Thermomechanical behavior and nonisothermal crystallization kinetics of poly(epsilon-caprolactone) and poly(epsilon-caprolactone)/poly(N-vinylpyrrolidone) blends

Poly(epsilon-caprolactone) (PCL) and PCL/Poly(N-vinylpyrrolidone) (PVP) blends are shown to have the potential to be used in a range of biomedical applications and can be processed with successive in-situ polymerization procedures. In this paper, the thermomechanical analysis of PCL and PCL/PVP blends was performed using dynamic mechanical analysis (DMA). The storage and loss moduli as a function of temperature and frequency were recorded. The nonisothermal crystallization kinetics of PCL and PCL/PVP blends were analyzed using Ozawa model and Mo-Liu equation, a combination equation of Avrami and Ozawa formulas. The Ozawa analysis failed to describe the nonisothermal crystallization behavior of blends, whereas the Mo-Liu equation successfully described the nonisothermal crystallization kinetics of PCL and PCL/PVP blends. In addition, the value of crystallization rate coefficient under nonisothermal crystallization conditions was calculated. The PCL/PVP blends compared with the pure PCL and PVP had a restrain effect on the crystallization kinetics of PCL in the blends. Combining the results of DMA and DSC, PVP effectively decreased the crystallinity of PCL and enhanced its damping properties, which indicated that PCL/PVP blends could be more suitable than PCL in some biomedical applications, as it might help in the dissipation of the mechanical energy generated by the patient movements.