FT-IR and FT-Raman study of hydrothermally degraded groundwood containing paper

Abstract

Accelerated aging test of paper is used to understand mechanisms of acidic hydrolysis and oxidative degradation of cellulose, hemicellulose and lignin. In recent years FT-IR and FT-Raman spectroscopy have been used together with mass spectrometry and nuclear magnetic resonance as well as chemometrics methods to characterize degradation products of paper. In this work we present FT-IR and FT-Raman spectra of hydrothermally treated sample of acid paper (Paper 3—bleached sulfite softwood pulp) in extreme humid conditions (100% humidity and 100 °C). Degradation reaction is monitored mainly based on CO stretching vibrations formed during the process of carbonyl compounds, however, some changes in CC stretching vibrations are also noticed. We showed that in these conditions paper undergoes oxidation process in which at least three new carbonyl species that can be characterized by their CO stretches are formed. Additionally, during this process, one can observe disappearance of the CC stretching that can be associated with changes that involve, for example, coniferyl alcohol. We also show that water molecules play very important role in this process. Thus, we report here, changes caused by hydrothermal treatment of groundwood containing paper mainly associated with the appearance of new carbonyl species, besides others, as well as rearrangement of existing hydrogen bond network.