Dielectric in situ monitoring of microgravity polymerizations

The objective of the research described here is to develop dielectric spectroscopy to monitor polymerization reactions and processes in microgravity. Ground based measurements have been made on both neat thermoset resins and solution polymerization reactions. Polymerization of diglycidyl ether of bisphenol A (DGEBA) using two curing agents, m-phenylenediamine (m-PDA), and 4,4'-diamino-diphenyl-methane (DDM) were investigated to determine the relationship between the dielectric spectra and the thermoset polymer network and morphology. The results for the epoxy thermosets indicate that this technique can be used to monitor the extent of polymerization and the qualitative nature of polymer network. The photopolymerization of 6-(2-methyl-4-nitroanilino)-2,4-hexadiyn-1-ol (DAMNA) in solution was also investigated to determine if gravitational effects could be observed using dielectric spectroscopy. The technique is able to distinguish between surface and solution polymerizations during formation of the polydiacetylene thin films. In addition, it is capable of monitoring convective effects during solution polymerization.