Polydienes kinetics

Comparison of chemiluminescence isothermal runs with oxygen uptake and DSC measurements has been at the centre of interest since practical industrial applications of the chemiluminescence method were attempted. It is a fact that the best comparison may be achieved when studying polymers that give a distinct induction time of oxidation typical for autoaccelerating curves of a stepwise developing oxidation. This is the particular case of polyolefins, polydienes and polyamides. The theoretical justification for the search of a mutual relationship between the oxidation runs found by the various methods follows directly from the kinetic analysis of the Bolland-Gee scheme of polymer oxidation. 

The above mechanism served as a prototype accounting for other similar polymerizations. However, the kinetics of propagation of lithium polydienes revealed a dependence on the polymer concentration lower than 1/2, apparently 1/4 or less order. This prompted the assumption that the lithium polydienyls form higher aggregates than dimers. 

The presence of cross-associated species needs to be considered in the interpretation of copolymerization kinetics. It has been found 269) that the reaction of poly(butadie-nyl)lithium with p-divinylbenzene in benzene solution proceeds at a rate which increases markedly with time. Such a result implies that the poly(butadienyl)lithium aggregate is less reactive than the mixed aggregate formed between the butadienyl-and vinylbenzyllithium active centers. Interestingly, no accelerations with increasing reaction time were found with poly(butadienyl)lithium and m-divinylbenzene nor with poly(isoprenyl)lithium and either the m- or p-divinylbenzenes. This general behavior was subsequently verified 270) by a series of size exclusion chromatography measurements on polydiene stars (linked via divinylbenzene) as a function of conversion. 

Ziegler-Natta Catalysts Kinetics of Ziegler-Natta Polymerizations Practical Features of Ziegler-Natta Polymerizations Comparisons of Cis-1,4-Polydienes Metallocene Catalysts... 

Martin MK, Ward TC, McGrath JE. The reactivity of polydiene anions with divinylbenzene. In McGrath JE, editor. Anionic Polymerization. Kinetics, Mechanisms, and Synthesis. ACS Symposium Series. Volume 166. Washington (DC) American Chemical Society 1981. p 557-580. 

It was found out that the relative viscosity decreases exponentially upon ozonation of SKD solutions (Figiue 10.1). As the viscosity is proportional to the molecular weight it follows that the polydiene consumption should be described by first or pseudo-first order kinetics. 

Cameron, G.G., Qureshi, M.Y, 1980. Eree-radical grafting of monomers to polydienes 4. Kinetics and mechanism of methyl-methacrylate grafting to polybutadiene. J. Polym. Sci. Part A Polym. Chem. 18(11), 3149-3161. 

Stereoregularity and MW nonuniformity of polyolefins and polydienes Polyolefins synthesised on complex Ziegler-Natta catalysts are products without uniform stereoregularity and MW. The reason for this effect is the existence of different types of AC with different stereospecificity. On the other hand, these catalysts are kinetically nonuniform (differ in reactivity). 

The swelling kinetics of polydiene-urethane epoxide crosslinked elastomer (PDUE) was investigated for the experimental verification of the theoretical analysis. It was pro-... 

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