EFFECT OF NATURAL RUBBER ON WOOD REINFORCED TANNIN COMPOSITES

M. A. MOSIEWICKI; M. I. ARANGUREN; A. A. S. CURVELO; J. BORRAJO

JOURNAL OF APPLIED POLYMER SCIENCE

Wiley

Lugar: New York; Año: 2007 vol. 105 p. 1825 - 1832

0021-8995

Natural rubber latex was added to composite materials formulated from a quebracho tannin adhesive crosslinked with hexamethylenetetramine (HEXA) and wood flour as reinforcing filler. The final microstructure of the thermoset modified by addition of different concentrations of latex was observed by scanning electron microscopy. The flexural and impact behavior of the modified materials was analyzed and related to the final microstructure of the composites. The effect of exposing the materials to humid environments was also evaluated. The measurements indicated that the addition of latex did not reduce significantly water absorption. However, it facilitated the preparation process of samples with low filler contents, because of the increased viscosity of the mixture that inhibited particle settling. On the other hand, the flexural properties increased with the addition of latex containing proteins, through a reaction similar to "tanning" in leathers. The impact properties presented a similar trend with the largest change occurring between 0 and 5% of natural rubber in the matrix formulation.