Synthesis of Oligo(oxyethylene) Methacrylate-ended Poly(n-hexyl isocyanate) Rodlike Macromonomers and Their Radical Copolymerization Behavior with Methyl Methacrylate

Abstract

A series of novel poly(n-hexyl isocyanate) (PHIC) rodlike macromonomers having an α-methacryloyloxyoligo(oxyethylene) group and an ω-acetyl group (MA-EOm-HIC-n-Ac, where m and n are the degrees of polymerization of oxyethylene (EO) and HIC, respectively) have been prepared. They were prepared by living coordination polymerization of HIC using corresponding titanium(IV) alkoxide complexes as an initiator in CH2Cl2 at room temperature, followed by termination with acetic anhydride as a terminator in the presence of BF3OEt2 as a Lewis acid. The radical copolymerization behavior of MA-EOm-HIC-n-Ac (M2) with methyl methacrylate (MMA) (M1) in benzene at 60 °C has thoroughly been investigated in order to evaluate an effect of a flexible oligo(oxyethylene) spacer (m) on the copolymerizability. The apparent reactivities (1/r1) of MA-EOm-HIC-n-Ac are lower than for MMA (1/r1 is ca. 0.52) and decrease slightly with increasing m. The copolymerizability of MA-EOm-HIC-n-Ac was compared with that of α-4-vinylbenzyoxy-ended PHIC macromonomers (VB-HIC-n-H). The decrease in the copolymerizability of the methacrylate-ended PHIC macromonomers is most likely due to the incompatibilities among the macromonomer, comonomer, and propagating polymer chain, together with the fact that methacrylate itself is much more influenced by the polymerization conditions than a styrenic monomer.