Abstract

• The pure chitosan membranes, un-modified and modified chitosan-calcium alginate composite membranes were prepared by using casting and autoclaving methods. All prepared chitosan composite membranes have smooth surfaces, highly transparent and pale yellow colour. The physicomechanical properties of prepared chitosan composite membranes were determined such as tensile strength, elongation at break and tear strength. According to the mechanical properties of the pure chitosan membranes, 2 % (w/v) chitosan was chosen as optimum condition and 2 % (w/v) chitosan, 0.1 % (w/v) sodium alginate, 0.2 % (w/v) calcium chloride solution were the most suitable for preparing chitosan-calcium alginate membranes. Swelling behaviour and water uptake of these membranes were determined as a function of contact time. Then, modified chitosan-calcium alginate composite membranes were prepared by using various percent of glycerine as a plasticizer. According to the physicomechanical properties of modified chitosan-calcium alginate-glycerine composite membranes, optimum ratio for membrane preparation was chosen. It was found that the modified chitosan-calcium-alginate-glycerine composite-1 membrane showed tensile strength 34.2 MPa, elongation at break 30 % and tear strength 55.5 kNm-1. The characterization of chitosan membranes, chitosancalcium alginate composite membranes and modified chitosan-calcium alginate-glycerine composite-1 membrane were studied by FT IR and SEM analyses. From FT IR analysis, the characteristic absorption peaks of modified chitosan-calcium alginate-glycerine composite membrane clearly showed that the two polymers were blended. SEM micrograph of modified chitosan-calcium alginate-glycerine composite membrane showed more homogeneous nature. The antimicrobial activities of all prepared chitosan membranes were tested by agar well diffusion method. From these results, all of the prepared chitosan membranes showed effective and efficient antimicrobial activities. The biodegradable nature of the prepared chitosan membrane, chitosan-calcium alginate composite membrane and modified chitosan-calcium alginate-glycerine composite membranes were studied by soil burial test.