Initiator‐fragment incorporation radical polymerization of ethylene glycol dimethacrylate in the presence of 1,1‐diphenylethylene: synthesis and characterization of soluble hyperbranched polymer nanoparticles

Abstract The polymerization of ethylene glycol dimethacrylate (EGDMA) as crosslinker was carried out at 70 and 80 °C in benzene using dimethyl 2,2′‐azobisisobutyrate (MAIB) as initiator at concentrations as high as 0.50–0.70 mol l −1 in the presence of 1,1‐diphenylethylene (DPE), where the concentrations of EGDMA and DPE were 0.50–0.70 and 0.25–0.50 mol l −1 , respectively. The polymerization proceeded homogeneously, without gelation, to give soluble polymers. The yield and molecular weight of the resulting polymers increased with time. The homogeneous polymerization system involved ESR‐observable DPE‐derived radicals of considerably high concentration (3.6–5.3 × 10 −5 mol l −1 ). The methoxycarbonylpropyl groups as MAIB‐fragments were incorporated as a main constituent (35–50 mol%) into the polymers (initiator‐fragment incorporation radical polymerization). The polymers also contained DPE units (15 mol%) and EGDMA units with double bonds (10–25 mol%) and without double bonds (20 mol%). Results from gel permeation chromatography (GPC)–multiangle laser light scattering (MALLS), transmission electron microscopy (TEM) and viscometric measurements revealed that the individual polymer molecules were formed as hyperbranched nanoparticles. Copyright © 2004 Society of Chemical Industry