Ionomeric blends of pyridine containing polymers with sulfonated PET

An investigation of acid-base interactions and zinc transition-metal complexations in ionomeric blends of sulfonated poly(ethylene terephthalate) (PET) with pyridine containing polymers will be discussed in relation to the level of specific intermolecular interactions, as measured with FTIR, and the degree of compatibilization, as observed from DSC and DMTA. Two pyridine containing polymer systems were evaluated: (1) a novel main-chain thermotropic liquid crystalline polyester containing pyridine dicarboxylate units, and (2) poly(ethyl acrylate-co-4-vinyl pyridine). Model thermotropic liquid crystalline polyester systems were developed and screened based on a set of macromolecular structure requirements directed toward future blends studies with PET and PBT. The first investigation discussed the preparation and characterization of TLCPs based on the biphenyl mesogen, 4,4$\sp\prime$-bis(6-hydroxyhexoxy)- biphenyl, BHHBP. Two series of TLCPs were prepared and characterized by CPOM, DSC, and WAXD. Both series of polymers exhibited smetic A phase types. The second investigation discussed the preparation and characterization of thermotropic liquid crystalline polyester based on the triad mesogen monomer, 4,4$\sp\prime$- (terephthaloyldioxy)dibenzoyl dichloride, (ClHTHCl). Various dihydroxy flexible spacers having chemical substituents similar in structure to the repeat units of PET and/or PBT were copolymerized with ClHTHCl and evaluated by CPOM, DSC, and WAXD. From this investigation, a series of polymers were characterized as an enantiotropic nematics. From this series, a candidate was selected as a model system, where the composition of flexible spacers was: 75% bis(4-hydroxybutyl) terephthalate and 25% 1,6-hexanediol. The flexible spacers of the model system was then modified to contain pyridine dicarboxylate units. This modified model system (TLCP$\sb{\rm N}$) was characterized as having a similar phase and phase-temperature relationship when compared to the model system. Upon development and characterization of TLCP$\sb{\rm N}$, ion exchange procedures were developed to exchange the sodium ions of PET-SO$\sb3$Na for hydrogen and subsequently hydrogen ions for zinc. Stoichiometric blends of both the free acid and zinc neutralized form of sulfonated PET were prepared and characterized by FTIR, DSC, and DMTA. For both these blends there was no evidence for specific intermolecular interactions or compatibilization. In the final investigation, both the free acid and zinc neutralized forms of sulfonated PET were blended with poly(ethyl acrylate-co-4-vinyl pyridine). The stoichiometric blends were prepared and characterized similar to the previous study. A zinc blend containing 77% sulfonated PET (7% SO$\sb3$Zn) and 23% poly(ethyl acrylate-co-4-vinyl pyridine) (10.6% VP) appeared to be predominately single phase by DSC and partially phase separated by DMTA. Where similar blends containing 58% poly(ethyl acrylate-co-4-vinyl pyridine) (5.2% VP) appear partially phase separated by both DSC and DMTA