Browsing by Author "Nagamadhu, M."

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A novel approach to determine the thermal transition of gum powder/hydro-gels using dynamic mechanical analysis
(American Institute of Physics Inc. subs@aip.org, 2018) Nagamadhu, M.; Jeyaraj, P.; Mohan Kumar, G.C.
The dynamic characterization of materials plays a major role in the present area. The many researchers are worked on solid materials and its characterization, it can be tested using dynamic mechanical analyzer (DMA), however, no such work on powder a semiliquid samples. The powder and liquid samples can also easily characterization as like solid samples using DMA. These powder samples are analyzed with a material pocket method which can be used to accurately determine very low levels of variation in powder properties, due to the high sensitivity of DMA to glass transitions. No such DMA studies on hydrogel and Gum powders. The gum powders are used in various applications start from food industries, pharmacy, natural gums paste, biomedical applications etc. among all this applications gum Ghatti is one of the powders using for varies applications. Around 50 milligrams of Ghatti powders are placed inside material pocket and analyzed storage modulus (Gâ€²), loss modulus (Gâ€³) and tan delta (Î´). Also, understand the curing and glass transition effect using water, glycerin and superplastic from room temperature to 200Â°C. The result shows that storage modulus decreases with increase in temperature in pure Ghatti powder. The surprising improvement in storage modulus was found with an increase in temperature with addition of water, glycerin, and superplastic. However, loss modulus and tan delta are also having very significant influence and also shows a clear peak of the tan delta. The loss modulus results were found to be improved by adding solidifying agents, along with this water and superplastic better influence. But glycerine found to be hydrogel in nature and thermodynamic properties are much influenced by frequency. Â© 2018 Author(s).
Characterization and mechanical properties of sisal fabric reinforced polyvinyl alcohol green composites: Effect of composition and loading direction
(Institute of Physics Publishing helen.craven@iop.org, 2019) Nagamadhu, M.; Jeyaraj, P.; Mohan Kumar, G.C.M.
This research focuses on microstructure characterization and exploring mechanical properties of sisal fabric reinforced Polyvinyl Alcohol composites using conventional vacuum-assisted pressure compression method. Naturally available sisal fiber is used as reinforcement material in this composite because of its abundant availability in Southern India. The sisal fiber, PVA and its composites were characterized using Fourier Transform Infrared Spectroscopy. Initially, Polyvinyl Alcohol polymer was cross-linked with Glutaraldehyde, and mechanical properties were evaluated. It was observed that 20% Glutaraldehyde and 80% Polyvinyl Alcohol polymer combination yielded best mechanical properties. Further, two plain and one weft rib were considered and their textile properties were characterized. The results revealed that fabric crimp and yarn linear density had significant influence on tensile properties of the fabric. Influence of different fabric properties such as weaving pattern, grams per unit area, and loading direction on mechanical properties of composites were analyzed. The woven fabric having least gram per unit area of sisal resulted in best mechanical properties like tensile, bending, and impact. The weft rib fabric composites in weft direction exhibited best mechanical properties. © 2019 IOP Publishing Ltd.
Dynamic Mechanical Analysis and Thermal Stability of Neem Wood Veneer Plastic Composites
(Elsevier Ltd, 2019) Nagamadhu, M.; Vijay Kumar, S.; Ravi Kumar, S.; Suraj, R.; Kumar, G.C.
The neem wood veneer is used as core materials in many of the wood structural applications. In this research work, neem wood polymer composite (NWPC) were prepared to understand the effect of weight fraction, stacking sequence, and interfacial bonding between neem wood veneer and epoxy material. NWPC were prepared conventional compression molding and Thermo-mechanical properties of wood epoxy composite samples were investigated by the dynamic mechanical analyzer over the temperature range from 30 to 180Â°C. Storage modulus (G') and Loss modulus (G") of NWPC samples exhibited significant effect with respect weight fraction of wood veneer. Similarly epoxy has good interfacial bonding agent to enhance the strength of multilayered wood polymer composites. However, the stacking sequence having major changes in dynamic mechanical properties, G' & G" increases along the wood fiber direction with negligible load bearing capacity in transfers direction. By changing the orientation of the wood veneer properties improved in both the direction. Additionally, scanning electron microscopy (SEM) evidently shows the interfacial bonding efficiency. Â© 2019 Elsevier Ltd.
Dynamic mechanical analysis of glutaraldehyde cross linked polyvinyl alcohol under tensile mode
(2019) Mohankumar, G.C.; Jeyaraj, P.; Nagamadhu, M.
