Preparation and Characterization of Nanocomposite Films from Chitin Whisker and Waterborne Poly(ester-urethane) With or Without Ultra-Sonification Treatment

Abstract

Two series of nanocomposite films were prepared from waterborne poly(ester-urethane) and chitin whisker with and without ultrasound treatment coded as CW/WPU and CHW/WPU, respectively. The effects of ultra-sonification method and chitin whisker content on the chemical compositions, crystallization behavior and miscibility were studied by attenuated total reflection Fourier transform infrared (ATR-FTIR), wide-angle X-ray diffraction (WXRD), dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). Thermal stability and mechanical properties of the films were measured by thermogravimetric analysis (TGA) and tensile test, respectively. The results revealed that both nanocomposite films exhibited a certain degree of miscibility when chitin whisker content was lower than 30 wt%, resulting in higher thermal stability and tensile strength than the pure waterborne poly(ester-urethane) film. Interestingly, the composite films CW/WPU with ultrasound treatment possessed better miscibility, storage modulus, thermal stability and tensile strength than those without ultrasound treatment over the entire composition range studied here. The difference can be attributed to the relatively higher dispersion level of whisker within poly(ester-urethane) matrix resulting in relatively stronger entanglement and interaction between both components. The ultrasound treatment can effectively improve the miscibility and mechanical properties of the casting nanocomposite films with nano-meter size chitin whisker added. This indicated that the structure, miscibility and mechanical properties of the nanocomposite films depended significantly on the preparation method.

Keywords:

• Nanocomposite
• waterborne polyurethane
• chitin whisker
• ultra-sonification

Acknowledgments

This work was supported by national high-tech R&D program (863 program) for the 11th five-year plan, Ministry of Science and Technology, P. R. China (2006AA100215), SRF for ROCS, State Education Ministry, P. R. China, the Special Fund for Basic Scientific Research of Central Colleges, China University of Geosciences (Wuhan) (contract grant number: CUGL090223), and the major grant of the State Key Laboratory of Geological Process and Mineral Resources (contract grant number: GPMR200918).