Made available in DSpace on 2014-12-17T15:42:01Z (GMT). No. of bitstreams: 1
MarcosPSG_DISSERT.pdf: 1772497 bytes, checksum: df93ce17acaae55571d307fc84ed5f3e (MD5)
Previous issue date: 2011-12-20 / Universidade Federal do Rio Grande do Norte / A partially hydrolyzed polyacrylamide (HPAM) is a copolymer composed of
acrylamide and sodium acrylate. Due to its wide range of applications there are different
methods for its quantification and characterization in solution systems. Evaluation of C* is
important to describe the transition from dilute to semi-dilute, behavior, when the solution
will have its characteristic viscosity at concentrations above C*. This dissertation describes
the determination of the critical concentration of overlap C* by potentiometry of partially
hydrolyzed polyacrylamide - HPAM under acidic conditions. Based on the law of mass action
and the proper treatment of the constant of aggregate formation, polymer molecular weight,
degree of polymerization and hydrolysis were calculated. The inflection point was determined
by the intersection of the resulting equation and mathematical development, statistically
satisfy the experimental points relating the number of moles of monomers (n), equilibrium
constant of formation of the entanglements (K*), pH, C* and acidity constant of the polymer
(Ka). The viscometric parameters of C* showed a percentage difference compared to
potentiometers. The results for the determination of C*, and degree of copolymerization
molar mass proved to be a simple alternative for the characterization of polymers with
protonated monomers and water soluble / A poliacrilamida parcialmente hidrolisada (HPAM) ? um copol?mero formado por
acrilamida e acrilato de s?dio. Em fun??o de sua ampla faixa de aplica??o existem diferentes
m?todos para a sua quantifica??o e caracteriza??o em solu??o. A avalia??o de C* ?
importante para descrever a transi??o do regime dilu?do para o semi dilu?do, isto ?, quando a
solu??o ter? sua viscosidade caracter?stica, em concentra??es acima de C*. Este trabalho
descreve a determina??o da concentra??o cr?tica de overlap C* por potenciometria da
poliacrilamida parcialmente hidrolisada HPAM em meio ?cido. Baseando-se na lei de a??o
das massas e no tratamento adequado da constante de forma??o do agregado polim?rico foram
calculados a massa molar, grau de hidr?lise e de polimeriza??o da HPAM empregada. O
ponto de inflex?o foi determinado pelo m?todo da interse??o e a equa??o resultante do
desenvolvimento matem?tico, satisfez estatisticamente os pontos experimentais, relacionando
o n?mero de mols de mon?meros (n), constante de equil?brio de forma??o do novelo (K*), pH
do meio, C* e constante de acidez do pol?mero (Ka). Os par?metros viscosim?tricos de C*
apresentaram uma diferen?a percentual em rela??o aos potenciom?tricos. Os resultados para
determina??o da C*, grau de copolimeriza??o e massa molar se mostraram uma alternativa
simples para caracteriza??o de pol?meros com mon?meros proton?veis e sol?veis em ?gua
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/17676 |
| Date | 20 December 2011 |
| Creators | Gomes, Marcos Paulo Salgado |
| Contributors | CPF:18822851404, http://lattes.cnpq.br/7623147392470166, Pereira, M?rcia Rodrigues, CPF:83115951787, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4788568T8, Nascimento, Maria Carolina Burgos Costa do, CPF:03449466496, http://lattes.cnpq.br/4409025248163428, Santana, Hosiberto Batista de, CPF:55184820434, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4796950P7, Costa, Marta |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Qu?mica, UFRN, BR, F?sico-Qu?mica; Qu?mica |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
Page generated in 0.0016 seconds