Polymer modification by supercritical impregnation

Thermodynamics and Kinetic Processes of Polymer Blends and Block Copolymers in the Presence of Pressurized Carbon Dioxide

“…[209] This method also provides an avenue to blends of hydrophobic polymers (e.g., PVC or PMMA) with water-soluble polymers (such as poly(methacrylic acid) (PMAA)) that are not easily accessible by conventional means. [210] Recall that blend compositions can be tuned by controlling parameters such as the exposure and reaction times, CO 2 pressure, temperature, and monomer/initiator concentrations. [203,207,[211][212][213] A decisive consideration here is that the blend composition is not limited by the solubility of the monomer in the fluid or matrix phase, since polymerization depletes the monomer reservoir and permits more than the equilibrium concentration of the monomer to penetrate into the polymer substrate.…”

“…They have found evidence of three coexisting phases: amorphous PMMA, amorphous UHMWPE, and crystalline UHMWPE. Domains of newly polymerized material are evenly distributed throughout the matrix and have been measured to be on the order of 10-100 nm in size in the PMMA/UHMWPE blend, [218] <200 nm in the PVC/PMAA system, [210] and 10-300 nm in PS/ silicone rubber and iPP/PS systems. [203,204] The domain size has been generally observed [203,204,215] to increase with increasing monomer content.…”

Supercritical CO2–assisted synthesis and characterization of a polystyrene/thermal polyurethane blend

“…21 All the samples, including virgin TPU and PS/TPU blends of different mass gains, were analyzed by means of DSC (see Table I). Each blend has two glass transitions, and the first T g comes close with increasing PS content in the blends.…”

Synthesis of copper-poly tetrafluoro-ethylene composites by supercritical impregnation process

“…ScCO 2 (supercritical carbon dioxide) has unique mass transport properties, which are engaged in extraction and impregnation applications [1]. Berens et al [2] suggested that compressed CO 2 could be useful to facilitate the impregnation of additives into glassy polymers.…”

“…Generally, metal complexes that contain fluoroacetylacetonate or cyclooctadecyl ligands have relatively high solubility in scCO 2 , but the impregnation ratio of impregnants into the polymers is not proportional to solute concentrations in scCO 2 [1][2][3][4]13]. Nevertheless, these metal complexes have been used to fabricate metallopolymer composites by supercritical impregnation [9,12].…”