END UNIT EFFECT ON THE T(G) OF DIFFERENTIATED SERIES OF PERFLUORO-POLY-(OXYMETHYLENE-CO-OXYETHYLENE) OLIGOMERS

Twelve series of linear oligomers of four different degrees of polymerization (x(n) = 8.77-41.55), having a common perfluorinated random copolymeric chain as molecular body and two equal foreign end units of one of the types listed in Table 1, have been synthesized by derivatization of base samples of one of them having a diolic--CH2OH functionality. The glass transition temperature T(g) of all the series was measured and thus examined as a function of x(n). A clear end unit effect is observed, dominantly determined in every series by chemical nature and structure of the end units, quantitatively expressed at any x(n) by different positive or negative T(g) deviations from the common asymptotic T(ginfinity) value. The results are also discussed in terms of copolymer end effect and of relation between T(g) and end copolymeric composition.