PHYSICAL TRANSITIONS IN POLYMERS PLASTICIZED BY INTERACTING PENETRANT

Plasticization by a penetrant of a polymer with the functional groups, specifically interacting (donor-acceptor type of interactions) with t he penetrant is analyzed by using the systems: ammonia which is an ele ctron-donor/aromatic polyamides, where amide group is as an electron-a cceptor; sulfur dioxide which is an electron-acceptor/polymers with el ectron-donor groups. It is shown that there is the plasticization of p olymer by penetrant as the result of the sorption of penetrant molecul es on the active functional groups of a polymer. There are four sectio ns (regions) on the concentration dependencies of the diffusion coeffi cient. The boundaries between them correspond to the transition of the polymer (or rigid phase of block-copolymer) from one glassy state to another (beta-transition), from glassy state to rubbery state (alpha-t ransition), and from rubbery state to the viscous-flow state. Essentia lly, the concentrations of a penetrant on the active functional groups , n, (or the degree of fullness of the effective sorptive capacity of the functional groups, phi), which corresponds to the alpha- and beta- transitions in the polymer, have the ratio: n(alpha)/n(beta)congruent to phi(alpha)/phi(beta)approximate to 4 +/- 1. Concentration barriers of the activation, corresponding to the alpha- and beta-transitions al so have the same ratio. It seems, that the process of alpha-relaxation in the polymer includes the intermolecularly correlated displacement of neighboring segments of the same size as in the beta-transition, i. e. close to the Kuhn's segment, but it is close to the correlated disp lacement of 3-5 segments. Relative concentration activation barriers o f the physical transitions depend on the energy of interaction between penetrant and functional group of polymer.