Szwarc Theory

This concept is due to Bjerrum, who in 1926 suggested that in simple electrolytes ions of the opposite charge could associate to form ion-pairs (Szwarc, 1965 Robinson Stokes, 1959). This concept of Bjerrum arose from problems with the Debye-Huckel theory, when the assumption that the electrostatic interaction was small compared with IcTwas not justified. 

Recent Advances in Polymer Chemistry (Szwarc). Recent Developments in Molecular Orbital Theory 2 147... 

The theory of unimolecular propagation for the cationic polymerisation of a bulk monomer was first developed by Szwarc (1978), and Equation (44) introduced by him has been named Szwarc s equation (Plesch, 1993). 

In the 1960 s, several groups of workers recognised that by modification of the Szwarc living polymer procedure of anionic polymerization it would be possible to synthesize polymers of fairly definitely known branched structure, which could be used to test existing theories of the effects of LBC on polymer properties, and a considerable amount of work has been published, which is summarised in Section 8. It may be said that the theories do not come very well out of comparison with experiment, and this work shows up the inadequacy of present understanding of the properties of branched polymers. 

Szwarc discovers the living polymers by anionic polymerisation Theory of paracrystallinity developed by Hosemann... 

When Szwarc et al. discovered [15,16], or rediscovered [17,18], the anionic living polymerization, a completely different preparation of these elastomers was proposed the study of TPEs passed from infancy to maturity. These authors used sodium metal naphthalene diinitiators to prepare poly (styrene-l>-isoprene-6-styrene), which was probably the first TPE with a perfectly defined structure. However, this copolymer could not be commercialized, as most of the poly-isoprene units were -3,4-, with poor elastomeric properties. It is only when the polymerization was initiated by alkyllithium that poly(styrene-l>-isoprene- -styrene) and poly (styrene-butadiene- -styrene) were obtained with the classical TPE properties very high tensile strength and elongation at break, very rapid elastic recovery, and no chemical crosslinking. Bailey et al [19] announced the existence of these materials in 1966 and Holden et al [20] published the corresponding theory in 1967 and extended it to other block copolymers. 

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