Low temperature dielectric relaxation of poly (L-lactic acid) (PLLA) by Thermally Stimulated Depolarization Current

International Conference on Recent Trends in Physics 2016

Patidar, Manju Mishra^1 ; Jain, Deepti^2 ; Nath, R.^1 ; Ganesan, V.^1

UGC-DAE Consortium for Scientific Research, Indore

MP-452001, India^1

MITS, Gole Ka Mandir, Gwalior

MP-474005, India^2

关键词: Biocompatible polyesters;    Biomedical applications;    Isothermal crystallization;    Low temperature regions;    Poly L lactic acid;    Relaxation phenomena;    Renewable resource;    Thermally stimulated depolarization currents;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/755/1/012039/pdf
DOI  :  10.1088/1742-6596/755/1/012039

来源: IOP

【 摘 要 】

Poly (L-lactic acid) (PLLA) is a biodegradable and biocompatible polyester that can be produced by renewable resources, like corn. Being non-toxic to human body, PLLA is used in biomedical applications, like surgical sutures, bone fixation devices, or controlled drug delivery. Besides its application studies, very few experiments have been done to study its dielectric relaxation in the low temperature region. Keeping this in mind we have performed a low temperature thermally stimulated depolarization current (TSDC) studies over the temperature range of 80K-400K to understand the relaxation phenomena of PLLA. We could observe a multi modal broad relaxation of small but significant intensity at low temperatures while a sharp and high intense peak around glass transition temperature, Tg∼ 333K, of PLLA has appeared. The fine structure of the low temperature TSDC peak may be attributed to the spherulites formation of crystallite regions inter twinned with the polymer as seen in AFM and appear to be produced due to an isothermal crystallization process. XRD analysis also confirms the semicrystalline nature of the PLLA film.