Effect of bubbles at interface on bonding mechanism between titanium and PET resin

Abstract

The dissimilar material bonded pure titanium (Ti) to polyethylene terephthalate (PET) was fabricated by applying a suitable pressure at the elevated temperature. When the bonding temperature increased up to near a melting point of PET, a lot of bubbles were generated at the bonding interface between both materials due to the gas components originated from ethylene glycol contained in PET, and the volume expansion of these bubbles caused the pressure effect at the interfaces, resulting in the acceleration of chemical bonding behavior such as Ti-C bonding formation. It was also clarified that the rapid cooling condition after the bonding process was effective to form the spherical bubbles individually dispersed at the interfaces and to decrease the number of these bubbles. According to the above analysis results, the optimum joining conditions successfully improved the bonding strength of Ti-PET dissimilar materials.