Polyurethanes from Direct Organocatalytic Copolymerization of p‐Tosyl Isocyanate with Epoxides

Abstract

The direct copolymerization of p-tosyl isocyanate (TSI) with epoxides, initiated by onium salts in the presence of trialkylborane, to produce polyurethanes is reported. The rate of copolymerization and the (regio)selectivity were investigated in relation to the trialkylborane and the initiator used. Under optimized conditions such copolymerizations have been successfully performed for a wide range of epoxides, including ethylene oxide, propylene oxide, 1-octene oxide, cyclohexene oxide, and allyl glycidyl ether. These copolymerizations afford a new category of polyurethanes, clear of side products such as cyclic oxazolidinone, isocyanurate, and poly(isocyanate) linkages. The experimental conditions used in this work are compatible with those for the organocatalytic (co)polymerization of other oxygenated monomers and CO 2 , holding the potential for their terpolymerization with p-tosyl isocyanate and the development of new materials with unprecedented properties.Scheme 1. Trialkylborane-mediated polymerization route to oxygenated polymers.

Triblock Copolymers from CO2, Propylene Oxide, and p-Tosyl Isocyanate of Higher Toughness than Polyethylenes

“…Although the degradation of PPPC and PU is well established, the degradability of PTPU has not been studied. Degradation tests on PTPU samples were thus conducted in organic solvents in the presence of sodium hydroxide at room temperature. We observed that PTPU is readily degradable under basic conditions.…”

“…Following that work, Xiong and co-workers copolymerized butylene oxide with methylphenyl isocyanate using triisobutylaluminum/onium salt Lewis pairs . Almost at the same time, the aptitude of p -tosyl isocyanate (TSI) to undergo clean alternating copolymerization with epoxides in the presence of TEB under conditions compatible with CO 2 /epoxides polycarbonate synthesis was unveiled by our group . This incited us to combine in the same copolymer a poly­(propylene carbonate- co -propylene oxide)­s (PPPC) block resulting from CO 2 /epoxide copolymerization and poly­( N -tosyl propylene urethane) (PTPU) blocks generated by TSI/epoxide copolymerization as a means to improve the mechanical properties of polycarbonate-based plastics.…”

“…25 Almost at the same time, the aptitude of p-tosyl isocyanate (TSI) to undergo clean alternating copolymerization with epoxides in the presence of TEB under conditions compatible with CO 2 /epoxides polycarbonate synthesis was unveiled by our group. 26 This incited us to combine in the same copolymer a poly(propylene carbonate-co-propylene oxide)s (PPPC) block resulting from CO 2 /epoxide copolymerization and poly(N-tosyl propylene urethane) (PTPU) blocks generated by TSI/epoxide copolymerization as a means to improve the mechanical properties of polycarbonate-based plastics. Indeed, PTPU exhibits a glass transition temperature of 107 °C, a value comparable to that of PCHC, but its chemical nature should be more favorable to phase separation with low T g polycarbonates (PPPC) than PCHC.…”

Design, Fabrication, and Performance Analysis of Fire‐resistant Damping Polyurethane

“…used copolymer modification to allow direct organocatalytic copolymerization of toluenesulfonyl isocyanates with epoxides to prepare polyurethanes. This work successfully paved the way for the copolymerization of epoxides with other heteroalkene monomers and expanded the scope of alkylborane‐mediated polymerization [18] . Ghasemi et al.…”