A comparison of the structure, thermal properties, and biodegradability of polycaprolactone/chitosan and acrylic acid grafted polycaprolactone/chitosan

The effects of replacing PCL with acrylic acid grafted PCL (PCL-g-AA) on the structure and properties of a PCL/chitosan composite were investigated. The properties of both PCL-g-AA/chitosan and PCL/chitosan were examined and compared using FTIR, 1H and 13C nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and a biodegradation test. With PCL-g-AA in the composite, compatibility with chitosan and, consequently, the properties of the blend were both much improved due to the formation of ester and imide groups that conferred better dispersion and homogeneity of chitosan in the matrix. Moreover, PCL-g-AA/chitosan had a lower melt temperature and was, therefore, more easily processed than PCL/chitosan. Resistance to water was higher in the PCL-g-AA/chitosan blend, and consequently so was its resistance to biodegradation in soil and in an enzymatic environment. Nevertheless, weight loss of blends buried in soil or exposed to an enzymatic environment indicates that both blends were biodegradable, especially at high levels of chitosan content. Both blends suffered deterioration in tensile strength and elongation at break after exposure to soil or enzymatic environments.