SURFACE PHENOMENA AND POLYMER MISCIBILITY OF PVC EVA BLENDS/

The study of the interface in polymer blends gives a riser full inform ation about the thermodynamical miscibility of the system. The surface tension studies of the pure copolymers have shown that the acetate co ntent plays the major role and this is also reflected in the interfaci al tension of the PVC blends. The results show a direct relationship b etween the interface thickness and the vinyl acetate content in rite E VA copolymer. Interaction parameter values show an inversely related c orrelation. Calculated values obtained from the appropriate equations have shown small discrepancies from experimental data. The Flory-Huggi ns parameters, theoretically calculated by using recent theories which suppose that the vitreous transition is a true transition, are in goo d agreement with the values obtained from calorimetric measurements. T hermal stability and the degradation process were also studied. The ex perimental data showed a relationship between the thermogravimetric cu rves and the degree of interaction in the mixtures as compared to pure polymers that are consistent with microscopy analysis. Kinetic parame ters and life time data of the mixtures were also calculated. (C) 1997 Elsevier Science Limited.