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Kalia S.,BAHRA University | Kumar A.,Singhania University | Kaith B.S.,Dr. B.R. Ambedkar University
Advanced Materials Letters | Year: 2011

For the synthesis of biocomposite materials for useful applications, it becomes necessary to modify the surface of natural fibers through chemical treatments. Morphology, structure and properties of natural fibers have an obvious effect on the mechanical properties of the biocomposite materials. It is thus necessary to know the morphology, thermal stability and crystalline behavior of original and modified fibers. In present paper, sunn hemp fibers (SHF) were chemically modified with ethyl acrylate and binary monomers (EA+MMA, EA+AA) through microwave radiations induced graft copolymerization. Various reaction parameters were optimized to get maximum grafting (91.8%). Morphology, thermal stability and crystalline behavior of original and modified fibers were investigated. Morphological and thermal studies showed that surface of sunn hemp fibers becomes rough and amorphous through graft copolymerization and thermal stability has been found to be increased. Microwave radiation induced grafting showed a diminutive effect on the crystalline behavior of the sunn hemp fibers as optimum time to get maximum grafting is very less (40 min) in comparison to conventional grafting. Synthesized graft copolymers were used as reinforcing material in preparation of polyhydroxybutyrate biocomposites. It has been observed that graft copolymers improved the interface between fiber and matrix and enhanced the mechanical strength of composites. ©2011 VBRI press.

Kalia S.,BAHRA University | Sheoran R.,Singhania University
International Journal of Polymer Analysis and Characterization | Year: 2011

It becomes necessary to change the surface morphology of natural fibers to improve the interfacial adhesion between matrix and fibers. To improve the compatibility between natural fibers and hydrophobic polymer matrices, various greener methods have been explored such as plasma treatment and treatments using fungi, enzymes, and bacteria. In the present article, we report the microwave-assisted grafting of methyl methacrylate onto ramie fibers (Boehmeria nivea) and cellulase enzyme-assisted biopolishing of ramie fibers using the bacteria Streptomyces albaduncus. The effects of these treatments on the properties of ramie fibers are discussed. The modified fibers were characterized by using FT-IR, SEM, XRD, and TGA/DTA techniques in order to determine their morphology, crystallinity, and thermal stability. This article also describes the comparative study of properties of biologically and chemically modified ramie fibers. © Taylor & Francis Group, LLC.

Kalia S.,University of Bologna | Kalia S.,BAHRA University | Thakur K.,Shoolini University of Biotechnology and Management Sciences | Kumar A.,Shoolini University of Biotechnology and Management Sciences | Celli A.,University of Bologna
Journal of Molecular Catalysis B: Enzymatic | Year: 2014

Use of lignocellulosics has increased enormously in food packaging, composites and textile industries due to their advantages over other traditional materials which include renewability, biodegradability and low cost etc. Lignocellulosic biomass, a major raw material in such industries usually displays a very poor microbial and moisture resistance. Biografting provides innovative solutions to increase the performance of lignocellulosics with new properties including strength and stiffness, resistance to moisture and microbial attack. Biografting of antibacterial and other organic molecules on lignocellulosic biomass is an environmentally friendly and best approach to incorporate desired functionalities for successful industrial applications. Laccase, lipases, peroxidases are among the enzymes being investigated for biografting of organic molecules onto lignin for improved properties of lignocellulosic biomass. Lack of availability of suitable antibacterial molecules in large amounts and cost-effectiveness are the major problems for the commercialization of this method. © 2014 Elsevier B.V.

Kalia S.,University of Bologna | Kalia S.,BAHRA University | Boufi S.,University of Sfax | Celli A.,University of Bologna | Kango S.,Jaypee University of Information Technology
Colloid and Polymer Science | Year: 2014

Interest in nanofibrillated cellulose has been increasing exponentially because of its relatively ease of preparation in high yield, high specific surface area, high strength and stiffness, low weight and biodegradability etc. This bio-based nanomaterial has been used mainly in nanocomposites due to its outstanding reinforcing potential. Solvent casting, melt mixing, in situ polymerization and electrospinning are important techniques for the fabrication of nanofibrillated cellulose-based nanocomposites. Due to hydrophilic character along with inherent tendency to form strong network held through hydrogen-bonding, nanofibrillated cellulose cannot uniformly be dispersed in most non-polar polymer matrices. Therefore, surface modification based on polymer grafting, coupling agents, acetylation and cationic modification was used in order to improve compatibility and homogeneous dispersion within polymer matrices. Nanofibrillated cellulose opens the way towards intense and promising research with expanding area of potential applications, including nanocomposite materials, paper and paperboard additive, biomedical applications and as adsorbent. © 2013 Springer-Verlag Berlin Heidelberg.

Kaith B.S.,National Institute of Technology Jalandhar | Sharma R.,Himachal Pradesh University | Kalia S.,BAHRA University | Bhatti M.S.,Guru Nanak Dev University
RSC Advances | Year: 2014

Guar gum based hydrogel was optimally synthesized using a response surface methodology (RSM) approach for enhanced swelling capacity. Maximization of the water absorption capacity of the synthesized hydrogel was achieved through sequential experimental design based optimization. A fractional factorial screening (Resolution-IV) approach was used to screen significant process variables for maximization of percentage swelling in phase-1. Studied reaction parameters were: (i) monomer concentration, (ii) initiator concentration, (iii) cross linker concentration, (iv) polymerization time, (v) reaction temperature, (vi) vacuum level, and (vii) pH of reaction mixture. A Pareto chart indicated monomer concentration, pH and initiator concentration as significant process variables which were further optimized using full factorial design (23) in phase-2. RSM based center composite design (CCD) was applied to maximize the percentage swelling for the two most significant variables (pH and initiator concentration) in phase-3. Statistical modeling using ANOVA predicted a near neutral range for pH (∼7.0) and an initiator concentration of 21-23 × 10-6mol L-1as optimum operating conditions for maximizing the percentage of swelling (5307%). Hydrogels were found to be highly pH sensitive and should be kept in a narrow range for maximization of percentage swelling. Thus, the sequential experimental design was helpful in achieving two fold increases in percentage swelling in a systematic way. Synthesized super absorbent polymers can be used as effective water-saving materials for horticultural and agricultural applications. This journal is © the Partner Organisations 2014.

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