Improving the Adhesion of Glass/Polypropylene (Glass/PP) and High-Density Polyethylene (HDPE) Surfaces by Open Air Plasma Treatment

The objective of this study is to investigate the bonding between glass reinforced polypropylene (glass-PP) and high-density polyethylene (HDPE) surfaces. These materials present low surface energy and surface adhesion problems. The atmospheric plasma treatment process enhances the adhesion between glass-PP and HDPE surfaces by increasing their surface energies. In this work, glass-PP and HDPE were subjected to the atmospheric/air plasma treatment by varying different parameters such as plasma intensity and number of treatments. Optimal plasma treatment conditions were then determined based on the bond strength between the surfaces after plasma treatment. Also, characterization techniques such as FTIR (Fourier Transform Infrared spectroscopy), SEM (Scanning Electron Microscopy), TGA (Thermogravimetric analysis) and surface energy determination via wettability inks were performed to understand the surface modification and chemical changes after plasma treatment. Furthermore, the effect of plasma treatment on glass/PP surface versus a neat PP surface was characterized to understand the effect of plasma treatment on fiber reinforced polymer versus neat polymer. The improvement of bond strength in glass/PP- HDPE panels was found to be higher than neat PP (neat Polypropylene)-HDPE panels. The G_1c (Mode 1 interlaminar fracture toughness) value of glass/PP- HDPE panels increase from 0.1 N/mm to 5.5 N/mm whereas, the G_1c value of neat PP- HDPE panels increase from 0.4 N/mm to 2.8 N/mm.