Nowadays researchers are looking out for biodegradable materials alternate to petroleum-based materials due to many global issues. Polyvinyl Alcohol (PVA) cross-linked with Glutaraldehyde (GA) polymer have found widespread applications in light-weight structures in replacement of non-biodegradable polymers. The PVA cross-linked with GA polymers were prepared using a conventional compression type molding technique. Dynamic Mechanical Analysis has been carried out to evaluate the tensile storage and loss modulus, tan delta, and elongation, in the temperature range of 25-160�C. The results exhibit improvement of thermo-mechanical properties at higher temperatures due to GA crosslinking. Experimental results indicate that the tensile storage and loss modulus were improved due to GA crosslinking. The elongation of PVA-GA decrease considerably with GA crosslinking. The shore D hardness improves with crosslinking up to 20% GA, and further marginal increase in hardness beyond 20% GA crosslinking. � 2018 Author(s).
Dynamic mechanical analysis of glutaraldehyde cross linked polyvinyl alcohol under tensile mode
(American Institute of Physics Inc. subs@aip.org, 2019) Mohan Kumar, G.C.; Jeyaraj, P.; Nagamadhu, M.
Nowadays researchers are looking out for biodegradable materials alternate to petroleum-based materials due to many global issues. Polyvinyl Alcohol (PVA) cross-linked with Glutaraldehyde (GA) polymer have found widespread applications in light-weight structures in replacement of non-biodegradable polymers. The PVA cross-linked with GA polymers were prepared using a conventional compression type molding technique. Dynamic Mechanical Analysis has been carried out to evaluate the tensile storage and loss modulus, tan delta, and elongation, in the temperature range of 25-160Â°C. The results exhibit improvement of thermo-mechanical properties at higher temperatures due to GA crosslinking. Experimental results indicate that the tensile storage and loss modulus were improved due to GA crosslinking. The elongation of PVA-GA decrease considerably with GA crosslinking. The shore D hardness improves with crosslinking up to 20% GA, and further marginal increase in hardness beyond 20% GA crosslinking. Â© 2018 Author(s).
Effect of drilling parameters on Neem wood veneer epoxy composites using grey relational analysis
(Elsevier Ltd, 2019) Jaiprakash, M.; Nagamadhu, M.; Karthikeyan, K.; Kiran; Shariff, M.; Kumar, G.C.
In recent trend the composites based wood are replacing the normal wood and other materials in various fields. The wood composites have cosmic properties like cheaper in cost, denser, free from defect, they can be machined in any way to make desired output product. This paper is all about investigation of wood properties and its behavior for drilling process. Drilling is one of the universal machining process that being carried out in the world.The purpose of drilling is to remove the excess of material from the work piece (specimen) to produce a hole and drilling is the primary process that need to be carried on the specimen to perform other machining operation (boring, reaming and tapping) as drilling got various level of importance in different applications, studying about drilling process and its parameter on different materials is important. This paper is all about the analysis of different drilling parameters such as feed rate (mm/min), spindle speed (rpm), Drill diameter on the quality of drilled hole. To study these factors Grey relation technique and Taguchi analysis is implemented. The result shows that feed rate is the major influencing parameter when compared to other cutting parameter and by selecting the optimal value,the quality of the drilled hole can be improved. Â© 2019 Elsevier Ltd.
Effect of stacking sequence on mechanical properties neem wood veneer plastic composites
(2018) Nagamadhu, M.; Mohankumar, G.C.; Jeyaraj, P.
This study investigates the effect of wood veneer stacking sequence on mechanical properties of neem wood polymer composite (WPC) experimentally. Wood laminated samples were fabricated by conventional hand layup technique in a mold and cured under pressure at room temperature and then post cured at elevated temperature. Initially, the tensile, flexural, and impact test were conducted to understand the effect of weight fraction of fiber on mechanical properties. The mechanical properties have increased with the weight fraction of fiber. Moreover the stacking sequence of neem wood plays an important role. As it has a significant impact on the mechanical properties. The results indicated that 0�/0� WPC shows highest mechanical properties as compared to other sequences (90�/90�, 0�/90�, 45�/90�, 45�/45�). The Fourier Transform Infrared Spectroscopy (FTIR) Analysis were carried out to identify chemical compounds both in raw neem wood and neem wood epoxy composite. The microstructure raw/neat neem wood and the interfacial bonding characteristics of neem wood composite investigated using Scanning electron microscopy images. � 2018 Author(s).
