ESTABILIDADE TÉRMICA E FLAMABILIDADE DE NANOCOMPÓSITOS DE POLIETILENO DE ALTA MASSA MOLAR PRODUZIDOS POR POLIMERIZAÇÃO IN SITU
THERMAL STABILITY AND INFLAMMABILITY OF NANOCOMPOSITES OF HIGH DENSITY POLYETHYLENE OBTAINED BY IN SITU POLYMERIZATION
Sara Pereira de Agrela, Luiz Rogério Pinho de Andrade Lima, Rosemário Cerqueira Souza
Resumo
Nanocompósitos de polietileno de alta massa molar com argila, grafita ou talco foram produzidos utilizando polimerização in situ direta em solvente usando um sistema catalítico tipo Ziegler (TiCl4 e trietilalumínio em hexano). O polímero produzido apresentou uma massa molar alta e degradação térmica em atmosfera inerte em temperatura acima de 400ºC. A degradação térmica dos polímeros nos nanocompósitos foi deslocada para temperaturas um pouco mais altas (até próximo de 500ºC) indicando um aumento da estabilidade térmica da matriz polimérica. Os testes de flamabilidade mostraram um efeito de redução ou atenuação da progressão das chamas para todos os nano-compósitos devido ao efeito de barreira para gases e compostos voláteis.
Palavras-chave
Abstract
High density polyethylene-clay, graphite or talc composites were produced using direct solvent in situ polymerization using a Ziegler catalyst system (TiCl4 and triethylaluminum in hexane). The produced polymer had a high average molecular weight and in inert atmosphere presents a thermal degradation above 400ºC. The thermal degradation of the polymers in the nanocomposites was shifted for higher temperature (until close to 500ºC) indicating an improvement in the thermal stability of the polymeric matrix. The inflammability tests clearly showed a retardation or attenuation effect of the flames progression for all nanocomposites due to the barrier effect for gases and volatile compounds.
Keywords
References
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