CERES :: Browsing by Author "Abhyankar, Hrushikesh"

Browsing by Author "Abhyankar, Hrushikesh"

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Open Access
Advanced carbon/flax/epoxy composite material for vehicle applications: vibration testing, finite elements modelling, mechanical and damping characterization.
(Cranfield University, 2015-05) Ampatzidis, Theofanis; Blackburn, Kim; Abhyankar, Hrushikesh
Nowadays, research in automotive and construction industries focuses on materials that offer low density along with superior dynamic and static performance. This goal has led to increasing use of composites in general, and carbon fibre (CF) composites in particular. CF composites have been adopted widely in the space industry and motorsports. However, their high stiffness and low density leads to low damping performance, which is responsible for increased levels of noise and reduction in service life. On the other hand, natural fibres (NF) like flax fibres (FF) are capable of delivering a much better damping performance. A hybrid composite comprising of FF and CF can potentially deliver both on strength and higher damping performance. In this study the mechanical and damping properties of CF, FF and their hybrid composites were examined. Composites' anisotropic nature affects their response to vibrations and so traditional damping experimental setups used for metals had to be ruled out. A damping set up based on Centre Impedance Method (CIM) was adopted for the purpose of this study which was based on an ISO standard originally developed for glass laminates. Standard tensile and flexural tests were conducted in order to characterise the performance of the hybrid composite. The experimental work was accompanied by finite elements analysis (FEA). The experimental data and FEA were used to optimize the hybrid structure layup with respect to damping and structural response.
Open Access
Aerogel/epoxy thermal coatings for carbon fibre reinforced plastic substrates
(Taylor and Francis, 2019-01-20) Krishnaswamy, Suryanarayanan; Abhyankar, Hrushikesh; Marchante, Veronica; Huang, Zhaorong; Brighton, James
The present work studies an aerogel/epoxy composite that was dip coated onto a carbon fibre substrate by adding the aerogel at the 1 h and the 1.5 mark of the epoxy cure. Both coatings show decrease in thermal conductivity values (39% and 47% respectively) when compared to a pure epoxy coating. The coatings’ reflectance spectra also provided further evidence for the existence of the nano-pores within the aerogel particles. The aerogel coating was modelled using material properties from literature and solved using finite element methods. The model, which validated using experimental data, was then used to predict the coating’s performance in cyclic thermal loads. Additionally, coatings on a single surface- top and bottom; were also modelled and compared with the double coating system wherein it was seen that the double coating system had the lowest rate of temperature change and fluctuations at steady-state in contrast to the bottom coating which, showed the fastest drop in temperature as well as the highest fluctuations at steady state conditions. The performance of the top coating was in the middle.
Open Access
Chronological review of the catalytic progress of polylactic acid formation through ring opening polymerization
(SCIENCEDOMAIN International, 2016-08-09) Dubey, Satya P.; Abhyankar, Hrushikesh; Marchante, Veronica; Brighton, James; Blackburn, Kim
The disposal of a large amount of polymer waste is one of the major challenges of this century. Use of bio-degradable polymers obtained from sustainable sources presents a solution to this problem. Poly lactic acid (PLA), a bio-degradable polymer, can be synthesized from sustainable sources as corn, starch, sugarcane and chips. Ring opening polymerization (ROP) of Lactide (LA) monomer using metal/bimetallic catalyst (Sn, Zn or Al) is the preferred method for synthesis of PLA. However, the PLA synthesized using such catalysts may contain trace elements of the catalyst. These catalyst traces are known carcinogens and as such should be (ideally) eliminated from the process. Use of the organic catalyst instead of metallic catalysts, may be one of the prominent solutions. Organic catalysts require the higher energy of activation for the ROP reaction of LA. Such energy requirement can be achieved through the application of alternative energy during the reaction. Alternative energy sources such as LASER, Ultrasound and microwave are prominent options to implement and process the ROP of PLA. This paper is an effort to emphasize the chronological review and to establish the current state-of-the-art in the field of PLA research.
