Mohini Saxena’s research while affiliated with Advanced Materials and Processes Research Institute and other places

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.

Synthetic fibers based materials have replaced most of the traditional metallic/ceramic materials for a number of applications owing to their enormous properties such as light weight, specific strength and modulus to name a few. Unfortunately, the traditional synthetic fibers are not desired from the health and environmental point of view. So, in this work, we have carried out the isolation, processing and characterization of cellulosic sisal fibers. These fibers were extracted for the first time by a simple and new unique mechanical extraction technique without affecting the quality of fibers. Subsequently these cellulosic sisal fibers were thoroughly characterized for their physicochemical, microstructure and mechanical properties. These fibers were then converted into fine textured sisal textile yarn made out of 3–6 sisal fibers in continuous operation and used for the preparation of new green materials. Different properties of fine textured sisal textile and the impact of sisal fine textile on the physical, microstructural, thermal and mechanical characteristics of the green materials were studied and discussed in detail.

Fibre matrix adhesions of sisal fibre with polymer were evaluated in terms of physico-chemical and mechanical properties. Effects of acetylation, acrylation, silanization, alkalization, and permanganate treatment on physical and chemical parameters as well as mechanical parameters such as tensile and impact behavior were investigated. Physical properties like density, moisture absorption, water absorption, void content and chemical properties like percentage of lignin, cellulose, and hemicelluloses were determined. From the findings, it was concluded that treatments such as acetylation, acrylation, and silanization can increase interfacial strength, wetting, and compatibility between fibre and matrix, leading to increase composite tensile strength. Acetylated sisal fibre and its polymer composites showed the highest tensile strength, less water absorption, and the acrylated sisal fibre composites showed the highest impact strength (46900 J/m2).

Polylactide found potential as a substitute of non renewable resources. It is biodegradable and biocompatible polymer. Ring opening polymerization of polylactide has gained the importance in pharmacological, biomedical and environmental fields. In the present study, L-lactide was successfully polymerized with synthesized zirconium catalyst i.e., N-methyl benzyl amine zirconium chloride compound in bulk and in solution (THF) and the effect of monomer to catalyst ratio on the molecular weight of polymer were studied. Catalytic compound is an organometallic five membered cyclic compound, synthesized by cyclometallation process. It was observed that cyclometallic zirconium compound can effectively polymerize L-lactide to high molecular weight polylactide. Cyclometallic compound and polylactide was characterized by FT-IR, H-1 and C-13 NMR, CHNS techniques. Molecular weight was determined by GPC and thermal study was done by TGA-DSC. Surface morphology and shape was evaluated via FESEM.

To meet the shelter component of the people, timber, bricks, blocks and concrete are being used as major construction materials in the building industries and all such materials are exploited from natural resources. Due to depletion of available natural resources like forest reserves, minerals (clay, limestone, aggregates etc) and its environmental consequences accentuate the importance of utilisation of wasted resources suitably for developing alternative building materials. In this context, fly ash generated from coal combustion process for electricity generation is considered as a potential engineering material which can be recycled and used effectively in a technically feasible, economically viable and socially acceptable manner. CSIR-AMPRI, Bhopal has developed expertise and created facilities for large scale utilisation of fly ash in making wood substitute composites, fired bricks, concrete blocks, coating materials/ paints and demonstrated by constructing proto type houses using fly ash based building materials for confidence and awareness generation. Furthermore, CSIR AMPRI has demonstrated the use of fly ash as soil modifier and micro nutrients to increase the agricultural productivity at different parts of India. This paper deals with the highlights of fly ash based building materials with special emphasis on fly ash composites as wood substitute. For manufacturing wood substitute composites, processed fly ash was mixed with polymer and catalyst and synthesized using natural fibre reinforcement in moulds of required dimensions. The fly ash based polymer composite products exhibited better tensile, flexural and impact strength. Fly ash composites are weather and corrosion resistant, termite, fungus, rot and rodent resistant and fire retardant. This durable and abrasive resistant fly ash composite is stronger than wood and could be used as a substitute for timber. The timber substitute composite is cost effective & maintenance free and has wider applications in construction industry for use as doors, windows, ceilings, flooring, partition, furniture etc.

