A novel low temperature bonding technique for plastic substrates using X-ray irradiation

The present study proposes a new low temperature bonding technique for two plastic substrates using deep X-ray irradiation. The deep X-ray irradiation causes the decrease of molecular weight of PMMA, which in turn decreases the glass transition temperature (T/sub g/). Lowered T/sub g/ on the surface of two PMMA sheets makes bonding possible at low temperature. The present study also offers a tool to predict the decrease of T/sub g/ based on the relationship between X-ray dose and molecular weight. Bonding experiments are conducted at various bonding temperatures near the desired T/sub g/. Then, the bonding strength is measured by means of a tensile test machine (MTS system). The bonding is found to be successfully achieved when the bonding temperature is 8/spl sim/15/spl deg/C higher than the desired T/sub g/. The bonding strength is about 0.96 MPa.