POTENTIAL USE OF GRAFT COPOLYMERS OF MERCERIZED FLAX AS FILLER IN POLYSTYRENE COMPOSITE MATERIALS

Graft copolymerization of binary vinyl monomers onto mercerized flax fiber was carried out for the enhancement of mechanical properties of polystyrene composites. Binary vinyl monomer mixture of AA+AN has been found to show maximum grafting (33.55%) onto mercerized flax. Graft copolymers thus synthesized were characterized with FT-IR spectroscopy, SEM, and TGA techniques. Mercerized flax (MF) showed maximum thermal stability in comparison to graft copolymers. It has been found that polystyrene composites reinforced with graft copolymers showed improvement in mechanical properties such as wear resistance, compressive strength, and tensile strength

Natural Fibers, Bio- and Nanocomposites

The field of bio- and nano- polymer composite materials for advanced structural and medical applications is a fast emergent area and subject of scientific attention. Natural fibers have received great interest as fillers for polymer composites because of the environmental issues in combination with their low cost. Cellulose nanofibers reinforced polymer composites is a fast growing area of research because of their enhanced mechanical, thermal and biodegradation properties. Composites with polymer matrices and cellulose nanofibers are increasingly regarded as an alternative to conventional composites. The properties of nanocomposite materials depend not only on the properties of their individual constituents but also on their morphology and interfacial characteristics. This rapidly expanding field is generating many exciting new materials with novel properties. The special issue will be interesting for researchers working in this field as it will deals with cellulose fibers, nanofibers and covers the latest advances in bio- and nano- polymer composite materials

Polymers at cryogenic temperatures

Kalia and Fu's novel monograph covers cryogenic treatment, properties and applications of cryo-treated polymer materials. Written by numerous international experts, the twelve chapters in this book offer the reader a comprehensive picture of the latest findings and developments, as well as an outlook on the field. Cryogenic technology has seen remarkable progress in the past few years and especially cryogenic properties of polymers are attracting attention through new breakthroughs in space, superconducting, magnetic and electronic techniques. This book is a valuable resource for researchers, educators, engineers and graduate students in the field and at technical institutions.Written by international experts, this book covers cryogenic treatment, properties and applications of cryo-treated polymer materials. Surveys new breakthroughs in space, superconducting, magnetics and electronics, and offers an outlook on progress to come

Microwave Enhanced Synthesis of Flax-g-poly(MMA) for Use in Phenolic Composites as Reinforcement

Graft copolymerization of methyl methacrylate (MMA) onto flax fiber under the influence of microwave radiations (MWR) was carried out. 24.64% grafting was found at 210W microwave power under optimum reaction conditions. The graft copolymers were characterized with FTIR spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Graft copolymers thus prepared were used in the preparation of phenol-formaldehyde (PF) composites. Modulus of rupture (MOR), modulus of elasticity (MOE) and stress at the limit of proportionality (SP) of composites were measured and it has been found that composites reinforced with Flax-g-poly(MMA) showed better mechanical properties in comparison to composites reinforced with raw flax

Cellulose-Based Bio- and Nanocomposites: A Review

Cellulose macro- and nanofibers have gained increasing attention due to the high strength and stiffness, biodegradability and renewability, and their production and application in development of composites. Application of cellulose nanofibers for the development of composites is a relatively new research area. Cellulose macro- and nanofibers can be used as reinforcement in composite materials because of enhanced mechanical, thermal, and biodegradation properties of composites. Cellulose fibers are hydrophilic in nature, so it becomes necessary to increase their surface roughness for the development of composites with enhanced properties. In the present paper, we have reviewed the surface modification of cellulose fibers by various methods. Processing methods, properties, and various applications of nanocellulose and cellulosic composites are also discussed in this paper

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Not AvailableLettuce is considered as a high value vegetable due to its richness in phytonutrients. Nowadays, it is produced all the year round and consumed fresh so that all the ingredients stay intact. Estimation of different elements in different types of lettuce is essential in developing nutritionally rich, good quality varieties for cultivation. Sixty two genotypes comprising both heading and non-heading types were analyzed for six mineral content such as Calcium, Sulphur, Zinc, Copper, Manganese and Iron. The genotypes studied belonged to six lettuce types, namely Latin (three), Stem (five), Crisphead (thirteen) Butterhead (Eight), Leaf (twenty three) and Cos (ten). Overall, latin types were rich in sulphur, while crisphead types were rich in calcium and copper and butterhead in zinc, manganese and iron. The stem types, however, were found to be lesser in most of the minerals compared to other types. The Pennlake Crisphead lettuce genotype had highest calcium content (390.07 ppm), New chicken stem type had highest sulphur content (7.80 ppm), L-S-2 leaf type had highest zinc content (29.91 ppm), Balmoral crisphead type had highest copper content (10.98 ppm), Great takes Katrain crisphead type had highest magnesium content (44.94 ppm) followed by Sheetal crisphead type (44.11 ppm) and All source butterhead type had highest iron content (605.52 ppm). The comprehensive analysis helped by providing detailed information about the composition of minerals of different types as well as genotypes. The information so obtained will go a long way in developing mineral content dense lettuce varieties.Not Availabl