Open Access
Development of CNC prototype for the characterization of the nanoparticle release during physical manipulation of nanocomposites
(Taylor & Francis, 2016-02-18) Gendre, Laura; Marchante, Veronica; Abhyankar, Hrushikesh; Blackburn, Kim; Temple, Clive; Brighton, James L.
This work focuses on the release of nanoparticles from commercially used nanocomposites during machining operations. A reliable and repeatable method was developed to assess the intentionally exposure to nanoparticles, in particular during drilling. This article presents the description and validation of results obtained from a new prototype used for the measurement and monitoring of nanoparticles in a controlled environment. This methodology was compared with the methodologies applied in other studies. Also, some preliminary experiments on drilling nanocomposites are included. Size, shape and chemical composition of the released nanoparticles were investigated in order to understand their hazard potential. No significant differences were found in the amount of nanoparticles released between samples with and without nanoadditives. Also, no chemical alteration was observed between the dust generated and the bulk material. Finally, further developments of the prototype are proposed.
Open Access
Development of novel flax bio-matrix composites for non-structural and structural vehicle applications
(Cranfield University, 2015) Zhu, Jinchun; Abhyankar, Hrushikesh; Zhu, Huijun
The use of natural fibres (e.g. flax, hemp etc.) instead of synthetic fibres (carbon and glass etc.) as composite reinforcements not only benefits the environment, but also provides economical lightweight products for transports. Although there are a few studies reported in literature on use of flax fibres, there is no comprehensive guide on use of flax fibres with bio-resins to re-engineer bio- composite systems that can be used in vehicle structures. The state-of-art of the current research towards using natural fibre reinforced composites is reviewed by the thesis. The review covers the performances of flax composites, concentrating on the effect of matrix types and existing development methods. The review also identifies the rational of selecting tannin resins and bio-epoxy resins to combine with flax fibre reinforcements. In the experimental work, mimosa tannin resin (natural phenolic resin) and pine- oil derived supersap epoxy resin are selected to manufacture the fully renewable flax composites. By tailoring the fibre configurations and chemical surface treatments, the resultant composites were investigated to provide information for engineers to understand the composite behaviours and properties. Mechanical properties (tension, flexural, shear, impact etc.) and physical properties (moisture, ageing etc.) were assessed through adequate tests and analysing methods. In addition, bio-sandwich structures based on the novel studied composites and commercial bio-foams were evaluated to study the energy absorption which could be very important in vehicle design. Based on the results, flax/supersap epoxy and flax/tannin composites are suitable for possible exterior structural and interior non-structural applications, respectively. The developed flax fibre composites with innovative bio-matrices have a potential to prevail in modern vehicle applications, due to the competitive performances, economic viability and environmental acceptability.
Open Access
Effect of akali, esterification and silane surface treatments on properties of flax fibres
(SCIENCEDOMAIN International, 2014-09-28) Zhu, J.; Brighton, J.; Zhu, H.; Abhyankar, Hrushikesh
In the recent decades, flax fibres can be used as laminate reinforcements with polymer matrix materials to form natural composites, providing outstanding environmental benefits and other characteristics such as reduced cost and light weight. The composite properties are limited by the poor natural fibre/polymer matrix adhesion, which could be improved by chemical modifications. The fibre properties, such as thermal and mechanical properties, after the treatments have a direct effect on the composite behaviors. In order to investigate the effect of treatments on fibre properties, non-woven flax fibre mats were subjected to alkali, esterification and silane treatment. Fourier transformation infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and tensile tests were conducted on the virgin and treated flax fibres. It was found that all the treatments resulted in the removal of pectin and lignin component within the primary cell wall as evidenced by the characteristic IR peak change. The results showed that the thermal stability of non-cellulose part of flax fibres was highly improved by esterification modifications. However, the decrease (20-30%) in fibre tensile properties after the treatments was possibly offset by the improvement in fibre/matrix adhesion.
