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Hydrophobic comonomers bisphenol-A and hexafluorobisphenol-A were incorporated as diol components in the sensor-coating material poly(ethylene maleate) (PEM), resulting in modified polymers, HCPEM and HFPEM, respectively. To assess the suitability of these polymers as sensor interfaces, the sorption/desorption isotherms and kinetics of water and a range of volatile organic vapors were obtained over the entire relative pressure range of 0.1 to 1.0, using an automated intelligent gravimetric sorption analyzer. The extent and rate of sorption of organic vapors were higher in the modified polymers compared to those of the parent polymer. Sorption hysteresis was observed at high relative pressures, especially with water and other hydrogen-bonded polar organic vapors. Polarizable vapors like toluene and benzene were sorbed more than nonpolarizable cyclohexane vapors. The sorption results were interpreted in terms of semiempirical models based on concepts of thermodynamic interaction parameter, partition coefficient, and linear solvation energy relationship. The study reveals the potential of sorption/desorption isotherms and kinetics in characterizing the sorption properties of coating materials that are used as an interface in acoustic wave sensors.

Six new polyether azomethines were synthesized by melt and solution polycondensation of six different diamines with 4,4′‐[1,4‐phenylene bis(oxy)] bisbenzaldehyde. The polymers synthesized by solution method are yellow to white in color and had inherent viscosities up to 0.59 dL/g in concentrated H2SO4. The polymers obtained by melt condensation show higher viscosity. Except polymer IV, others are insoluble in common organic solvents. The polymers were characterized by IR, x‐ray, elemental analysis, and DSC study. The thermal stability of the polymers was evaluated by TGA and IGA study. Polymers I‐III are highly thermally and thermooxidatively stable and exhibit no appreciable decomposition up to 420°C both in air and nitrogen atmosphere. It was shown that the curing of the polyazo‐methines takes place by opening up of the CHN linkages at higher temperature. The electrical conductivities of the virgin and iodine doped polymers were as high as 10−11−10−16 and 10−6−10−8S cm−1, respectively, at 30°C. Electronic spectra of the undoped polymers (I‐III) indicated a large bathochromic shift of the ⌅ – ⌅* absorptions band (376 nm) due to CN bonds of the model compound. This can be attributed to extensive delocalization of the electrons along the polymer chain. © 1995 John Wiley & Sons, Inc.

SYNOPSISTen new polyesterazomethines have been synthesized by solution polycondensation of five different diamines with 4,4'-[terephthaloyloxy]bis-3-ethoxybenzaldehyde and 4,4'-[isophthaloyloxy]bis-3-ethoxybenzaldehyde using dimethylacetamide in the presence of anhydrous LiCL. Fibrous polymers were precipitated by pouring the solutions into water. The polymerization proceeds rapidly to give highly viscous solutions. The resulting polymers were characterized by viscosity measurement, IR, x-ray diffraction study, elemental analysis, and DSC study. 'H-NMR spectra of some of the polymers were also recorded. The thermal stability of the polymers was evaluated by TGA and IGA study. Electronic spectra of the polymers were recorded in H2S04. 0 1996 John Wiley & Sons, Inc.