title: Use of thermogravimetric analysis to monitor the effects of natural laccase mediators on flax pulp.
abstract: The effects of 1-hydroxybenzotriazole (HBT) and the natural laccase mediators gallic acid, caffeic acid and p-hydroxybenzoic acid, on the enzymatic bleaching of flax pulp were compared. The treatment was performed under atmospheric air and oxygen pressure, and, for the first time, monitored by thermogravimetric analysis (TGA) for comparison with chemical analysis, FTIR and X-ray diffraction (XRD) spectroscopies. Thermogravimetric data were simulated by applying a nucleation kinetic equation to a combustion model based on four pseudo-components (hemicellulose, amorphous and crystalline cellulose, and lignin). The results thus obtained show that the effects of the natural mediators are similar to those of HBT and lead to increased order in cellulose microfibril surfaces. An increase in pulp crystallinity was additionally exposed by the XRD and FTIR techniques, and a reduction in microfibril equatorial size by the XRD patterns. Simulated DTG curves were used to determine the kinetic parameters for thermal degradation.
authors.affiliation: Department of Textile and Paper Engineering, Universitat Politècnica de Catalunya, Colom 11, E-08222 Terrassa, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Vila
authors.forename: Agustín García
authors.initials: AG
authors.lastname: Barneto
authors.forename: Amanda
authors.initials: A
authors.lastname: Fillat
authors.forename: Teresa
authors.initials: T
authors.lastname: Vidal
authors.forename: José
authors.initials: J
authors.lastname: Ariza
mesh_terms: D018533:Biomass; D002482:Cellulose / Q000737:chemistry; D003198:Computer Simulation; D003460:Crystallization; D019597:Flax / Q000737:chemistry*; D005936:Glucans / Q000032:analysis; D007700:Kinetics; D042845:Laccase / Q000378:metabolism*; D008031:Lignin / Q000032:analysis; D008956:Models, Chemical; D010100:Oxygen / Q000494:pharmacology; D010209:Paper; D058105:Polymerization / Q000187:drug effects; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013818:Thermogravimetry / Q000379:methods*; D014961:X-Ray Diffraction; D014990:Xylans / Q000032:analysis
chemical_list: D005936:Glucans; D014990:Xylans; D002482:Cellulose; D008031:Lignin; D042845:Laccase; D010100:Oxygen