Effect of stacking sequence on mechanical properties neem wood veneer plastic composites
(American Institute of Physics Inc. subs@aip.org, 2018) Nagamadhu, M.; Mohan Kumar, G.C.; Jeyaraj, P.
This study investigates the effect of wood veneer stacking sequence on mechanical properties of neem wood polymer composite (WPC) experimentally. Wood laminated samples were fabricated by conventional hand layup technique in a mold and cured under pressure at room temperature and then post cured at elevated temperature. Initially, the tensile, flexural, and impact test were conducted to understand the effect of weight fraction of fiber on mechanical properties. The mechanical properties have increased with the weight fraction of fiber. Moreover the stacking sequence of neem wood plays an important role. As it has a significant impact on the mechanical properties. The results indicated that 0Â°/0Â° WPC shows highest mechanical properties as compared to other sequences (90Â°/90Â°, 0Â°/90Â°, 45Â°/90Â°, 45Â°/45Â°). The Fourier Transform Infrared Spectroscopy (FTIR) Analysis were carried out to identify chemical compounds both in raw neem wood and neem wood epoxy composite. The microstructure raw/neat neem wood and the interfacial bonding characteristics of neem wood composite investigated using Scanning electron microscopy images. Â© 2018 Author(s).
Influence of extender on Thermo-mechanical Properties of melamine-urea-formaldehyde [MUF] for wood adhesive applications
(Elsevier Ltd, 2019) Nagamadhu, M.; Ravi Kumar, S.; Suraj, R.; Manjunath Iyer, K.B.; Kumar, G.C.
Now a day's many researchers are trying to build alternative materials for raw wood, by using wood composite materials as an alternative. However, in wood polymer composites major limitations on adhesive materials and its bonding strength effect with economy. In this paper melamine-urea-formaldehyde (MUF) wood adhesive properties were determined over a range of temperature. MUF prepared by considering 1:2.3 weight ratio of urea to the formalin, at 90Â°C and pH is adjusted to 7.5-8.0 and second urea is added at certain time interval to reduce the formaldehyde emission. MUF has certain properties like flow time, viscosity, solid content, water tolerance, shelf life which is calculated by the observation made. The cost of MUF adhesive can be controlled by adding extender (Maida). As wood polymer composites subjected to over a range of temperature. It's necessary to understand the thermo-mechanical properties of MUF reinforced with Maida as an extender using Dynamic Mechanical Analyzer (DMA). The DMA gives in-phase component like storage modulus, loss modules and tan delta. The results show that storage modulus increases with adding extender even at higher temperature, these shows that by adding extender MUF resist the intermolecular motion. The damping factors were found to be increases by adding extender. Tan delta of MUF exhibiting narrow peak with higher magnitude indicates more energy dissipates, by adding the extender it reduces. The adding extender Maida (MD) water absorption decreases, this shows better MUF having better bonding with extender. Â© 2019 Elsevier Ltd.
Influence of glutaraldehyde on dynamic properties of poly(vinyl alcohol) polymer
(ICE Publishing, 2020) Mohan Kumar, G.C.M.; Jeyaraj, J.; Nagamadhu, M.
This study investigated the dynamic mechanical properties of poly(vinyl alcohol) (PVA; (CH2CH(OH)) n ) cross-linked with glutaraldehyde (GA; OHC(CH2)3CHO).*The cross-linked polymer was prepared by using a conventional casting technique and then treated with sulfuric acid (H2SO4) for 24 h.*The flexural properties during static and dynamic modes were studied using a three-point bending condition.*The static flexural properties are improved with the addition of 30% GA in PVA, with higher value of strain.*It was observed that the dynamic mechanical properties of PVA improved significantly with an increase in cross-linking percentage.*The storage and loss moduli increased drastically with the addition of the cross-linker up to 20%, and marginal changes occurred with further addition of the cross-linker.*The fracture behavior was transformed from ductile to brittle for more than 20% cross-linker.*Shifting of the rubber region and liquid region with higher temperatures was observed in storage and loss modulus plots.*Improvement in the adhesion factor, cross-linking density and effectiveness was observed for GA up to 25%.*The test duration was estimated using the Williams-Landel-Ferry model for different temperatures.*The major changes were in the modulus in the rubbery plateau region.*The cross-linked polymer had much greater storage and loss moduli, indicating a closer network structure and higher stiffness.* © 2020 ICE Publishing: All rights reserved.
