Syntheses, Characterization and Applications of Graft Copolymers of Sago Starch - A Review

Modified natural polymers with improved structural, physical, and chemical properties have been gaining increasing importance in the industry as they are abundant, cheap, renewable, and biodegradable. Graft copolymerization is one of the effective ways to improve the properties of natural polymers. Sago starch (SG) based graft copolymers are becoming increasingly important due to their remarkable adhesion, high water absorbency, and biodegradability. There are many reports on the physico-chemical characteristics, pharmaceutical applications, and several other chemical modifications (esterification, etherification, oxidation of OH groups etc.) of SG, but only a few review articles include studies on its graft copolymers. This review article summarizes use of different chemical initiators and irradiation techniques for generation of starch macroradicals. It also includes the effect of monomer and initiator concentration, reaction time, and temperature on grafting parameters such as percentage grafting and grafting efficiency. It discusses the employment of techniques such as Infra-red spectroscopy, Scanning Electron Microscopy, Thermogravimetric analysis, Differential Scanning Calorimetry, and X-ray diffraction in the characterization of graft copolymers of SG. Owing to excellent mechanical and swelling properties, graft copolymers of SG find application in various fields such as chelating resins, drug delivery systems, wound dressing, coagulants, paper additives, film coatings etc.