ORCID Profile
0000-0003-0647-8577
Current Organisation
Nanyang Technological University
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Publisher: Elsevier BV
Date: 12-2006
Publisher: WORLD SCIENTIFIC
Date: 12-2006
Publisher: Elsevier BV
Date: 11-2003
Publisher: IOP Publishing
Date: 14-01-2008
DOI: 10.1088/0957-4484/19/05/055708
Abstract: The major objectives of this work are to understand the effects of organoclay, its extent of exfoliation and orientation, and indenter geometry on the scratch characteristics of polyamide 6/organoclay nanocomposites. Two different organically treated clays are used for this purpose and their structural parameters in a polyamide 6 matrix quantified. It is shown that, while the material properties are important for scratching resistance, they are not the only determinants of the scratch performance of materials. Further, despite proving beneficial to scratch resistance, in terms of residual depth, the presence (and exfoliation) of organoclay promotes the formation of brittle cracks during scratching. But with no organoclay layers, plastic flow controls the scratch damage in neat polyamide 6 with large residual depths. Factors such as orientation of clay layers and variations of indenter tip geometry also exert dominant effects on scratch penetration resistance and damage. Additionally, significant plastic flow and rotation of organoclay layers from the original configuration are observed underneath the sliding indenter.
Publisher: Elsevier BV
Date: 2007
Publisher: Elsevier
Date: 2008
Publisher: MDPI AG
Date: 02-10-2020
Abstract: Material-scale tests involving milligrams of s les are used to optimize fire-retardant coating formulations, but actual applications of these coatings require them to be assessed with structural-scale fire tests. This significant difference in the scale of testing (milligrams to kilograms of s le) raises many questions on the relations between the inherent flammability and thermal characteristics of the coating materials and their “performance” at the structural scale. Moreover, the expected “performance” requirements and the definition of “performance” varies at different scales. In this regard, the pathway is not established when designing and formulating fire-retardant coatings for structural steel sections or members. This manuscript explores the fundamental relationships across different scales of testing with the help of a fire-protective system based on acrylic resin with a typical combination of intumescent additives, viz. ammonium polyphosphate, pentaerythritol, and expandable graphite. One of the main outcomes of this work dictates that higher heat release rate values and larger amounts of material participating in the pyrolysis process per unit time will result in a rapid rise in steel substrate temperature. This information is very useful in the design and development of generic fire-retardant coatings.
Publisher: Elsevier BV
Date: 10-2011
Publisher: Elsevier BV
Date: 06-2014
Publisher: Informa UK Limited
Date: 02-2003
Publisher: American Scientific Publishers
Date: 02-2013
Publisher: Elsevier
Date: 2010
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier BV
Date: 03-2012
Publisher: Elsevier BV
Date: 06-2003
Publisher: Informa UK Limited
Date: 02-2003
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 08-2003
Publisher: Elsevier BV
Date: 2004
Publisher: MDPI AG
Date: 05-08-2017
DOI: 10.3390/MA10080909
Publisher: Elsevier BV
Date: 12-2005
Publisher: MDPI AG
Date: 11-08-2017
DOI: 10.3390/MA10080935
Publisher: Wiley
Date: 02-05-2005
Publisher: Wiley
Date: 2004
DOI: 10.1002/PEN.20175
Publisher: Elsevier BV
Date: 07-2009
Publisher: Elsevier BV
Date: 07-2018
Publisher: Informa UK Limited
Date: 09-2002
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9TA10130F
Abstract: The functionalized TMD nanolayers have the potential to introduce multi-functionalities into polymer matrices, thus leading to the development of high-performance multi-functional composites/nanocomposites.
