Vinyl Ester Resin Matrix Research Articles

Mechanical properties of vinyl ester hybrid composite laminates reinforced with screw pine and glass fiber

<abstract> <p>The screw pine and E-glass fibers were hybridized in the vinyl ester resin matrix to prepare the hybrid composite laminates in the present communication. Hybrid composite laminates at the constant volume fraction of 35.12% has been fabricated using the hot press compression molding in two forms, namely dispersed and skin-core, to evaluate the mechanical properties. Mechanical properties of composite laminates were studied based on the various volume fraction of glass fiber content (0, 3.32, 8.15, 12.44 and 16.53 vol.%). The scanning electron microscopy (HITACHI S-3000N) was used to study the fracture surface of composite laminates. The results of hybrid composite laminates were compared with a neat resin sample and screw pine fiber (35.12 vol.%) alone composite. The results revealed that the mechanical properties of both the type of composite laminates increased as glass fiber addition was increased. The SPF18.59/GF16.53 hybrid composite laminate exhibits the highest level of mechanical properties because of the concentration and higher elongation percentage of glass fibers. Moreover, the skin-core type composites perform better than those of the dispersed type hybrid composites. Because of the stretching nature of screw pine fibers, they elongate when the load is transferred from glass fibers to screw pine fibers, resulting in an increase in mechanical properties. The property values were predicted using a theoretical model, and it was found that the two were in good agreement.</p> </abstract>

Property Changes of Chopped Glass Fiber‐Reinforced Sheet Molding Compound Composite in Acid‐Base Environment

To investigate the influence of acid‐base environments on the properties of chopped fiber‐reinforced resin matrix composites, corresponding unsealed specimens were prepared. These specimens were immersed in sodium hydroxide, hydrochloric acid solution, and deionized water for varying durations, after which their mechanical properties and surface hardness were tested. Changes in chemical composition, as well as alterations in fiber and resin matrix, were observed from a microscopic perspective. The results indicate that fracture at the fiber/matrix interface and hydrolysis aging of the matrix are the primary reasons for degradation in the mechanical properties of the composite. After 28 days of immersion, the hardness retention rates were found to be 54.34%, 75.96%, and 74.15% for deionized water, NaOH solution, and HCl solution, respectively. Similarly, the retention rates of tensile strength were 56.99%, 51.97%, and 58.32%, respectively. These findings provide valuable insights for the application of chopped fiber‐reinforced vinyl ester resin matrix composite materials in equipment designed in acid‐base environments.

Effect of nano hybrid additives on low velocity impact responses of aramid composite plates: example of CNT and ZrO2

Aramid reinforced composites are advanced materials that are widely used in many industrial applications thanks to their combination of high strength and lightness. Nano additives are of great importance for improving the mechanical properties of aramid reinforced composites and reducing costs. In this paper, multi-walled Carbon Nanotube (CNT) and Zirconia (ZrO2) nano hybrid additives were used to determine the effect on the mechanical characterization of aramid composite plates. Therefore, low velocity impact responses of aramid fiber reinforced composites were investigated by adding ZrO2 and CNT nano hybrid additives to the Polives 701 polymer vinylester resin matrix. Low velocity impact tests were carried out at 10 J and 15 J. As a result of the experiments, the effects of nano hybrid additives on the impact absorption properties of aramid composite plates were determined. By determining the maximum force, displacement and time values, the effect of CNT and ZrO2 nano hybrid additives on the impact resistance of the composite plates was analyzed. In addition, it contributed to the development of composite materials used in industrial applications by providing information on increasing the performance of composite materials by using nano additives. As a result of this study, it was determined that the strength of the composite material increased proportionally when the CNT additive was used, and the material became embrittled when the ZrO2 additive was used.

A Comparison Study on Toughening Vinyl Ester Resins Using Different Nanocarbon Materials.

