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Structural Analysis of Aromatic Liquid Crystalline Polyesters
Department of Chemistry and Biochemistry, University of Arizona, 1306 E University Blvd, Tucson, AZ 85721, USA
Solvay Advanced Polymers, 4500 McGinnis Ferry Rd., Alpharetta, GA 30005, USA
* Author to whom correspondence should be addressed.
Received: 21 December 2010; in revised form: 13 January 2011 / Accepted: 20 January 2011 / Published: 27 January 2011
Abstract: Laboratory preparations of liquid crystalline prepolymers, distillates accompanying prepolymers, final polymers, and sublimates accompanying final polymers were examined. NaOD/D2O depolymerization of prepolymers and polymers back to monomers with integration of the 1H NMR spectra showed up to 6% excess of carboxyls over phenol groups, caused partly by loss of the low-boiling comonomer hydroquinone through distillation during prepolymerization and leaving anhydride units in the polymer chain. ESI− MS and MS/MS of hexafluoroisopropanol extracts of the prepolymer detected small molecules including some containing anhydride groups; ESI+ MS showed the presence of small cyclic oligomers. 1H NMR (including TOCSY) spectra provided more quantitative analyses of these oligomers. The final polymerization increases the length of the polymer chains and sublimes out the small oligomers. Anhydride linkages remaining in the polymer must make LCP’s more susceptible to degradation by nucleophilic reagents such as water, alkalis, and amines.
Keywords: copolymerization; LCP’s; mass spectrometry; NMR; polyesters
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MDPI and ACS Style
Hall, H.; Ahad, S.; Bates, R.; Bertucci, M.; Contreras, C.; Dospinoiu, A.; Lin, G.; Singletary, N.; Somogyi, A. Structural Analysis of Aromatic Liquid Crystalline Polyesters. Polymers 2011, 3, 367-387.
Hall H, Ahad S, Bates R, Bertucci M, Contreras C, Dospinoiu A, Lin G, Singletary N, Somogyi A. Structural Analysis of Aromatic Liquid Crystalline Polyesters. Polymers. 2011; 3(1):367-387.
Hall, Henry; Ahad, Samiul; Bates, Robert; Bertucci, Maria; Contreras, Cristina; Dospinoiu, Alexandru; Lin, Guangxin; Singletary, Nancy; Somogyi, Arpad. 2011. "Structural Analysis of Aromatic Liquid Crystalline Polyesters." Polymers 3, no. 1: 367-387.