Synthesis and rapid expansion in supercritical carbon dioxide through porous sintered metal plate of poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate)

Poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate) [poly(TA‐N)] was synthesized in dry benzene using AIBN as an initiator at 60°C. The effects of the monomer concentration ( C m ), initiator concentration ( C i ), and reaction time on the polymerization were investigated. The results of DSC and TGA showed that when the C i remains constant, the higher the C m value is, the better the thermal character for the product in the range of experiments. When the reaction was conducted for 30 h, polymerization is almost completed. The C i should remain lower than 0.25 g/100 g monomer when the C m is lower than 15 g/L. When the C m is higher than 15 g/L, the C i should be increased slightly. When the C m remains constant, it was observed that an increase in the C i increases the yield (mass of polymer after reaction/mass of monomer before reaction). On the other hand, the melting ( T m ) and decomposition ( T d ) temperatures of the reaction product decrease, except when the C m reaches 20 g/L and the reaction time is 30 h. High purity CO 2 was continuously pumped using a high pressure syringe pump. Rapid expansion of poly(TA‐N) in supercritical CO 2 happened under control through a porous sintered metal plate. The poly(TA‐N) morphology was analyzed with a scanning electron microscope. An amorphous polymer was formed at a preexpansion temperature of 45°C. Fibers were formed at temperatures of around 60–80°C. An increase of the temperature slightly increases the particle size. At 105°C, most of the particles are spheres and dendrites. The corresponding CO 2 flow rate upon expansion was 2.5–5.0 ± 0.3 L/min (STP) and the pressure drop was 2 MPa. At the higher CO 2 flow rate, the spheres and dendrites became smaller. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2763–2768, 2003