This study aims to comprehensively compare and evaluate the toughening effects of different nanocarbon materials on vinyl ester resins. Four typical nanocarbon materials, including graphene, graphene oxide (GO), single-walled carbon nanotubes (SWCNTs), and multi-walled carbon nanotubes (MWCNTs), were used as reinforcing fillers for vinyl ester resins. These four nanocarbon materials were dispersed in the vinyl ester resin matrix by the combination of high-speed stirring and probe sonication, and their dispersion states were observed with optical microscopy. The effects of incorporating different nanocarbon materials on the viscosities, thermal properties, tensile properties, and fracture toughness of the resulting modified vinyl ester resins were systematically investigated. The results indicate that the four nanocarbon materials show enhanced toughening effects on the vinyl ester resin in the sequence of SWCNTs, GO, MWCNTs, and graphene. Compared with the control resin, the modified vinyl ester resin containing 0.2 wt% graphene shows 45% and 54% enhancements in the critical stress intensity factor (KIC) and critical strain energy release rate (GIC), respectively. The incorporation of the four nanocarbon materials has almost no effect on the glass transition temperatures of the resulting modified vinyl ester resins. This study provides valuable insights into the selection of nanocarbon additives for enhancing the toughness of vinyl ester resins.

Effect of Fiber Length and Loading on the Mechanical Characterization of Cyperus Pangorei Fiber Reinforced Vinyl Ester Composites

Polymer composites fabricated using plant fibers have become a dominant role in number of industries due to the outstanding results of their physical and mechanical characteristics when compared to traditional materials. The current study aims to develop lightweight and affordable composite materials using Cyperus pangorei fiber (CPF) and a vinyl ester (VE) resin matrix. Comparing the characteristics of composite materials created with different fiber lengths (3 to 11 mm) and contents (10 to 50% weight). The composite with 7mm fiber length and 40% of fiber content demonstrated the highest level of stability among the various fiber weight and lengths percentages tested. A composite system's fiber contents have a significant impact on its overall performance. The bonding of fibers and matrix of the specimens were good, according to SEM analysis. As a result, the current study suggests that the optimal CPF-reinforced VE composites would be a capable substitute to traditional materials for value-added engineering products.

Achieving superior anti-corrosion properties of vinyl ester resin coatings via compositing with 3-methacryloxy propyl trimethoxysilane functionalized MXene nanosheets

Exposure of steel to harsh marine environment can cause serious corrosion, which significantly affects its durability. In this study, a novel two-dimensional MXene nanosheets were functionalized with 3-methacryloxy propyl trimethoxysilane (γ-MPS@MXene) followed by introducing into the vinyl ester resin (VER) through solution blending method to enhance the anti-corrosion properties of the coatings. The effects of γ-MPS@MXene incorporation on the mechanical properties, thermal stability, dynamic thermo-mechanical properties, UV aging resistance, anti-corrosion properties of the VER nanocomposites were systematically investigated. The optimum tensile strength, elastic modulus, hardness, thermal stability and UV aging resistance of γ-MPS@MXene VER nanocomposites can be achieved when composited with 0.08 wt% γ-MPS@MXene. The electrochemical impedance spectroscopy(EIS) results demonstrate the introduction of γ-MPS@MXene nanosheets into the VER enhanced the anti-corrosion properties of the composites coating remarkablely and the anti-corrosion mechanism was also revealed. The favourable interfacial interaction between γ-MPS@MXene and VER matrix through covalent cross-linking diminished interfacial defects of the composite coating and was also beneficial to enhancement of the compatibility, the well-dispersed γ-MPS@MXene in VER created a “labyrinth effect”, which prolonged the diffusion path of corrosive medium to the carbon steel substrate. This research provides a promising strategy for the fabrication of heavy anti-corrosion nanocomposite resin coatings, which can realize long-term corrosion protection of metal substrates.

