Influences of Integrated Tempo-Mediated Oxidation and Recycling on the Properties of TMP Fibers

Abstract

In order to improve the properties of thermomechanical pulp (TMP), the influences of the TEMPO (2,2,6,6-tetramethylpiperidyl-1-oxyl radical)-mediated oxidation on recycled TMP properties were investigated, and the impacts of recycling process on TEMPO-mediated oxidized TMP properties were studied as well. The results showed that TEMPOmediated oxidation is an effective way to enhance the recycled TMP inter-fiber bonding dependent properties due to the introduction of carboxylic acid groups onto pulp, while the oxidation had some negative impacts on the tear index, zero span tensile index, and brightness. The oxidation-recycling (O-R) process had remarkable adverse impacts on TMP compared with the recycling-oxidation (R-O) process. The tensile, burst, tear strengths, as well as the zero-span tensile strength dropped sharply when oxidized TMP was recycled, and the physical strength properties decreased with the increasing recycling times. The opacity was improved after the O-R treatment, although the O-R treatment had an adverse impact on the pulp brightness.

Prospects for Maintaining Strength of Paper and Paperboard Products While Using Less Forest Resources: A Review

“…Such chemical derivatization of fiber surfaces can be viewed as a relatively aggressive strategy, compared to relying on adsorption. Carboxylation, leading to higher bonding strength in paper, has been achieved by periodate oxidation (Alince 1975), by carboxymethylation (Ruffini 1966;Lindström and Carlsson 1982;Laine et al 2003;Torgnysdøtter and Wågberg 2003), by ozone treatment (Minor et al 1993), by TEMPO-mediated oxidation (Kitaoka et al 1999;Le Roux et al 2006;Song and Law 2010;Aracri et al 2012;Ma et al 2012), or by enzyme-catalyzed derivatization with various carboxylic acid or aldehyde-containing species (Liu et al 2013). Most of the cited studies showed increased strength of paper prepared from the modified fibers.…”