Effect of degree of deacetylation of chitosan on thermal stability and compatibility of chitosan-polyamide blend

Abstract

The effect of the degree of deacetylation of chitosan on the chemical structure, thermal properties, and compatibility of chitosan/polyamide66 (CS/PA66) blends were investigated. Blends of CS with PA66 were prepared via the solution casting technique by using 85% formic acid. Structural interaction between PA66, CS, and CS/PA66 blends were analyzed by infrared spectroscopy. FT-IR spectra showed displacement of the carbonyl band of the amide group of chitosan toward smaller wave numbers, indicating possible existence of hydrogen bonding between the two macromolecules. Thermal and morphological behavior of films containing chitosan with degree of deacetylation (DD) ranging from 52.9% to 85% in the polymer blends were investigated by thermogravimetric analysis and scanning electron microscopy. Thermal analysis showed that the CS/PA66 blends became more thermally stable than pure chitosan. The morphological behavior observed by scanning electron microscopy indicated phase segregation in all types of blending. Acetyl content in chitosan was found to influence the degree of compatibility. Decreasing the acetyl group or increasing the DD of chitosan increases the compatibility of the CS/PA66 blends.