The Preparation And Structure Charaterization Of Starch Ternary Graft Copolymer In Inverse Emulsion Method

Starch grafted acrylic acid/acrylamide copolymer is widely used in many fields, such as agriculture and forestry, household chemicals, health care, petrochemical and other. As a polymer compound is mainly determined by the nature of its structure, therefore, summarized its reaction rule, and in-depth analysis of the impact of reaction conditions on the product structure, preparation with high conversion rate of starch/acrylic acid/acrylamide graft copolymer has the vital significance. To find the inverse emulsion prepared starch/acrylic acid/acrylamide graft copolymer optimal reaction conditions, paper uses sequential experimental design method, including single-factor test, factorial experimental design, central composite experimental design to build Central composite design mathematical model, comprehensive study of the reaction temperature, monomer starch ratio, monomer ratio, the amount of initiator, the neutralization degree and stirring speed on grafting rate. The results show that the temperature and the neutralization degree has a significant effect on the grafting rate, optimal reaction conditions:temperature56.3℃, starch quality monomer ratio1.7, acrylamide/acrylic monomer molar ratio0.875,1.5%of the amount of initiator, neutralization degree79.25%, stirring speed450r/min. Under this condition, the product of the theoretical value of the grafting rate of48.35%, found48.38%, close to the predicted result. Use of ultrasonic outfield prepared starch/acrylic/acrylamide copolymer, compared with without ultrasonic graft copolymer, analysis of the structure of its surface by using an optical microscope. Using modern instrumental analysis methods FTIR, TG, SEM, XRD, etc. on graft copolymers and branched products were structural characterization. FTIR spectra showed that acrylic/acrylamide monomer was successfully grafted on cassava starch, and determining the molar ratio of the branched graft copolymer acrylic and acrylamide by FTIR quantitative analysis. TG analysis showed that the thermal stability of St/acrylic/acrylamide graft copolymer has improved slightly but not significantly. SEM photographs showing the surface morphology of cassava starch is changed, and the use of ultrasonic prepared a graft copolymer structure is more evacuate, the reaction is more complete. XRD diffraction pattern showed that the pasting and graft reaction changing the state of aggregation of starch.