INTERFACIAL ADHESION BETWEEN GLASS FIBERS AND ACRYLIC-BASED MATRICES AS STUDIED BY MICROMECHANICAL TESTING

The quality of adhesion between a polymer matrix and reinforcing fibers, which may be affected by the composite processing parameters, strongly conditions the performances of the final part and so has to be evaluated. For this purpose, PMMA/glass fiber (GF) model specimens were prepared by in-situ polymerizing a MMA-based reactive mixture onto a single glass filament. Two micromechanical tests on single filament composites have been used to evaluate the interfacial adhesion: the single fiber fragmentation test and the microbond test. Fibers sizing nature and sample processing conditions have been varied to study the influence of these parameters on fiber/matrix interface. Interfacial shear strength (IFFS) values were evaluated according to well-known theoretical models and compared with values obtained on thermosets glass/epoxy reference samples. PMMA/GF interfacial adhesions which have been evaluated by fragmentation test compete with the one measured on epoxy system. In contrast, a much better adhesion was observed in the epoxy systems for microdroplet specimens. The sizing nature does not impact significantly the PMMA/GF adhesion quality. On the contrary, the latter strongly depends on the sample preparation conditions (monomer evaporation.) and so it can be reasonably anticipated that the composite processing conditions will significantly impact the interface quality.