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Previous issue date: 2014-07-30 / O presente trabalho tem como objetivos extrair a fibra da folha do abacaxizeiro tipo P?rola para obter bast?es (?whiskers) de celulose destas fibras tratadas quimicamente, para utiliza??o como refor?o na fabrica??o de filmes de Biocomp?sito com Poli ?lcool Vin?lico (PVA) e Poli (?cido l?tico) (PLA) como matrizes. As amostras foram caracterizadas utilizando an?lises como TGA, FTIR e DSC. Tamb?m foram realizados ensaios das folhas para a identifica??o de macro e micro nutrientes. As amostras dos filmes de biocomp?sitos foram usadas para ensaios mec?nicos de tra??o nos filmes e o teste de biodegrada??o aer?bica, bem como nos filmes de 100% de PVA e PLA. A extra??o da fibra foi efetuada numa desfibradeira autom?tica, e em seguida as fibras extra?das foram lavadas v?rias vezes para remover as impurezas e foram tratadas com NaOH (hidr?xido de s?dio) e NaClO (hipoclorito de s?dio), para remover as impurezas inerentes ?s fibras e a cor natural, respectivamente. Em seguida, as fibras tratadas foram submetidas a um processo de hidr?lise com ?cido sulf?rico a 13,5%, para obten??o de bast?es de celulose. Foram produzidos filmes biocomp?sitos de PVA e PLA com bast?es de celulose nas concentra??es de 0%, 1%, 3%, 6%, 9% e 12%. ?gua destilada a 80?C ? 5 na dilui??o de PVA e diclorometano para a dilui??o do PLA na temperatura ambiente. Na prepara??o dos filmes foi utilizado o m?todo de ?casting?. Posteriormente foram realizados os testes de absor??o de ?gua pelos filmes produzidos. Para o ensaio mec?nico de tra??o dos filmes foi utilizada a norma ASTM D638-10 com velocidade de 50 mm/min. O teste estat?stico Qui-quadrado foi empregado para a verifica??o da exist?ncia de diferen?as significativas em n?vel de 0,05: comprimentos das folhas do abacaxizeiro e dos bast?es, procedimentos utilizados para filtra??o em filtro utilizando seringa de 0,2 ?m e filtragem atrav?s de centrifuga??o. Foi realizado estudo de hidrofilidade dos filmes com base no ?ngulo de contato. Tamb?m foi aplicado o teste Estat?stico T-Student com n?vel de signific?ncia (0,05) para comparar as espessuras dos filmes de PVA e PLA e das propriedades mec?nicas (tra??o). Na avalia??o da biodegradabilidade dos biocomp?sitos, bem como os filmes de 100% das matrizes de PVA e PLA, foi utilizado o teste de Sturm norma D5209. Os resultados indicam a presen?a de bast?es de celulose com comprimentos variandos de 7,33 nm a 186,17 nm. As espessuras em m?dia dos filmes de PVA e PLA eram de 0,153 ?m e 0,210 ?m, respectivamente. Foi observada uma forte correla??o linear diretamente proporcional entre a tra??o dos filmes de PVA e a concentra??o de bast?es de celulose nos filmes (0,7336), da espessura do filme de 0,1404. Juntos, a porcentagem de bast?es de celulose e a espessura dos filmes, correlacionaram 0,8740. No caso dos filmes de PLA, a correla??o entre o teor dos bast?es de celulose e a tra??o foi fraca, inversamente proporcional (-0,0057) e a espessura em -0,2602, totalizando -0,2659, isto ?, os bast?es de celulose n?o aderiram totalmente ao PLA. Na compara??o dos resultados da tra??o das duas matrizes polim?ricas, os bast?es de celulose contribu?ram na melhoria das propriedades mec?nicas no caso de PVA, mas h? uma diferen?a com rela??o a PLA. Nos testes de biodegradabilidade, foi observado a degrada??o total do filme de PVA ap?s 27 dias, enquanto o filme de PLA degradou em 20 dias, o que comprova que os filmes produzidos s?o biodegrad?veis. / This work has the main objective to obtain nano and microcrystals of cellulose, extracted from
the pineapple leaf fibres (PALF), as reinforcement for the manufacture of biocomposite films
with polymeric matrices of Poly(vinyl alcohol) (PVA) and Poly(lactic acid) (PLA). The
polymer matrices and the nano and microcrystals of cellulose were characterised by means of
TGA, FTIR and DSC. The analysis was performed on the pineapple leaves to identify the macro
