The mechanism of alkyl ketene dimer (AKD) sizing on cellulose model films studied by sum frequency generation vibrational spectroscopy
Sum frequency generation vibrational spectroscopy (SFS) was employed to study the alkyl ketene dimer (AKD) sizing mechanism employed in the papermaking industry for hydrophobization of cellulose. The AKD was spun coat onto model cellulose films, which resulted in ≈ 2.6 nm thick AKD layers. The chain orientation of AKD molecules during the sizing process was measured at different temperatures. It was demonstrated that the chain orientation and conformation of AKD do not correlate with observed changes in sizing. The distribution of AKD molecules on model cellulose surfaces as a function of time and temperature was imaged via fluorescence microscopy to complement SFS measurements. It was concluded that the distribution of AKD plays a major role in the sizing effect.
KeywordsSum frequency generation vibrational spectroscopy Cellulose Alkyl ketene dimer (AKD) Sizing mechanism Contact angle Fluorescence microscopy
Financial support for the present work was kindly provided by the Graduate School, and the Forest Bioproduct Research Institute, of the University of Maine. Additional financial support was provided by the School of Materials Science and Engineering, of the University of Shanghai for Science and Technology. The authors thank Dr. Douglas W. Bousfield for assistance with the contact angle measurements, Dr. Samuel T. Hess for assistance with the fluorescence microscopy measurements, and Dr. Douglas Gardner for assistance with the AFM measurements.
- Eklund D, Lindstrom T (1991) Paper chemistry: An introduction. DT Paper Science Publications, GrankullaGoogle Scholar
- Esser A, Ettl R (1997) On the mechanism of sizing with alkyl ketene dimer (AKD): physico-chemical aspects of AKD retention and sizing efficiency. In: Fundamentals of papermaking materials, vol 2. Pira Int, pp 997–1020Google Scholar
- Gess JM, Rende DS (2005) Alkenyl succinic ankydride (ASA). Tappi J 49:25–30Google Scholar
- Isogai A (1997) Factors influencing on retention of alkyl ketene dimer. In: Fundamentals of papermaking materials, vol 2. Pira Int, pp 1047–1071Google Scholar
- Roberts JC (1996) The chemistry of paper. RSC paperbacks. The Royal Society of Chemistry, CambridgeGoogle Scholar
- Rohringer P, Bernheim M, Werthemann DP (1985) Are so-called reactive sizes really cellulose reactive? Tappi J 68:83–86Google Scholar
- Scott WE (1996) Principles of wet end chemistry. Tappi Press, AtlantaGoogle Scholar
- Tompkins HG, McGahan WA (1999) Spectroscopic ellipsometry and reflectometry. Wiley-Interscience, New YorkGoogle Scholar
- Yu L, Garnier G (1997) Mechanism of internal sizing with alkyl ketene dimers: the role of vapor deposition. In: Fundamentals of papermaking materials, vol 2. Pira Int, pp 1021–1046Google Scholar