A New approach to Functionalize Agar and K-carrageenan Based Thin Films with Improved Barrier Properties

摘要

Agar and K-carrageenan are seaweed polysaccharides and by virtue of their gelling nature,they exhibit excellent film forming properties.We have disclosed recently a novel process for preparation of biodegradable film from semi-refined K-carrageenan(US Patent No.7,067,568).A new approach of functionalization of seaweed polysaccharide based thin films leading to partial hydrophobization using methyl methacrylate(MMA)was achieved by carrying out grafting reaction prior to casting the films,in the presence of potassium persulphate(KPS)in the film forming dispersions based on agar or K-carrageenan under microwave irradiation,instead of using the film directly for this reaction as it is usually done.The hydrophobicity of the films was measured by contact angle and swellability measurements,which showed that the films thus prepared became significantly hydrophobic compared to those of the parent polysaccharides.FT-IR(ATR),SEM-EDAX and ESI-MS/MS analysis confirmed grafting of methyl methacrylate(MMA)on the polysaccharides and films.The pore size of the films determined from water vapour permeability(WVP)values indicated their potential utility in pervaporation and gas separation membrane applications.The biodegradability of the functionalized films was also studied.This study thus provides a new one-pot method of preparing partially hydrophobic thin films,which would have wider applicability.