Influence of the network structure and void content on hygrothermal stability of resol resin modified with epoxy-amine

L. B. MANFREDI; A. FRAGA; A. VÁZQUEZ

JOURNAL OF APPLIED POLYMER SCIENCE

John Wiley and Sons, Inc

Lugar: Hoboken, NJ, USA; Año: 2006 vol. 102 p. 588 - 597

0021-8995

Epoxy-amine was blended with a resol type phenolic resin in order to study the relation between the morphology and the water absorption of this system. Blends with resols with two different formaldehyde/phenol molar ratios were studied. Dynamic-mechanical and thermogravimetric analyses were performed in order to determine the variation in the crosslink density with the addition of epoxy-amine to the resol. There was observed a diminution in the Tg value and an increment in the height of the tan d peak, as well as a higher thermal degradation with the increment of epoxy-amine content in the blends. Water absorption measurements were made on the samples and the maximum water uptake and the diffusion coefficient were calculated for the blends. It was observed that these parameters were related with the morphology of the specimens. On one hand, the maximum water uptake was observed to depend on the void content of the blends and on the other hand, the diffusion coefficient appears to be related to the hydrophilic character of the materials. The same behaviour was observed for the two resols studied.