Flexural strength and ballistic performance of vinyl ester resin/aramid fiber composites toughened by graphene nanosheets

The fiber reinforced polymer (FRP) armor composites are kinds of composite materials specially designed and manufactured to prevent the penetration of high-speed bullets and fragments. The FRP composites are commonly composed of reinforcing fibers, resin matrix and their interfacial structures. The vinyl ester resin (VER) is a kind of thermosetting resin commonly applied in the field of high performance bulletproof composites. However, the VER has the problem of insufficient toughness after curing, which seriously limits its application. In this research, the graphene nanosheets were homogeneously dispersed into VER matrix by ultrasonic-assisted dispersing process. The effects of graphene content on the mechanical and dynamic mechanical thermal properties of VER castings were investigated. The graphene-toughened VER/aramid fiber (AF) composites were prepared by hand layup-vacuum bag molding process. The influences of graphene content on the flexural strength and ballistic resistance of VER/AF composites were investigated. The results showed that the tensile strength, elongation at break, flexural strength and non-notch impact strength of VER casting filled with 0.1 wt.% graphene increased by 5.6%, 27.6%, 11.7% and 90.5%, respectively, compared with those of unfilled VER casting. The glass transition temperature Tg of VER casting gradually increased with the increase of graphene content. The hand layup-vacuum bag molding process effectively reduced the filtering effect of the fiber fabrics on graphene sheets. When the amount of graphene was 0.1 wt.%, the flexural strength of VER/AF composite was increased by 34.2%. Due to the improvement of fracture toughness of the resin matrix, the ballistic limit velocity V 50 and specific energy absorption of the VER/AF composites were both improved.

Evaluation of shear property of Screw pine fiber/glass fiber reinforced vinyl ester hybrid composites

To evaluate the shear property, screw pine fibers are hybridized with glass fibers in a vinyl ester resin matrix. Two types of screw pine/glass fiber reinforced vinyl ester hybrid composites were created (dispersed and skin-core). A hydraulic compression molding method was used to create composites with a total fiber loading of 35.12 vol%. The shear property of composites was evaluated based on their form. After tests, scanning electron microscopy was used to conduct fractographic studies on the fracture surface of the hybrid composite specimen. Furthermore, neat resin samples and Screw pine alone composites were prepared and tested for comparison. The results revealed that the addition of glass fiber increased the shear property of composites. In both types of composites, the composite with 18.59 vol% Screw pine fibers and 16.53 vol% glass fibers has a high level of shear property. However, the skin-core type composites outperformed the dispersed type composites.

Simultaneous improvements of the fire safety, mechanical properties and water resistance of vinyl ester resin composites by introducing microencapsulated ammonium polyphosphate by polytriazole

Achieving a good balance between mechanical properties and flame retardancy of vinyl ester resin (VER) remains a challenge for traditional inorganic retardants. Herein, a reactive coating shell was constructed on the surface of ammonium polyphosphate (APP) through click chemical reaction. The microencapsulated APP (MAPP) was introduced into and reacted with VER matrix. The coating and the reaction between the filler and the matrix bring a dual effect on comprehensive properties. 10 wt% addition of MAPP not only endow material with better fire safety including a limiting oxygen index of 27.1%, 44% reduction of total heat release, and 38% reduction of total smoke production, but also enhance the flexural and notched Izod impact strength compared with pure VER. The composite exhibits enhanced water resistance, as evidenced by relatively less reduction of flexural strength after immersing in boiling water for 6 h. The dual function enhancement strategy can provide new ideas to prepare composites with balanced flame retardancy, water resistance and mechanical properties.

Mechanical properties and dimensional stability of jute/VER-isocyanate hybrid matrix composites

Some composites of alkali treated jute fibers and vinylester-isocyanate/urethane hybrid resin were fabricated. The mechanical, thermo-mechanical, fractographic and aging behavior of these composites were studied and compared with the parent vinylester resin (VER) matrix composites. Using hybrid resin matrix, the impact strength of jute composites was increased by ∼20% over the VER matrix composites. It was, however, accompanied by the marginal improvement in their tensile and flexural properties. Dynamic mechanical analysis showed increased storage modulus and broadened tan δ peak when VER-isocyanate hybrid resin was used as a matrix material compared with the parent VER matrix in jute composites showing its superior stiffness and flexibility. In humid environment, a decrease in the weight gain and swelling thickness was observed for VER-isocyanate hybrid matrix jute composites after 60 days exposure when compared with the parent VER matrix composites. Under accelerated water aging, the drop of 12–24% in the tensile strength was noticed for VER-isocyanate hybrid matrix jute composites as compared to ∼29% for VER matrix composites. The changes in the mechanical response of all composites can be well co-related with their fractographic evidences existed onto the tensile fracture surfaces in both dry and wet conditions.

