Synthesis of a Novel Double Crosslinking Amphoteric Cassava Starch

摘要

The grafted copolymerization of dimethyldiallylammoniumchloride (DMDAAC) and N,N'-methylene bisacrylamide onto cassava starch was investigated with water as solvent and ammonium persulfate-sodium sulfite as redox initiator. In above conditions, double crosslinking amphoteric cassava starch was synthetized by using sodium hydroxide as catalyst, epichlorohydrin as crosslinking agent and chloroacetic acid as etherification agent. The DS and DC could reach to 0.108 and 0.391 respectively under the following conditions: m(AGU) : m(DMDAAC)=1:1.5, the initiator mass fraction 3.5% (vs. dry starch), grafted polymerization temperature 45°C and time for 5 h, etherification temperature 50°C and time for 5 h, n(AUG):n(ClCH_2COOH)=1:1 and n(AUG):n(NaOH)=1:1.5. The product was characterized by infrared spectrum (FTIR), scanning electron microscopy (SEM) and X-ray diffraction spectrum (XRD). The results indicate that the cassava starch is modified successfully, and the final product is a novel double crosslinking amphoteric cassava starch.