Increase in the global greenhouse gases emission drastically increases the hot weather. Due to mismanagement of waste and natural resources, we have already experienced several warning from global warming and climate change. Waste are indeed wasted resources, at this juncture, it is imperative to leverage the R&D organizations expertise, technologies and research strength to achieve quantum cost, environmental & social benefits on waste based alternative composite materials for optimum universal benefits.The present study discuss about the recycling opportunity of hazardous jarosite waste released from zinc industry in making value added composite bricks using coal combustion residues (CCRs) and marble processing residues (MPRs) as additives along with clay under sintering processes. The statistically designed experimental trials showed that the S/S sintered composite products developed from 1:1 jarosite waste clay ratio with 15 % CCRs or MPRs application attained the quality of >35kg/cm 2 recommended compressive strength by Indian Standard specification (BIS 2248:1992) for its use for construction purposes. Moreover, toxic elements present in the leachate of sintered jarosite composite products were found to be with in the acceptable limits as indicated by USEPA-TCLP limits for use in engineering applications. The optimised mixture proportion and response characteristics showed good agrement with the model results. The utility of the concept developed in the present study was successfully demonstrated by constructing and operating a bench-scale facility for manufacturing of sintered jarosite composite bricks which will leads to cross sector waste recycling and pan industry waste exchange opportunities.

The natural resources of the World are depleting very fast due to the high rate of exploitation and low rate of restoration, leading to an increase in global warming and pollution hazards. In recent years, there has been increasing interest in the substitution of synthetic fibers in reinforced plastic composites by natural plant fibers such as jute, coir, flax, hemp, and sisal. Sisal is one of the natural fibers widely available in most parts of the world; it requires minimum financial input and maintenance for cultivation and is often grown in wastelands, which helps in soil conservation. Advantages of sisal fiber are: low density and high specific strength, biodegradable and renewable resource, and it provides thermal and acoustic insulation. Sisal fiber is better than other natural fibers such as jute in many ways, including its higher strength, bright shiny color, large staple length, poor crimp property, variation in properties and quality due to the growing conditions, limited maximum processing temperatures. In recent years, there has been an increasing interest in finding innovative applications for sisal fiber-reinforced composites other than their traditional use in making ropes, mats, carpets, handicrafts, and other fancy articles. Composites made of sisal fibers are green materials and do not consume much energy for their production.

This investigation deals with the property characterization and utilization of abundantly available and renewable resources of plant fibers such as jute and sisal. These plant fibers along with industrial wastes (fly ash and red mud) have been used for synthesizing value added composite materials. Relevant engineering properties such as physical and mechanical, resistance to abrasive wear, weathering and fire, etc., of the plant fiber reinforced polymer matrix composites so synthesized were characterized. The characteristics of conventional wood and other commercially available potential candidate building materials were also compared to assess the application potential of the newly developed materials vis-a-vis their conventional counterparts. The study reveals that the developed polymer—natural fiber—industrial (inorganic) waste composites attain far superior mechanical properties and resistance to abrasive wear, fire, water absorption, weathering, and chemical attack, as compared to their conventional counterparts such as wood, medium density fibre (MDF) boards, particle board, etc. The versatile material system so developed has potential for wood substitute applications like door shutters, flooring tiles, roofing sheets, partitions, etc., and is envisaged to significantly contribute towards forest conservation and environmental protection. The study strongly suggests that the newly developed plant fiber and/or industrial waste reinforced polymer composite materials are quite capable to serve as a potential cost and energy effective, technologically viable, and attractive substitute to the conventionally used wood and other identical materials. The study gains significance from the fact that earlier investigators have focussed their attention mainly towards exploring the use of chopped (sisal), and textile (jute) composites for different engineering applications including building while the present study examines the suitability of abundantly available natural fibers such as sisal and jute in the presence of otherwise harmful industrial wastes like red mud and fly ash for synthesizing polymer-based composites. This is followed by assessing the potential of the developed composite materials as a cost and energy effective wood substitute for building applications.