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 03-2004
Publisher: Elsevier
Date: 2013
Publisher: The Electrochemical Society
Date: 02-2006
DOI: 10.1149/1.2149207
Publisher: Informa UK Limited
Date: 09-2003
Publisher: Wiley
Date: 21-11-2020
DOI: 10.1002/APP.50299
Publisher: Elsevier BV
Date: 10-2023
Publisher: Wiley
Date: 02-08-2004
Publisher: American Chemical Society (ACS)
Date: 02-06-2010
DOI: 10.1021/MA100633Y
Publisher: IEEE
Date: 2006
Publisher: Oxford University Press (OUP)
Date: 08-2004
DOI: 10.1017/S1431927604880164
Abstract: Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Publisher: Wiley
Date: 12-2002
Publisher: Elsevier BV
Date: 03-2014
Publisher: Elsevier BV
Date: 11-2007
Publisher: Informa UK Limited
Date: 06-2002
Publisher: American Scientific Publishers
Date: 02-2008
DOI: 10.1166/JNN.2008.023
Publisher: SAGE Publications
Date: 28-03-2022
DOI: 10.1177/07349041221085898
Abstract: Flammability of intumescent coatings at the materials-scale is “expected” to have an impact on their fire resistance offered to the steel member. However, to what extent and at what stage during the exposure to an imposed fire curve in a furnace are not thoroughly established. The role of different functionality of the flame-retardant additives in this process is also not clear despite a thorough understanding of their thermal decomposition mechanisms. In an effort to better understand some of these aspects, in this work, model systems based on different flame-retardant additives in epoxy are chosen to cover various strategies (like intumescent, radical quenching, and endothermic behavior) that are typically employed to reduce the flammability of a coating system. The flame-retardant additives chosen are ammonium polyphosphate, tetrabromobisphenol-A, 9,10-dihydro-9-oxa-10-phosphaphenanthrene oxide, and aluminum trihydroxide. The effects of flame-retardant additives on the curing, thermal decomposition, and flammability of epoxy resin are investigated. Reactive flame-retardant additives, in particular, are found to reduce the enthalpy associated with curing of epoxy by more than 45%. However, as the amount of hardener incorporated in these formulations is not controlled despite the presence of reactive flame-retardant additives, this had a negative effect on the thermal decomposition behavior of the epoxy/flame-retardant formulations, and consequently on the calculated decomposition activation energies. Heating rate seems to be a dominating parameter influencing the flammability of the formulations. Peak heat release rate values, irrespective of the formulation, increased by more than 1382%–1970% by changing the heating rate in a pyrolysis flow combustion calorimeter from 6°C/min to 100°C/min. As the flammable volatiles released per unit time are higher at high heating rates, ignition and subsequent flaming of the coating occurred in the furnace tests, where a cellulosic fire curve was simulated. This has significantly influenced the fire resistance times.
Publisher: Elsevier BV
Date: 10-2003
Publisher: Elsevier BV
Date: 02-2004
Publisher: Elsevier BV
Date: 10-2011
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 06-2016
Publisher: Elsevier BV
Date: 07-2012
Publisher: Oxford University Press (OUP)
Date: 08-2004
DOI: 10.1017/S1431927604880176
Abstract: Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Publisher: IOP Publishing
Date: 09-10-2007
Publisher: Elsevier BV
Date: 05-2010
Publisher: Elsevier BV
Date: 2023
Publisher: Elsevier BV
Date: 07-2012
Publisher: Elsevier BV
Date: 06-2016
Publisher: Informa UK Limited
Date: 10-2003
Publisher: Elsevier BV
Date: 11-2017
Publisher: American Chemical Society (ACS)
Date: 2007
DOI: 10.1021/MA0621122
Publisher: American Chemical Society (ACS)
Date: 26-03-2012
DOI: 10.1021/AM201654B
Abstract: A facile and efficient approach was developed to simultaneously functionalize and reduce graphene oxide (GO) with p-phenylene diamine (PPD) by simple refluxing. This was possible by the nucleophilic substitution reaction of epoxide groups of GO with amine groups of PPD aided by NH(3) solution. As a consequence, electrical conductivity of GO-PPD increased to 2.1 × 10(2) S/m, which was nearly 9 orders of magnitude higher than that of GO. Additionally, after the incorporation of GO-PPD in polystyrene (PS), the composites exhibited a sharp transition from electrically insulating to conducting behavior with a low percolation threshold of ~0.34 vol %, which was attributed to the improved dispersion and the reduction of GO-PPD. Thermal stability of the PS/GO-PPD composite was also ~8 °C higher than that of PS.
Publisher: Elsevier BV
Date: 10-2014
Publisher: Informa UK Limited
Date: 02-2003
Publisher: American Chemical Society (ACS)
Date: 21-11-2016
Abstract: Dispersion and spatial distribution of graphene sheets play crucial roles in tailoring mechanical and functional properties of their polymer composites. Anisotropic graphene aerogels (AGAs) with highly aligned graphene networks are prepared by a directional-freezing followed by freeze-drying process and exhibit different microstructures and performances along the axial (freezing direction) and radial (perpendicular to the axial direction) directions. Thermal annealing at 1300 °C significantly enhances the quality of both AGAs and conventional graphene aerogels (GAs). The aligned graphene/epoxy composites show highly anisotropic mechanical and electrical properties and excellent electromagnetic interference (EMI) shielding efficiencies at very low graphene loadings. Compared to the epoxy composite with 0.8 wt % thermally annealed GAs (TGAs) with an EMI shielding effectiveness of 27 dB, the aligned graphene/epoxy composite with 0.8 wt % thermally treated AGAs (TAGAs) has an enhanced EMI shielding effectiveness of 32 dB along the radial direction with a slightly decreased shielding effectiveness of 25 dB along the axial direction. With 0.2 wt % TAGA, its epoxy composite exhibits a shielding effectiveness of 25 dB along the radial direction, which meets the requirement of ∼20 dB for practical EMI shielding applications.
