Dielectric relaxation phenomena of polylactic acid with β -crystalline chitin

Abstract

β -crystalline chitin was added to polylactic acid (PLA), and this PLA was then heat-treated at 100°C for one minute. The crystallinity of the heat-treated PLA increased to more than 40%, and its crystallization speed also increased significantly. The temperature dependency of these materials' relative permittivity (ε r ′) and relative dielectric loss factor (ε r ′ ′) was also examined. The dielectric absorption peak value in ε r ′ ′ curve of the PLA to which chitin was added and was smaller than that of PLA without chitin. Additionally, the Havriliak-Negami relaxation function was used to produce approximation curves for the frequency dependency of ε r ′ and ε r ′ ′ of chitin with PLA added at 80°C. As a result, the relaxation strength (Δε) of the chitin with PLA added was smaller than that of the PLA without chitin, and the relaxation time (τ) of the chitin with PLA added was approximately 2.5 times larger than that of the PLA without chitin. © 2012 Katsuyoshi Shinyama et al.