Open Access
Effect of extrusion and compression moulding on the thermal properties of nylon-6/silica aerogel composites
(SAGE, 2017-10-03) Krishnaswamy, Suryanarayanan; Tinsley, Lawrence; Marchante, Veronica; Addepalli, Sri; Huang, Zhaorong; Abhyankar, Hrushikesh
The article presents the effect of a lower extrusion speed and compression moulding processes on the thermal properties of polyamide 6 (PA-6)/aerogel composite. Scanning electron and optical microscope images showed that although most of the aerogel was destroyed during extrusion at 65 r/min, extrusion at 5 r/min showed a better retention of the aerogel structure. However, when subjected to moulding in a compression press, both composites extruded at different speeds suffered significant damage. Nevertheless, the extruded samples did show a lower thermal conductivity compared to the virgin polymer. Further, it was observed that the sample extruded at 5 r/min had a lower damage coefficient value with an overall loss of around 33% to the aerogel structure when compared to the material extruded at 65 r/min, which endured a structural loss of 41% to the aerogel in it.
Open Access
Effect of extrusion and compression moulding on the thermal properties of Nylon-6/Silica Aerogel Composites: Experimental Data
(Cranfield University, 2017-10-05 16:38) Krishnaswamy, Surya; Tinsley, Lawrence; Marchante, Veronica; Addepalli, Sri; Huang, Zhaorong; Abhyankar, Hrushikesh
The paper presents the effect of a lower extrusion speed and compression moulding on the thermal properties of PA-6/Aerogel composite. SEM/EDX and optical microscope images showed that although most of the aerogel was destroyed during extrusion at 65 rpm, extrusion at 5 rpm showed better retention of the aerogel structure. However, when subjected to moulding in a compression press, both composites suffered significant damage. Nevertheless, the final thermal conductivity and damage coefficient values did show an improvement in the thermal insulation properties of the samples extruded at 5 rpm compared to the samples extruded at 65 rpm and the virgin polymer (PA-6) with the former losing around 33% of the structure of the aerogel particles compared to 41% for the later.
Open Access
Effect of fibre treatments on mechanical properties of flax/tannin composites
(Cranfield University Press, 2013-09-19) Zhu, Jinchun; Zhu, Huijun; Abhyankar, Hrushikesh; Njuguna, James
Due to the inherent environmental benefits of using natural resin (tannin) and natural fibre (flax), flax/tannin composites could be potentially used for vehicle applications. One of the main limitations is the hydrophilic property of flax, resulting in the poor fibre/hydrophobic matrix interface quality. Alkali, acetylation, silane treatment and enzymatic treatment were selected to modify non-woven flax mats to prepare the composites. The fibre morphology was studied through scanning electronic microscopes (SEM). The effects of fibre pre-treatments on dynamic and static mechanical properties of composites were investigated through adequate experiments, such as dynamic mechanical analysis (DMA) and static tensile testing. The modified rougher fibre surface broadened the glass transition peaks of composites due to the improved surface adhesion. However, there is no big improvement of tensile strength after modifications. The pure NaOH (sodium hydroxide) treated composites remain the tensile properties and offer good flax/tannin wettability.
Open Access
The effect of temperature changes on to quasi-static tensile and flexural performance of glass fibre reinforced PA66 composites
(Cranfield University Press, 2013-09-19) Butterworth, Ian; Abhyankar, Hrushikesh; Westwood, Keith; Njuguna, James; Brighton, James; Mouti, Zakaria
A significant method of reducing CO2 emissions in road vehicles is to reduce the vehicle mass. One means in which this can be achieved is to adopt lightweight materials such as thermoplastic composites. Thermoplastics offer advantages in term of weight when compared to conventional steel and aluminium casting. In this study thermal mechanical testing has been conducted on two types of commercial polyamide 66 (PA66) with 35 wt.% short glass fibre reinforcement. One of the materials was impact modified with an elastomer to increase material toughness. Experimental results showed both the reinforced PA66 materials to be temperature dependent. All test results demonstrated the trade-off in the mechanical properties of the two materials especially the impact modified. PA66 with 35 wt.% short glass fibre exhibits the best tensile strength, flexural strength and modulus for each temperature tested. Whereas the impact modified PA66 with 35 wt.% short glass fibre exhibits the higher strain and toughness for each temperature tested.
