Effects of paper mill recycling sludge application on the mechanical properties of composites based on recycled polymers

Mechanical properties of composite produced from recycled polymers (polyethylene and polypropylene) and paper mill sludge from two different sources (waste water sludge (s) and sludge on the DAF) were examined. Three levels of paper sludge (15، 30 and 45 wt %) were used to produce composites. Haake machine was used to blend materials and to produce standard samples، injection molding system was utilized. The mechanical properties including bending (strength and modulus) and impact strength were measured. Results showed that composites containing PP polymer and waste water sludge have higher mechanical properties than PE polymer and sludge on the DAF. The addition of both types of sludge as filler، results in enhancement of tensile properties compare to pure polymer. In the case، the higher content of sludge on the DAF was used، tensile strength of the composite decreased. Adding both types of sludge as filler، impact strength was lower than pure polymer. It was shown that composites containing sludge on the DAF have lower impact property than waste water sludge.