title: The influence of pulping and washing conditions on the properties of Eucalyptus grandis unbleached kraft pulps treated with chelants.
abstract: The influence of different addition points of a chelating agent and a counter-ion exchange on the properties of Eucalyptus grandis unbleached kraft pulps is studied. Seven pulps were considered: two laboratory kraft pulps with or without the inclusion of the chelant DTPMPA (diethylene triamine penta (methylene phosphonic acid)), a mill kraft pulp and four mill pulps after Ca(+2) or Na(+) counter-ion exchange followed, or not, by washing with DTPMPA addition. The laboratory pulps required lower beating energy than the industrial pulps for achieving 30 degrees SR, and the corresponding handsheets also showed better strength and optical properties, as well as a more homogeneous and smooth surface. The counter-ion exchange decreases the mechanical resistances and increases brightness. However, the effects of Ca(+2) are deeper than those of Na(+). DTPMPA added to pulping causes a decrease in calcium content whereas as a washing additive does not have a relevant impact on the mechanical and optical properties.
authors.affiliation: Programa de Investigación de Celulosa y Papel, FCEQyN, Universidad Nacional de Misiones, Félix de Azara 1552, 3300 Posadas, Misiones, Argentina. m_c_area@fceqyn.unam.edu.ar
authors.forename: M C
authors.initials: MC
authors.lastname: Area
authors.forename: M G V S
authors.initials: MG
authors.lastname: Carvalho
authors.forename: P J
authors.initials: PJ
authors.lastname: Ferreira
authors.forename: F E
authors.initials: FE
authors.lastname: Felissia
authors.forename: O M
authors.initials: OM
authors.lastname: Barboza
authors.forename: D I
authors.initials: DI
authors.lastname: Bengoechea
mesh_terms: D001709:Biotechnology / Q000379:methods*; D002118:Calcium / Q000737:chemistry; D002614:Chelating Agents / Q000737:chemistry* / Q000494:pharmacology; D002852:Chromatography, Ion Exchange / Q000379:methods; D005052:Eucalyptus / Q000378:metabolism*; D007220:Industrial Waste; D007477:Ions; D008855:Microscopy, Electron, Scanning / Q000379:methods; D063065:Organophosphonates / Q000494:pharmacology; D016062:Porosity; D012964:Sodium / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D002614:Chelating Agents; D007220:Industrial Waste; D007477:Ions; D063065:Organophosphonates; D014867:Water; D012964:Sodium; D002118:Calcium