Telechelic Poly(methyl acrylate)s as Constituents for Multiblock Poly(urethane urea)s

摘要

New poly(urethane urea)s based on telechelic poly(methyl acrylate)s (PMAs) and different diisocyanates and diamines are prepared by a two-step polyaddition process-formation of an isocyanate telechelic prepolymer followed by chain extension with a diamine to form the final poly(urethane urea)s. Hydroxyl-telechelic or mixed amino-hydroxyl-telechelic PMAs are obtained by two different concepts: (i) according to the first concept methyl acrylate (MA) was polymerized by single electron transfer-living radical polymerization (SET-LRP) using 2-hydroxyethyl 2-bromoisobutyrate as initiator followed by nucleophilic substitution of the halogen end group with n-butylamine, 2-methylamino ethanol, or 3-amino-1-propanol and (ii) according to the second concept after SET-LRP under the same conditions the halogen end group is converted to an azide followed by a click reaction using sodium azide and propargyl alcohol in a one-pot reaction. Applying the second concept, a hydroxyl-functional PMA with a share of 83 mol bifunctionality is obtained. This PMA-diol is used in polyaddition reaction with different diisocyanates (isophorone diisocyanate (IPDI), 4,4'-methylenebis(cyclohexyl isocyanate) (HMDI), and 4,4'-methylenediphenyl diisocyanate (MDI)) resulting in an isocyanate-telechelic prepolymer followed by chain extension with the corresponding diamines (isophorone diamine (IPDA), 4,4'-methylenebis(cyclohexyl amine) (HMDA), and 4,4'-methylenediphenyl diamine (MDA)). The polyurethane based on hydroxyl-telechelic PMAs and IPDI/IPDA has a molecular weight of M-n = 44 500 g mol(-1) and a dispersity D = 3.5, respectively; those based on HMDI/HMDA and MDI/MDA have M-n = 24 600 g mol(-1) and D = 2.2 and M-n = 16 100 g mol(-1) and D = 2.0, respectively.