Open Access
Improving mechanical properties of novel flax/tannin composites through different chemical treatments
(Elsevier, 2015-02-12) Zhu, Jinchun; Zhu, Huijun; Immonen, K.; Brighton, James; Abhyankar, Hrushikesh
Due to the inherent environmental benefits of using renewable materials, mimosa tannin resin (a natural phenolic resin) reinforced by flax fibres could offer desirable characteristics (lightweight, economic and low environmental impact) aiming at reducing carbon footprint of superlight electric vehicles. The non-woven flax mats were chemically treated (alkali, acetylation, silane and enzymatic treatment) to prepare tannin composites through compression moulding (130 °C/35 min/1.5 MPa). The change in fibre morphology was seen in SEM (scanning electronic microscope) images. The treatments (except enzymatic) showed significant improvement in tensile properties, along with enhancement (acetylation) in flexural properties, but little effect on impact resistance for all treatments. APS (aminopropyl triethoxy siloxane) treated composites showed highest tensile strength of 60 MPa and modulus of 7.5 GPa. BTCA (butanetetracarboxylic acid) treatment led to the highest flexural strength of up to 70 MPa. NaOH treatment retained the impact failure force of about 0.5 kN and sustained the saturation energy (4.86 J) compared to untreated composites (4.80 J).
Open Access
Manufacturing of novel aerogel based thermal coating systems for carbon/epoxy composite substrates.
(2018-06) Krishnaswamy, Suryanarayanan; Abhyankar, Hrushikesh; Huang, Zhaorong
To try and increase the applicability of carbon fibre composites, the present work considers the use of thermal coatings on its surface. After a study on relevant literature pertaining to conventional and alternate thermal barrier coatings, it was believed that YSZ-based and/or aerogel-based systems had the most potential. But successful application of these coatings required additional research, particularly on processing routes and long-term performance. Therefore to try and achieve a more efficient thermal coating on composite substrates, aerogel-based materials were investigated since they showed the most promise. These aerogel/polymer composites were further characterized using different morphological, optical and thermal techniques. The experimental results showed particularly promising trends for aerogel/epoxy materials whose best sample had an aerogel damage coefficient value of 18.3%. Hence, this system was applied as a coating on a carbon fibre reinforced polymer substrate and the whole system showed better thermal performance compared to a pure epoxy coating. The coating and the substrate were subsequently modelled and solved using finite element analysis to determine the most effective system under a cyclic thermal load. Although, the selection of the coating type (double, top or bottom) is dependent on the exact application; the top coating displayed the best performance balance. Nevertheless, both, experimental measurements and simulation results in the current work point to a potential application of the coating in industries such as aerospace, automotive and/or construction.
Open Access
Mathematical modelling and simulation of continuous, highly precise, metal/eco-friendly polymerization of Lactide using alternative energies for reaction extrusion
(Cranfield University, 2016-07) Dubey, Satya P.; Abhyankar, Hrushikesh; Brighton, James L.
Polylactic acid (PLA) is one of the most promising bio-compostable and biodegradable thermoplastic made from renewable sources. PLA, is typically obtained by polymerising lactide monomer. The technique mainly used for ring opening polymerization (ROP) of Lactide is based on metallic/bimetallic catalyst (Sn, Zn, and Al) or other organic catalysts in suitable solvent. However, the PLA synthesized using such catalysts may contain trace elements of the catalyst, which may be toxic. In this work, reactive extrusion experiments using stannous octoate Sn(Oct)2 and tri-phenyl phosphine (PPh)3 were considered to perform ROP of lactide monomer using ultrasound as an alternative energy (AE) source for activating and/or boosting the polymerization. Mathematical model of ROP of lactide, was developed to estimate the impact of reaction kinetics and AE source on the polymerization process. Ludovic® software, a commercial code was used. It was adopted for the simulation of continuous reactive extrusion of PLA. Results from experiments and simulations were compared to validate the simulation methodology. Results indicate that the application of AE source in reaction process boost the PLA formation rate. Result obtained through Ludovic simulation and experiments were validated. It was shown that there is a case for reducing the residence time distribution (RTD) in Ludovic due to the ‘liquid’ monomer flow in the extruder. This change in the parameters resulted in validation of the simulation. However, it was concluded that the assumption would have to be established by doing further validations.The simulation model includes the details of kinetics of reactions involved with in the process and helps to upscale the reaction output. This work also estimates the usefulness and drawbacks of using different catalysts as well as effect of alternative energies and future aspects for PLA production.
