Interpenetrating polymeric networks from diacetone acrylamide oxime blocked isocyanates

A novel polymerizable blocking agent, N-(1-1{dollar}spprime{dollar}-dimethyl-3-oxobutyl) acrylamide oxime (DAAOX) has been synthesized from N-(1-1{dollar}spprime{dollar}-dimethyl-3-oxobutyl) acrylamide (DAA) through the oximation process. Fourier Transform Infrared Spectroscopy (FT-IR), and Differential Scanning Calorimetry (DSC) were used to characterize the conversion and properties of the blocking agent synthesized.; To be a polymerizable blocking agent, two functional groups, the oxime and the vinyl group, in DAAOX must be active, and the amide group must be non-reactive. Differential scanning calorimetry and titration to determine NCO group content were used to demonstrate the low reactivity of the sterically hindered amide group in DAAOX.; The Kaufman Iodine value titration was used to characterize the double bond-containing DAAOX blocked isocyanates. Through the titration valves, one could infer that there was no side reaction due to a sterically hindered amide/isocyanate reaction. Moreover, the molecular weights of the DAAOX blocked isocyanates could be calculated from the iodine values.; The reactivity of the oxime group with various aliphatic diisocyanates was measured by both titration and the DSC method. The DSC method was carried out via a Borchardt-Daniel analysis by using a single dynamic DSC thermogram of the reaction.; The reactivity of the vinyl group was also measured by using DSC. A Kissinger analysis was used to obtain the kinetic parameters of the free radical polymerization of both DAA and DAAOX. These studies of the effect of the oxime group on the polymerization of the double bond showed that the polymerization was retarded by the oxime group.; An FT-IR method was used to study some aspects of the deblocking reactions. The degrees of deblocking of various DAAOX blocked aliphatic diisocyanates versus temperature were measured. The tendency toward the deblocking reaction of various DAAOX blocked isocyanates follows the steric strain relief theory. The effects of catalyst on the deblocking-curing reaction of DAAOX blocked isocyanates were investigated.; The degree of polymerization of the deblocking DAAOX was measured by DSC and TGA. The data from either method showed the same results that around 80% of the deblocking DAAOX polymerized under the curing conditions. The total weight loss when used in powder coatings was as low as 3%.; The applications of DAAOX blocked isocyanates were demonstrated by preparing three types of powder coatings. Compared to the coatings from the traditional {dollar}epsilon{dollar}-caprolactam blocked isocyanates, the powder coatings from DAAOX blocked isocyanates have not only an environmental advantage but also superior properties.