NC State
D. Tatsumi and T. Yamauchi. Depth profile of paper additives within a pulp fibre. In The Fundamentals of Papermaking Materials, Trans. of the XIth Fund. Res. Symp. Cambridge, 1997, (C.F. Baker, ed.), pp 789–814, FRC, Manchester, 2018


Paper sheets containing polyacrylamide(PAM)as a paper chemical additive have been analysed by attenuated total reflectance Fourier transform infrared (ATR/FT-IRS spectroscopy. Absorbance ratios of the selected band of PAM to that of cellulose were used to determine PAM content. In order to determine the distribution of the additive in the radial direction of pulp fibre, ATR/FT-IR analysis was carried out after successive etching of the paper sheet. From the relationship between etching time and the thickness of removed surface layer it is possible to follow the partial concentration profiles of the additive as a function of distance from the original surface. The obtained profiles are found to be consistent with those of variable-angle ATR/FT-IR depth profiling method qualitatively. Being distributed from fibre surface toward the centre of fibre wall, PAM exists, on the whole, close to fibre surface. Addition level does not affect the distribution curve, i.e. the concentration at every depth level is roughly proportional to the addition level. In the case of a paper sheet from heavily beaten pulp, this tendency is not so clear i.e. PAM shows broad distribution at near surface layer. PAM whose molecular weight is low is distributed widely toward the inner side of the fibre wall.

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