Strength of bonded joints at elevated temperatures after radiation cross-linking

Abstract

In this study there was found that ionizing beta radiation increased the strength of bonded joints and improved the adhesion properties of low-density polypropylene (LDPE) and highdensity polyethylene (HDPE). Bonded joints at elevated temperature (60 °C) were tested. Generally, for the formation of quality bonded joint it is important to wet the adhesive bonding surface well. Wettability is characterized by the contact angle of wetting. The liquid has to have a lower surface tension than the solid in order to be able to wet the solid substance. The measurement results indicated that ionizing beta radiation was a very effective tool for improvement of adhesive properties and increased the strength of bonded joints of studied polymers at elevated temperature (60 °C). Bonded surfaces with ionizing beta radiation doses of 0, 66, 132, 165 and 198 kGy were irradiated. The best results were achieved by irradiation at doses of 165 kGy by which the highest surface energy and the highest strength of bonded joints of HDPE and LDPE were achieved.