Self diffusion of phthalic acid ester molecules

A study was made of self diffusion of molecules of several pure phthalates (dimethylphthalate, dibutylphthalate and dioctylphthalate) and their molecules added to PVC by a NMR pulse method. It was shown that the temperature relation of the coefficient of self diffusion of pure phthalates is satisfactorily described by the Einstein-Hill theory. Self diffusion of phthalates introduced in PVC is treated on the basis of the activation theory. Energies of cavity formation in diffusion of single phthalate molecules in a PVC matrix were calculated. The relation between the activation energy of self diffusion and plasticizer concentration was described. It was shown that the type of self diffusion of phthalates depends on the state of the polymer matrix. © 1978