Browsing by Author "Pappu, Asokan"

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    Manufacturing and characterization of sustainable hybrid composites using sisal and hemp fibres as reinforcement of poly (lactic acid) via injection moulding
    (Elsevier, 2019-05-20) Pappu, Asokan; Pickering, Kim L.; Thakur, Vijay Kumar
    Natural polymers based composites offers significant advantages over synthetic fibre reinforced petroleum matrix based composites with regard to biodegradability, biocompatibility, design flexibility and sustainability. This work reports for the first time manufacturing of hybrid fibre reinforced biodegradable composites using sisal and hemp fibre with polylactic acid employing melt processing and injection moulding techniques. Granulated sisal and hemp fibres were blended and hybrid composites were manufactured using aliphatic polyester made up of lactic acid (PLA) through extrusion and injection moulding and their performance was evaluated. Experimental results revealed that density, elongation at break and water absorption capacity of hybrid composites were 1.14 ± 0.07 g/cm3, 0.93 ± 0.35% and 1.06 ± 0.18% respectively. The achieved mean tensile strength (46.25 ± 6.75 MPa), Young’s modulus (6.1 ± 0.58 GPa) and specific tensile strength (38.86 ± 5.0) of hybrid fibre reinforced PLA composites were improved compared to neat PLA. The flexural strength (94.83 ± 11.21 MPa), flexural modulus (6.04 ± 0.55 GPA) and specific flexural strength (79.76 ± 8.80) of hybrid fibre composites also showed better performance than those of neat PLA. Incorporation of sisal and hemp fibre with polylactide remarkably increased the impact strength of composites. Overall, the hybrid composites demonstrated good performance suggesting that they have great potential for use as an environmentally friendly alternative material in automotive, packaging, electronics, interiors and agricultural applications.
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    Recycling marble wastes and Jarosite wastes into sustainable hybrid composite materials and validation through Response Surface Methodology
    (Elsevier, 2019-09-01) Pappu, Asokan; Thakur, Vijay Kumar; Patidar, Ravi; Asolekar, Shyam R.; Saxena, Mohini
    During marble processing such as cutting, polishing and grinding, a considerable amount of fine residues refereed as marble processing rejects (MPRs) are produced and have become a serious environmental issue. So the current study deals with the conversion of MPRs into hybrid ceramic composite bricks (CCB) with Jarosite waste in a clay matrix system. Mix design and optimization of CCB was performed to illustrate the potentials of MPRs and Jarosite wastes as low-cost high-value composites materials. Response Surface Methodology (RSM) model was also used in this work for simulation and to optimize the process for improving CCB quality employing classic mixture approach. Detoxification through mineralogical changes was achieved during firing composite bricks at 960 °C ± 2 °C and was confirmed using the XRD analysis. Compressive strength of CCB using 15% MPRs with 1:1 Jarosite waste - clay matrix ratio met the standard quality (>35 kg/cm2) for its use in construction purpose. It is evident from the RSM model results and statistical analysis for the response compressive strength, shrinkage, water absorption capacity, density and leachate concentration of Cd as well as Pb in the CCB is in laudable agreement with actual experimental performance.
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    Resource efficiency impact on marble waste recycling towards sustainable green construction materials
    (Elsevier, 2018-06-18) Thakur, Anil Kumar; Pappu, Asokan; Thakur, Vijay Kumar
    India is one of the biggest marble producing country in the world (∼10%). State of Rajasthan has nearly 85% of marble production capacity. Recently, the massive quantity of marble waste fine particulates generated in marble industry has become a major environmental hazard issue. Major minerals present in marble waste are calcite (CaCO3) and dolomite (CaMg (CO3)2). The particle sizes of marble waste particulates has been found to be 200 μm (D90). The chemical composition of marble wastes reveals oxides of calcium (CaO), silica (SiO2), alumina (Al2O3) and alkaline oxides (Na2O, K2O). Apart from that, iron oxide, mica, fluorine, chlorite and organic matter have also been noticed. Marble waste has been explored for possible utilization in industries, thereby it helps in preventing the environmental problems such as dumping and pollution. This article addresses the efficiency of marble wastes for materials development, leading to create some sustainable green composite materials for construction applications.
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    Synthesis and characterization of new class of geopolymer hybrid composite materials from industrial wastes
    (Elsevier, 2019-05-09) Thakur, Anil Kumar; Pappu, Asokan; Thakur, Vijay Kumar
    Geopolymer belongs to a new class of emerging materials for a number of applications owing to the advantages such as low cost; higher compressive strength; improved fire & acid resistance as well as reduced greenhouse gas emission. In this work, we explore the effective utilization of marble waste as a reactive filler and binder for the development of fly ash based geopolymer hybrid composite materials using extrusion process. The effect of marble waste content on the physico–chemical and mechanical characteristics of prepared hybrid materials was studied through various characterization techniques. The geopolymerization was conducted at two different molarities of sodium hydroxide in which the effects of materials properties were studied. The results indicate that the materials prepared at higher molarity exhibits better performance in terms of compressive strength (4.61–6.52 MPa) (2–4M). The silicon dioxide present in fly ash reacts with calcium hydroxide present in marble waste forming calcium silicate hydrate network and possibly contributes to the increment in the interfacial bonding in marble waste infiltrated geopolymer matrix. Overall, this improved interfacial adhesion yielded an increase in compressive strength and bulk density but also decreased the water absorption of the developed material. The results of this study not only indicate an effective utilization of marble waste for the production of geopolymer hybrid composite materials via an eco–friendly route but also provide an economical and sustainable route for management of marble waste currently generated in various countries of the world.
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    Towards sustainable micro and nano composites from fly ash and natural fibers for multifunctional applications
    (Elsevier, 2017-05-24) Pappu, Asokan; Kumar, Vijay
    Manufacturing of petroleum based synthetic materials, exploitation of timber products from forest reserves, improper management of industrial wastes and natural resources greatly persuade the environmental contaminations and global warming. To find viable solutions and reduce such alarming issues, innovative research work on recycling of unutilized materials such as fly ash and natural cellulosic polymers has been reported in this work to develop advanced sustainable hybrid micro/nano composites. In this study, the use of natural cellulosic sisal fibers with fly ash has enhanced the tensile properties and surface finish of composites. Fly ash particulates acted as fillers, additives, as well as surface-finishing medium and sisal fibers as reinforcing elements in achieving glossy finish sustainable composites. The developed composites have been found to be stronger than wood, plastics and have many opportunities for multifunctional applications.