Influence of amine activators and reaction parameters on grafting reaction between polystyrene and starch

Abstract

Polystyrene graft corn starch copolymers (PS-g-starch) were synthesized by emulsion polymerization using sodium dodecylsulfate (SDS) as the emulsifier and potassium persulfate (PPS) as the initiator. Influences of temperature (25–75 °C), monomer (0.56–0.96 mol/dm3) and initiator (0.007–0.020 mol/dm3) concentration, reaction time (15–300 min), and type of amine activator and its concentration (0.005–0.08 mol/dm3) on the percentage of grafting (G, %) and yield (Y, %) were investigated. Amines showed dual impact on grafting reaction, some of them were activators and other were inhibitors, where N,N-dimethylethanolamine gave the maximal and 1-(2-hydroxyethyl) piperazine gave the minimal value of percentage of grafting. The maximum percentage of grafting was 32.55 %, while in case of piperazine derivate percentage of grafting was zero. Successful grafting was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The maximum percentage of grafting was obtained under the following reaction conditions: 10.00 g of starch, monomer concentration was 0.96 mol/dm3, initiator concentration was 0.015 mol/dm3, reaction time was 15 min, temperature of 75 °C, and N,N-dimethylethanolamine was used as activator in concentration of 0.01 mol/dm3.