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

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-P n BA-OH), poly( n -octyl acrylate) (HO-P n OA-OH), and poly( n -lauryl acrylate) (HO-P n LA-OH), respectively. HO-PA-OHs are prepared by the N- (trimethylsilyl)bis(trifluoromethanesulfonyl)imide (Me 3 SiNTf 2 )-catalyzed group transfer polymerizations (GTPs) of n -butyl acrylate ( n BA), n -octyl acrylate ( n OA), and n -lauryl acrylate ( n LA) 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 ( i Pr 3 SiO-PA-OSi i Pr 3 s) 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 1 H NMR spectroscopy and FT-IR measurements. The thermal properties of the resulting polyacrylate-based polyurethanes are investigated by differential scanning calorimeter.