Abstract:

Undecylenic acid/maleic anhydride copolymer(UMA) was prepared by precipitation polymerization method with undecylenic acid(UA) and maleic anhydride(MAH) as raw materials, azobisisobutyronitrile(AIBN) as initiator. The influences of monomer ratio, initiator dosage, and reaction temperature on polymerization were studied. The copolymer was characterized by FT-IR, ¹³C NMR, DSC and the mass fraction of anhydride of copolymer was measured. The results of FT-IR and ¹³C NMR showed that the copolymerization of UA and MAH successfully proceeded under the experimental conditions. When the reaction temperature was 75 ℃, the dosage of AIBN was 0.75%, with the increase of the amount of MAH, the molecular weight of copolymer decreased, the conversion rate and anhydride content incresed first and then declined slightly. When n(UA):n(MAH) was 40:60, the conversion rate and mass fraction of anhydride reached the maximum, 61.78% and 20.05%, respectively, which was basically consistent with the change of glass transition temperature(T_g) of DSC curves. Increasing the initiator dosage and reaction temperature was beneficial to the copolymerization but the molecular weight decreased, so the appropriate reaction conditions could be selected according to the properties of the desired polymer. When the n(UA):n(MAH) was 40:60, the T_g reached the maximum, 71.98 ℃.

Key words: undecylenic acid, maleic anhydride, precipitation polymerization, copolymerization, mass fraction of anhydride