Study of plasticizer-oligomer and plasticizer-polymer interactions by dielectric analysis: maltose-glycerol and amylose-glycerol-water systems

Dielectric analysis was performed on amorphous maltose-glycerol and amylose-glycerol-water systems. A primary relaxation, appearing in the range of the calorimetric glass transition temperature, was observed in the maltose-glycerol system. From 0% (w/w) to approximately 30% (w/w) glycerol, a secondary relaxation was observed at lower temperature in both systems. In this concentration range, the addition of glycerol shifted the primary relaxation to lower temperature and the secondary relaxation to higher temperature. For mixtures containing around 30% (w/w) glycerol, the relaxation map revealed a merging of the primary and secondary relaxations or a disappearance of the secondary relaxation. Above 30% (w/w) glycerol in the amylose-glycerol-water system, indication of a phase separation was obtained. This behaviour is compared with the relaxation behaviour of some plasticized synthetic polymers (polyvinylchloride and polyisoprene). (C) 1998 Elsevier Science Ltd. All rights reserved.