LAUSR

Local molecular dynamics of polymer systems based on polyvinylbutyral is studied via the IR Fourier spectroscopy of conformation-inhomogeneous probes. The compositions of the studied binary mixtures of polyvinylbutyral with polymethylmethacrylate are 80: 20, 60: 40, 40: 60, and 20: 80. The temperatures of the secondary relaxation transitions and the difference between the enthalpies of conformation of the probe molecules in these systems are obtained. The effective sizes of mobile free-volume elements, the diffusion of which results in the transport of small molecules upon membrane gas separation, are estimated.