Structure and Properties of Cellulose-Starch Blend Films Regenerated from Aqueous Sodium Hydroxide Solution

Abstract

It was reported in 1984 that cellulose could be dissolved in aqueous sodium hydroxide solution when the intramolecular hydrogen bonds of cellulose were partially broken down by physical treatments such as steam explosion. Although there have been many studies on alkali-soluble cellulose, little is known about cellulose blends made from aqueous sodium hydroxide solution. Therefore, we investigated the structure and properties of cellulose-starch blend films regenerated from the solution. The blends had a porous structure with an average pore size increased from 1 to 6 μm with increased starch content. These pores were observed separately from each other, leading to high water and oil absorbencies of these blend films (the oil absorbency of the blend film containing 50 % starch was over 400 %, ten times that of cellulose film). The results of X-ray measurements, dynamic viscoelastic measurements, enzyme etching, and iodine staining suggested that cellulose and starch were miscible in the amorphous regions but incompatible in the crystalline regions of the cellulose-starch blend films.