and micronutrients. The fibers of the leaves of the pineapple were extracted in a desfibradeira
mechanical. The PALF extracted were washed to remove washable impurities and subsequently
treated with sodium hydroxide (NaOH) and sodium hypochlorite (NaClO) in the removal of
impurities, such as fat, grease, pectates, pectin and lignin. The processed PALF fibers were
hydrolysed in sulfuric acid (H2SO4) at a concentration of 13.5 %, to obtain nano and
microcrystals of cellulose. In the manufacture of biocomposite films, concentrations of
cellulose, 0 %, 1 %, 3 %, 6 %, 9% and 12% were used as reinforcement to the matrices of PVA
and PLA. The PVA was dissolved in distilled water at 80 ? 5 oC and the PLA was dissolved in
dichloromethane at room temperature. The manufacture of biocomp?sitos in the form of films
was carried out by "casting". Tests were carried out to study the water absorption by the films
and mechanical test of resistance to traction according to ASTM D638-10 with a velocity of 50
mm/min.. Chi-square statistical test was used to check for the existence of significant
differences in the level of 0.05: the lengths of the PALF, lengths of the nano and microcrystals
of cellulose and the procedures used for the filtration using filter syringe of 0.2 ?m or filtration
and centrifugation. The hydrophilicity of biocomp?sitos was analysed by measuring the contact
angle and the thickness of biocomp?sitos were compared as well as the results of tests of
traction. Statistical T test - Student was also applied with the significance level (0.05). In
biodegradation, Sturm test of standard D5209 was used. Nano and microcrystals of cellulose
with lengths ranging from 7.33 nm to 186.17 nm were found. The PVA films showed average
thicknesses of 0.153 ?m and PLA 0.210 ?m. There is a strong linear correlation directly
proportional between the traction of the films of PVA and the concentration of cellulose in the
films (composite) (0,7336), while the thickness of the film was correlated in 0.1404. Nano and
microcrystals of cellulose and thickness together, correlated to 0.8740. While the correlation
between the cellulose content and tensile strength was weak and inversely proportional (-
0,0057) and thickness in -0.2602, totaling -0,2659 in PLA films. This can be attributed to the
nano and microcrystals of cellulose not fully adsorbed to the PLA matrix. In the comparison of the results of the traction of the two polymer matrices, the nano and microcrystals have helped
in reducing the traction of the films (composite) of PLA. There was still the degradation of the
film of PVA, within a period of 20 days, which was not seen in the PLA film, on the other hand,
the observations made in the literature, the average time to start the degradation is above 60
days. What can be said that the films are biodegradable composites, with hydrophilicity and the
nano and microcrystals of cellulose, contribute positively in the improvement of the results of
polymer matrices used.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/19396 |
| Date | 30 July 2014 |
| Creators | Rocha, Brismark G?es da |
| Contributors | 18222161415, http://lattes.cnpq.br/8553209522282182, Silva, Dany Geraldo Kramer Cavalcanti e, 00049547429, http://lattes.cnpq.br/8363044275404035, Nascimento, Jos? Heriberto Oliveira do, 02452573493, http://lattes.cnpq.br/7033735079037677, Silva, K?sia Karina de Oliveira Souto, 00851738435, http://lattes.cnpq.br/4712628443097348, Belarmino, D?bora Damasceno, 03275919431, http://lattes.cnpq.br/2796094668776975, Alexandre, M?rcio Eliel de Oliveira, 13045750478, http://lattes.cnpq.br/4397086727762033, Ladchumananandasivam, Rasiah |
| Publisher | Universidade Federal do Rio Grande do Norte, P?S-GRADUA??O EM ENGENHARIA MEC?NICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| 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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