Investigation of PVA/ws-chitosan hydrogels prepared by combined γ-irradiation and freeze-thawing

• Published in: Carbohydrate polymers 2008-08, Vol.73 (3), p.401-408
• Main Authors: Yang, Xiaomin, Liu, Qi, Chen, Xiliang, Yu, Feng, Zhu, Zhiyong
• Format: Article
• Language: English
• Subjects: antibacterial properties; Applied sciences; chitosan; Escherichia coli; evaporation rate; Exact sciences and technology; Freeze-thawing; freezing; gel fraction; hydrocolloids; Hydrogels; Irradiation; Organic polymers; Physicochemistry of polymers; polyvinyl alcohol gels; porosity; Properties and characterization; rheological properties; Rheology; Solution and gel properties; swelling (materials); thawing; Water soluble chitosan; wound dressings
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2007.12.008

γ-Irradiation combined with freeze-thawing, i.e. irradiation followed by freeze-thawing and freeze-thawing followed by irradiation, was applied to prepare poly(vinyl alcohol) (PVA)/water soluble chitosan (ws-chitosan) hydrogels for wound dressing. The properties of these hydrogels were investigated and compared to those prepared by freeze-thawing and by irradiation, respectively. Hydrogels made by irradiation followed by freeze-thawing show larger swelling capacity and mechanical strength, higher thermal stability, lower water evaporation rate, and are less turbid than those made by pure freeze-thawing and freeze-thawing followed by irradiation. Hydrogels made by irradiation alone cannot be used as wound dressing due to their poor mechanical strength. SEM results show that the final structure of hydrogels made by combined irradiation and freeze-thawing is mainly determined by the first processing step. It is found that the appropriate amount of ws-chitosan can endow hydrogels with large swelling capacity and mechanical strength. The presence of ws-chitosan provides the hydrogels with good antibacterial activity against Escherichia coli (E. coli).