A physical organic chemistry approach to dissolution of cellulose: effects of cellulose mercerization on its properties and on the kinetics of its decrystallization


Autoria(s): RAMOS, Ludmila A.; MORGADO, Daniella L.; GESSNER, Fergus; FROLLINI, Elisabete; SEOUD, Omar A. El
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

20/10/2012

20/10/2012

2011

Resumo

The effects of alkali treatment on the structural characteristics of cotton linters and sisal cellulose samples have been studied. Mercerization results in a decrease in the indices of crystallinity and the degrees of polymerization, and an increase in the alpha-cellulose contents of the samples. The relevance of the structural properties of cellulose to its dissolution is probed by studying the kinetics of cellulose decrystallization, prior to its solubilization in LiCl/N,N-dimethylacetamide (DMAc). Our data show that the decrystallization rate constants and activation parameters are only slightly dependent on the physico-chemical properties of the starting celluloses. This multi-step reaction is accompanied by a small enthalpy and large, negative, entropy of activation. These results are analyzed in terms of the interactions within the biopolymer chains during decrystallization, as well as those between the two ions of the electrolyte and both DMAc and cellulose.

CNPq (National Council of Research)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

FAPESP (State of Sao Paulo Research Foundation)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Identificador

ARKIVOC, p.416-425, 2011

1551-7004

http://producao.usp.br/handle/BDPI/31403

http://apps.isiknowledge.com/InboundService.do?Func=Frame&product=WOS&action=retrieve&SrcApp=EndNote&UT=000294801700034&Init=Yes&SrcAuth=ResearchSoft&mode=FullRecord

Idioma(s)

eng

Publicador

ARKAT USA INC

Relação

Arkivoc

Direitos

restrictedAccess

Copyright ARKAT USA INC

Palavras-Chave #Cotton linters #sisal #mercerization #cellulose dissolution #decrystallization #kinetics #CHLORIDE/N,N-DIMETHYLACETAMIDE SOLVENT SYSTEM #HOMOGENEOUS SOLUTION CONDITIONS #ACETYLATION #ACETATES #LINTERS #FILMS #WATER #SISAL #Chemistry, Organic
Tipo

article

original article

publishedVersion