Publisher: Elsevier BV
Date: 05-2013
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.JENVMAN.2018.10.083
Abstract: A 32-week leaching column study was carried out in the greenhouse to investigate the effects of incorporation of gypsum, cattle manure, biosolids, gypsum plus cattle manure and gypsum plus biosolids into the topsoil layer (0-10 cm) on growth of Rhodes grass, and on root distribution and chemical and microbial properties in the topsoil and subsoil (10-30 cm) layers of seawater neutralized bauxite residues. The columns were leached for a period of 8 weeks prior to sowing Rhodes grass and during that time the bulk of the salts accumulated during seawater neutralization were leached out. The main cation leached was Na
Publisher: Elsevier BV
Date: 08-2004
Publisher: Elsevier BV
Date: 06-2017
Publisher: Informa UK Limited
Date: 02-2004
Publisher: Elsevier BV
Date: 11-2021
Publisher: American Chemical Society (ACS)
Date: 08-02-2013
DOI: 10.1021/AM3024405
Abstract: Inspired by the radical scavenging function of melanin-like materials and versatile adhesive ability of mussel-adhesion proteins, dopamine-modified clay (D-clay) was successfully incorporated into polypropylene (PP) using an amine-terminated PP oligomer as the compatibilizer. Although the PP/D-clay nanocomposites exhibit intercalated morphology, the incorporation of D-clay greatly improves the thermo-oxidative stability and UV resistance of PP owing to the strong radical scavenging ability of polydopamine (PDA) and large contact area between PP and the PDA coating on clay mineral. Moreover, the reinforcement effect brought by D-clay is fairly significant at very low clay loadings probably owing to the strong interfacial interactions between the layered silicates and the compatibilizer as well as that between the compatibilizer and the PP matrix. The work demonstrates that D-clay is a type of promising nanofiller for thermoplastics used for outdoor applications since it stabilizes and reinforces the polymers simultaneously.
Publisher: Elsevier BV
Date: 05-2015
Publisher: Informa UK Limited
Date: 10-2003
Publisher: Elsevier BV
Date: 07-2003
Publisher: Elsevier BV
Date: 11-2018
Publisher: Elsevier BV
Date: 06-2004
Publisher: MDPI AG
Date: 19-05-2022
Abstract: The emphasis on sustainability in materials related to the construction and transportation sectors has renewed interest in the usage of natural fibers. In this manuscript, a different perspective is taken in adopting oil palm fibers (OPF) to develop composite panels and understand their acoustic, mechanical, and water susceptibility (including warm water analysis) properties to provide an insight into the potential of these panels for further exploration. The binder for these composite panels is a water-based acrylic resin, and for reinforcement purposes, fly ash and other metal oxides are used. It is shown that the presence of fibers positively influences the acoustic absorption coefficient in the critical mid-frequency range of 1000–3000 Hz. Even the noise reduction coefficient values highlighting the octave band are higher by more than 50% in the presence of fibers as compared to traditional refractory boards. Quasistatic indentation and drop-weight tests have also highlighted the excellent performance of the composite panels developed in this work. Though the water immersion tests on composite panels and subsequent analysis showed relatively minor changes in their performance, the immersion of the panels in caustic warm water for 56 days has resulted in their severe degradation with a loss of more than 65% in flexural strength.
Publisher: Elsevier BV
Date: 04-2004
Publisher: Informa UK Limited
Date: 10-2002
Publisher: Springer Science and Business Media LLC
Date: 09-2017
Publisher: American Chemical Society (ACS)
Date: 17-05-2021
Publisher: Trans Tech Publications, Ltd.
Date: 2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.465.169
Abstract: The fracture behaviour of laminated materials was studied in this work. The materials used in this work were low-density polyethylene (LDPE) laminated on polyethylene (PET). The thickness of the LDPE was 27 µm and the PET was 100 µm. Experiments were performed by using a 2-leg trousers specimen to analyse the tearing behaviour of the laminate in relation to the delamination. A clear delamination zone was observed during the crack propagation by tearing. Furthermore, a finite element calculation was performed to simulate the behavior around the crack tip during the tearing. A correlation between adhesion and crack propagation was discussed. Finally, the theory of Essential Work of Fracture (EWF) was used for predicting the specific total work of fracture along the tear path across the plastic zones.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4RA06215A
Abstract: Interaction of relative humidity with solvent(s) is relatively more important in obtaining surface pores than solvent volatility and phase separation.
