INTERDIFFUSION AT INTERFACES OF POLYMERS WITH DISSIMILAR PHYSICAL-PROPERTIES

The interface between two different polymers is characterized theoreti cally by using a model. This model is based on the assumption that the monomeric friction coefficients of the two polymers are identical but a strong function of the matrix composition. This model predicts that the concentration profiles are highly asymmetric with substantial swe lling of the slower-diffusing component by the faster component. To pr edict the behavior of interdiffusion, three quantities are used: dista nce of interface Z(t) due to the swelling, interfacial width W(t) whi ch is most sensitive to the detailed composition profiling, and mass t ransport M(t) due to interdiffusion. It is found that the more dissimi lar polymer pairs, the faster the movement of the interface, the quick er its interfacial width saturates to a limiting value and the slower its mass transport. These results are in qualitative agreement with so me experiments.