Investigation of the suitability of fiber reinforced polymer matrix composites for facilities operating in marine environment

This paper is related to the production and investigation of the structure, the mechanical and physicochemical properties of two kinds of fibre reinforced polymer matrix composites in order to assess their suitability as materials used in equipment operating in marine environment. The one of the investigated composites has a polyester resin matrix and a reinforcement phase of six-layer fibreglass, and the other one has a vinylester resin matrix and a reinforcement phase which is a combination of three-layer fibreglass and three-layer biaxial fibreglass. A comparative analysis has been made of the relative weight, tensile strength and bending strength of the two types of composite materials.

Experimental Investigation of Flexural Strength of Banana Fiber Reinforced Composites

The present generation widely makes use of en number of composites in the field of materials technology, with a very high performance and costs appropriate for the applications such as structural and automotives etc. Fiber reinforced composites are those composites that are called as the oldest and frequently used composite materials, in which Banana fibers are the most common ones. Nowadays consciousness and environmental awareness about using natural fibers as a serious alternative has been keep on increasing globally. And also in these present days natural fiber reinforced polymer composites are being widely used in various engineering applications. Natural fibers such as jute, sisal, palm, coir and banana are the most commonly used reinforcements. In vinyl ester resin matrix banana fibers have been used as reinforcement. This work deals with the study of effect of sodium hydroxide (NaOH) on fibers in addition with alumina (Al2O3) particulate. It is seen that the flexural strength value of UT, UT+ Al2O3, T+ Al2O3 has increased with increase in the fiber content.

Effect of Nanoiron Particles Reinforced Blended Polymer Nanocomposites on Mechanical Properties

We report on the preparation of nanocomposites using epoxy and vinylester blend in which nanoiron filler was dispersed to evaluate the mechanical performance. Different weight ratios viz.1,2,3,4,5 & 7wt.% of nanoiron particles were dispersed into the matrix to prepare different systems to evaluate the optimization of performance. Nanoiron was also prepared by chemical reduction method and nanocomposites were prepared by hand layup process. Three blade Mechanical stirrer and ultra-sonicator was used while preparing the modified to keep the non-homogeneity nanoparticle at bay. Mechanical properties such as hardness, tensile strength, flexural strength, impact strength and compression strength properties were performed. Nanoiron particles functionalization nepotisms the fabrication composites through the remedial temperature at low as associated to the as-synthesised nano particles occupied vinylester nano composites. Mechanical property values improved owing to the standardized nanoparticle chemical bonding and spreading between vinylester matrix and nanoparticles. Then the combination nanoiron particles into the vinylester resin matrix it becomes magnetically harder. Machines generated mechanical property values were compared and analysed with system generated software analysis of variance (ANOVA) values. Machine values and ANOVA values were measured for the specimens of epoxy+vinylester+nanoiron, where the nanoiron is varying viz. 1, 2, 3, 4, 5 and 7 wt.%.

Thermo-mechanical properties of fused borosilicate syntactic foams

The coefficient thermal expansion, a (CTE) of glass microballoon/vinyl ester syntactic foam was determined using dimensional changes of a temperature gradient plot. The CTE was measured and found to be up to 53-63 % lower than the vinyl ester resin matrix when mixing with different weight percentages of the glass microballoon ranging from 2 wt.% to 10 wt.% using a thermomechanical analyzer (TMA). The results of CTE showed that it has a strong relationship with the syntactic foam density (r), radius ration (h) ,cavity porosity (fg) and matrix porosity (fm). Experimental results showed that the CTE decreases when glass microballoons are added into the composites measured at different temperatures ranging from 30 oC to 70 °C. The CTE from the experimental results were also compared with Turner’s modification model for composites for its suitability for thermal expansion of syntactic foams. The results indicate that Turner’s modification model exhibits a close correlation with the reduction up to 80 % of CTE based on experiment.

