SYNOPSISThe thermal degradation of Nafion-H, Nafion-K, and the mixture of each of these with poly (methyl methacrylate) (PMMA) has been studied. A mechanism is proposed for the thermal degradation of Nafion-H that involves an initial cleavage of the carbon-sulfur bond leading to SO2 an OH radical and a carbon-based radical. This carbon-based radical then undergoes further degradation. The addition of PMMA to Nafion-H inhibits further degradation of the Nafion carbon-based radical and instead radical recombination reactions between PMMA fragments and this Nafion radical dominate the reaction scheme. The replacement of the hydrogen in Nafion-H with a potassium (i.e., Nafion-K) produces a much more robust material that does not degrade under conditions similar to those used for Nafion-H. Nafion-K has little effect on the degradation of PMMA.

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A new semicrystalline polyimide has been synthesized from 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride and 2,2‐dimethyl‐1,3‐(4‐aminophenoxy)propane. The polymer has a high glass transition temperature of 230°C and a melting temperature of 325°C. Its overall crystallization rate between 240 and 325°C is quite fast (t1/2<10min) and relatively insensitive to the crystallization temperature. Although the degree of crystallinity obtained is dependent on the crystallization conditions, it can be as high as 50%. The polymer's morphology, which was examined with transmission electron microscopy (TEM), has a randomly stacked, ribbon‐like, lamellar texture. Both TEM and polarized light microscopy show that mature spherulites do not develop. The crystal unit cell, which was determined from wide‐angle X‐ray diffraction measurements on highly oriented films, is monoclinic with a = 0.960nm, b = 0.582nm, c = 2.46nm and γ = 81.1°.

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SYNOPSISThe thermal degradation of poly (methyl methacrylate) (PMMA) , in the presence of manganese chloride has been studied by sealed tube reactions and thermogravimetric analysis coupled to FT-IR spectroscopy. From sealed tube reactions it was found that the degree of mixing of the MnC12 and PMMA has an important effect on monomer formation. In systems where the two components are simply poured together, the amount of monomer is about half that observed for the thermolysis of PMMA alone; when the two components are thoroughly mixed by dissolution in solvent, the monomer yield falls to zero. The TGA-FT-IR experiment on solvent mixed material does show the presence of monomer. In sealed tubes, monomer may not escape and must repolymerize, while in the TGA experiment the monomer is swept out before reaction may occur. Monomer production also commences at temperatures lower than those for degradation of PMMA alone. It is apparent that manganese chloride catalyzes both the degradation of polymer to monomer and the reoligomerization of this monomer. The gases that are produced include CO, C O P , CH3Cl, HCl, and CH,. A mechanism is proposed to account for all of these products and a manganese ionomer is the final product of the reaction.