Synthesis of Polyacrylate‐Based Polyurethane by Organocatalyzed Group Transfer Polymerization and Polyaddition

Abstract

The current work describes the synthesis of novel polyacrylate‐based polyurethanes through the polyaddition of hexamethylene diisocyanate (HDI) with α,ω‐hydroxyl end‐functionalized polyacrylates (HO‐PA‐OHs), including α,ω‐hydroxyl end‐functionalized poly(n‐butyl acrylate) (HO‐PnBA‐OH), poly(n‐octyl acrylate) (HO‐PnOA‐OH), and poly(n‐lauryl acrylate) (HO‐PnLA‐OH), respectively. HO‐PA‐OHs are prepared by the N‐(trimethylsilyl)bis(trifluoromethanesulfonyl)imide (Me3SiNTf2)‐catalyzed group transfer polymerizations (GTPs) of n‐butyl acrylate (nBA), n‐octyl acrylate (nOA), and n‐lauryl acrylate (nLA) in toluene at room temperature using the functional 1‐(2‐triisopropylsiloxyethoxy)‐1‐triisopropylsiloxy‐2‐methyl‐1‐propene as an initiator and the low ceiling temperature acrylate, 2‐(triisopropylsiloxy)ethyl α‐phenylacrylate, as a terminator, followed by the desilylation of the resulting α,ω‐triisopropylsiloxy end‐functionalized polyacrylates (iPr3SiO‐PA‐OSiiPr3s) using tetra‐n‐butylammonium fluoride (TBAF). The polyaddition reactions between HO‐PA‐OHs and HDI are carried out in toluene using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) as the catalyst to afford the target polyacrylate‐based polyurethanes. The polymer structures are characterized by 1H NMR spectroscopy and FT‐IR measurements. The thermal properties of the resulting polyacrylate‐based polyurethanes are investigated by differential scanning calorimeter.

Defluorinative Esterification and 1,3-Dietherification of (Trifluoromethyl)alkenes with Alcohols: Controlled Synthesis of α-Arylacrylates and 1,3-Diethers

“…Valuable functional moieties such as ether, cyclopropane, and tetrahydro-2 H -pyran could be tolerated, providing ample potential for further synthetic applications. Significantly, α-arylacrylate 3u , as a useful functional terminator for polymerization reactions, was isolated in a 63% yield, which is traditionally synthesized from the unstable 2-phenylacryloyl chloride in a 47% yield . Interestingly, the defluorinative reaction of (trifluoromethyl)­alkene 1a with 2-((tert-butyldimethylsilyl)­oxy)­ethan-1-ol gave 3v′ in a 71% yield, which was derived from the deprotection of the tert-butyldimethylsilyl group with the in situ-generated fluoride, while 6-chlorohexan-1-ol afforded 3w′ in a 73% yield.…”