Please use this identifier to cite or link to this item: http://hdl.handle.net/10316/87207
DC FieldValueLanguage
dc.contributor.authorAguado, Roberto-
dc.contributor.authorLourenço, Ana F.-
dc.contributor.authorFerreira, Paulo J. T.-
dc.contributor.authorMoral, Ana-
dc.contributor.authorTijero, Antonio-
dc.date.accessioned2019-06-21T11:20:50Z-
dc.date.available2019-06-21T11:20:50Z-
dc.date.issued2019-05-20-
dc.identifier.issn1572-882X (Online)pt
dc.identifier.urihttp://hdl.handle.net/10316/87207-
dc.description.abstractCationized fibers and other kinds of chemically modified fibers impart many advantages in papermaking, but unfeasibly long reaction times are necessary to attain acceptable degrees of substitution, due to the low reactivity of bleached kraft pulps. In this work, different aqueous pretreatments were tested in order to activate cellulose towards a 60 min-long etherification with a quaternary ammonium reagent. Severe decrystallization treatments, namely alkalization with NaOH 20%, NaOH/urea or FeTNa, conducted to the best reactivity results (substitution from 2 to 10%), but the fiber properties were harshly affected. Pretreatments involving H3PO4 at different concentrations were also performed, with distinct results, from unnoticeable effects at 20% to amorphization and excessive depolymerization at 80%. Finally, aqueous ammonium thiocyanate was tested as activator and had little effect on fibers, although the addition of ammonia resulted in high degrees of substitution, while maintaining the pulps’ capability to retain inter-fiber water and cellulose I as the prevalent allomorph.pt
dc.language.isoengpt
dc.publisherSpringerpt
dc.rightsembargoedAccesspt
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/pt
dc.subjectActivationpt
dc.subjectCationization of cellulosept
dc.subjectDegree of crystallinitypt
dc.subjectPretreatmentpt
dc.subjectSwellingpt
dc.subjectX-ray diffractionpt
dc.titleThe relevance of the pretreatment on the chemical modification of cellulosic fiberspt
dc.typearticle-
degois.publication.firstPage5925pt
degois.publication.lastPage5936pt
degois.publication.issue10pt
degois.publication.titleCellulosept
dc.relation.publisherversionhttps://link.springer.com/article/10.1007/s10570-019-02517-7pt
dc.peerreviewedyespt
dc.identifier.doi10.1007/s10570-019-02517-7pt
degois.publication.volume26pt
dc.date.embargo2020-05-19*
uc.date.periodoEmbargo365pt
item.grantfulltextopen-
item.fulltextCom Texto completo-
item.languageiso639-1en-
crisitem.author.deptFaculdade de Ciências e Tecnologia, Universidade de Coimbra-
crisitem.author.parentdeptUniversidade de Coimbra-
crisitem.author.researchunitCoimbra Chemistry Center-
crisitem.author.researchunitResearch Center for Chemical Processes and Forest Products-
crisitem.author.parentresearchunitFaculdade de Ciências e Tecnologia, Universidade de Coimbra-
crisitem.author.orcid0000-0001-9864-1794-
crisitem.author.orcid0000-0002-4503-6811-
Appears in Collections:FCTUC Eng.Química - Artigos em Revistas Internacionais
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