Nonisothermal crystallization kinetics and thermomechanical properties of multiwalled carbon nanotube-reinforced poly(ε-caprolactone) composites

BACKGROUND: The technological development of poly (e-caprolactone) (PCL) is limited by its short useful lifespan, low modulus and high crystallinity. There are a few papers dealing with the crystallization behavior of carbon nanotube-reinforced PCL composites. However, little work has been done on the crystallization kinetics of melt-compounded PCL/multiwalled carbon nanotube (MWNT) nanocomposites. In this study, PCL/MWNT nanocomposites were successfully prepared by a simple melt-compounding method, and their morphology and mechanical properties as well as their crystallization kinetics were studied. RESULTS: The MWNTs were observed to be homogeneously dispersed throughout the PCL matrix. The incorporation of a very small quantity of MWNTs significantly improved the storage modulus and loss modulus of the PCL/MWNT nanocomposites. The nonisothermal crystallization behavior of the PCL/MWNT nanocomposites exhibits strong dependencies of the degree of crystallinity (X-c), peak crystallization temperature (T-p), half-time of crystallization (t(1/2)) and Avrami exponent (n) on the MWNT content and cooling rate. The MWNTs in the PCL/MWNT nanocomposites exhibit a higher nucleation activity. The crystallization activation energy (E-a) calculated with the Kissinger model is higher when a small amount of MWNTs is added, then gradually decreases; all the E-a values are higher than that of pure PCL. CONCLUSION: This paper reports for the first time the preparation of high-performance biopolymer PCL/MWNT nanocomposites prepared by a simple melt-compounding method. The results show that the PCL/MWNT nanocomposites can broaden the applications of PCL. (C) 2008 Society of Chemical Industry.