Improvement in Adhesive Performance of Single-Lap Joining Composite Lamınates by Using Nano-Montmorillonite Modified Epoxy (original) (raw)
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Tensile and Flexural Properties of Montmorillonite Nanoclay Reinforced Epoxy Resin Composites
Advanced Materials Research, 2015
In this work, montmorillonite (MMT) nanoclay reinforced epoxy resin was prepared to study the effect of nano filler on tensile and flexural properties of its nanocomposite. MMT was first sonicated for 2 hours with an acetone where the ratio was 50 mL acetone: 1g clay. After being sonicated the clay was added to an epoxy resin matrix at 80 o C and mixed until the acetone was removed. Tensile and flexural tests were investigated to understand the effect of clay on the mechanical properties of MMT reinforced epoxy nanocomposite. In general, the mechanical properties of MMT/epoxy nanocomposites were slightly increased as the clay loading was increased up to 1 phr. However, for the amount of nanoclay more than 1 phr the result showed significantly decrease in mechanical properties. It was found that by adding the nanoclay up to 1 phr, the Young's and flexural modulus increased around 6.75% and 6.61%, respectively. Since the nanoclay has higher elastic modulus as compared to epoxy resin, the addition of clay increased the modulus of its nanocomposites. On the other hand, at 2 phr of nanoclay the tensile strength, Young's modulus, flexural strength and flexural modulus deceased around 44.12%, 17.24%, 17.84% and 10.77% respectively compared to pure epoxy. For more than 1 phr of filler the clay distributions might not be well dispersed and thus more agglomerations occurred in the composites. It can be concluded that, 1 phr of MMT filler was the optimum amount that can be reinforced with epoxy resin in term of tensile and flexural properties.
Mechanics of Composite Materials, 2014
Compositions based on an ED-20 resin with three types of modifiers: natural montmorillonite (MMT) Cloisite Na + , organomodified MMT Cloisite 30B, and halloysite, were investigated. An optimum regime was chosen for preparation of the epoxy/modifier systems by employing the ultrasonic mixing. The rheological characteristics of suspensions were used to estimate the distribution of modifier in the epoxy oligomer. According to rheological data, the best dispersion of MMT in the epoxy oligomer after ultrasonic stirring was observed for the organomodified MMT Cloisite 30B. The maximum shear adhesion strength was also observed for the epoxy resin+Cloisite 30B systems. For the systems with 2 wt. % of Cloisite 30B, the increase in the adhesion strength was up to 65% as compared with that of the pristine epoxy oligomer.
Seawater Durability of Nano-Montmorillonite Modified Single-Lap Joining Epoxy Composite Laminates
El-Cezeri Fen ve Mühendislik Dergisi, 2018
The objective of this study was to investigate of nano-montmorillonite modified epoxy composite single-lap bonded joints, after being exposed to seawater immersion in order to understand the effect of seawater environment on their performance. To prepare the nano adhesives, nano montmorillonite (2 wt %) was incorporated into epoxy resin. Composite bonded specimens which manufactured with VARIM (Vacuum Assisted Resin Infusion Method) were prepared accordance with ASTM D5868-01 and immersed in seawater for 6 months. As a result of seawater immersion, considerable reductions were observed in the adhesives performance. However, the properties of 2 wt% nano montmorillonite/epoxy adhesives were observed that the performance changed less after exposing to seawater. Scanning electron microscope (SEM) and optical microscope were used to investigate the microstructures of the damage surfaces.
Materials Research
Due to their biodegradability, affordability, low density, and numerous other benefits, natural fiber polymer composites are preferable to conventional GFRP in maritime applications. However, when exposed to moisture, their mechanical qualities deteriorate. A significant agricultural waste called pineapple leaf fiber (PALF) can be employed as reinforcement in epoxy matrices. Improved interfacial bonding between phases improves interfacial bonding and hence enhance mechanical and water absorption properties. Only evaluation of mechanical properties is undertaken in this paper. Nanoclay in 1.5 and 3 wt% was incorporated in epoxy resin via magnetic stirring and ultrasonication. PALF fibers were subjected to NaOH treatment and was analyzed using SEM and FTIR techniques. Hand layup and compression moulding were used to fabricate composites using a nanoclay-epoxy resin combination and chemically treated PALF (20 & 30 wt%). The combination of 30 wt% PALF and 1.5 wt% nanoclay results in the maximum mechanical properties, namely tensile and flexural properties. The results of SEM investigation of fractured specimens show that interfacial bonding in epoxy composites containing PALF is poor while that in epoxy composites containing PALF and 1.5 wt% nanoclay is excellent. Due to nanoclay agglomerations, bonding is inadequate at 3 wt% nanoclay, which lowers the mechanical properties.
