One‐shot synthesis of high molar mass polyurethane in supercritical carbon dioxide

Abstract

Well‐defined polyurethane–polydimethylsiloxane particles of tunable diameter in the range of 0.5–20 μm were synthesized in “one‐shot” by step‐growth polymerization using supercritical carbon dioxide (scCO2) as a dispersant medium. Polymerizations were carried out at 60 °C and above 25 MPa, after the solubility of each reactant in scCO2 has been determined in its typical reaction concentration. The synthesis of such copolymers was achieved by polyaddition between short aliphatic diols, that is, ethylene glycol, 1,4‐butanediol (BD) or polyethylene oxide (Mn = 200 g mol−1), and tolylene‐1,4‐di‐isocyanate (TDI) in the presence of mono or di‐isocyanate‐terminated polydimethylsiloxane (PDMS) as reactive stabilizers and dibutyltin dilaurate as a catalyst. The nature of the diol used as well as the functionality of the reactive stabilizer incorporated was found to have a dramatic effect on the molar mass and the morphology of the resulting product. Thus, copolymers obtained from the polyaddition of BD and TDI in the presence of di‐isocyanate‐terminated PDMS exhibit molar mass up to 90,000 g mol−1. Thermal behaviors of copolymers were also examined by differential scanning calorimetry. All samples exhibited only one glass transition temperature (Tg) and were found to be totally amorphous. A logical decrease of the Tg was observed as the length of the diol incorporated increased, that is, as the density of urethane linkages within the polymer decreased. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5649–5661, 2007

Lithium Depletion and the Rechargeability of Li–O2 Batteries in Ether and Carbonate Electrolytes

“…At 60 °C and a typical polymerization concentration of 2.5 wt % versus CO 2 , this diisocyanate is soluble above pressures of 17 MPa. 5c n ‐Butanol was chosen as an appropriate monofunctional model of the primary aliphatic polyols commonly used in PU synthesis and it forms a single supercritical phase with CO 2 above 10 MPa at 60 °C 17. Our kinetic measurements were thus performed at T =60 °C and P =24 MPa to ensure a single supercritical phase.…”

Synthesis of Polyurethane/Poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate) Particles in Supercritical Carbon Dioxide

“…As an extension to our previous studies,19–22 this paper aims at investigating a fluoro‐based polymer as a reactive stabilizer for the synthesis of polyurethane particles in scCO 2 . This article focuses on the synthesis by ATRP of newly designed end‐functionalized poly(1,1,2,2‐tetrahydroperfluorodecyl acrylate)s (PFDA) and their use as reactive stabilizers for the preparation of super‐hydrophobic polyurethane particles.…”

“…In this context, we investigated the effects of chain end functionality and chain length of a series of newly designed reactive PFDA as stabilizers for PUR synthesis in scCO 2 . The polymerizations were carried out in a stainless steel reactor 19–22. The latter was connected to a 12 mL stainless steel cell used for TDI additions.…”

“…We recently investigated a step‐growth dispersion polymerization between several short aliphatic diols, such as ethylene glycol (EG) or 1,4‐butanediol (BD) and tolylene‐2,4‐diisocyanate (TDI), carried out in scCO 2 in the presence of mono‐ and diisocyanate‐terminated polydimethylsiloxanes 19–22. This allowed us to synthesize new core‐shell polyurethane‐based particles of tunable diameter exhibiting high molar masses.…”

Total replacement of solvent in polyurethane synthesis using carbon dioxide soluble 1,3‐dichlorodistannoxane catalysts

“…Moreover, the catalysts are neither recyclable nor separable. There are few reports that disclose the synthesis of polyurethane in CO 2 , but these involve either a nonrecyclable catalyst13 or copolymer formation 14…”