EFFECT OF COUPLING AGENTS ON THE THERMAL AND MECHANICAL PROPERTIES OF PP-JUTE FABRIC COMPOSITES

BETIANA A. ACHA; MARÍA M. REBOREDO; NORMA E. MARCOVICH

POLYMER INTERNATIONAL

JOHN WILEY & SONS, Ltd.

Lugar: CHICHESTER, ENGLAND; Año: 2006 vol. 55 p. 1104 - 1113

0959-8103

Composites with different jute fabric content and polypropylene were prepared by compression molding. The composite tensile modulus increased as fiber content increased, although the strain at break decreased due to the restriction imposed to the deformation of the matrix by the rigid fibers. Moreover, and despite of the chemical incompatibility between the polar fiber and the PP matrix, the tensile strength increased with jute content because of the use of long woven fibers. The interfacial adhesion between jute and PP was improved by the addition of different commercial maleated polypropylenes to the neat PP matrix. The effect of these coupling agents on the interface properties was inferred from the resulting composite mechanical properties. The out-of plane instrumented falling weight impact (IFWI) tests showed that compatibilized composites had lower propagation energy than uncompatibilized ones, which was a clear indication that the adhesion between matrix and fibers was better in the former case since fewer mechanisms of energy propagation were activated. These results were in agreement with those found in tensile tests, inasmuch as the compatibilized composites exhibited the highest tensile strength. Scanning electron microscopy also revealed that the compatibilized composites exhibited less fiber pullout and smoother fiber surface than the uncompatibilized ones. The thermal behavior of the PP-compatibilizer blends was also analyzed by differential scanning calorimetry, to confirm that the improvements in the mechanical properties were the result of the improved adhesion between both faces and not due to the changes in the crystallinity of the matrix.