Recent studies on radical polymerization

Abstract

Different aspects of radical polymerization have been investigated in the author's laboratory. 1) Radical oligomerization has been studied by GC-MS and some kinetic parameters obtained in this way (chain transfer and reinitiation constants, reactivity ratios) compared with the results of classical experiments.2 ) Star-shaped polymers have been obtained by using a series of polyfunctional chain transfer agents; the experimental results agree very well with the theoretical expectations. 3 ) A reexamination of the copolymerization equation showed that the steady-state assumption is not a necessary condition for the kinetic derivation and that all approaches are conceptually equivalent. 4 ) The structure and the 2D NMR spectra of hemiisotactic polypropylene obtained by radical inclusion polymerization are discussed.Radical polymerization is often considered as an old and obsolete subject of polymer science, no longer worthy of further attention. This statement, however, can be easily confuted.The birth and development of radical polymerization dates back to the first half of this century and was due to the efforts of a great number of scientists who proposed a consistent explanation for most of the experimental facts known at that time.Attention was directed mainly to the kinetic interpretation as this gives a quantitative (or semiquantitative) prediction of the reaction rate and molecular weight. More subtle features of the process were disregarded.Structural aspects in particular were hardly investigated due to the lack of instrumentation existing at that time.The situation, however, has chanqed v e r y much in the last few 0 1991 Hiithig & Wepf Verlag, Base1 CCC 0258-0322/91/$02.50