Improving the mechanical properties of blends of recycled HDPE and urea-formaldehyde resin

Mechanical properties such as tensile modulus, tensile strength, and elongation at break of high-density polyethylene (HDPE) filled with recycled urea formaldehyde grit (UFG) were evaluated in the range of 0-25% of filler volume fraction. The tensile modulus increased up to around 10% filler content, but remained constant at higher filler levels. Kerner's equation models the initial part of the response reasonably well, while the behavior at higher filler content can be assigned to poor adhesion between the filler particles and the matrix. Tensile strength and elongation at break decreased with increasing filler content as predicted by the Nicolais and Nielsen equations, respectively. Efforts were made to improve the properties using surface treatments of the filler.