Molecular mass distribution of oligomers in products of tetrafluoroethylene radical telomerization

Abstract

The molecular mass distributions (MMD) of perfluorinated oligomers in products of tetra-fluoroethylene (TFE) radical polymerization in various solvents (telogens) were determined from an analysis of differential thermogravimetric curves and data of gel permeation chromatography and mass spectrometry. Radiolysis of the telogens generates radicals initiating polymer chain growth. The choice of the solvent and TFE concentration makes it possible to obtain oligomers with the controlled average chain length from 4 for 40 CF2 fragments and specified terminal groups. The polymerization of TFE in THF and propylene oxide affords oligomers with cyclic terminal groups capable of further polymerization due to ring opening. The appearance of two MMD maxima (low-molecular-weight at n 1 ∼6–8 and high-molecular-weight at n 2 > 10 shifting towards high n with an increase in the TFE concentration) is caused by the formation of colloidal solutions of oligomers.