcements improves the storage modulus value of vinyl ester more than 65% at room temperature. Significant improvement in storage modulus was found in the presence of MWCNTs.

Abstract: In this study carbon fibre reinforced epoxy, unsaturated polyester, and vinyl ester based, binary (two-component) hybrid matrix polymer composites were produced and mechanically characterized by interlaminar shear tests. Fracture surface of tested composites were investigated by scanning electron microscopy. Toughness of hybrid matrix composites were identified and compared to that of the reference, non-hybrid matrix ones.

Abstract: The natural fiber reinforced polymer composites are recognized as an alternative to wood and plastics in recent years. The natural plant fibers are extracted from various parts of the tree and are used in polymer composites.The present investigation is focused on the improvement of tensile strength of coir-vinyl ester composites by impregnation of bio particulates such as alumina, red mud and rice husk. The fracture method of composite specimens are analyzed with the help of scanning electron micrographs.The observed range of tensile strength values are studied using statistical procedure and non linear regression models are developed.

Abstract: – The usage of steel in offshore deep water area contributes to the massive load of the offshore platform which will lead to the massive operational cost. Therefore, the reduction of weight of platform is the major issue that need to be tackled properly. The great improvement in strength to weight ratio compare to steel and high resistivity to corrosion makes Glass Fibre Reinforced Polymer (GFRP) grating preferable. GFRP gratings are normally made of two types of processes which are moulded and pultruded and it is usually consists of glass fibre and bonding matrixes of vinyl ester (VE), polyester (PE), or phenolic (PHE). However there is still doubt on GFRP grating application for offshore due to no consensus guidelines for the design of GFRP grating and there are many several types of GFRP grating available to be chosen. This paper presenting the study on two types of GFRP grating strength with variation of bonding matrixes under flexural static load. A total of six specimens of GFRP grating which consist of 1 each of molded vinyl ester, molded polyester, molded phenolic, pultruded vinyl ester, pultruded polyester and pultruded phenolic were tested to failure in flexure. The main parameters concerns in this study are 1) max load vs. mid-span deflection and 2) failure mode of the specimens.

Abstract: Glass Fiber Reinforced Polymer (GFRP) gratings are normally made of two types of processes which are molded and pultruded. It consists of glass fiber and bonding matrixes of vinyl ester (VE), polyester (PE), or phenolic (PHE). The great improvement in strength to weight ratio compare to steel and high resistivity to corrosion makes GFRP grating preferable. However, the use of GFRP grating in offshore is scarce due to issues related to durability and the harsh environment Based on the observation, the accelerated ageing process affects the performance of GFRP gratings by reducing its strength in flexural static load test. Therefore; this study concentrates on the effect of accelerated ageing on GFRP grating. A total of 18 GFRP grating specimens which consist of 6 each of molded Vinyl Ester, molded Polyester and pultruded Phenolic. The entire specimens were aged by immersion in seawater at elevated temperature (60 °C) for the period of 2 month. The main parameters concerns in this study are 1) Max Load vs. Immersion Period, 2) Max Load vs. Deflection graph of results.

Abstract: Excellent physical and mechanical properties of carbon nanotubes (CNTs) make them outstanding candidate as fillers to fabricate multi-functional polymer composites. It is assumed that a high level of dispersion in the preparation stage may lead to a more effective nanocomposite. In this research, the dispersion state of multi-walled carbon nanotubes (MWNTs) at various contents in an unsaturated vinyl ester resin is investigated during fabrication by on-line monitoring the viscosity of suspensions as a function of sonication time and energy introduced. The results show that initial viscosities of suspensions increase by adding more MWNTs to the resin. The viscosities gradually increase during the sonication and reach to maximum values, when it is assumed that the dispersion is completed. After this step the viscosity subsequently decreases. The energy density required to achieve a good dispersion of MWNTs in vinyl ester is obtained. The qualities of dispersion in cured composites are characterized by examining the sections using the scanning electron microscope (SEM) to confirm the results of viscosity measurements. The stabilization of MWNTs is achieved by adding a commercial dispersant and stabilizer, BYK-P 104S, by 0.0375 wt% . The results indicate that adding more surfactant to the suspension makes it unstable and leads to flocculation. The stabilization of suspensions is investigated by using viscosity measurement. Also, FT-IR is used to determine the possible mechanism of surfactant to stabilize the MWNTs in vinyl ester.

Abstract: One kind of vinyl ester has been synthesized by treating epoxy resin with acrylic acid in toluene and characterized by Fourier transform infrared spectroscopy (FTIR). FTIR results showed that the epoxy resin is indeed reacted with acrylic acid through epoxy group and carboxyl of acrylic acid. The influences of reaction factors have been studied in detail. Experimental and properties testing results showed that this kind of vinyl ester, which obtained under the conditions of the temperature is 100 °C, amount of catalyst is 1.0 wt% and the feed ratio is 1.02:1(the molar ratio of acid to epoxy), is suitable as thickener for SMC(Sheet Moulding Compound).

Abstract: An experimental testing program is being conducted to evaluate the effects of environmental exposure on the mechanical properties of glass/vinyl ester filament wound pipes. The effects of artificial exposure on the flexural and fracture properties are reported in this paper. Three point bending specimens were employed to characterize the flexural properties. Fracture resistance was assessed using pre-cracked notched ring specimens. Specimens were exposed for 300, 1000, and 3000 hours in the environment of interest before testing at room temperature. The exposure conditions presented in this paper include: dry heat at 40
C, dry heat at 70
C, 65% and 100% relative humidity at room temperature; and salt spray and seawater environments at room temperature. The results of this study indicate that the flexural strength and stiffness; and the fracture resistance of the tested GFRP composite do not show significant degradation due to prior exposure to the environments investigated for up to 3000 hours. The flexural ductility is shown to degrade after exposure in high humidity environment.