Seeded emulsion polymerization of methyl methacrylate using aqueous polyurethane dispersion: effect of hard segment on grafting efficiency

Seeded emulsion polymerization of methyl methacrylate (MMA) using aqueous polyurethane dispersion as seed particle was undertaken to investigate the effect of hard segment on the grafting efficiency. The hard segment consists of isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA), where the portion of hard segment varied from 19.6 to 35.4%. The effects of IPDI and DMPA contents on the grafting efficiency were confirmed by both FT-IR and thin layer chromatograph equipped with flame ionization detector (TLC/FID). The grafting efficiency increased with increasing hard segment content, i.e. IPDI and DMPA. From the quantitative results of FT-IR spectra and TLC/FID analysis, it was found that the relative area of NH peak (1550 cm−1) varied significantly against the contents of IPDI. These results suggested that NH bonds in the hard segment play an effective role of grafting reaction with MMA.