title: Cellulose oxidation by Laccase-TEMPO treatments.
abstract: In this work, laccase-TEMPO (Lac-T) treatments were applied to bleached commercial dissolving pulp in order to introduce carbonyl and carboxyl groups, which were found to improve dry and wet strength-related properties. Also the solubility behavior towards xanthate reactions was assessed. The effect of a refining step (R) before the oxidative treatment, the absence or presence of oxygen pressure, TEMPO dose (2 or 8% oven dried pulp) and reaction time (8 or 20h) were thoroughly examined. Treatments conducted in the presence of oxygen pressure exhibited greater amount of functional groups. Introducing a pre-refining treatment resulted in similar functional groups but higher wet strength was achieved. Specifically, a high W/D strength ratio was observed, indicating that wet strength-related property was satisfactorily developed. Besides the fact that all Lac-T treatments caused severe cellulose degradation, no fiber strength loss was detected. In fact, all oxidized samples presented higher Wet Zero-Span Tensile Strength, mainly in R+ Lac-T (O2) sample, which suggested the formation of hemiacetal linkages between the new introduced aldehyde groups and available free hydroxyl groups resulting from fibrillation.
authors.affiliation: CELBIOTECH_Paper Engineering Research Group, Universitat Politècnica de Catalunya, BarcelonaTech, 08222 Terrassa, Spain. Electronic address: elisabet.quintana@etp.upc.edu.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Quintana
authors.affiliation: CELBIOTECH_Paper Engineering Research Group, Universitat Politècnica de Catalunya, BarcelonaTech, 08222 Terrassa, Spain.
authors.forename: M Blanca
authors.initials: MB
authors.lastname: Roncero
authors.affiliation: CELBIOTECH_Paper Engineering Research Group, Universitat Politècnica de Catalunya, BarcelonaTech, 08222 Terrassa, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Vidal
authors.affiliation: CELBIOTECH_Paper Engineering Research Group, Universitat Politècnica de Catalunya, BarcelonaTech, 08222 Terrassa, Spain. Electronic address: cristina.valls@upc.edu.
authors.forename: Cristina
authors.initials: C
authors.lastname: Valls
mesh_terms: D002482:Cellulose / Q000378:metabolism*; D003497:Cyclic N-Oxides / Q000378:metabolism*; D042845:Laccase / Q000378:metabolism*; D000074266:Materials Science; D010084:Oxidation-Reduction
chemical_list: D003497:Cyclic N-Oxides; D002482:Cellulose; D042845:Laccase; C003959:TEMPO
keywords: 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) (PubChem CID: 2724126); 2,2-azinobis(3-thylbenzothiazoline-6-sulfonic acid) (ABTS) (PubChem CID: 6871216); Carboxyl groups; Dissolving pulp; Hemiacetal linkage; Laccase; TEMPO