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Natural polysaccharide based hydrogels display unique properties such as biodegradability, biocompatibility, stimuli-responsive characteristics and biological functions making them a materials of choice for diverse applications. Indeed during the last few years, a number of biorenewable polymers based hydrogels have attracted great interest for miscellaneous applications including biomedical, toxic ion removal and water purification. Keeping in mind the advantages of biorenewable polymers, this article summarizes for the first time, the recent development in psyllium polysaccharide based hydrogels. Different methods for preparation of polysaccharide hydrogels along with characterization, their swelling behavior and different mechanisms of solvent diffusion are critically reviewed. This article also comprehensively discusses the structure-property relationships of polysaccharide hydrogels and highlights the application potential for prime performance of the resulting hydrogels. Effect of different reaction conditions and monomers on different properties of the resulting hydrogels have been explored. The most important properties of polysaccharide hydrogels relevant to their biomedical/environmental applications are also identified, especially for the use of polysaccharide hydrogels as drug delivery/flocculant and superabsorbent systems. It is anticipated that the interest in natural polysaccharide based hydrogel will continue to grow as value – added green materials for multifunctional applications.

Recently there has been a growing interest in substituting traditional synthetic polymers with natural polymers for different applications. However, natural polymers such as cellulose suffer from few drawbacks. To become viable potential alternatives of synthetic polymers, cellulosic polymers must have comparable physico-chemical properties to that of synthetic polymers. So in the present work, cellulose polymer has been modified by a series of mercerization and silane functionalization to optimize the reaction conditions. Structural, thermal and morphological characterization of the cellulose has been done using FTIR, TGA and SEM, techniques. Surface modified cellulose polymers were further subjected to evaluation of their properties like swelling and chemical resistance behavior.

Natural biomasses such as natural fibers have been traditionally used as reinforcement in polymer biocomposites for structural applications. However, the resulting biocomposites are sensitive to harsh environmental conditions, which results in poorer properties in the biocomposites. Therefore, in the present study an attempt has been made to modify the surface properties of natural cellulosic biomass by the graft copolymerization technique. This article discusses the synthesis, characterization, and physicochemical properties of the raw and graft copolymerized natural cellulosic biomass. Cellulosic biomass–based grafted copolymers were characterized with scanning electron microscopy (SEM), FT-IR spectrophotometry, and thermal analysis (TGA) techniques.

Renewable cellulosic biofibers appear to be a promising substitute to synthetic fibers as reinforcement in different kinds of polymers. The prime objective of this work was to determine water absorption, chemical resistance, and mechanical properties of the green composites reinforced with ecofriendly natural cellulosic Saccharum cilliare fibers. The mechanical and physicochemical properties of the green composites have been investigated as a function of fiber loading for assessing their applicability in different potential applications in everyday life. The green composites thus prepared have been found to show a universal trend of an increase in properties with fiber loading up to 30%, and beyond this the properties decrease. A fiber/matrix interaction between the polymer and reinforcement has been analyzed based on the mechanical and morphological studies. Overall results suggest that the natural cellulosic S. cilliare fibers were capable of serving as a feasible reinforcement for green polymer composites. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E427–E435, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21290

The present work deals with the graft copolymerization of ethyl acrylate (EA) onto lignocellulosic natural fibers of the Himalayan region in air in the presence of potassium persulfate (KPS) as initiator. Raw fibers and the graft copolymers after the completion of copolymerization reaction were subjected to evaluation of different properties. Correlation of physicochemical properties with the graft copolymerization reaction mechanism is discussed. Characterization of the graft copolymers was carried out with scanning electron microscopy, Fourier transform-infrared spectrophotometry, and thermogravimetric analysis.

Natural cellulosic fibers are one of the smartest materials for use as reinforcement in polymers possessing a number of applications. Keeping in mind the immense advantages of the natural fibers, in present work synthesis of natural cellulosic fibers reinforced polymer composites through compression molding technique have been reported. Scanning Electron microscopy (SEM), Thermo gravimetric/Differential thermal/Derivative Thermogravimetry (TGA/DTA/DTG), absorption in different solvents, moisture absorbance, water uptake and chemical resistance measurements were used as characterization techniques for evaluating the different behaviour of cellulosic natural fibers reinforced polymer composites. Effect of fiber loading on mechanical properties like tensile strength, flexural strength, compressive strength and wear resistances has also been determined. Reinforcing of the polymer matrix with natural fibers was done in the form of short fiber. Present work indicates that green composites can be successfully fabricated with useful mechanical properties. These composites may be used in secondary structural applications in automotive, housing etc.

