Taslim Ur Rashid

Evaluation of Fat Binding Capacity of Gamma Irradiated Chitosan Extracted from Prawn Shell

We previously studied the effects of 2–100 kGy gamma radiation (generated from 6°Co) on physicochemical, thermal, morphological, and antimicrobial properties of chitosan. The results demonstrated that these properties of chitosan were largely influenced by the action of gamma radiation. In addition, the fat binding capacity (FBC) of chitosan was found to be increased with increasing irradiation doses. In this work a thorough in-vivo investigation on mice was performed to examine FBC of irradiated chitosan (30–100 kGy) in animal bodies. Different groups of mice specimens were fed with γ-irradiated chitosan along with natural rodent chow and cheese as well as sufficient supply of water. The unconsumed lipid measured in feces was found to increase by 67% in mice whose diet included 100 kGy irradiated chitosan, relative to that nonirradiated chitosan. After twelve weeks of intimate observation, mice were sacrificed to examine triglyceride (TG) and total cholesterol (TC) content in mice blood. The results demonstrated that TG and TC values of mice fed with γ-irradiated chitosan were significantly lower than that of the control. All of these findings are expected to enhance the future research on irradiated chitosan to be used as potential fat reducer in human metabolism.

Preparation and characterization of poly (ethylene glycol) grafted Ca-alginate fibers by γ-irradiation for biomedical applications

Radiation processing, being a physical process, is an environmentally friendly alternative to chemical modifications. It is economically viable, safe, and possesses several advantages over other conventional methods employed for modification and grafting. To improve the physico-mechanical properties of Ca-alginate fiber (CaAF), poly (ethylene glycol) (PEG) was grafted by applying γ-radiation of different intensities. The effect of γ-irradiation on the physico-mechanical, thermal, morphological, thermal and water aging, water, and simulated body fluid (SBF) uptake were evaluated. FT-IR results confirmed that PEG was successfully grafted onto Ca-alginate fibers by γ-irradiation. From the detailed experimental results, irradiation doses and PEG concentration were optimized for grafting processes. The results showed that 50% PEG and 2.5 kGy irradiation dose yielded the highest tensile strength. Differential scanning calorimetric (DSC) analysis showed that with increasing γ-intensity a decrease of dehydration temperature of the fibers had occurred. On the other hand, the glass transition temperature (T g) increased with increasing irradiation dose. The tensile cracked surfaces of the grafted alginate fibers were analyzed by scanning electron microscope (SEM) in order to monitor their surface morphologies. The SEM images of the cracked surfaces demonstrated that spherical shape rods were present for irradiated fiber sample while no such rods were observed for non-irradiated fibers. The characteristic data obtained from SBF and water uptake, and water and thermal aging experiments indicated that CaAF grafted with 50% PEG by applying 2.5 kGy γ-irradiation can be potentially employed for biomedical purposes, such as surgical suture.

Preparation of Rayon Fiber-Reinforced Polypropylene Composites by Extrusion Techniques

Hybrid composites from rayon fibers (∼2–5 cm size) and polypropylene (PP) were fabricated by using an extruder. Fibre content of the composite was varied from 5–30% by weight and physico-mechanical properties of the composites were measured. Surface morphology as observed by SEM showed good interface adhesion between rayon and PP matrix. Furthermore inclusion of rayon (up to 15% fiber inclusion) in the composite increased tensile, bending and hardness properties. As the fiber content in the composite increased more than 15%, physico-mechanical properties decreased due to the decrease of fiber matrix adhesion. The change of tensile properties due to environmental aging was carried out by keeping the composite under soil for 1 month and tensile properties were measured periodically. The aging result suggests that composites retained about 75% of its original tensile and bending strength even after 1 month soil burial. The modified fibers were also used for the study. As such the fibers were treated with vinyl-trimethyoxysilane and methanol solution and irradiated under UV before being used with PP in extruder. The results showed retardation of the physico-mechanical properties for composites obtained from irradiated rayon fibers than the composites fabricated from non irradiated rayon fibers.

