@PhDThesis{Santos:2017:SíCaHí,
author = "Santos, Ester Pinheiro dos",
title = "S{\'{\i}}ntese e caracteriza{\c{c}}{\~a}o de h{\'{\i}}bridos
celul{\'o}sicos modificados com {\'o}xidos met{\'a}licos
hidratados para aplica{\c{c}}{\~a}o como aditivos em espumas
r{\'{\i}}gidas de poliuretano",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2017",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2017-06-23",
keywords = "celulose, {\'o}xidos met{\'a}licos hidratados, h{\'{\i}}bridos
org{\^a}nico-inorg{\^a}nico, poliuretano, comp{\'o}sitos,
cellulose, hydrous metallic oxide, organic-inorganic hybriids,
polyurethane, composites.",
abstract = "O sinergismo de propriedades entre diferentes componentes em um
{\'u}nico material torna-se cada vez mais atrativo, no que se
refere {\`a} diversidade de aplica{\c{c}}{\~o}es assim como na
utiliza{\c{c}}{\~a}o de subprodutos agroindustriais. Al{\'e}m
disso, a busca por fontes renov{\'a}veis aliada {\`a} elevada
disponibilidade evidenciam as fibras lignocelul{\'o}sicas como
precursoras no desenvolvimento de novos materiais. Os
h{\'{\i}}bridos org{\^a}nico-inorg{\^a}nicos apresentamse
promissores, podendo ser aplicados em v{\'a}rios setores, tais
como cat{\'a}lise, adsor{\c{c}}{\~a}o e como aditivos em
matrizes polim{\'e}ricas para a produ{\c{c}}{\~a}o de membranas
e comp{\'o}sitos. A proposta deste trabalho {\'e} desenvolver e
caracterizar h{\'{\i}}bridos, provenientes da
combina{\c{c}}{\~a}o entre a celulose da folha de bananeira e os
{\'o}xidos met{\'a}licos hidratados de ni{\'o}bio
(Nb\$_{2}\$O\$_{5}\$.nH\$_{2}\$O), de alum{\'{\i}}nio
(Al\$_{2}\$O\$_{3}\$.nH\$_{2}\$O) e de zinco
(ZnO.nH\$_{2}\$O), visando a produ{\c{c}}{\~a}o de espumas
r{\'{\i}}gidas de poliuretano e verificar o efeito destes
aditivos h{\'{\i}}bridos e seus precursores nas propriedades
t{\'e}rmicas e mec{\^a}nicas dos comp{\'o}sitos. Inicialmente,
as folhas de bananeira foram submetidas a diferentes tratamentos
qu{\'{\i}}micos, a fim de avaliar a modifica{\c{c}}{\~a}o mais
eficiente para o isolamento da celulose. Posteriormente, os
h{\'{\i}}bridos foram sintetizados via precipita{\c{c}}{\~a}o
convencional e um estudo de propor{\c{c}}{\~a}o foi realizado,
com diferentes rela{\c{c}}{\~o}es m{\'a}ssicas entre a celulose
e os {\'o}xidos met{\'a}licos hidratados. O estabelecimento da
melhor propor{\c{c}}{\~a}o de cada aditivo h{\'{\i}}brido foi
determinado por termogravimetria. Os h{\'{\i}}bridos escolhidos
foram caracterizados por testes de absor{\c{c}}{\~a}o de
{\'a}gua, DSC, FTIR, DRX, MEV/EDX e, em seguida, incorporados
{\`a} matriz de poliuretano para a s{\'{\i}}ntese das espumas
r{\'{\i}}gidas. Os comp{\'o}sitos foram obtidos mediante a
adi{\c{c}}{\~a}o de 1 a 5 \% m/m dos h{\'{\i}}bridos
escolhidos, al{\'e}m dos respectivos precursores (celulose e
{\'o}xidos met{\'a}licos hidratados), e caracterizados por TGA,
DSC e ensaio de compress{\~a}o. Os resultados de termogravimetria
indicaram as propor{\c{c}}{\~o}es
97Celfb/3Nb\$_{2}\$O\$_{5}\$.nH\$_{2}\$O,
94Celfb/6Al\$_{2}\$O\$_{3}\$.nH\$_{2}\$O e 97Celfb/3ZnO.nH2O
como as melhores rela{\c{c}}{\~o}es celulose/{\'o}xido
(h{\'{\i}}bridos). As curvas DSC exibiram o efeito da
fra{\c{c}}{\~a}o inorg{\^a}nica na supress{\~a}o de calor,
evidenciando os h{\'{\i}}bridos
97Celfb/3Nb\$_{2}\$O\$_{5}\$.nH\$_{2}\$O e
94Celfb/6Al\$_{2}\$O\$_{3}\$.nH\$_{2}\$O com propriedades em
potencial para atuarem como retardantes de chamas. As
an{\'a}lises de EDX confirmaram a incorpora{\c{c}}{\~a}o dos
metais na matriz celul{\'o}sica, corroborando com os resultados
de DRX e FTIR. Nos testes de absor{\c{c}}{\~a}o de {\'a}gua o
h{\'{\i}}brido 94Celfb/6Al\$_{2}\$O\$_{3}\$.nH\$_{2}\$O
apresentou a maior redu{\c{c}}{\~a}o no car{\'a}ter
hidrof{\'{\i}}lico, comparado {\`a} celulose isolada e aos
demais h{\'{\i}}bridos, o que nos induz a esperar por um aditivo