Graft copolymerization of cellulosic biopolymers with synthetic polymers is of enormous interest because of its application in biofiltration, biosorption, biomedical, biocomposites and various other eco-friendly materials. Synthesis of graft copolymers of methyl acrylate onto mercerized Grewia optiva biofibers using ferrous ammonium sulfate–potassium per sulfate as redox initiator in air was carried out. Different reaction parameters such as amount of solvent, monomer concentration, initiator molar ratio, reaction time and reaction temperature were optimized to get the maximum percentage of grafting. The graft copolymers thus formed were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential thermal analysis and differential thermogravimetric techniques. A plausible mechanism for explanation of the graft copolymerization reactions pattern shown is offered. The effect of grafting percentage on the physico–chemical properties of raw as well as grafted Grewia optiva biofibers has also been investigated. The graft copolymers have been found to be more moisture resistant and also showed better chemical and thermal resistance. Green polymer composites were also successfully prepared through compression molding technique by using grafted Grewia optiva biofibers as reinforcement.

In the present study, free radical induced graft-copolymerization of natural cellulosic polymers (Grewia optiva) has been carried out to develop the novel materials meant for green composites and many other applications. During the graft copolymer synthesis diverse reaction parameters that significantly affect the percentage of grafting were optimized. The structural, thermal and physico-chemical changes in the natural cellulosic polymers based graft copolymers have been ascertained with scanning electron micrography, Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA) and swelling studies. The swelling studies of the grafted cellulosic polymers have been carried out in different solvents to assess the possible applicability of these natural polymers. Green composites were also prepared using raw/grafted cellulosic polymers. It has been found that grafted polymers (Grewia optiva) based green composites gives better tensile properties than the parent natural cellulosic polymers based composites.

Cellulose-based materials are one of the most significant candidates for the preparation of a number of copolymers by graft copolymerization owing to their linear structure, providing good reinforcing properties to the resulting copolymers. Therefore, in the present study, in an effort to develop novel low-cost ecofriendly green polymeric materials, graft copolymers based on lignocellulose were synthesized by graft copolymerization of methyl methacrylate. Different reaction parameters were optimized to get the optimum graft yield, and the graft copolymers were subjected to the analysis of different physicochemical properties. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E741–E748, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21317

In the present work, graft copolymerization of ethyl acrylate (EA) onto mercerized natural cellulosic polymers in air in the presence of potassium persulfate (KPS) as initiator to impart low water absorbency is reported. Synthesized cellulose graft copolymers were characterized with FT-IR spectrophotometry, scanning electron microscopy (SEM), and thermal analysis TGA/DTA techniques. Thermal stability of natural polymer-g-poly (EA) was found to be more than that of raw and mercerized cellulosic polymers. On grafting, the graft copolymers were also found to exhibit more moisture, chemical, and thermal resistance.

The increasing demand for green, environmentally friendly materials has resulted in new natural fiber–based materials as replacements for nondegradable materials derived from petroleum resources that are currently being used for a number of applications. Hence, this study deals with long fiber–reinforced green polymer composites fabricated using the compression molding technique. Initially, green composites were produced with long fibers using 10, 20, 30, and 40 wt.% fiber loading. A fiber content of 30 wt.% was found to exhibit optimum mechanical properties. Physicochemical properties of the composites were also tested to check their application potential in everyday life.

Cellulose-graft-poly (methylacrylate) copolymers were prepared by microwave assisted free radical polymerization to develop an efficient rapid way to alter the surface properties of the cellulosic fibers. The effect of microwave radiation doses, ratio of monomer, solvent and initiator concentrations were determined to get the highest percentage of grafting. The graft copolymers were characterized by FTIR and SEM studies. The results clearly demonstrate that graft polymerization successfully occurred onto the cellulose backbone. The cellulose-graft-poly (methylacrylate) copolymers have been found to be more water- and moisture-resistant as well as also revealing enhanced chemical and thermal resistance.

Scientific research has been invigorated by a new class of biodegradable materials as alternatives to polymers derived from fossils. Such biomaterials can also offer economic advantages because they are derived from renewable resources. Several biopolymers (gelatin, chitin, chitosan, starch, pectin, cellulose and its modified versions, etc.) have been exploited to produce films and formulations. Their use is limited because of fast degradation, predominant hydrophilic character, and, in some cases, unsatisfactory mechanical properties. However, the properties of these polymers can be improved by using inorganic fillers such as additives. Halloysite nanotube is a promising green filler for this purpose.