TITLE:
Supercritical Fluid Impregnation of Essential Bark Oil in Copolymers of L-Lactide with 7-Membered Cyclic Compounds
AUTHORS:
Chikara Tsutsumi, Teruyuki Hara, Yuka Ueno, Yuushou Nakayama, Takeshi Shiono
KEYWORDS:
Biodegradable Polyester, L-Lactide Copolymer, Supercritical Carbon Dioxide, Impregnation
JOURNAL NAME:
Journal of Biomaterials and Nanobiotechnology,
Vol.5 No.3,
July
2,
2014
ABSTRACT: In order to develop a novel
controlled-release material, we previously attempted to impregnate poly(L-lactide) (poly(L-LA)), poly(L-LA-ran-CL) (CL: ε-caprolactone) or poly(L-LA-ran-TEMC)
(TEMC: tetramethylene carbonate) with low boiling point, organic useful
compounds using supercritical carbon dioxide (scCO2) as the solvent.
In this work, the factors influencing impregnation of poly (L-LA) random copolymers
with useful compounds were investigated under scCO2 using the copolymers
previously used. The influence of temperature, pressure, and time on the
impregnation contents of the useful compounds on the copolymers was evaluated.
The polymer used, which is a base of this material, was poly(L-LA-ran-CL), poly(L-LA-ran-TEMC), or poly(L-LA-ran-DXO)
(DXO: 1,5-dioxepan-2-one). Statistical random copolymers of L-LA with CL, TEMC,
or DXO were synthesized using Sn(oct)2 as a catalyst at 150°C for
24 h without solvent. Preparation of the controlled-release materials was
carried out using essential bark oil from Thujopsis
dolabrata var. hondae and
synthetic L-LA random copolymers as a base material under scCO2. The
impregnation experiment, which investigated the influence of pressure, was conducted
in the range of 10 to 20 MPa. The influence of temperature on impregnation was
carried out at 40°C to 100°C. Impregnation time was varied from 1 to 5 h. The
pressure of essential oil impregnated into poly(L-LA) random copolymers was
the highest at 14 MPa. In the influence of temperature on impregnation, the
amount of essential oil increased with increasing temperature.