Antiplasticizing effect of triethyl citrate on an isosorbide-based polycarbonate

Abstract

The effects of triethyl citrate (TEC) on the viscoelastic properties of a copolycarbonate comprising isosorbide and 1,4-cyclohexanedimethanol (ISB-PC) were studied in both the molten and solid states. TEC acted as an antiplasticizer for ISB-PC and increased its modulus in the glassy state, as demonstrated in a blend comprising 10 wt% TEC. Because antiplasticization reduces the free volume fraction, the water content of the copolycarbonate films, which is known to affect various properties, decreased following the addition of TEC. Furthermore, TEC greatly decreased the zero-shear viscosity. The experimental values were much lower than those predicted by the Berry–Fox formula. This suggested that the monomeric frictional coefficient was reduced. In other words, a small amount of TEC greatly enhances the flowability of ISB-PC.