Preparation of plywood panels using waste milk pouches as an adhesive

Abstract

Recycling of single use plastic like milk pouches, oil pouches, etc. for high value products can have significant environmental, social and economic implications. The present study focuses on the utilization of waste milk pouches made out of low-density polyethylene as the bonding agent in preparation of plywood panels. Plywood panels with varying content of polymeric content (milk pouch layers) were prepared and evaluated for physical and mechanical properties. The results indicated that with increase in the dosage of milk-pouch content, both physical as well as mechanical properties of the plywood improved substantially. There was nearly three folds difference in modulus of rupture of panel prepared with 80 g/m2 and 310 g/m2 polymer content. Similarly, tensile strength, modulus of elasticity also increased significantly with increase in polymer content. The glue shear strength, which is very important for plywood, was found to be influenced by the quantity of polymer. Glue shear strength for panel with 80 g/m2 polymer was 0,75 MPa which increased to 1,90 MPa in panel with 310 g/m2 polymer content. It was observed that for strong bonding it is essential that the quantity of polymer should be sufficient enough to penetrate into the pores of wood creating a mechanical interlocking of veneers. The study opens up the scope of recycling of waste milk pouches in the preparation of formaldehyde free plywood.