Amine activators influence on grafting reaction between methacrylic acid and starch

The aim of this work was synthesis of grafted copolymers of poly(methacrylic acid) and starch (PMAA-graft-starch) with high percentage of grafting, G (%). The effect of temperature (55–75 °C), concentration of methacrylic acid monomer (0.775–1.452 mol/dm3), amount of initiator potassium persulfate (PPS) (0.00075–0.0025 mol), reaction time (30–270 min) and nature and amount (0.001–0.005 mol) of amine activator on percentage of grafting were investigated. The following amine activators were used: N,N-dimethylaminoethanol, N,N-diethylaminoethanol, triethylamine, propylamine, iso-butylamine, pentylamine, hexylamine, 4-(2-hidroxyethyl) morpholine and 1-(2-hidroxyethyl) piperazine. The graft copolymer was characterized by Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy. The highest G was 40.92%. Reaction conditions were as follows: 10.00 g of starch, monomer concentration was 0.775 mol/dm3, temperature of 70 °C, the amount of PPS was 0.001 mol. The 4-(2-hidroxyethyl) morpholine was used as amine activator in amount of 0.001 mol.