Thermal analysis and miscibility of chitin/polycaprolactone blends

Chitin/polycaprolactone (PCL) blends were prepared by melt-blending of chitin and PCL with varying amounts of chitin. Thermal analysis of DSC, DMTA, and FTIR were used to characterize the blends. Results showed that increases in the amount of chitin did not cause a decrease in either the melting point or the crystallization point of PCL. The loss-modulus curve did not show a change of glass-transition temperature (T,) from a dynamic temperature ramp test, which revealed that the pure chitin/PCL blend was not miscible at any ratio. When chitin n-butyrate (CB) was partly substituted for chitin in the blend, both the melting point and crystallization point of the PCL component was depressed, which implied an improvement of the miscibility of the blend. Furthermore, FTIR characterization suggested an interaction between the components. However, T, did not change compared to that of the pure PCL in the loss-modulus curve, that is to say, that the modification of the miscibility by the introduction of CB to the blend lay only in the interfacial region, although not at the molecular level. (C) 2001 John Wiley & Sons, Inc.