Fabrication of core-shell structured PSA@chitosan cryogels for water purification in emergencies

• Main Author: Cheong, Daren Di Lun
• Other Authors: Hu Xiao
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Materials
• Online Access: http://hdl.handle.net/10356/58977
• Institution: Nanyang Technological University

Cryogels are polymeric materials with interconnecting network of pores that allows it to absorb water many times its initial mass and to swell quickly with good mechanical properties. This report investigates the effects of coating a chitosan layer on the surface of poly(sodium acrylate) (PSA) cryogels. The PSA cryogels were synthesized by cryo-polymerizing sodium acrylate and N,N’-methylenebis(acrylamide) (MBA) with ammonia persulphate (APS) and N, N, N, N’-tetramethylethylyenediamine (TEMED) as the initiator and activator, respectively. Different variables such as initial coating state (swollen, deswollen and dry), coating concentration (0.1%, 1% and 2%) and coating duration (1min, 5min, 9min) were used to control the chitosan coating. Furthermore, glutaraldehyde was used as a crosslinker of the chitosan-coated cryogels. The effects of each variable on the performance of the cryogel were evaluated in terms of the degree and rate of swelling, and turbidity removal efficiency. It was found that the optimum chitosan-coated cryogels were based on swollen cryogels coated with 1% chitosan concentration for 5 min. The chitosan-coated cryogels were effective to reject up to 83.6% of bentonite in highly turbid water with a swelling degree of 98.4 g/g. This report also compares the SEM images and fatigue properties between some of the chitosan-coated cryogels and uncoated cryogels.