Improving the bonding of polyethylene to E-glass/epoxy composites using ultraviolet irradiation

Abstract One of the problems in type-IV pressure vessels (composite pressure vessels with a thermoplastic inner liner) is the quality of bonding between the liner to the outer reinforcement layer. In the present research, the effect of the ultraviolet (UV) irradiation on the surface of the high-density polyethylene (HDPE) for the co-bonding process of E-glass/epoxy composites to HDPE liner was investigated experimentally. To recognize the effect of the UV irradiation on the surface properties, the contact angle measurement, and the atomic force microscopy (AFM) were performed. Asymmetric double cantilever beams (ADCB) tests were conducted to determine the strain energy release rate (SERR) as a factor indicating the crack resistance of the joint. According to the results, it was found that 20 min of UV irradiation exposure time presented the lowest contact angle on the surface of HDPE, and the highest strain energy release rate in ADCB specimens. The result of the tensile test for HDPE under the UV radiation demonstrated less than 8% degradation in the mechanical properties. Therefore, it can be concluded that 20 min of UV irradiation exposure time could be used as a surface treatment of the HDPE liner of type-IV pressure vessels.