Quality Assurance and Characterization of Adhesives Used for NIC Target Assembly

Ultraviolet (UV)-cured adhesives are used to assemble targets for the National Ignition Campaign. Since cure behavior and adhesive strength are critical to successful, leak-free production of targets, it is desirable to establish a testing procedure to verify the viability of adhesives. To measure reaction conversion, we used Fourier transform infrared spectroscopy, viscometry, and differential scanning calorimetry (DSC) each specially adapted to allow UV exposure within the measuring instrument. We found that photo-DSC was the most sensitive technique of those we investigated for measuring conversion and reaction rate. The effect of adhesive age was measured. We found that as adhesives aged the total heat of reaction dropped.