Formation of colloid solutions and gels during the radiation-chemical telomerization of tetrafluoroethylene in acetone

Abstract

The polymerization of tetrafluoroethylene (TFE) is initiated by the radicals generated by the radiolysis of acetone. The oligomer chain length n increases with an increase in the initial monomer concentration C. The transition from the true to the colloid solution at C ≈ 0.07 mol/l takes place at an average telomer chain length of \( \bar n \) ≈ 5. The transition of the colloid solution into gel is observed at C ≈ 0.30–0.35 mol/l. The acetone/TFE ratio in the centrifugation sediment decreases with an increase in the centrifugal acceleration and C. Its minimal value of ∼4 is attained at C > 2 mol/l when \( \bar n \) ≈ 12–15. The mean particle diameter in the phase separation region is 0.6–0.8 µm. A scaling model of radical polymerization is proposed to explain the molecular-mass distribution of telomers.