The relationship between the structure and reactivity of aliphatic-aromatic polyamides in the presence of CuI in an inert atmosphere was probed by reacting a family of benzamides with varying degrees of substitution on the amide nitrogen. Experiments with benzamide, N-methylbenzamide, N,N-dimethylbenzamide, N-hexylbenzamide, and N,N-dihexylbenzamide allowed comparison of primary, secondary, and tertiary benzamides and identification of the degradation pathways influenced by CuI. The presence of copper iodide enhanced the reactivity of all of the benzamides. Loadings as low as 0.5% led to higher conversion and increased recoverable product yields. Reaction path selectivities were also affected by the addition of CuI. The selectivity to benzene increased for all reactants, and the pathway leading to N-alkylation increased for the reaction of NHB. In all, these results revealed three major reaction pathways influenced by CuI: 1) N-C bond cleavage; 2) N-H bond cleavage; and 3) removal of the amide functional group from the aromatic ring. Kinetic results and visible color changes suggested a direct interaction of CuI with the reactant benzamide. Three electron-rich sites on the reactant benzamide, namely, the lone pairs on the carbonyl oxygen, the lone pair on the amide nitrogen and the aromatic ring, are likely sites of interaction of Cu+. Models invoking the subsequent reaction of complexes formed from Cu+ ion interaction at each of these sites account for the observed products well. (C) 1997 John Wiley & Sons, Inc.

An experimental study to determine the effect of copper (I) iodide (CuI) on the rate and product distribution of degradation of a model of an aliphatic-aromatic polyamide was carried out. N,N-Dihexylisophthalamide (DHI) was reacted in both an inert argon atmosphere and a pure oxygen environment at 350 degrees C with CuI added in amounts ranging from 0 to 20% by weight. The rate of disappearance of DHI was enhanced by an order of magnitude when 0.5% by weight of CuI was added and was an increasing function of increasing CuI loading. Reaction in pure O-2 increased the rate of DHI degradation by two orders of magnitude over that for neat DHI pyrolysis. The rate of disappearance of DHI in O-2 was relatively unchanged when 5% CuI by weight was added. The transformations of DHI and its products are organized in terms of a set of reaction rules. This ''reaction operator'' formalism allowed computer generation of the reaction network and facilitated estimation of kinetic parameters. (C) 1995 John Wiley and Sons, Inc.

An experimental study to determine the effect of copper(I) iodide and water on the rate and product distribution of aliphatic-aromatic polyamide degradation was carried out by using N,N'-dihexylterephthalamide (DHT) and N,N'-dihexylisophthalamide (DHI) as models of the amide functionality. DHT was reacted in an inert argon atmosphere at 350 degrees C in the presence of CuI added in amounts ranging from 0-5% by weight. The rate of disappearance of DHT was enhanced by a factor of three with the addition of 0.5% CuI. Increases to 5 wt % did not change the disappearance kinetics further. Comparison of the behavior of DHT and DHI revealed that changes in rate of disappearance and product yields were dependent on the relative positions of the amide substituents. Reaction of DHI was enhanced more significantly at a given CuI loading. The rate of disappearance of DHI and DHT and the selectivity to N-hexylbenzamide increased with the addition of water in loadings ranging from 0.148M to 0.193M. The reactivity of DHI was more greatly enhanced at a given water loading. These differences were attributed to electronic effects, as evaluated by differences in atomic partial charges, and physical effects. (C) 1995 John Wiley and Sons, Inc.

The dependence of the thermal stability of high-performance poly(arylether sulfones) (PAES) on the initial molecular weight distribution and backbone structure was assessed experimentally and through computer simulation. Reaction of PAES polymers resulted in the formation of an insoluble gel fraction and significant changes in weight and number average molecular weights of the sol fraction. A PAES with alternating ether and sulfone linkages formed a larger fraction of gel at a given reaction time than a PAES with the hydroquinone moiety. For a given chemical composition, more rapid molecular weight changes and gel fraction formation were observed for the polymer with the higher value of the initial weight average molecular weight. The growth of molecular weight was also faster for the polymer with the broader initial distribution. The simultaneous increase in M(w) and decrease in M(n) suggested the occurrence of two types of overall reactions: scission and addition. Simulation of these reactions using Monte Carlo kinetics allowed estimation of the range of probability for bond scission, R, of 0.5 < R ( 0.8 capable of accounting for the observed experimental behavior. The dependence of the simulated molecular weight changes on the initial molecular weight distribution agreed qualitatively with the experimental trends. (C) 1995 John Wiley & Sons, Inc.

