Filler migration methods

An IR spectroscopy technique was developed to study the plasticiser migration from polymer compositions to the air environment. The applicability of the method was demonstrated for filled PVC compositions plasticised with di-n-butyl phthalate. Values for the effective diffusion coefficient(D) of the plasticiser were calculated from the spectroscopic data. An increase in the chalk content in a PVC composition led to a monotonic increase in D, whereas kaolin-filled compositions exhibited a more complex behaviour. The observed pattern of changes in D with varying filler content was correlated with the competing interaction of components in the system. 20 refs. (Full translation of Vys.Soed.B, 44, No.2, 2002, p.363-8)... 

The close similarity of the data from modelling and experiments suggests that silane, if allowed to migrate to the surface of the filler, forms a closely packed monomolecular layer. The surface area occupied is related to the orientation of the molecule and its size, rather than to the type of substrate (filler) on which it is deposited. According to other studies,silane molecules can also be oriented horizontally, and their actual orientation probably depends on the method of application (concentration, type of solvent, etc.). 

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