Preparation, Morphology And Crystallization Of Aliphatic Polyesters/Carbon Nanotubes Nanocomposites

In this dissertation, preparation, morphology and crystallization behaviors of two kinds of biodegradable aliphatic polyesters/multi-walled carbon nanotubes nanocomposites were studied in detail with various techniques.First, biodegradable poly(ethylene succinate) (PES)/carboxyl-functionalized multi-walled carbon nanotubes (f-MWNTs) nanocomposites were prepared through solution casting method. Scanning electron microscopy observations show a homogeneous dispersion of f-MWNTs throughout the PES matrix. Effect of f-MWNTs on the crystallization behavior of PES was investigated in detail under different crystallization conditions in this work. For both nonisothermal and isothermal melt crystallization, the addition of f-MWNTs enhances the crystallization of PES apparently due to the heterogeneous nucleation effect. The Ozawa method may describe the nonisothermal melt crystallization of neat PES and its nanocomposites. The Avrami method may fit the isothermal melt crystallization kinetics of neat PES and its nanocomposites; moreover, the overall crystallization rate of PES is enhanced significantly while the crystallization mechanism remains unchanged in the presence of f-MWNTs in the nanocomposites. The crystal structure of PES remains unchanged in the PES/f-MWNTs nanocomposites despite the presence of f-MWNTs.Biodegradable poly(butylene succiate-co-butylene adipate) (PBSA)/multi-walled carbon nanotubes (MWCNTs) nanocomposite was prepared via a simple melt compounding method at 1 wt% MWCNTs content. Scanning and transmission electron microscopy observations reveal a fine dispersion of MWCNTs throughout the PBSA matrix. Both nonisothermal and isothermal melt crystallization of PBSA has been enhanced significantly in the nanocomposite relative to neat PBSA due to the presence of MWCNTs; however, the crystal structure of PBSA remains unchanged.