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Not AvailableLettuce is considered as a high value vegetable due to its richness in phytonutrients. Nowadays, it is produced all the year round and consumed fresh so that all the ingredients stay intact. Estimation of different elements in different types of lettuce is essential in developing nutritionally rich, good quality varieties for cultivation. Sixty two genotypes comprising both heading and non-heading types were analyzed for six mineral content such as Calcium, Sulphur, Zinc, Copper, Manganese and Iron. The genotypes studied belonged to six lettuce types, namely Latin (three), Stem (five), Crisphead (thirteen) Butterhead (Eight), Leaf (twenty three) and Cos (ten). Overall, latin types were rich in sulphur, while crisphead types were rich in calcium and copper and butterhead in zinc, manganese and iron. The stem types, however, were found to be lesser in most of the minerals compared to other types. The Pennlake Crisphead lettuce genotype had highest calcium content (390.07 ppm), New chicken stem type had highest sulphur content (7.80 ppm), L-S-2 leaf type had highest zinc content (29.91 ppm), Balmoral crisphead type had highest copper content (10.98 ppm), Great takes Katrain crisphead type had highest magnesium content (44.94 ppm) followed by Sheetal crisphead type (44.11 ppm) and All source butterhead type had highest iron content (605.52 ppm). The comprehensive analysis helped by providing detailed information about the composition of minerals of different types as well as genotypes. The information so obtained will go a long way in developing mineral content dense lettuce varieties.Not Availabl

Chitosan and Starch-Based Hydrogels Via Graft Copolymerization

Graft copolymerization is an attractive method for surface functionalization of natural polymers and can be initiated by chemical methods, radiation technique, and other systems. Polymer grafting onto polysaccharides is an effective method for the synthesis of superabsorbents. Depending upon the type of monomers and the conditions employed the properties of graft copolymers vary to a large extent. Chitosan is a nontoxic, biocompatible polysaccharide, and starch is a natural hydrophilic biopolymer. Both these are most abundant natural organic materials which are extensively investigated in the development of biodegradable and environment-friendly materials. Their hydrogels are of utmost importance for wide use in many fields including structural transplants, target drug delivery, tissue engineering, biosensors, adsorbents, etc. In this chapter, the various techniques used for the synthesis of chitosan/starch graft copolymers, their properties and possible applications are discussed in detail

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Not AvailableGuggulsterone is an aromatic steroidal ketonic compound obtained from vertical rein ducts and canals of bark of Commiphora wightii (Arn.) Bhandari (Family - Burseraceae). Owing to its multifarious medicinal and therapeutic values as well as its various other significant bioactivities, guggulsterone has high demand in pharmaceutical, perfumery and incense industries. More and more pharmaceutical and perfumery industries are showing interest in guggulsterone, therefore, there is a need for its quantitative determination in existing natural populations of C. wightii. Identification of elite germplasm having higher guggulsterone content can be multiplied through conventional or biotechnological means. In the present study an effort was made to estimate two isoforms of guggulsterone i.e. E and Z guggulsterone in raw exudates of 75 accessions of C. wightii collected from three states of North-western India viz. Rajasthan (19 districts), Haryana (4 districts) and Gujarat (3 districts). Extracted steroid rich fraction from stem samples was fractionated using reverse-phase preparative High Performance Liquid Chromatography (HPLC) coupled with UV/VIS detector operating at wavelength of 250 nm. HPLC analysis of stem samples of wild as well as cultivated plants showed that the concentration of E and Z isomers as well as total guggulsterone was highest in Rajasthan, as compared to Haryana and Gujarat states. Highest concentration of E guggulsterone (487.45 μg/g) and Z guggulsterone (487.68 μg/g) was found in samples collected from Devikot (Jaisalmer) and Palana (Bikaner) respectively, the two hyper-arid regions of Rajasthan, India. Quantitative assay was presented on the basis of calibration curve obtained from a mixture of standard E and Z guggulsterones with different validatory parameters including linearity, selectivity and specificity, accuracy, auto-injector, flow-rate, recoveries, limit of detection and limit of quantification (as per norms of International conference of Hormonization). Present findings revealed the role of environmental factors on biosynthesis of guggulsterone isomers under natural conditions.Not Availabl

Surface modification of plant fibers using environment friendly methods for their application in polymer composites, textile industry and antimicrobial activities: a review

Plant fibers are hydrophilic in nature due to attraction/interaction between the hydroxyl groups of fiber components and water molecules. The hydrophilic nature of plant fibers often results in poor compatibility with hydrophobic polymer matrices. Therefore, it becomes necessary to modify the surface of plant fibers for better binding between fiber and matrix. Most of the chemical treatments involve mercerization, acetylation, benzoylation, isocyanate treatment and grafting of synthetic polymers. Surface modification of plant fibers using chemical treatments becomes less attractive because of a number of limitations. Environment friendly methods such as plasma treatment, treatments using fungi, enzymes and bacteria, can be used for the surface modification of plant fibers. In this article, we have reviewed various environmentally friendly methods for surface modification and their effect on the properties of plant fibers and reinforced polymer composites. The applications of modified plant fibers in textile industry and antimicrobial activities are also discussed in this article