Certain Plasticizing Peculiarities of Polyvinyl Chloride Films Obtained from Solutions

摘要

It appears most probable that the vibrations of the polymer-molecule carbon skeleton interact in the 1000-1200/cm range with vibrations of the C-C groups present in the plasticizers (DBP and glycerine). Plasticizer dibutyl phthalate (DBP) molecules present in the films contain a carbon chain with less inhibited internal rotation than the polymer molecules, which are cohesively bound into micelles. Hence, the low-intensity band of one C-C valence vibration (1111/cm of the polymer carbon chain is absorbed by two bands (1070 and 1150/cm), which reflect two valence vibrations of the more flexible plasticizer molecule. This is confirmed by the fact that the band intensity rises with increasing plasticizer concentration. The most conspicuous intensity increase of these bands is observed when films are formed from solutions in dichloroethane (DCE). This is because DCE, a poor solvent for PVC by comparison with cyclohexane, lowers the degree of intramicellar plasticizing. The concentration of plasticizer molecules not bound to the polymer then increases, with the result that the intensities of the corresponding bands in the IR spectrum also increase. (Author)