Publisher: American Chemical Society (ACS)
Date: 20-01-2021
Publisher: Wiley
Date: 15-03-2005
DOI: 10.1002/POLB.20397
Publisher: Wiley
Date: 04-2016
Publisher: Elsevier BV
Date: 07-2005
Publisher: ASMEDC
Date: 2005
Abstract: Recent developments in miniaturization of polymeric components for microelectromechanical systems (MEMS) and nanotechnology applications require that the load applied be very small in the range of μN and nN and the contact radius in nanometers to achieve certain purposes like nanofabrication, nanomachining or nanopatterning. So, it is necessary to understand the basic nanotribological mechanisms to describe the stress fields associated with the asperities, crack initiation and growth, material removal, etc. This study reveals the nano-scale nature of intimate contacts by using atomic force microscopy during nano-scratching of nylon 66/SEBS-g-MA/organoclay ternary nano-composites produced by different blending sequences and having contrasting microstructures using a standard diamond Berkovich indenter at a low load of 1 mN and a low sliding velocity of 1 μm/s. It is shown that the constraint effect of exfoliated organoclay on the nylon matrix material is much more important than on the dispersed soft domains in resisting the nanoscratch, as indicated by the lower scratch penetration depth. However, the absence of clay in the soft SEBS-g-MA phase promotes cavitation under these nanoscratch conditions. Conversely, the presence of organoclay in SEBS-g-MA restrains the cavitation of the latter, and its absence in the nylon matrix material is deleterious as indicated by the higher scratch penetration depth. The results presented also suggest that the ternary nanocomposites are preferred to the binary nano-composites, particularly the exfoliated nylon 66/organoclay nanocomposite. This research extends our basic knowledge and provides new insights of the nature of nano-scale processes that happen during nanoscratching of polymer nanocomposites. The outcome of the work also raises critical questions like, penetration depth versus morphology left behind the tip, which needs an in-depth understanding of a broad range of materials.
Publisher: WORLD SCIENTIFIC
Date: 11-03-2018
Publisher: Elsevier BV
Date: 2016
Publisher: Informa UK Limited
Date: 09-2003
Publisher: Elsevier BV
Date: 2010
Publisher: Springer Science and Business Media LLC
Date: 12-08-2016
Publisher: Elsevier BV
Date: 2009
Publisher: Springer Science and Business Media LLC
Date: 23-09-2021
Publisher: Oxford University Press (OUP)
Date: 08-2003
Publisher: MDPI AG
Date: 10-07-2017
DOI: 10.3390/MA10070776
Publisher: Informa UK Limited
Date: 09-2003
Publisher: Elsevier BV
Date: 05-2004
Publisher: Wiley
Date: 04-2016
Publisher: American Chemical Society (ACS)
Date: 10-2006
DOI: 10.1021/CM0617135
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier
Date: 2012
Publisher: Elsevier BV
Date: 03-2009
Publisher: American Chemical Society (ACS)
Date: 07-11-2017
Abstract: In this Research Article, we report on the development of water-based flame retardant coating based on phospho-nitrogen combination for cotton fabrics. A one-step spray-on process was employed to coat the fabrics by taking advantage of the spontaneous reaction between para-phenylenediamine (PDA) and tetrakis(hydroxymethyl)phosphonium chloride (THPC) resulting in an instantaneous precipitation of poly[1,4-diaminophenylene-tris(dimethyl hydroxymethyl)phosphine] (PApP) on the fabric surface. The effectiveness of PApP in improving the flame retardant properties like ignition resistance and lateral flame spread were evaluated in accordance with ASTM D6413 and BS EN ISO 15025 flammability tests. Despite the early (thermal) decomposition onset for coated fabrics under both oxidative and pyrolytic conditions, remarkably, self-extinguishing behavior (<3 s) without any lateral flame spread was observed. Possible reaction scheme was also proposed to correlate flame retardant mechanism of the coated fabrics with the observations. Additional analysis via pyrolysis combustion flow calorimetry and vertical flame testing before and after washing showed that flame retardant efficiency did decrease with washing, but the overall performance was still promising.
Publisher: American Chemical Society (ACS)
Date: 20-02-2008
DOI: 10.1021/CM703285S
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/CH06418
Abstract: Addition of a small percent of clay to polymers improves their stiffness, strength, dimensional stability, and thermal, optical, and barrier properties. Improvements are often attributed to the availability of large numbers of clay nanolayers with tremendous interfacial area. Despite the positive effects from the addition of clay, there are unresolved issues, such as embrittlement, thermal stability, flame retardancy, scratch–wear response of the resultant nanocomposites, and/or achieving a balance between different mechanical and physical properties. In this review, we discuss these issues and the approaches that have been adopted in the expectation of resolving and understanding them, with particular emphasis on our recent and current research.
No related grants have been discovered for Aravind Dasari.