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Previous issue date: 2011-02-28 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this work, the plant species Copernicia prunifera (Miller) H. E. Moore (carnauba),
naturally occurring which prevails in the northeast region of Brazil was the subject of studies
aiming its use as external coating of pipelines used in petroleum industry. The part of the
plant worked were the leaves, also called straw, which were coated with resinous material.
For this purpose, it was necessary to evaluate the effectiveness of the use of acrylic resins in
the straw carnauba coating. The properties of the untreated carnauba straw and chemically
treated with sodium hydroxide, hexane and carbon tetrachloride were investigated by ATRFTIR,
SEM and thermal analysis. The first two techniques showed that treatment with
solvents has caused major changes in the straw surface, while the thermal analysis indicated
that the sodium hydroxide caused variations in thermal stability of straw constituents. Water
absorption measurements showed that treatments have accelerated the absorption process and
the reduction of contact angle values for treated samples with solvents indicated higher
hidrophilicity of straw. The tensile tests showed lower values of elastic modulus and tensile
strength for treated samples. Furthermore, coatings using pure commercial resins A and B
as well as the formulations with clay were applied in straw and they were examined once
again through thermal analysis, water absorption measurements, contact angle and mechanical
tests. To analyze the effect of heat ageing, samples were subjected to tensile tests again in
order to assess its resistance. The results showed that the resins/clay formulations increased
thermal stability of straw, they promoted a good impermeabilization and caused significant
decrease in the values of elastic modulus and tensile strength. Evaluating the ageing effect on
the mechanical properties, it has been showed good recovery to the coated straw with the
formulations A 60 and A 80% in modulus and tensile strength values and elongation at break
values have remained very close. It is thus concluded that the carnauba straw can be used as a
coating of pipelines with significant cost savings, since there is no need for pretreatment for
its use and shows itself as a viable biotechnology alternative, contributing to the quality of
coatings material and environment preservation. / Neste trabalho, a esp?cie vegetal Copernicia prunifera (Miller) H. E. Moore
(carna?ba), de ocorr?ncia natural predominante da regi?o Nordeste do Brasil, foi alvo de
estudos objetivando sua utiliza??o como revestimento externo de dutos da ind?stria do
petr?leo. A parte da planta trabalhada foram as folhas, tamb?m chamadas de palhas, que
receberam um revestimento resinoso. Para tanto, foi necess?rio avaliar a efic?cia do uso de
resinas acr?licas no revestimento da palha de carna?ba. As propriedades da palha n?o-tratada e
tratada quimicamente com hidr?xido de s?dio, hexano e tetracloreto de carbono foram
investigadas por FTIR-ATR, MEV e TG. As duas primeiras t?cnicas mostraram que os
tratamentos com os solventes provocaram maiores modifica??es na superf?cie da palha,
enquanto o estudo termogravim?trico indicou que o hidr?xido de s?dio causou varia??es na
estabilidade t?rmica dos constituintes da palha. Medidas de absor??o de ?gua mostraram que
os tratamentos aceleraram o processo de absor??o e a redu??o dos valores de ?ngulo de
contato para as amostras tratadas com os solventes indicou aumento da hidrofilicidade das
palhas. Os ensaios mec?nicos apresentaram menores valores de m?dulo el?stico e tens?o de
ruptura para as amostras tratadas. Al?m disso, revestimentos com resinas comerciais puras
A e B assim como composi??es com argila foram aplicados nas palhas e estas foram
analisadas novamente atrav?s da termogravimetria, medidas de absor??o de ?gua, ?ngulo de
contato e resist?ncia mec?nica. Para analisar o efeito do envelhecimento t?rmico realizado, as
amostras foram submetidas mais uma vez aos ensaios mec?nicos, a fim de avaliar sua
resist?ncia. Os resultados mostraram que as formula??es resinas/argila aumentaram a
estabilidade t?rmica da palha, promoveram uma boa impermeabiliza??o e causaram
significativa redu??o nos valores de m?dulo el?stico e tens?o de ruptura. Ao avaliar o efeito
do envelhecimento nas propriedades mec?nicas, percebeu-se boa recupera??o nos valores de
m?dulo e tens?o para a palha revestida com as formula??es A 60 e A 80%. J? os resultados de
deforma??o mostraram que os valores permaneceram bem pr?ximos. Dessa forma, conclui-se
que a palha de carna?ba pode vir a ser utilizada como revestimento de dutos com significante
redu??o de custos, j? que n?o h? a necessidade de tratamento pr?vio para seu uso e mostra-se
como uma alternativa biotecnol?gica vi?vel, contribuindo com a qualidade de material de
revestimentos e a preserva??o do meio ambiente.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/17648 |
| Date | 28 February 2011 |
| Creators | Fernandes, J?ssica Emanuela de Ara?jo |
| Contributors | CPF:83115951787, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4788568T8, Maciel, Maria Aparecida Medeiros, CPF:37320165449, http://lattes.cnpq.br/5360188002708095, Sousa, Emanuel Alves de, CPF:00823037460, http://lattes.cnpq.br/8566005165321301, Pereira, M?rcia Rodrigues |
| 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 | English |
| 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 |
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