Pyrolysis of two representative poly(aryl ether sulfones) (PAES) with anti without the isopropylidene link revealed its important role in controlling the overall thermal stability. This was probed quantitatively by the development of mechanistic pyrolysis models for single components and model compound mixtures of phenyl sulfone (PS), phenyl ether (PE) and 2,2-diphenylpropane (DPP). Model development on the computer allowed ''on-the-fly'' calculation of species' properties using computational quantum chemistry. This also provided quantitative values of model parameters. The reactivity differences of the polymers were interpreted in terms of the predicted changes in the product spectra when PS and PE were pyrolyzed with and without the reactant DPP. The increased selectivity to benzene and the decreased selectivity to (phenylsulfonyl)biphenyl with DPP present suggested an increase in the ratio of bond scission to bond formation that accounted for the decreased tendency of the isopropylidene-containing PAES for molecular weight increase and gel formation, two global measures of thermal stability.

Journal of Polymer Science Part A: Polymer ChemistryVolume 32, Issue 3 p. 567-569 Rapid Communication EPDM-g-polyethersulfone via Diels–Alder chemistry Barry D. Dean, Barry D. Dean Amoco Performance Products, Inc. Alpharetta, Georgia 30202Search for more papers by this author Barry D. Dean, Barry D. Dean Amoco Performance Products, Inc. Alpharetta, Georgia 30202Search for more papers by this author First published: February 1994 https://doi.org/10.1002/pola.1994.080320317Citations: 5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References and Notes 1 B. D. Dean, J. Appl. Polym. Sci., 32, 5619 (1986). 2 F. Severini, M. Pegararo, and L. DiLandro, Angew. Makromol. Chem., 190, 177 (1991). 3 A. Gadkari and M. F. Farona, Polym. Bull., 14, 503 (1985). 4 J. J. Ma, D. Pang, and B. Huang, J. Polym. Sci. Polym. Chem. Ed., 24, 2853 (1986). 5 R. C. Thamm, W. H. Buck, S. W. Caywood, J. M. Meyer, and B. C. Anderson, Angew. Makromol. Chem., 58/59, 345 (1977). 6 R. C. Thamm and W. H. Buck, J. Polym. Sci. Polym. Chem. Ed., 16, 539 (1978). 7 B. D. Dean, U.S. Pat. 4,731,418 (1988) (to ARCO Chemical Co.). 8 B. D. Dean, J. Appl. Polym. Sci., 47, 2013 (1993). 9 T. E. Attwood, D. A. Barr, T. King, A. B. Newton, and J. B. Rose, Polymer, 18, 359 (1977). 10 T. E. Attwood, A. B. Newton, and J. B. Rose, Br. Polym. J., 4, 391 (1972). 11 N. G. Random, K. J. Bruza, and R. A. Kirchhoff, Polym. Prepr., 32(1), 385 (1991). Citing Literature Volume32, Issue3February 1994Pages 567-569 ReferencesRelatedInformation

The model oligomers 2,2-bis[[4-(phenylsulfonyl)phenoxy]phenyl] propane (ISO) and 4,4'-bis[4(phenylsulfonyl)phenoxy]-1,1'-biphenyl (BP) were reacted neat in argon at 425 OC to compare the thermal stability of poly(aryl ether sulfones). Sulfur dioxide was the major gas product, BP generating a slightly higher evolution rate. The weight-average molecular weight increased with reaction time for both oligomers, but after 60 min, the rate of increase was higher for BP. A quantitative molecular level explanation of these observations focuses on the reactive isopropylidene link in ISO. Fission of the weak Ph-SO2-Ph bond produces phenyl radicals that abstract hydrogen and add to the oligomer backbone. The latter reaction results in increases in M(W) and a net weakening of the aryl-SO2 bond, which leads to increased rates of SO2 evolution. The value of the relative rate, R(rel), of radical addition to H-abstraction was higher for BP than for ISO due to easily abstractable isopropylidene hydrogens.

Polyarylate monofunctionally terminated with a 1,2-dihydrobenzocyclobutene group undergoes thermally initiated grafting reactions onto ethylene/propylene/nonconjugated diene rubber via the Diels-Alder reaction between the diene (benzocyclobutene) and the dienophile (pendant unsaturation on the EPDM). Characterization of the graft copolymer(s) is presented as is the resultant thermoplastic elastomeric mechanical performance exhibited by the graft copolymers.

Amorphous polyarylates derived from 12-50 mol % of a t-butyl-substituted diacid, e.g., 5-t-butylisophthalic acid, exhibit miscibility with the amorphous phase of polyamides having aromatic and aliphatic character. Equally critical to blend miscibility is the aliphatic/aromatic carbon atom ratio (exclusive of the amide functionality) of the polyamide. An aliphatic/aromatic carbon atom ratio (alpha) greater than 1.4 but less than 2.5 is necessary.