Influence of textile properties and textile pattern on sisal reinforced Poly Vinyl Ester (Flex GR 200-60) composite
(Taylor and Francis Ltd., 2023) Nagamadhu, M.; Kivade, S.B.; Basavaraju, S.; Garje Channabasappa, M.K.; Subramanya, R.; Malyadri, T.
This paper focuses on the effect of yarn diameter, the density of yarn, woven type, Gram per Square Metre (GSM) and weight fraction fibre on tensile, flexural and impact properties of weaved sisal composite. Various types of woven fabrics were prepared from sisal fibres, and these fabrics are used to prepare the composites of variable weight fraction (Wff) as 20, 40, 50 and 60 percent by maintaining proper alignment of warp and weft direction. The tensile, flexural, and impact properties were found to increase with Wff content in all types of woven pattern composites. Plain 1 (P1) shows better mechanical properties as compared to Plain 2 (P2) and Plain 3 (P3)-based composites, and this shows GSM has a higher significance on mechanical properties. Further, the influence of woven pattern was analysed and found that the plain woven exhibits better tensile strength, but the herringbone exhibits better flexural and impact strength. Scanning Electron Microscope evidenced that good interfacial bonding between fibre and matrix interface. © 2022 Informa UK Limited, trading as Taylor & Francis Group.
Influence of textile properties on dynamic mechanical behavior of epoxy composite reinforced with woven sisal fabrics
(Springer, 2020) Nagamadhu, M.; Jeyaraj, J.; Mohan Kumar, G.C.
Due to low cost and environmentally friendly characteristics, natural fibers gain much attention over synthetic fiber. The aim of the present work is to characterize the textile properties of three different types of sisal fabric and study dynamic mechanical properties and water absorption behavior of the sisal fabric reinforced epoxy composite. Influence of grams per square meter of fabric, weaving pattern of the fabric on textile properties of the fabric is studied first. Further, the effect of the same on the dynamic mechanical properties of the sisal composites is studied. Effect of fiber weight percentage and dynamic frequency on dynamic mechanical properties also studied. Results reveal that the storage modulus (G?) decreases with increasing temperature in all the woven types of composites under consideration. However, Plain 2 (P2) and Weft Rib (WR) composites have shown better values of G? even after the glass transition temperature (Tg). From the results, it is also evident that storage and loss modulus (G??) increases when the yarn diameter decreases which is observed at a higher temperature also. It is also observed that fabric density also plays a significant role in the enhancement of G? and G?? values. The water absorption of Plain 1 (P1) based composites are found to be less compared to the other types of composites analyzed. © 2020, Indian Academy of Sciences.
Mechanical and tribological behavior of woven sisal fabric
(Faculty of Engineering, University of Kragujevac tribology@fink.rs Sestre Janjic 6 Kragujevac 34000, 2019) Nagamadhu, M.; Jeyaraj, P.; Mohan Kumar, G.C.
A study has been carried out to investigate the Mechanical and Tribological Properties of Woven Sisal Fabric. Two Plain fabrics were prepared by changing gram per unit area (GSM), and one weft rib fabric is prepared to understand the effect of woven structure on mechanical and wear properties. These fabrics textile properties were determined as per textile ASTM standards. The tensile properties of these fabrics were studied in both warp and weft directions. Further, pilling resistance, abrasion resistance and wear properties of these fabrics were studied using L27 Taguchi Orthogonal Array. The tensile properties were found to be better in weft direction as compared to warp direction in all type of fabrics. The pilling resistances were found better in weft rib fabrics. The abrasion resistance is exhibited better at higher GSM. From the results, it also reveals that higher the crimp value more the resistance against adhesion wear using Pin on disk method. More the yarn linear density more the resistance for adhesion wear. However, the wear load, woven pattern and traveling distance have a significant impact on weight loss and frictional force. © 2019 Published by Faculty of Engineering.
Mechanical Properties of Chemical Treated Woven Banana/Polyvinyl Alcohol Composites
(ICE Publishing, 2019) Gunge, A.; Kivade, S.B.; Nagamadhu, M.
Present work investigates the effect of chemical treatment on mechanical properties of plain woven banana fabrics (PWBF) reinforced to polyvinyl alcohol (PVA) bio-degradable matrix composite. Woven banana fabrics are chemically treated with different percentages of concentration (0.5, 1, 2, 3 and 4%) for 4 hours at room temperature. The banana fabrics and PVA are used in the ratio of 55% and 45% weight fraction respectively. Composites are prepared using hand-layup method. The samples are tested according to different ASTM standard for tensile, flexural and impact.The results are exhibited that tensile, flexural and impact properties were found to increase with potassium permanganate (KMnO4) treatment. The 1% potassium permanganate treated fabrics shows very good mechanical properties compared to untreated, 0.5, 2, 3 and 4% treated fabrics, 1% treated fabrics gives 68.07% increment in the tensile strength of the composite compared to the untreated fabrics composite. The scanning electron microscopy (SEM) also reveals 1% treated has the better interfacial bonding between fabrics and matrix. This contributes to improvement in the mechanical properties of the composite. © 2019 ICE Publishing: All rights reserved.
