Synthesis Of Polyvinylamine Macromonomer By Aqueous ATRP And Its Copolymerization

Polyacrylamide with a bromine atom end group (PAM-Br) was synthesized by atom transfer radical polymerization (ATRP) of acrylamide (AM) in water at 70℃using ethyl-2-bromopropionate (EPN-Br) as an initiator. The molecular weight and molecular weight distribution of the PAM-Br were characterized by aqueous gel permeation chromatography (GPC). It was found that the molecular weight and molecular weight distribution of PAM-Br were affected by changing concentration of AM, ratio of AM monomer to initiator and reaction time. The reaction process contributed to the basic rule of ATRP under a low molar ratio of [AM]:[EPN-Br]=25:1. Furthermore, the polyacrylamide macromonomers (MAA-PAM) with a vinyl double end groups were successful prepared by the nucleophilic substitution reaction of bromine atom to methacrylic acid (MAA) in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as catalysis. Then polyvinylamine macromonomers (MAA-PVAm) were obtained by Hofmann degradation reaction of MAA-PAM at 0℃. The structure of MAA-PAM and MAA-PVAm were characterized by using Fourier transformation infrared (FTIR) and nuclear magnetic resonance (NMR). The polymeric microspheres were also prepared by dispersion copolymerization of MAA-PVAm macromonomer with styrene using 2,2'-azobisisobutyronitrile as an initiator in ethanol/water mixed solvent. The polymeric microspheres have sphere morphology and uniformity of diameters based on the observation of scanning electron microscopy (SEM).