The kinetics and mechanism of the low temperature post-polymerization of allylamine in the presence of phosphoric acid☆

It was found by low temperature calorimetric analysis that post-polymerization takes place with close to 100% yields in the system allyl amino-phosphoric acid during the slow defrosting of specimens subjected to γ-irradiation at −196° with 0.5 to 10 Mrad. The kinetics of this process were investigated. At −196° the EPR spectrum of the γ-irradiated glass-like system is in keeping with the allyl hydrocarbon radical, the latter being a product of the radiolysis of AA (I) in a system containing the alkyl propagation radical (II). Radical decay is observed for I on heating the system to −80–100°, while the concentration of II varies only inappreciably all the way to 0°. Direct proportionality was observed between the initial rate of low temperature post-polymerization measured at a fixed temperature and the number of radicals of type II at the same temperature, which points to a radical mechanism of post-polymerization. The molecular weights of the resulting polymers are inversely proportional to the number of propagation radicals recorded by EPR for a constant degree of conversion, and are in good agreement with calculated MW values. This means that the low temperature post-polymerization of AA in H3−PO4 takes place under conditions marked by virtual absence of decay of active centres and likewise of chain transfer.