On the synthesis of acrylamide oligomers

Abstract

AbstractThe synthesis of low‐molecular‐weight poly(acrylamide)s (M̄n = 500 – 1 000) is described. Metal‐activated and non‐activated polymerization in aqueous solution was investigated employing hydrogen peroxide as initiator. Among four transition metal salts considered, Cu2+ cations proved to be the most efficient in decomposing H2O2 molecules and were used as activator. The experiments were run at three reaction temperatures (60, 80 and 95°C), at three H2O2 levels (4, 5 and 6 wt.‐% on monomer), and at four Cu2+ levels (900, 600, 300 and 0 ppm by weight of metal on monomer). Thus, ist was possible to prepare acrylamide oligomers with monomer conversions exceeding 95%, and with Mn values covering the narrow range indicated above. Within these low limits a molecular weight control is impossible, even with inclusion of the differentiated levels of Cu2+cations. Intrinsic viscosities are very low, too ([η]) = 20 – 50 cm3/g, without any relations of the individual values to variations of the given process parameters. The work provides an industrial route to very‐low‐molecular‐weight acrylamide oligomers.