Modification of biomedical polymers in dense fluids. Miscibility and foaming of poly(p-dioxanone) in carbon dioxide + acetone fluid mixtures

详细信息	查看全文 | 推荐本文 |

• 作者：Erdogan Kiran ; ^{ekiran@vt.edu}
• 关键词：Poly(p-dioxanone) ; Polymer ; Miscibility ; Foaming ; Bioabsorbable ; Carbon dioxide ; Acetone
• 刊名：The Journal of Supercritical Fluids
• 出版年：2012
• 期刊代码：60_08968446
• 类别：ce
• 出版时间：June, 2012
• 卷：66
• 期：Complete
• 页码：372-379
• 文件大小：1432 K

摘要

This paper reports on the miscibility and foaming of a bioabsorbable polymer, poly(p-dioxanone) in CO₂ + acetone mixtures at high pressures. Liquid-liquid miscibility pressures have been determined in acetone for polymer concentrations in the range from 1 to 15 wt%over a temperature range from 70 to 170 掳C. Phase boundaries were also determined for 5, 7.5 and 10 wt%solutions in CO₂ (11 wt%) + acetone (89 wt%); and for 7.5 wt%polymer solutions in CO₂ (25 wt%) + acetone (75 wt%) fluid mixture. The solutions in both acetone and in acetone + CO₂ mixtures were found to display UCST type behavior. In solvent mixtures, miscibility pressures show a marked increase with increased carbon dioxide content. At 150 掳C, for the 7.5 wt%polymer solution, the miscibility pressures increased from about 25 MPa in pure acetone to 40 MPa in 10 wt%CO₂ mixture and to about 65 MPa in 25 wt%CO₂ containing mixture. Foaming experiments were carried out in a specially designed mold with porous plates in pure carbon dioxide and also in mixtures containing acetone at low addition levels (<1 wt%) at temperatures between 80 and 100 掳C and at pressures between 20 and 45 MPa. Foams with relatively large and distinctly interconnected pores with pore diameters in the range from 20 to 100 渭m were generated if pressures were greater than 20 MPa and the temperatures were less than 92 掳C. Larger pores and interconnectivity were favored when foaming was carried out from mixtures containing acetone.