Recent Updates on Immobilization of Microbial Cellulase

Several new types of carriers and techniques have been implemented in recent years to improve the traditional cellulase immobilization process, which aims to enhance its loading, activity, and stability with reduced cost for various industrial applications. This chapter summarizes the recent advancements in all aspects of microbial cellulase enzyme like the types of cellulases, their microbial sources, structure, and properties, immobilization factors, and industrial applications. Common cellulase inducers and existing immobilization matrices are highlighted along with insights into the recent developments for each of them. Different immobilization techniques, the types of reactors used so far, and their effect on the immobilized cellulase are thoroughly discussed. More importantly, this review focuses on the future immobilization processes of cellulase and their potential for the most modern industrial applications.

Cellulase in Waste Management Applications

Our society produces a lot of voluminous waste of biomass every day, which are mainly lignocellulose in origin. It is the most abundant plant cell wall component of the biosphere and the most plentiful biological compound on terrestrial earth. The successful conversion of cellulosic waste from domestic, industrial, and municipal sources through economically feasible processes to valuable by-products has long been admitted as a desirable endeavor. The degradation of cellulosic materials has gained increasing attention due to its worldwide availability and enormous potential for transforming them into sugars, fuels, and chemical feedstocks. Enzymatic hydrolysis of cellulosic biomass holds tremendous promise due to the high specificity and production of high yields of glucose without generation of degradation products, unlike acid/alkali hydrolysis. It has lower utility cost and hydrolysis occurs under mild reaction conditions. Microorganisms that degrade cellulose are abundant and universal in nature. The enzymatic hydrolysis of cellulose requires the use of cellulase enzyme. Fungi and bacteria are the main cellulase-producing microorganisms. A “twofold” benefit could be achieved through a sustainable bioconversion of biomass by cellulase enzyme. First, it would reduce the amount of cellulosic waste and diminish its effects on our environment; and second, the bioconversion of waste would be an alternative source of fuel energy to shrink our growing dependence on fossil fuels.

Gelatin-Based Hydrogels

Hydrogels are crosslinked polymers that are able to absorb large amount of water, permit solutes within their swollen matrices, and provide sustained delivery of absorbed solutes. The use of various types of functional biopolymers as scaffold materials in hydrogels has become of great interest not only as an underutilized resource but also as a new functional material of high potential in various fields. T. U. Rashid (*) · S. Sharmeen · S. Biswas · T. Ahmed · A. K. Mallik · M. Shahruzzaman · M. Nurus Sakib · P. Haque · M. M. Rahman Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering and Technology, University of Dhaka, Dhaka, Bangladesh e-mail: taslim@du.ac.bd # Springer International Publishing AG, part of Springer Nature 2018 Md. I. H. Mondal (ed.), Cellulose-Based Superabsorbent Hydrogels, Polymers and Polymeric Composites: A Reference Series, https://doi.org/10.1007/978-3-319-76573-0_53-1 1 Among them, gelatin has been considered as highly potential candidate to be utilized as hydrogel component because of its hydration properties such as swelling and solubility; gelling behavior such as gel formation, texturizing, thickening, and water-binding capacity; and surface behavior like emulsion and foam formation, stabilization, adhesion and cohesion, protective colloid function, and film-forming capacity. In addition, its properties of biocompatibility, low toxicity, antimicrobial activity, and biodegradability make it suitable for diversified biomedical applications. Many works have been reported in various scientifically reputable journals and publications worldwide that seem to have potential or satisfactory contribution of gelatin-based hydrogels. Numerous fields of application of gelatin hydrogels include, not limited to, usage as safer release system in agrochemicals, nutrient carriers for plants, drug and cell carrying devices, bioadhesives, wound healing, tissue engineering, etc. The purpose of this chapter is to compile the recent information on developments in gelatin-based hydrogel preparation, as well as new processing conditions and potential novel or improved applications.