Thermal Expansion Properties of Fused Borosilicate Syntactic Foams

The thermal properties such the coefficient thermal expansion, α (CTE) of fused borosilicate syntactic foam was determined using dimensional changes of a temperature gradient plot. The CTE was measured and found to be achieved the value lower than the vinyl ester resin matrix when mixing with different weight percentages of the glass microballoon ranging from 2 wt.% to 10 wt.% using a thermomechanical analyzer (TMA). These results showed that it has a strong relationship with the syntactic foam physical properties such density, radius ration,cavity porosity and matrix porosity. Experimental results showed that the CTE decreases when glass microballoons are added into the composites measured at different temperatures ranging from 30 °C to 70 °C. The CTE from the experimental results were also analysed using Turner’s modification model for composites for its suitability for thermal expansion of syntactic foams.

Improving the interfacial strength of carbon fiber/vinyl ester resin composite by self-migration of acrylamide: A molecular dynamics simulation

A molecular dynamics simulation was performed to investigate the migration of acrylamide (AM) to the carbon fiber (CF) surface from a liquid vinyl ester resin (VE), as well as the effect on the interfacial strength of CF/VE composite. The analysis of monomer concentration profile after the system equilibrium shows that an AM-rich interphase region was formed and the interfacial bond energy was increased. This can be explained by the greatest average atomic binding energy of AM with the CF surface. The migration of AM was confirmed experimentally by a depth profiling method using plasma etching and X-ray photoelectron spectroscopy. The AM molecules in interphase could chemically bond CF surface and VE matrix. As a result, the interface shear strength and interlaminar shear strength of CF/VE composite were enhanced by 126.98% and 81.86%, respectively.

Preparation of carbon fiber unsaturated sizing agent for enhancing interfacial strength of carbon fiber/vinyl ester resin composite

The practical application of carbon fiber (CF) reinforced vinyl ester resin (VE) composite was hampered seriously by the poor interfacial adhesion property. In this work, a novel unsaturated sizing agent was designed and prepared to improve the interfacial strength by covalently bonding CF with VE matrix. The main component of the sizing agent, N-(4′4-diaminodiphenyl methane)-2-hydroxypropyl methacrylate (DMHM), was synthesized and confirmed by FTIR and NMR. XPS results of sized carbon fiber (SCF) showed that DMHM has adhered to desized fiber surface and reacted with some active functional groups on the surface. The SCF was characterized by high surface roughness and surface energy (especially the polar component), which means better wettability by VE. As a result, the interface shear strength and interlaminar shear strength of SCF/VE composite were enhanced by 96.56% and 66.07% respectively compared with CF/VE composite, benefited mainly from the strong and tough interphase.

Dispersion study of clay nanoparticles in vinylester resin

Resistance to sea‐water penetration in fiber‐reinforced polymer composites is highly desirable for marine applications. This can be achieved by incorporating nanoparticles into polymer matrix, due to high aspect ratio of the platelets where small percentage of nanoclay particles properly dispersed in matrix can generate very large surface area for polymer/filler interactions. However, effective dispersion aiming for exfoliation and intercalation of nanoclays in resin is one of the major challenges faced for manufacturing of nanocomposites. In the present work, a suitable protocol is established for effective dispersion of Cloisite 15A nanoparticles in vinylester resin matrix. Dispersion study is conducted for different loading levels of nanoparticles and parameters are optimized. The extent of dispersion is characterized by performing X‐ray diffraction and high resolution transmission electronic microscopic image analysis. It is found that overnight swelling of nanoclays in resin followed by 45 min of ultrasonication at 220 V, 50–60 Hz frequency and 0.5 cycle per sec results in good amount of interaction with certain degree of exfoliation for loading level up to 6%. The nano particle dispersed resin is characterized to study the effect of nanoparticles on key manufacturing properties of resin matrix like rheology and cure kinetics. J. VINYL ADDIT. TECHNOL., 23:E51–E57, 2017. © 2016 Society of Plastics Engineers

