How properties of cellulose acetate films are affected by conditions of iodine-catalyzed acetylation and type of pulp
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The present study has been carried out to consider the effect of acetylation conditions and type of bleached pulps [Kraft and SO2–ethanol–water (SEW) pulps] on the properties of obtained cellulose acetates (CA) and their films. The acetylation reaction in the absence of solvent was performed by using acetic anhydride and iodine as a catalyst. The efficiency of acetylation and the degree of substitution, crystallinity, transparency, tensile strength, young modulus, differential scanning calorimetry, water vapor permeability (WVP), scanning electron microscope and atomic force microscopy images were studied. The results showed that the while the Young’s modulus and transparency increased by up to 8% of the catalyst due to the increase in iodine charge; higher iodine levels led to embrittlement of the film. The increase in the ratio of acetic anhydride to pulp (A:P) from 10:1 to 20:1 with 4% catalyst led to a reduction of the DS by 8–10%, the crystallinity by 25%, the Young’s modulus by 13–25%, and transparency by 1–34% of a CA obtained from SEW and Kraft pulp, respectively. With the use of higher amounts of the catalyst (8%) and a ratio of A:P equal to 20:1, all properties of CA were suitable for film preparation. WVP of films from Kraft pulp and SEW pulp showed a decrease of about 8.5% and 18% respectively when increasing the iodine amount from 4 to 8% in acetylation. The tensile strength of CA films was initially increased by enhancing the amount of iodine, but then reduced in a similar way to other properties. The condition of acetylation can be adjusted to produce a high-quality CA film according to the characteristics of the pulp used as raw material.
KeywordsAcetylation Iodine Substitution degree Transparency Young modulus
The authors would like to acknowledge the Ministry of Science, Research and Technology of Iran (Grant No. 215549) for their financial support.
- ASTM (2005) Standard test methods for water vapor transmittance of materials, designation E 96/E 96M – 05Google Scholar
- ASTM (2007) Standard test method for haze and light transmittance of transparent plastics, method ASTM D 1003-07Google Scholar
- Fischer S, Thümmler K, Volkert B, Hettrich K, Schmidt I, Fischer K (2008) Properties and applications of cellulose acetate. In: Macromolecular symposia, vol 262, no 1. WILEY-VCH, pp 89–96Google Scholar
- Iakovlev M, You X, van Heiningen A, Sixta H (2014) SO2–ethanol–water (SEW) fractionation process: production of dissolving pulp from spruce. Cellul J 21(3):1419–1429Google Scholar
- Marson GA, Seoud OAE (1999) A novel, efficient procedure for acylation of cellulose under homogeneous solution conditions. Polym Sci 74:1355–1360Google Scholar
- Rodriguez FJ, Coloma A, Galotto MJ, Guarda A, Bruna JE (2012a) Effect of organoclay content and molecular weight on cellulose acetate nanocomposites properties. Polym Degrad Stab 97(1996–2001):23Google Scholar
- Schaller J, Meister F, Schulze T, Krieg M (2013) Novel absorbing fibres based on cellulose acetate. Len zinger Berichte 91:77–83Google Scholar