Facile Preparation of Biocomposite from Prawn Shell Derived Chitosan and Kaolinite-Rich Locally Available Clay

A novel composite material was prepared from prawn shell derived chitosan (CHT) and locally available kaolinite-rich modified Bijoypur clay (MC) using a facile technique in which dilute acetic acid was used as a solvent for dissolving chitosan and composite fabrication whereas distilled water was used for preparing the clay dispersion. Bijoypur clay mainly consists of kaolinite clay mineral and it was modified with the dodecyl amine to make it organophilic. Morphology and properties of the composites (different weight ratio of MC and CHT) have been studied and compared with those of pure CHT and MC. Purification and modification of Bijoypur clay were investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier transformed infrared spectroscopy (FTIR) analyses. The fabrication of CHT-MC composites was confirmed by FTIR analysis. Thermogravimetric analysis (TGA) and differential scanning colorimetry (DSC) were used to investigate the thermal stability of the composites. It was observed that dispersed clay improves the thermal stability and enhances the hardness of the matrix systematically with the increase of clay loading. In this study, a better insolubility in both acidic and alkaline media of the composites is also observed compared to pure chitosan.

Preparation of Chitin-PLA laminated composite for implantable application

The present study explores the possibilities of using locally available inexpensive waste prawn shell derived chitin reinforced and bioabsorbable polylactic acid (PLA) laminated composites to develop new materials with excellent mechanical and thermal properties for implantable application such as in bone or dental implant. Chitin at different concentration (1–20% of PLA) reinforced PLA films (CTP) were fabricated by solvent casting process and laminated chitin-PLA composites (LCTP) were prepared by laminating PLA film (obtained by hot press method) with CTP also by hot press method at 160 °C. The effect of variation of chitin concentration on the resulting laminated composites behavior was investigated. The detailed physico-mechanical, surface morphology and thermal were assessed with different characterization technique such as FT-IR, XRD, SEM and TGA. The FTIR spectra showed the characteristic peaks for chitin and PLA in the composites. SEM images showed an excellent dispersion of chitin in the films and composites. Thermogravimetric analysis (TGA) showed that the complete degradation of chitin, PLA film, 5% chitin reinforced PLA film (CTP2) and LCTP are 98%, 95%, 87% and 98% respectively at temperature of 500 °C. The tensile strength of the LCTP was found 25.09 MPa which is significantly higher than pure PLA film (18.55 MPa) and CTP2 film (8.83 MPa). After lamination of pure PLA and CTP2 film, the composite (LCTP) yielded 0.265–1.061% water absorption from 30 min to 24 h immerse in water that is much lower than PLA and CTP. The increased mechanical properties of the laminated films with the increase of chitin content indicated good dispersion of chitin into PLA and strong interfacial actions between the polymer and chitin. The improvement of mechanical properties and the results of antimicrobial and cytotoxicity of the composites also evaluated and revealed the composite would be a suitable candidate for implant application in biomedical sector.

Preparation and characterization of bijoypur clay-crystalline cellulose composite for application as an adsorbent

Biocomposite prepared from cellulose and Bijoypur clay (Kaolinite) exhibited enhanced properties compared to their original counterparts. Cellulose extracted from jute fiber and Bijoypur clay modified with a surfactant were combined to fabricate a biocomposite by exfoliation-adsorption method. A comparative study was carried out to determine thermal stability and adsorption capacity of the composite and raw materials. Characterizations of the biocomposites were carried out by Fourier transform infrared spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM) analysis. FT-IR analysis showed successful modification of clay and incorporation of polymer and organoclay in the biocomposites. The composite has exhibited better thermal properties with increasing clay percentage in TGA analysis. Moreover, the composite showed improved adsorption capacity of hexavalent chromium in stock solution compared to natural adsorbent such as cellulose and clay. Correspondence to: Mohammed Mizanur Rahman, Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering and Technology, University of Dhaka, Dhaka, Bangladesh, Tel: +880-2-9661920-70/7392; Fax: +880-2-9667222; E-mail: mizanur.rahman@du.ac.bd