que proporcione aumento de ades{\~a}o na interface fibra/matriz
polim{\'e}rica, resultando em melhores propriedades t{\'e}rmicas
e mec{\^a}nicas. Os resultados t{\'e}rmicos e mec{\^a}nicos
evidenciaram o h{\'{\i}}brido
94Celfb/6Al\$_{2}\$O\$_{3}\$.nH\$_{2}\$O como o melhor
aditivo na formula{\c{c}}{\~a}o para o comp{\'o}sito PU + 1\%
m/m 94Celfb/6Al\$_{2}\$O\$_{3}\$.nH\$_{2}\$O. ABSTRACT: The
synergism properties between different components in an unique
material become increasingly attractive, as regards the variety of
applications like the use of agro industrial by-products.
Furthermore, the search for renewable sources combined with high
availability evidence the lignocellulosic fibers as precursor in
the development of new materials. Organic-inorganic hybrids have
to be promising and can be applied in several sectors, such as
catalysis, adsorption and as additives in polymer matrices in the
production of membranes and composites. The purpose of this work
is to develop and characterize hybrids derived from the
combination between the cellulose of leaf bananas plant and
hydrous metallic oxides of niobium (Nb2O5.nH2O), aluminum
(Al2O3.nH2O) and zinc (ZnO.nH2O), aiming at the production of
rigid polyurethane foams and to verify the effect of these
additives hybrid and their precursors on the thermal and
mechanical properties of the composites. Initially, the banana
leaves were submitted to different chemical treatments, in order
to evaluate the most efficient modification for isolation of
cellulose. After, the hybrids were synthesized through
conventional precipitation and a proportion study was performed,
with different mass relations between the cellulose and the
hydrous metallic oxides. The establishment of the best proportion
of each additive hybrid was determined by thermogravimetric
analysis. The selected hybrids were characterized by water
absorption tests, DSC, FTIR, DRX, MEV/EDX and then incorporated
into the polyurethane matrix for the synthesis of rigid foams. The
composites were obtained by adding 1 to 5 % m/m of the chosen
hybrids, beyond to the respective precursors (cellulose and
hydrous metallic oxides) and characterized by TGA, DSC and
compression test. The results of thermogravimetric analysis
indicated the proportions 97Celfb/3Nb2O5.nH2O, 94Celfb/6Al2O3.nH2O
and 97Celfb/3ZnO.nH2O as the best cellulose/oxide ratios
(hybrids). DSC curves exhibited the effect of oxides on heat
suppression, evidencing the hybrids 97Celfb/3Nb2O5.nH2O and
94Celfb/6Al2O3.nH2O with potential properties to act as flame
retardants. EDX analyzes confirmed the incorporation of the metals
in the cellulosic matrix, corroborating with the results of XRD
and FTIR. In the tests of water absorption, the hybrid
94Celfb/6Al2O3.nH2O presented the greatest reduction in
hydrophilic character, compared to the isolated cellulose and the
other hybrids, which induces us to wait for an additive that
provides increased adhesion at the fiber/polymeric matrix
interface, resulting in better thermal and mechanical properties.
The thermal and mechanical results show the hybrid
94Celfb/6Al2O3.nH2O as the best additive in the formulation for
the composite PU + 1% m/m 94Celfb/6Al2O3.nH2O.",
committee = "Nono, Maria do Carmo de Andrade (presidente/orientadora) and
Silva, Maria L{\'u}cia Caetano Pinto da (orientadora) and
Machado, Jo{\~a}o Paulo Barros and Soares Neto, Turibio Gomes and
Pardini, Luiz Claudio and Ancelotti Junior, Antonio Carlos",
englishtitle = "Synthesis and characterization of cellulosic hybrids modified with
hydrous metallic oxides for application as additives in rigid
polyurethane foams",
language = "pt",
pages = "247",
ibi = "8JMKD3MGP3W34P/3PAKJLH",
url = "http://urlib.net/ibi/8JMKD3MGP3W34P/3PAKJLH",
targetfile = "publicacao.pdf",
urlaccessdate = "27 abr. 2024"
}