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Polyacetals, owing to the acid sensitivity of the acetal linkage, are attractive candidates for end uses in which acid sensitivity is a desirable property, e.g. photo- or electron-resists. Acid catalyzed degradation of poly (2-butyl-1,3,6-trioxocane) (1) has been studied. With ethyl tosylate as the catalyst, the cyclic monomer 2 was the major product. The minor products are cis and trans isomers of C3H7CH=CH-OCH2CH2OCH2CH2OH, and three stereoisomers of C3H7CH=CH-OCH2CH2OCH2CH2O-CH=CH-C3H7 elucidated by 1H and 13C NMR, IR, electron impact and chemical ionization MS, and in the case of 2 also by comparison with an authentic sample. With 98% H2SO4 as the catalyst 2 is only a minor product. The major products are diethylene glycol, valeraldehyde, and 1,4-dioxane with some 2-butyl-1,3-dioxolane. Capillary GC/Mass spectrometry led to identification of the following less abundant products: tri-n-propylbenzene, alpha, beta- unsaturated aldehydes and cyclic dimer. The products of H2SO4-catalyzed decomposition of polymer were also obtained by heating monomer 2 with H2SO4. A detailed mechanism for the formation of the 8-member ring 2 in the decomposition is proposed which involves unzipping proceeds via open carbocation intermediates. According to the principle of microscopic reversibility, the same open carbocation is the propagating species in the polymerization of 2 under similar conditions.

The onset of decomposition of poly(4-methyl-1,3-dioxolane) was lowered from 70 degs. by 0.1 weight % p-toluene sulfuric acid to 170 degs. producing more than 81% yield of monomer. Protonation forms cyclic oxonium ion followed by depolymerization. Minor products are isomers of hydroxymethyl-2-hydroxyl-2-methyl ethyl ether and bis(2-hydroxyl-2-methyl ethoxyl)methane rearrangements of the oxonium ions. The first order rate constant of acidolysis of poly(4-methyl-1,3-dioxolane) is ca. 8.5 kcal/mole which is much smaller than about 17 kcal/mole for the acidolysis of poly(1,3-dioxolane).

Polyacetals, owing to the acid sensitivity of the acetal linkage, are attractive candidates for end uses in which acid sensitivity is a desirable property, e.g. photo- or electron-resists. Many polysaccharides belong to this general class and owe many of their special properties to the acetal linkage. We report here a study of acid-catalyzed decomposition of poly(2-butyl-1,36-trioxocane) under two sets of conditions: mild leading to depolymerization, and drastic leading to more profound degradation. A mechanism for depolymerization involving open chain oxy-carbocation intermediates operates.

Interests in electrically conducting polymers have grown from polyacetylene to other polymers. One of the objectives of this research project, initiated this year, is in elucidating structure-conductivity relationships for new aromatic polymers.

Electron paramagnetic resonance saturation experiments have been carried out on undoped polyacetylene and in the doped polymer as a function of dopant concentration. The relaxation times of undoped trans- (CH)x show considerable variability from sample, T1 = (2.7 + or - 1.7) x 10 to the -5 sec and T2=(7.8 + or - 1.0) x 10 to the -8 sec suggesting sensitivity to trace impurities. Exposure to air reduces T1 to 8.1 x 10 to the -6 sec and T2 to 6.6 x 10 to the -8 sec; this effect is reversible. Using radio-assay techniques with 125 sub I, it was possible to prepare and characterize samples of known dopant concentration at the level of parts per million (ppm). There are three distinct regimes which characterize the effect of iodine concentration on the EPR characteristics of trans-(CHIy)x.

Synthetic procedures for selective nitromercuration via phase transfer catalysis have been developed for usage with water insoluble poly(butadiene), poly(isoprene), and carboxyl terminated butadiene acrylonitrile copolymers. (Author)

Methyl alpha-chloroacrylate (MCA) and methyl alpha-bromoacrylate (MBA) were copolymerized with methyl methacrylate (MMA) over a broad range of composition. The copolymers were exposed to gamma-radiation to determine chain scission susceptibility. The mechanisms of degradation of copolymers towards radiation was suggested from product analysis. The radiolysis of copolymers of MMA with MCA and MBA are dominated by the alpha-halogenated monomers. (Author)