The effect of filler loading and process route on the three-point bend performance of waste based composites

The three-point bend behaviour of polyester resin composites loaded with high volume fractions of recycled waste materials has been investigated to determine the effect of composition and processing route on performance. Flyash powder and quarry waste were chosen as candidate fillers. Fillers were added either separately or combined. Three-point bend specimens were manufactured by conventional gravity mould casting, by degassing prior to casting or by vibration moulding. The addition of filler to the resin matrix resulted in a steady reduction in ultimate flexural strength from approximately 85 MPa for the pure resin to approximately 40 MPa for 50% filled material. As filler levels were increased above this level, the strength rapidly decreased. A corresponding increase in flexural stiffness with increasing filler amount was also evident. For a given amount of filler, flexural strength decreased with increasing particulate filler size. The flexural modulus appeared to be unaffected. The effect of matrix reinforcement on the performance of heavily filled (>75% by volume) polyester resin is also presented. Matrix reinforcement resulted in the production of high strength/high modulus materials with filler contents up to 75% and it is envisaged that these filler ratios can by further increased without a loss of flexural strength. (C) 2003 Elsevier Ltd. All rights reserved.