International Polymer Science and Technology, 2012
An examination is made of the effect of modifying montmorillonite with organic compounds and its ultrasound treatment on the rheological properties of filled epoxy oligomers and the structure and physicomechanical properties of cured composites. To improve the physicomechanical properties of filled epoxy composites, it is recommended that use be made of modified montmorillonite of grade Cloisite 30B, which has the best compatibility with the epoxy matrix.
Journal of Composites Science
Carbon-fiber-reinforced plastics are composite materials with record-high specific strength, which depends on the efficiency of stress redistribution between the reinforcing fibers by the polymer matrix. The problem is the accurate assessment of adhesion in the carbon fiber–polymer matrix system since it affects the overall strength of the composite. This paper provides a novel electrochemical method for determining adhesion by estimating the critical length of carbon fibers that protrude above the fracture surface of the fiber-reinforced composite using their electrical conductivity and insulating properties of the polymer matrix. The method has been successfully applied to evaluate adhesion in carbon plastics having an epoxy matrix filled with nanoparticles of different anisometry: carbon nanotubes, organomodified montmorillonite, or detonation nanodiamonds. In addition to adhesion measurements, the effect of nanoparticles on the viscosity of epoxy binder, its impregnation efficie...
Influence of nano toughened epoxies in the bonding characteristics of adhesive joints
Adhesive joints are proving to be an excellent solution for joining similar or dissimilar substrates due to their elevated and enhanced bonding characteristics. They are found to frequently replace the traditional joints due to their ability to distribute load. Hence, the substantiation of the joint strength lies in the strengthening of the adhesion characteristics. Among the many parameters which promote the adhesive strengthening, the fusion of nano particles (NPs) has occupied a prominent area of research due to their promotional ability to enhance the mechanical properties of the joint. Hence the need is there to conduct a comprehensive review into the types of NPs, methodologies of dispersion, the % by wt of NP addition, and the changes that take place in the mechanical and chemical perspectives in the adhesive layer as well as the interface zones between the adhesive and the substrate. So, the paper is committed to conduct a comprehensive but relevant review in this direction of adhesive strengthening paving the way for adhesive joint strength substantiation.
Journal of Adhesion Science and Technology, 2010
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Nanofillers modification of Epocast 50-A1/946 epoxy for bonded joints
Chinese Journal of Aeronautics, 2014
Epocast 50-A1/946 epoxy was primarily developed for joining and repairing of composite aircraft structural components. The objective of the present work is to modify the Epocast epoxy resin by different nanofillers infusion. The used nanofillers include multi-walled carbon nanotubes (MWCNTs), SiC and Al 2 O 3 nanoparticles. The nanofillers with different weight percentages are ultrasonically dispersed in the epoxy resin. The sonication time and amplitude for MWCNTs are reduced compared to Al 2 O 3 and SiC nanoparticles to avoid the damage of MWCNTs during sonication processes. The fabricated neat epoxy and twelve nanocomposite panels were characterized via standard tension and in-plane shear tests. The experimental results show that the nanocomposites materials with 0.5wt% MWCNTs, 1.5wt% SiC and 1.5wt% Al 2 O 3 nanoparticles have the highest improvement in the tensile properties compared to the other nanofiller loading percentages. The improvements in the shear properties of these nanocomposite materials were respectively equal to 5.5%, 4.9%, and 6.3% for shear strengths, and 10.3%, 16.0%, and 8.1% for shear moduli. The optimum nanofiller loading percentages will be used in the following papers concerning their effect on the bonded joints/repairs of carbon fiber reinforced composites. ª 2014 Production and hosting by Elsevier Ltd. on behalf of CSAA & BUAA.
International Journal of Adhesion and Adhesives, 2018
In the current study, the synergistic effect of a multi-walled carbon nanotube (MWCNT) and a nanoclay (C30B) on the mechanical, morphological and thermal behaviour of an epoxy based adhesive was investigated. The adhesive strength was investigated by conducting lap shear tests and from the test results it was observed that, Ep/1.0 C30B adhesive possessed the highest adhesive strength among all the adhesive formulations investigated and showed a 52% enhancement as compared to the pristine epoxy. Fracture analysis of different adhesive systems was investigated using scanning electron microscopy (SEM). SEM micrographs revealed that nanomaterials with different shapes and dimensions provide distinct features on the fracture surfaces due to the different energy dissipation mechanisms which they promote. The morphological variations of the epoxy based nanocomposite adhesives were investigated using transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. The curing kinetics of the different nanofiller reinforced epoxy adhesives were examined using a nonisothermal differential scanning calorimetric (DSC) technique. The activation energy (E a) was calculated by applying Kissinger's method and found to be increased for the Ep/1.0 CNT/1.0 C30B adhesive system as compared to the pristine epoxy. This increment can be attributed to the physical impediment impacted by the nanomaterials on the curing reaction of the epoxy resin. The degradation kinetics of the adhesive systems were also studied using thermogravimetric analysis (TGA). The corresponding activation energies (E) of the adhesive systems obtained by Kissinger's model were found to increase with addition of nanofillers, thus indicating improved thermal stability.