NUMERICAL MODELLING AND VALIDATION OF 12.7 MM FSP IMPACT INTO ALFC SHIELD – ARMOX 500T STEEL PLATE SYSTEM

The study develops a methodology for numerical modelling and simulation of a 12.7 mm 13.4 g FSP fragment impact into the ALFC shield – ARMOX 500T steel plate system. The ALFC shield is composed of the ALF energyabsorbing subsystem and a 10 mm-thick 99,7% Al 2O3 alumina ceramic layer. The ALF subsystem is designed to absorb blast wave impact energy induced by explosive materials up to 10 kg TNT. The ceramic layer is designed to stop fragments from IED explosion. The 5 mm-thick Armox 500T steel plate constitutes the body bottom segment of a light armoured vehicle. The ALF subsystem has the following layered structure: Al2024 aluminium alloy plate, SCACS hybrid laminate plate, ALPORAS aluminium foam, SCACS hybrid laminate plate. The layers are joined with Soudaseal 2K chemoset glue. SCACS hybrid laminate contains the following components: VE 11-M modified vinylester resin (matrix), SWR800 S-glass plain weave fabric, Tenax HTA40 6K carbon plain weave fabric, Kevlar 49 T 968 aramid plain weave fabric. The total thickness of the ALFC shield amounts to 90 mm. Proof ground tests of a 12.7 mm 13.4 g FSP fragment impact into the ALFC shield – ARMOX 500T steel plate system have been performed at impact velocity 715 m/s and used for experimental validation of numerical modelling and simulation. In the numerical modelling, the aluminium alloy plate and Armox 500T steel plate are working in the elasto-plastic range according to Johnson–Cook model. The 99.7% Al 2O3 alumina ceramic is working in elasto-short range according to JH-2 Johnson–Holmquist model. The simulations correspond to large displacements, large deformations and potential contact among all the components of the system. In FE mesh, the 8-node 24 DOF hexahedral finite elements with single integration point have been used. Failure criteria governing ad-hoc erosion of finite elements have been applied. The FEM modelling, simulation and postprocessing have been carried out using Catia, HyperMesh, LS-DYNA and LS-PrePost systems. The simulation results in the form of displacement/penetration contours and the FSP final deformation have been compared with the experimental results.

NUMERICAL MODELLING AND DESIGN OF ALFC SHIELD LOADED BY 20 MM FSP FRAGMENT

The study develops numerical modelling and design of the ALFC shield loaded by the 20 mm 54 g FSP fragment moving at impact velocity of 1800 m/s (fragmentation simulation of IED devices), used to protect 5 mm-thick Armox 500T steel plate. The ALFC shield is composed of the ALF energy-absorbing subsystem and a 99.7% Al 2O3 alumina ceramic layer. The ALF subsystem is designed to absorb blast wave impact energy induced by explosive materials up to 10 kg TNT. The ceramic layer is aimed at stopping FSP fragments. The 5 mm-thick Armox 500T steel plate reflects the body bottom segment of a light armoured vehicle. The main purpose of the study is to determine the minimum thickness of the ceramic layer at which the 5 mm-thick Armox 500T steel plate is fully protected from perforation. The ALF subsystem has the following layered structure: Al2024 aluminium alloy plate, SCACS hybrid laminate plate, ALPORAS aluminium foam, SCACS hybrid laminate plate. The layers are joined with Soudaseal 2K chemoset glue. SCACS hybrid laminate contains the following components: VE 11-M modified vinylester resin (matrix), SWR800 glass S plain weave fabric, Tenax HTA40 6K carbon plain weave fabric, Kevlar 49 T 968 aramid plain weave fabric. The total thickness of the ALF shield amounts to 76 mm. In the numerical modelling, the aluminium alloy plate and Armox 500T steel plate are working in the elasto-plastic range according to Johnson–Cook model. The 99.7% Al 2O3 alumina ceramic is working in elasto-short range according to JH-2 Johnson–Holmquist model. The simulations correspond to large displacements, large deformations and contact among all the components of the system. In FE mesh, the 8-node 24 DOF hexahedral finite elements with single integration point have been used. Additional failure criteria governing ad-hoc erosion of finite elements have been applied. The FEM modelling, simulation and postprocessing have been carried out using Catia, HyperMesh, LS-DYNA and LS-PrePost systems. The simulation results are presented in the form of displacement – perforation contours and the FSP final deformation for both the FSP–shield–plate and the FSP–plate systems. It has been pointed out that 18 mm-thick ceramic layer protects the LAV body bottom plate from perforation.