Open Access
Measurement of nanoparticles release during drilling of polymer nanocomposites
(Institute of Physics, 2015-05-26) Gendre, Laura; Marchante Rodriguez, Veronica; Abhyankar, Hrushikesh; Blackburn, David; Brighton, James
Nanomaterials are one of the promising technologies of this century. The Project on Emerging Nanotechnologies [1] reports more than 1600 consumer products based on nanotechnology that are currently on the market and advantages link to the reinforcement of polymeric materials using nano-fillers are not to demonstrate anymore. However, the concerns about safety and its consumer perception can slow down the acceptance of nanocomposites. Indeed, during its life-cycle, a nanotechnology-based product can release nano-sized particles exposing workers, consumers and environment and the risk involved in the use and disposal of such particles is not well known. The current legislation concerning chemicals and environment protection doesn’t explicitly cover nanomaterials and changes undergone by nanoparticles during the products’ life cycle. Also, the possible physio-chemical changes that the nanoparticles may undergo during its life cycle are unknown. Industries need a standard method to evaluate nanoparticles release during products’ life cycle in order to improve the knowledge in nanomaterials risk assessment and the legislation, and to inform customers about the safety of nanomaterials and nanoproducts. This work aims to propose a replicable method in order to assess the release of nanoparticles during the machining of nanocomposites in a controlled environment. For this purpose, a new experimental set-up was implemented and issues observed in previous methods (background noise due to uncontrolled ambient environment and the process itself, unrepeatable machining parameters) were solved. A characterisation and validation of the chamber used is presented in this paper. Also, preliminary testing on drilling of polymer-based nanocomposites (Polyamide-6/Glass Fibre reinforced with nano-SiO2) manufactured by extrusion and injection moulding were achieved.
Open Access
Mechanical properties and impact energy absorption of hybrid thermoplastic nanocomposite structures
(2016-01) Silva, Francesco; Abhyankar, Hrushikesh; Brighton, James L.
This thesis focuses on the mechanical properties and the impact energy absorption capabilities of injection moulded hybrid three-phase polymer composites. Its main aim is to investigate the effect of different micro and nano sized filers on the mechanical properties; such as stiffness, strength, ductility, impact resistance and energy absorption capability; of short-fibre reinforced thermoplastic composites. Extensive experimental and numerical investigations were core to the research. Six different, three-phase composites, were manufactured by the integration of two types of nano-reinforcements (either nano-silica or nano-clay), or micro glass-spheres, into two types of short glass-fibre reinforced thermoplastic matrices (either Polypropylene (PP) or Polyamide (PA6)). The materials were characterized using Transmission Electron Microscopy (TEM), Wide Angle X Ray Diffraction (WAXD) and optical microscopy. The effect of matrix and reinforcement material on the mechanical properties and the energy absorption capabilities of polymer composites were studied in detail. The results are compared with the properties of standard two-phase glass-fibre reinforced polymer composites. Initial experiments focused on quasi-static uniaxial tensile and compression tests, as well as quasi-static crash tests of the conical structures. Subsequently, dynamic drop weight impact crash tests of the conical structures were conducted to investigate the influence of the nano reinforcement on the energy absorption capabilities of the polymer composites. To study propagation of the dynamic cracks and the energy absorbing mechanism, the impact event was recorded using a high-speed camera. The fracture surface was investigated with scanning electron microscopy (SEM). Furthermore, improved simulation tools were developed to accurately and effectively model nanocomposite structures subjected to dynamic loads. A constitutive model with orthotropic yield, strain rate sensitivity and strain energy density based failure criterion, was developed and implemented into Ls Dyna Finite Element (FE) code. The results show that by changing the filler and the matrix material, it is possible to control the mechanical properties and the energy absorption capability of the glass-fibre reinforced polymer nanocomposites. An increase in the mechanical properties (stiffness, strength or ductility) of PA6 composites was observed. Furthermore, nano-silica and glass-spheres reinforcements were found to improve the energy absorption capabilities of PA6 composites by changing the mode of failure, whereas nano-clay reinforcement caused a decrease in that capability. Little or negative influence of the nano-fillers was observed, when combined with PP based composites. The experimental findings were used to generate, calibrate and validate the user defined material model. The structural FE modelling proved that the model was capable of accurately and effectively representing the nanocomposite structures subjected to static and dynamic loads. Furthermore, it provided a valuable input for better understanding of the structural failure mechanism, observed in the three-phase nanocomposite structures.
