Sorption and diffusion of compressed carbon dioxide in polycaprolactone for the development of porous scaffolds

M.A. FANOVICH; P.T.JAEGER

MATERIALS SCIENCE & ENGINEERING. C, BIOMIMETIC MATERIALS, SENSORS AND SYSTEMS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2012 vol. 32 p. 961 - 968

0928-4931

In this work different phenomena related to sorption of carbon dioxide in polycaprolactone (PCL) have beeninvestigated systematically. The use of compressed carbon dioxide is discussed for obtaining porous scaffoldsfrom this biocompatible polymer. In order to determine the plasticization effect of carbon dioxide on the degreeof foaming it is necessary to discuss sorption data with respect to morphological features of the polymer atconditions nearby the melting point. The amount of carbon dioxide dissolved and the kinetics of the sorptionprocess are found to depend strongly on temperature and pressure. The solubility takes values of up to25 wt.% being favoured by a melting and glass transition temperature depression which can be observed alongwith an enhanced mass transfer rate. In general, CO2 sorption in PCL increases linearly with pressure. Whendecompressing, microfoaming occurs which enhances the rate of gas release. Changes in morphology andcrystallinity occur as a consequence of the pressure treatment. Compared to the melting temperature at atmosphericpressure there is a dramatic reduction observed under pressure where melting occurs already at atemperature below 40 °C. Even after pressure-treatment, there is a remaining change in melting temperatureand crystallinity observed. Optimum conditions for obtaining adequate porous scaffolds of PCL are a relativelyslow decompression after treatment at 17MPa and 35 °C.