Effects of glass bead content and surface treatment on viscoelasticity of filled polypropylene/elastomer hybrid composites

The dynamic mechanical properties of A-glass bead filled polypropylene (PP) /ethylene-propylene-diene monomers polymer (EPDM) ternary composites have b een measured over a temperature range fi om -80 degrees C to 100 degrees C and at a fixed frequency of 1 Hz, using a dynamic mechanical analyser (DMA) , to identify the effects of the filler content and its surface treatment w ith a silane coupling agent on the dynamic viscoelastic behaviour. The resu lts show that the storage modulus (E-c') and loss modulus (E-c'') of these composites with 10% volume fraction of EPDM at 25 degrees C increase nonlin early with increasing volume ti action of glass beads (phi(g)). At the same test conditions, the E-c' value of the PP/EPDM filled with pretreated glas s beads is higher than that of the uncoated glass bead filled PPI EPDM syst em, especially at higher phi(g), while the difference in E-c'' between both systems is very small. The mechanical damping for the former decreases wit h increasing phi(g), but the opposite is true for the latter. The glass tra nsition temperature of these composites varies irregularly with phi(g). The dynamic complex viscosity increases nonlinearly with an increase of phi(g) . In addition, the interfacial structure between the matrix and inclusions has been observed by means ofa scanning electron microscope. (C) 1999 Socie ty of Chemical Industry.