Acessibilidade / Reportar erro

Stress cracking failure of PET/clay composites

This study investigates stress-cracking failure of polymer/clay composites. Tensile and stress relaxation tests were conducted to evaluate the stress cracking resistance of PET and PET/clay in the presence of sodium hydroxide aqueous solution. The X-ray diffraction analyses showed that the clay formed a typical structure of a microcomposite, and not an exfoliated structure. The presence of clay causes stress concentration, with a strong consequence to the stress cracking behavior, but the effects depend on the lamellar ordering and the content of clay. When the clay lamellae are less ordered the rise in stress concentration is lower, but causes more surface cracks on the polymer, suggesting that the barrier effect was not very effective. Molar mass measurements showed that the clay accelerates the chemical attack of the matrix when higher concentrations of NaOH are used, but reduces the effect of mechanical stress on degradation.

PET; clay; stress-cracking; nanocomposites


Associação Brasileira de Polímeros Rua São Paulo, 994, Caixa postal 490, São Carlos-SP, Tel./Fax: +55 16 3374-3949 - São Carlos - SP - Brazil
E-mail: revista@abpol.org.br