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

Abstract

This work demonstrates catalytic synthesis of polyurethanes using 1,3‐dichlorodistannoxane catalysts (1) in carbon dioxide (CO2) and carbon dioxide expanded liquids (CXL). Catalytic polyurethane synthesis was also performed in pure organic solvent (dimethylformamide) for comparison. In this study, mainly, 4, 4′‐methylene‐bis‐(phenyl isocyanate) (MDI) as the diisocyanate precursor and ethylene glycol (EG) as the diol precursor were used for polyurethane synthesis. In addition to MDI, hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), and p‐isocyanatobenzylisocyanate (PIBI) were also used for polyurethane synthesis with different diols or triol in CO2. Polyurethanes with a molecular weight ranging from 3000 to 70,000 were synthesized depending upon the combination of diisocyanate and diol used. Comparable yields of polyurethanes were obtained using an all butyl group substituted (1a) catalyst in CO2 (55 bars, 50°C) and in DMF (50°C). Additionally, the yield and polydispersity index (PDI) of polymer formed in neat CO2 was comparable with those synthesized in the largely used organic solvent DMF. Interestingly, catalyst 1a in CXL (55 bars, 50°C) gave higher yields, and polymers with lower PDI (1.19). Reactions carried out in scCO2 at 145 bars using PIBI and EG were found to be about three times faster than the reaction carried out in DMF. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Environment‐friendly chemical recycling of aliphatic polyurethanes by hydrolysis in a CO2‐water system

“…H‐PU was found to be insoluble in common solvents, such as DMF, DMAc, DMSO, methanol, ethanol, toluene, chloroform, hexane, and ethyl acetate. H‐PU was previously synthesized by other researchers and described to be soluble in common solvents . On the contrary, Ambrožič and Žigon reported that H‐PU has a poor solubility .…”

“…In all reactions, 20 mL of water and 0.50 g of PU were used. 20,21 On the contrary, Ambro zič and Zigon reported that H-PU has a poor solubility. 22 This difference in solubility might be due to the molecular weight of H-PU.…”

Polyurethane/poly(ethylene‐co‐ethyl acrylate) and functional carbon black‐based hybrids: Physical properties and shape memory behavior

“…1 Polyurethanes have been frequently employed in engineering components, electrical encapsulation, mineral extraction industry, foams, medical implants, paints, coatings, sealants, and adhesive. 2 These polymers exhibit varying characteristics ranging from rigid thermoplastic to thermoset materials. Various synthetic strategies have been developed to control the polymer properties for diverse potential applications.…”

“…Polyurethane (PU) is one of the most important classes of polymers with distinctive structural features and technical applications . Polyurethanes have been frequently employed in engineering components, electrical encapsulation, mineral extraction industry, foams, medical implants, paints, coatings, sealants, and adhesive . These polymers exhibit varying characteristics ranging from rigid thermoplastic to thermoset materials.…”