Modification in polyethylene–iron oxide joints induced by laser irradiation

The laser welding is a thermal bonding technique with high localized heating that produces a strong adhesion between polymers. The plastic is able to absorb the laser energy with the use of embedded fillers in itself. In this work we studied blends made by polyethylene and different amount of fillers (iron oxide, red color). Mechanical and physical analyses were performed with the aim to study the effect of filler percentage on the welding features. Experimental results showed that the filler amount influences the optical properties of the polyethylene since it regulates the amount of adsorbed energy and the depth of the material layers involved in the welding. A high concentration of filler improves the absorption laser energy, decreasing the layers involved in the welding and worsening the mechanical strength of the joint. Vice versa, a low filler amount involves deeper layers of the material so that the sealing action improves. The efficiency of the joint can be regulated by the filler concentration. Some applications of thermoplastic polymeric joints with different geometries are proposed and discussed.