Improving adhesion performance of polyethylene surfaces by cold plasma treatment

In this paper, the effects of low pressure plasma treatment on surface energy of polyethylene samples and on shear properties of adhesive bonded joints based on these substrates have been investigated. In particular, the optimization of two plasma process parameters, exposure time and power input, was studied performing contact angle evaluation and lap-shear tests. The plasma treatment was also compared with a conventional primer treatment, for which it is a clean and effective alternative. As a measure of the durability of both treatments, the bond shear strength immediately after bonding was compared with that after a storage period in the laboratory environment. The experimental results show that the optimized plasma process may remarkably increase wettability properties of polyethylene surfaces and shear strength of bonded joints, even higher than those treated with primer and that these good properties remain quite unchanged even after some days of storage in a laboratory.