Open Access
Mechanical properties of three-phase polyamide 6 nanocomposites
(Cranfield University Press, 2013-09-19) Gendre, Laura; Abhyankar, Hrushikesh; Njuguna, James; Ermini, Valentina
This work focus on the mechanical properties of three-phase nanocomposites using multiscale reinforcements. The influence of the nano-fillers content, as well as the temperature were studied. Polyamide-6 reinforced with short glass fibre 30 wt.% and with an addition of nanoclay (montmorillonite) and/or nanosilica (SiO2) were tested in order to characterise their tensile properties at room temperature and at 65oC just above the polyamide 6 glass transition temperature. SEM analysis were conducted on the fracture surface of the tensile bars. SEM investigations showed the importance of the interaction matrix/filler for the material behaviour. Our study also shows that the increase of OMMT percentage in polyamide-6/glass fibre composite made the material more brittle and had a negative effect on the tensile properties. Further, for the silica-based nanocomposites, an optimum was found for a nanofillers content of 1wt.%.
Open Access
Microwave energy assisted synthesis of poly lactic acid via continuous reactive extrusion: modelling of reaction kinetics
(Royal Society of Chemistry, 2017-03-27) Dubey, Satya P.; Abhyankar, Hrushikesh; Marchante, Veronica; Brighton, James L.; Bergmann, Björn; Trinh, Giang; David, Chantal
The most commonly used batch process to manufacture PLA is ring opening polymerization (ROP) of lactide monomer in a suitable solvent, in the presence of a metallic/bimetallic catalyst (Sn, Zn, and Al) or other organic catalysts. However, this process does not lend itself to safer/cleaner and high throughput (and high volume) manufacturing. Continuous reactive extrusion of lactide monomer using a suitable reaction input has the potential to increase the throughput, and this route has been explored in the literature. In this work, reactive extrusion experiments using stannous octoate Sn(Oct)2 and tri-phenyl phosphine (PPh)3, were considered to perform ROP of lactide monomer using the microwave as an alternative energy (AE) source for activating and/or boosting the polymerization. Implementation of a microwave generator in a section of the extruder is one of the novelties of this research. A simulation model of ROP of PLA was formulated to estimate the impact of reaction kinetics and AE source on the polymerization process. Ludovic® software was used for the simulation of continuous reactive extrusion of the process. Experimental and simulated results were compared for the validation of the methodology. This work also highlights the advantages and drawbacks of most conventional metal catalysts, the effect of alternative energies on reaction mechanism, and safe and efficient production of PLA.