A novel approach to determine the thermal transition of gum powder/hydro-gels using dynamic mechanical analysis
(2018) Nagamadhu, M.; Jeyaraj, P.; Mohankumar, G.C.
The dynamic characterization of materials plays a major role in the present area. The many researchers are worked on solid materials and its characterization, it can be tested using dynamic mechanical analyzer (DMA), however, no such work on powder a semiliquid samples. The powder and liquid samples can also easily characterization as like solid samples using DMA. These powder samples are analyzed with a material pocket method which can be used to accurately determine very low levels of variation in powder properties, due to the high sensitivity of DMA to glass transitions. No such DMA studies on hydrogel and Gum powders. The gum powders are used in various applications start from food industries, pharmacy, natural gums paste, biomedical applications etc. among all this applications gum Ghatti is one of the powders using for varies applications. Around 50 milligrams of Ghatti powders are placed inside material pocket and analyzed storage modulus (G?), loss modulus (G?) and tan delta (?). Also, understand the curing and glass transition effect using water, glycerin and superplastic from room temperature to 200�C. The result shows that storage modulus decreases with increase in temperature in pure Ghatti powder. The surprising improvement in storage modulus was found with an increase in temperature with addition of water, glycerin, and superplastic. However, loss modulus and tan delta are also having very significant influence and also shows a clear peak of the tan delta. The loss modulus results were found to be improved by adding solidifying agents, along with this water and superplastic better influence. But glycerine found to be hydrogel in nature and thermodynamic properties are much influenced by frequency. � 2018 Author(s).
Short term creep behavior of neem wood veneer epoxy composites
(American Institute of Physics Inc., 2023) Nagamadhu, M.; Kivade, S.B.; Vijay Kumar, S.V.; Kumar, G.C.M.
Neem wood used many structural applications due to its coarse grain with interlocking fibers leads to excellent mechanical properties with a very good life. However, wood structures are exposed to various environmental conditions, so it is necessary to investigate the effect of time and temperature for different stacking sequences. This paper aims to explore the importance of time and temperature of neem wood veneer epoxy composites at various stacking sequence and interfacial bonding. The Dynamic Mechanical Analyzer used to study short term creep at a nitrogen environment using a three-point bending condition. The result shows neat neem wood veneer exhibit a higher percentage of strain as compared to neem wood epoxy composites. On the other hand, the stacking sequence having significant changes in dynamic mechanical and creep studies, storage modulus (G') & loss modulus (G'') increases along the wood fiber direction with minor load-bearing capacity in lateral direction. By varying the orientation of the wood veneer mechanical and thermo-mechanical properties improved in both longitudinal and lateral direction. Â© 2023 Author(s).
Study on tearing strength of woven sisal fabrics for tents and polymer composite applications
(Taylor and Francis Ltd., 2023) Nagamadhu, M.; Kivade, S.B.; Jeyaraj, J.; Kumar, G.C.; Shivaraj, B.W.; Bharath, K.N.
The use of plant fibers as a reinforcement in composites has increased daily owing to their favorable environmental considerations. Fabric properties play a significant role in alignment during composites processing, enhancing the composite properties. However, the fabric structures are formed by warp and weft yarns. These yarns are subjected to axial and shear loads, respectively. However, very limited work has been carried out on the study involving the tearing strength of the fabric. So it is necessary to study the effect of the tearing load of fabrics before converting them into composites. This paper focuses on the tearing strength of the sisal woven fabrics in both warp and weft directions. Two plain and one weftrib fabrics are prepared using sisal fibers, and their physical properties were characterized as per textile testing standards. Tear strength has been determined by Elmendorf Tear and Single Rip Tear Method by varying crosshead speeds. The result shows that woven patterns and number yarns significantly impact tearing strength. In the case of the weft rib pattern, the warp direction exhibits the highest tearing strength compared to the weft direction. Also, in the case of weftrib fabrics, the weft direction indicates better-tearing strength than another woven pattern. © 2023 The Author(s). Published with license by Taylor & Francis Group, LLC.