الفهرس 
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Abstract
The present work aimed to study the possibility of synthesizing, characterizing and utilizing of modified compatible chitin/cellulose blends solutions in different forms (beads, films and/or fibers). This work divided into three main parts:
Part I: Preparation, Characterization and Antibacterial Properties of Cyanoethylchitosan / Cellulose Acetate Blended Films
Modification of chitosan (CS) by means of blending with other polymers is a convenient method to improve its physical properties for practical utilization. The similarity of cellulose and chitosan in primary structures might facilitate the formation of homogeneous films. Mixing cyanoethylchitosan (CECS) with cellulose acetate (CA) overcomes mechanical weakness of CS films. CECS is prepared by reaction of chitosan with acrylonitrile in the vapour phase under a different reaction conditions, namely, sodium hydroxide concentration and reaction period. Blended films of CECS and CA are made by casting from dimethylformamide (DMF) followed by impregnation in water. CECS / CA films obtained are characterized by nitrogen content, tensile strength, elongation at break, FTIR and thermogarvimetric analysis (TGA). Antibacterial activity of films prepared against Gram (-ve) and Gram (+ve) bacteria is measured via both Disk Diffusion Method and Bacterial Count Method. Blended films show good antibacterial effects towards Gram (+ve) bacteria than Gram (-ve) ones. Antibacterial activities of blended films increased by increasing the CECS content in the blended films while the tenacity of these films gradually decreased. Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) show that CECS possesses higher effect on Gram (+ve) bacteria S. aureus than Gram (-ve) bacteria E. coli. In the meantime, CECS is much more powerful in inhibition of bacteria than CS itself.
Part II: Preparation, Characterization and Antibacterial Properties of Carboxymethylchitosan / Viscose Blended Films
Modification of Chitosan(CS) using monochloroacetic acid in the presence of sodium hydroxide under different reaction conditions were studied to determine the optimum conditions for preparing the O-carboxymethylchitosan (O-CMCS). The prepared O-CMCS was characterized by its nitrogen content, degree of substitution and its solubility in different solvent or water under different pH values. Evaluation of the antibacterial activity of CS and O-CMCS expressed in MIC and MBC against E. coli as Gram (-ve) bacteria and S. aureus as Gram (+ve) bacteria via broth tube dilution method was investigated. O-CMCS / viscose blended films were prepared by mixing O-CMCS and viscose in water as co-solvent, and regenerated in coagulation bath mentioned in the experimental part. The obtained O-CMCS / viscose blended films were characterized via its nitrogen content, tensile strength, elongation at break, Fourier transform infrared spectroscopy (FT-IR) and Thermal Gravimetric Analysis (TGA). Evaluation of the antibacterial activity of the O-CMCS / viscose blended films, against Gram (-ve) bacteria and Gram (+ve) bacteria was measured via both Disk Diffusion Method and bacterial count methods. These blended films show good antibacterial effects towards both Gram (+ve) and Gram (-ve) bacteria. The antibacterial activity of the blended films increased and the tensile strength decrease as the O-CMCS percent increase in the blended film.
Part III: Electrospinning of Cyanoethylchitosan and Cellulose Acetate
Chitosan is a well known anti-microbial polymer. It is desired to develop and evaluate inexpensive chitosan based structures with high surface area using electrospun nanofibers. Due to the difficulty in electrospinning chitosan, cyanoethylchitosan was synthesized and electrospinning trials of its solutions were conducted. Cyanoethylchitosan nanofibers were obtained from cyanoethylchitosan solutions using trifluoroacetic acid as a solvent. Nanofiberwebs of fiber diameter range of 51-459 nm was obtained from 4%-10% cyanoethylchitosan solution in trifluoroacetic acid was successfully electrospun in an electric field of 3 and 5 kV/cm. A cotton gauze fabric was the substrate for the cyanoethylchitosan mats. Contact kill performance of the structures against a range of microbes was carried out using the disc diffusion method. The trials indicated that the nanofiberwebs exhibited an excellent antimicrobial behavior. In other words, for equal area (covered discs used), the antibacterial properties are more or less at the same level for both films and nanofibers used, however, the weight amount used of the material is higher by a factor of 103 than the material used in case of nanofibers for the same material. Moreover, finishing of textiles by making use of nanofibers are much easier than by formation of films on textile surfaces which might need a lot of precautions.