Organic reactions on high polymers

When organic high polymer reactions are compared to similar reactions carried out on low molecular weight compunds, some special characteristics become evident, which are directly related with the polymeric structure of the substances. These characteristics may be pointed out either from comparative kinetic measurements, either from the structural organic analysis of the reaction products. From kinetic point of view, a distinction must be made between mono‐and bifunctional reactions. For monofunctional reactions, the similarity of reaction kinetics between a polymeric molecule and its low molecular weight homologous compound is only disturbed if the electrical potential of the mecromolecule increases in the course of the reaction, or (and) if the shape of the molecule changes. Examples are given in the cases of vinyl pyrrolidone copolymers, polymethacrylamide and related polymers. As soon as the reaction becomes itself multifunctional, the differences are very important; intramolecular functional interaction very often become prevalent, and they are necessarily related with the internal structure and tacticity of the polymer molecule. Examples are given on copolymers of (meth)acrylic acid with methyl methacrylate and with acrylamide of different compositions, which confirm and complete some previous data of MORAWETZ. By the use of partially hydrolyzed polymethacrylic esters, the influence of the isotacticity, the syndiotacticity and atacticity has been demonstrated directly. From the organic and structural point of view the functionality of the reaction is also very important; the course of the reaction differ only from that of the low molecular compounds when the reaction is multifunctional. Sometimes interfunctional condensation occurs during the synthesis of the polymer, e.g. in the cases of polymethacrylamide, polyalpha‐chloroacrylic acid or during further transformation reactions of the polymer. Some apparently unexpected results are discussed and further explained. Sometimes the interaction may be concomitant with some chain degradation, as in the case of the F RIEDEL ‐C RAFTS reactions applied to polyvinyl derivatives. The influence of the stereochemical composition of the polymeric chain is also illustrated with cyclization reactions on polyacrylic acids of different tacticity depending on their methods of synthesis. Reactions including peroxidic groups which determine the degradation phenomena as well as the grafting possibilities, were intentionally omitted.