Convenient synthetic method of starch/lactic acid graft copolymer catalyzed with sodium hydroxide

Abstract

Copolymer of starch grafted with lactic acid (LA) could be directly prepared by reaction of cornstarch with lactic acid and with sodium hydroxide (NaOH) as the catalyst. The structure of starch/LA copolymer was characterized by IR, XRD, SEM and 1H-NMR. The effects of NaOH concentration, ratios of starch and LA, reaction temperature and reaction time on the grafting degree were also investigated and the results showed that the highest grafting degree of starch could reach 33·60% when the graft copolymerization was carried out in 0·40 mol l -1 NaOH aqueous solution for 9 h at 90°C with 1: 6 ratio of starch and lactic acid. © Indian Academy of Sciences.