SynopsisThe thermal degradation behavior of polyacrylamide and poly(acry1amide-co-acrylate) was studied by differential scanning calorimetry, thermogravimetric analysis, gas chromatography/ m a s spectrometry, and carbon-13 solid state nuclear magnetic resonance. The degradation products over the temperature range of 115-450OC were characterized. Mechanisms are proposed for the degradation processes involved. *Deceased.

SYNOPSISDried samples of polyacrylamide in an He atmosphere have been subjected to thermogravimetric analysis in the 30-600°C range, and the evolved gases were monitored by FTIR. Water, ammonia, and small quantities of carbon dioxide are released in the first stages of decomposition (22O-34O0C), where the polymer chains remain intact and the reaction occurs on the pendant amide groups. In the second stage of decomposition ( 340-440°C), the majority of the weight loss occurs, and main chain breakdown occurs, releasing carbon dioxide, water, nitrile compounds, and imides. Trapping of the gases in this stage and analysis by GC-FTIR and GC-MS reveals the presence of more than 20 decomposition products, and confirms that a large proportion of these can be assigned to glutarimide and its substituted analogs. Imidization and dehydration reactions on the amide groups, as well as free radical breakdown of the main chains, with inter-and intramolecular hydrogen transfer, can account for many of the products of the decomposition. 0 1993 John Wiley & Sons, Inc.ature, thermal stability, and mechanism of decomposition.2-'2 PAM is amorphous with a glass transition temperature ( T,) of 184°C.6 When heated thermogravimetrically at rates of 5-20°C min-' , undried samples of this polymer decompose in at least three stages. The first stage (20-220°C) corresponds to loss of bound H20, and the second (220-340°C) to loss of NH3 by imidization (intra-and intermolecular) and H 2 0 by dehydration. The third region ( >34OoC) represents substantial weight loss, and is normally attributed to main chain breakdown.Evolved gas analysis can yield substantial insight into the mechanism of thermal decomposition. Maurer and Harvey' used thermogravimetry-mass spectrometry (TG-MS) on PAM to identify NH3, H20, and COZ as gases that evolve during decomposition. Leung, Axelson, and Van Dyke2 used MS to determine the presence of several evolved gases ( NH3, H20, CO,, N2, and CO) when samples of PAM were heated isothermally at various elevated temperatures. Toth et a1.l' used TG-MS to identify H20, NH3, CO, C02, HCN, and some low molecular 1807

Several polymers have been prepared by electropolymerization of mixtures of pyrrole (PY) and 2,2′‐bithiophene (BT). Cyclic voltammetry on prepared polymer films shows three anodic oxidation peaks, two of which match the oxidation potentials of homopolymeric PY and BT, and a third which is intermediate. UV/visible spectroscopy displays a unique spectrum for each of the reduced and oxidized forms of these polymers. Nernstian plots from UV/visible data exhibit three well‐defined redox couples in polymer films produced at 1.3 V. Overall, the data strongly support the formation of a copolymer, consisting of three distinct oxidizable units. Two of these can be attributed to short blocks of either PY or BT, and a third to random and alternate groupings of PY and BT. The polymers produced are electrically conductive, but the conductivity drops rapidly as BT units are introduced into a homopolymer of PY. © 1992 John Wiley & Sons, Inc.

This study focuses on the interaction between polyamide and butyl or bromobutyl rubbers blended in a high shear environment. The fact that these two normally incompatible systems can be mixed is explained by a chemical reaction that occurs between polyamide and the butyl rubber components during processing. Measurement of the melt viscosity and differential scanning calorimetry of these blends, along with analysis of the extracted soluble butyl rubber component, supports the presence of small quantities of block or graft polymers in the system, signifi-cant crosslinking during the blending process, and possibly other interactions between the blend components. The effect of electron beam radiation on interaction in these blends was briefly evaluated and was found to increase crosslinking in the blends, with some degradation of the polyamide component.

An hydration scale (Wo) for aqueous sulfolane and dimethyl sulfoxide (DMSO) has been developed that represents the effect of the solvent on the equilibrium hydration of a series of trifluoroacetoKd phenones; ZH2O # Z + H 2 0 . The equilibrium constants are correlated with the substituent parameter o+; p+ = -1.62 for dehydration. The function Wo, defined as W, = pK,= -log (fi/fiH,o.aH,o) is zero for pure water and rises to a value of 2.72 in 99 mole % sulfolane. Wo in aqueous DMSO is negative from 0 to 85 mole % DMSO, meaning that these systems hydrate the ketones to a greater extent than does pure water. trifluoroacetophenones (standard state, water) and (b) the hydrating ability of solvent mixtures that range from pure water to 99 mole% tetramethylene sulfone (sulfolane) or dimethyl sulfoxide (DMSO). To preserve the analogy with Hammett-type acidity functions the equilibrium equation is written so that the hydrate is on the left and the ketone on the right.The dehydration constant, K,, takes the form Therefore [2] pK, = -log --log --