| The recent development of grinding techniques for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) sample preparation has opened new horizons for the analysis of synthetic polymers exhibiting solubility problems. Now, for the first time, mass spectrometry can be used to directly elucidate critical information on mass, structure, and end group distributions generated from the synthesis of poorly soluble/insoluble synthetic polymers. This dissertation introduces two new grinding methods for the analysis of insoluble synthetic polymers along with studies to examine the reaction mechanisms for creating these polymers.;In the first manuscript, the evaporation-grinding method (E-G method) was developed to allow the first direct mass spectral analysis of completely insoluble ODA-PMDA polyimide films. The second manuscript extends the application of the E-G method through optimization studies using poorly soluble Nomex fibers with subsequent application of the optimized E-G method to insoluble Kevlar fibers. This manuscript also describes the development of the resolvated-evaporative-grinding method (R-E-G method) for the analysis of these poorly soluble/insoluble wholly aromatic polyamides (aramids).;The third manuscript describes the application of the optimized E-G method to study the imidization process of ODA-PMDA poly(amic acid). Careful examination of the MALDI-TOF mass spectra, taken at various heating intervals, revealed critical temperatures of imidization (130--160°C), average molecular mass growth, and previously unreported end group changes. EGA/GC/MS identified the source of these changes being monomer trapped in the solid poly(amic acid) and evolved during the curing process.;Questions from the aramid study in the second manuscript were addressed in the fourth manuscript using the MALDI-TOF MS E-G method to examine nine samples of low molecular mass poly(m-phenylene isophthalamide) (MPD-I) fibers, which were synthesized using various percent molar ratios of diamine-to-diacid chloride. This study revealed a direct correlation between the formation of cyclic species and the ratios of diamine-to-diacid chloride used in their synthesis. These findings validate our previous work, with commercially available Nomex fibers, and suggest that the ratio of reactants used in the synthesis of high molecular mass Nomex can be revealed by examination of the abundance of cyclic species. |
