Supercritical fluid mixing: preparation of thermally sensitive polymer composites containing bioactive materials

Abstract

We report the use of supercritical carbon dioxide (scCO 2 ) to create a diverse range of polymeric composites incorporating thermal and solvent labile guest materials such as proteins; no additional co-solvents are required; the entire process can be carried out at near ambient conditions; polymer morphology is controllable; high loadings of guest species can be achieved and the protein function is retained.

Repair of critical size defects in the rat cranium using ceramic‐reinforced PLA scaffolds obtained by supercritical gas foaming

“…An overall rating was obtained using weighting factors (53 for the capsular thickness, 33 for the cellular response observed in the capsule, 53 for the neutrophils, 23 for the FBGCs, 13 for the lymphocytes, 13 for macrophages, and 13 for the fibroblasts). Reactions were classified into 6 categories, which were as follows: no reaction (0), minimal (1-10), slight (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25), moderate (26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40), marked (41-60), and excessive (>60).…”

“…[25][26][27] Polymer-based foams can be processed in different ways: solvent casting/particulate leaching, 28,29 thermally induced phase separation, or emulsion freezedrying, 30-33 gas foaming. [34][35][36] The latter technique has the main advantage of avoiding the use of potentially toxic organic solvents. 37 Gas foaming is based on the use of a gas porogen, and can be decomposed into several steps: gas dissolution, bubble nucleation, growth, and stabilization.…”

High-pressure rheological analysis of CO2-induced melting point depression and viscosity reduction of poly(ε-caprolactone)

“…For PCL80, exposure to 240 bar of CO 2 at 80 °C produces a viscosity (~3 kPa.s) which is even lower than the ambient pressure viscosity obtained at 180 °C (~6 kPa.s). Therefore, these measurements demonstrate the significant opportunities that high-pressure CO 2 processing of polymers could deliver in terms of energy saving and processing of thermally labile materials [17].…”

“…CO 2 has been exploited as a solvent for polymerisations [7,8], as a foaming agent [1,[9][10][11][12][13], for precipitation/separation [14], particle formation [15,16] and encapsulation [17].…”

“…High-pressure CO 2 is able to plasticise and effectively liquefy many polymers at temperatures below their glass transition temperatures (T g ) and melting points (T m ) [2,16,[18][19][20][21][22][23][24][25][26][27], thereby opening up opportunities for new processes and incorporation of thermally labile molecules [17,28].…”