Open Access
Modelling and validation of synthesis of poly lactic acid using an alternative energy source through a continuous reactive extrusion process
(MDPI, 2016-04-22) Dubey, Satya P.; Abhyankar, Hrushikesh; Marchante, Veronica; Brighton, James L.; Blackburn, Kim; Temple, Clive; Bergmann, Björn; Trinh, Giang; David, Chantal
PLA is one of the most promising bio-compostable and bio-degradable thermoplastic polymers made from renewable sources. PLA is generally produced by ring opening polymerization (ROP) of lactide using the metallic/bimetallic catalyst (Sn, Zn, and Al) or other organic catalysts in a suitable solvent. In this work, reactive extrusion experiments using stannous octoate Sn(Oct)2 and tri-phenyl phosphine (PPh)3 were considered to perform ROP of lactide. Ultrasound energy source was used for activating and/or boosting the polymerization as an alternative energy (AE) source. Ludovic® software, designed for simulation of the extrusion process, had to be modified in order to simulate the reactive extrusion of lactide and for the application of an AE source in an extruder. A mathematical model for the ROP of lactide reaction was developed to estimate the kinetics of the polymerization process. The isothermal curves generated through this model were then used by Ludovic software to simulate the “reactive” extrusion process of ROP of lactide. Results from the experiments and simulations were compared to validate the simulation methodology. It was observed that the application of an AE source boosts the polymerization of lactide monomers. However, it was also observed that the predicted residence time was shorter than the experimental one. There is potentially a case for reducing the residence time distribution (RTD) in Ludovic® due to the ‘liquid’ monomer flow in the extruder. Although this change in parameters resulted in validation of the simulation, it was concluded that further research is needed to validate this assumption.
Open Access
Morphological, optical and thermal characterisation of aerogel-epoxy composites for enhanced thermal insulation
(SAGE, 2018-08-15) Krishnaswamy, Suryanarayanan; Bhattacharyya, Debabrata; Abhyankar, Hrushikesh; Marchante Rodriguez, Veronica; Huang, Zhaorong; Brighton, James
The present work explores the possibility of introducing aerogel at different stages of the epoxy resin cure to identify the most effective method that ensures minimal destruction of the aerogel particles. The aerogel particles are added at 0.5 h, 1 h and 1.5 h after the resin and the hardener are mixed together. Additionally, the effect of a wetting agent that improves the interface between the aerogel and the resin is also investigated. The different materials are characterised using optical images and ESEM-EDX to determine the most effective processing route. Additional data are also provided by determining the different material’s optical transmittance and reflective characteristics. From the experimental results, it is observed that the addition of aerogel at the 1-h mark proves to be the most efficient route to follow. In addition, the wetting agent displays a negligible effect on the samples in the study; hence, its usage is advocated due to its influence on the interface strength. Therefore, the aerogel/epoxy/wetting agent sample with the aerogel added at the 1 h mark looks promising. A 13.3% decrease in thermal conductivity when compared with the pure resin/hardener sample along with the damage coefficient value of 0.183 demonstrates the material’s potential for thermal insulation applications.
Open Access
Morphological, optical and thermal characterisation of aerogel/epoxy composites for thermal insulation applications
(Cranfield University, 2018-08-23 11:35) Krishnaswamy, Surya; Bhattacharyya, Debabrata; Abhyankar, Hrushikesh; Marchante Rodriguez, Veronica; Huang, Zhaorong; Brighton, James
The present work explores the possibility of introducing aerogel particles at different stages of the epoxy resin cure to find the most effective method that ensures minimal destruction of the former along with a high degree of mouldability for the composite material. The aerogel particles are added at 0.5 hours, 1 hour and 1.5 hours after the resin and the hardener are mixed together. Additionally, the effect of a wetting agent that improves the interface between the aerogel and the resin is also investigated. The different materials are characterised using optical images and electron microscope with energy dispersive X-ray spectroscopy to determine the most effective processing route. Additional data is also provided by determining the different material€™s optical transmittance and reflective characteristics. From the experimental results, it is seen that the addition of aerogel at the 1 hour mark proves to be the most efficient route to follow. In addition, the wetting agent displays a negligible effect on the samples in the study; hence its usage is advocated. Therefore, the aerogel/epoxy/wetting agent sample with the aerogel added at the 1 hour mark is the most promising material. A 13.3% decrease in thermal conductivity when compared with the pure resin/hardener sample along with the calculated aerogel damage coefficient value of 0.227 (22.7%) confirms its promise and potential for thermal insulation applications.