UV curing is using UV light as the energy source to induce the polymerization of liquid monomers and oligomers to form a solid polymer. Because UV polymerization is fast and energy-saving and a UV curable system has no VOC (volatile organic compound), this new technology has developed rapidly from thin film applications to thick sample applications. In addition, since the UV cure process can be controlled spatially and temporally, it also has an important application to make gradient materials with locally optimized properties. However, most research on UV cure is based on thin film applications, and the cure kinetics of thick samples are more complex and not well understood.;In this study, we focus on the UV cure kinetics of CD540 (ethoxylated (4) Bisphenol-A dimethacrylate) thin and thick samples (2-8 mm). A photo-bleaching initiator, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Irgacure 819), is used in the system. UV cure kinetics are complex, especially when the sample is thick, since the light intensity is a function of depth and also a function of exposure time. In order to understand the complex cure kinetics of thick samples, we first studied the variation in the transmitted intensity and initiator concentration through the depth in thick samples. Based on the experimental measured transmitted intensity, a Matlab program was written to predict the intensity versus depth and exposure time of a thick sample. Then, the UV cure kinetics of thin samples (0.05 mm) were studied. In this part, we studied the effect of light intensity, initiator concentration, and temperature on the cure kinetics experimentally and theoretically. A model was developed based on a unimolecular termination mechanism in order to predict the cure kinetics at different conditions for thin samples. Combining the Matlab program for calculating the intensity in thick samples and the model for calculating the cure kinetics of thin samples, the cure kinetics through the depth of thick samples were predicted and compared with experimental results measured by frequency dependent dielectric sensing.;The diffusion of free radicals in a UV cure free radical cure system was studied by monitoring the cure in the dark nonirradiated region under a mask. In addition, a free radical thermal cure of an acrylic resin was characterized in order to study oxygen diffusion from the surface layers into deeper layers.

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Frequency Dependent Electromagnetic Sensing (FDEMS) provides a sensitive, convenient, automated means for monitoring the infiltration, polymerization, and degradation processes in polymeric systems. In situ FDEMS sensing monitored both the Hercules Corporation's 3501-6 epoxy resin system and the Minnesota Mining and Manufacturing Corporation's PR500 epoxy resin system during the Resin Transfer Molding (RTM) infiltration and cure process. FDEMS sensing observed the resin position, viscosity, degree of cure, and the buildup in macroscopic properties such as modulus. Degradation of Nylon-11 in various accelerated aging and operational environments was also monitored by in situ FDEMS sensing. By monitoring the entire polymerization and degradation process, in situ FDEMS sensing was able to provide important real time information about the current physical state of various polymeric materials.

Norbornene anhydride precursors were functionalized with hydrophilic moieties to yield water soluble monomers which were then polymerized without protecting groups. Homopolymer synthesis was accomplished with excellent control over molecular weight and polydispersity using Grubbs' 3rd generation catalyst at ambient temperature and pressure. Molecular weights ranged from 3 to 76 kDa with polydispersity indexes varied from 1.05 to 1.15. Copolymers were made by sequential addition of two functionalized norbornene anhydrides monomers to produce Double Hydrophilic Block Copolymers (DHBCs). All polymers were demonstrated to exist in solution as single solvated chains by dynamic and static light scattering experiments. Superabsorbent gels were prepared from carboxylic acid, amine and hydroxyl functionalized norbornene monomers. Swelling ratios for these gels were studied as a function of crosslink density and aqueous solution pH.