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Previous issue date: 2017-06-28 === As fibras lignocelul?sicas t?m se tornado alternativas econ?micas e ecol?gicas para uso
como refor?os ou cargas em comp?sitos com pol?meros virgens ou reciclados. O
presente trabalho foi subdividido em tr?s artigos que abordaram diferentes aspectos do
desenvolvimento de comp?sitos. O primeiro envolveu a modifica??o de part?culas
lignocelul?sicas, utilizando o l?quido da casca da castanha de caju (LCC) como fonte de
cardanol, tendo por objetivo o incremento da degradabilidade de comp?sitos de
polipropileno (PP) com diferentes tipos de part?culas lignocelul?sicas. Ensaios de termooxida??o
e an?lises do comportamento mec?nico, da composi??o qu?mica e das
propriedades f?sicas das amostras, permitiram a verifica??o de que os comp?sitos
produzidos com part?culas modificadas com o LCC se degradaram na metade do tempo
dos comp?sitos convencionais. O segundo artigo objetivou a otimiza??o da metodologia
de modifica??o qu?mica da superf?cie de part?culas lignocelul?sicas com LCC, que
tamb?m pode ser utilizada como etapa intermedi?ria na funcionaliza??o das part?culas
lignocelul?sicas, pois introduz em sua superf?cie s?tios de maior reatividade. A efici?ncia
das metodologias de modifica??o qu?mica foi avaliada com o uso de t?cnicas de
microscopia eletr?nica de varredura (MEV), espectroscopia de infravermelho por
transformada de Fourier (FTIR), termogravimetria (TG) e ?ngulo de contato. Tamb?m foi
avaliado o comportamento das part?culas modificadas em comp?sitos com polipropileno.
As propriedades dos comp?sitos obtidos foram avaliadas por ensaio de tra??o e an?lise
t?rmica din?mico mec?nica (DMTA). O terceiro artigo abordou a produ??o de
comp?sitos de PP com farinha de madeira de cajueiro e farinha de folha de carna?ba.
As propriedades f?sicas, mec?nicas e morfol?gicas foram avaliadas por TG, calorimetria
explorat?ria diferencial (DSC), DMTA, e MEV. Comp?sitos obtidos com fibras in natura,
mercerizadas e compatibilizadas com anidrido maleico foram comparados, tendo sido
observados os melhores desempenhos nos comp?sitos com o uso do anidrido maleico
e farinha da folha de carna?ba. === Lignocellulosic fibers have become an economical and ecological alternative for use as
reinforcements and fillers in composites made of virgin or recycled polymers. The present
work was subdivided in three papers that focus different aspects of the development of
composites. The first one had involved the modification of lignocellulosic particles, using
the cashew nut shell liquid (CNSL) as the source of cardanol. The objective was
increasing in the degradability of polypropylene (PP) composites made of different types
of lignocellulosic particles. Thermo-oxidation tests and analyzes of the mechanical
behavior, chemical composition and physical properties of the samples allowed the
verification that composites produced with CNSL-modified particles degraded in half the
time of the conventional ones. The second article aimed at optimizing the methodology
of chemical modification of lignocellulosic particles surface with CNSL that can also be
used as an intermediary step in further functionalization of lignocellulosic particles, as it
introduces upon its surface higher reactivity sites. The efficiency of the chemical
modification methodologies was evaluated with the use of scanning electron microscopy
(SEM), infrared spectroscopy (FTIR), thermogravimetry (TGA) and contact angle. The
behavior of composites made of the modified particles in polypropylene matrix was also
evaluated by mechanical tests and dynamic mechanical thermal analysis (DMTA). The
third paper dealt with the production of PP composites made of cashew wood flour and
carnauba leaf flour. The physical, mechanical and morphological properties were
evaluated by TGA, differential scanning calorimetry, mechanical tensile and flexural tests,
and SEM. Composites made of bulk fibers, mercerized and coupled with maleic anhydride
were compared and the best performances were observed in the composites using maleic
anhydride as coupling agent and carnauba fibers.
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