Study On The Properties And Reaction Kinetics Of Poly Lactic Acid / Modified Sweet Potato Residue

The chemical modification methods of preparing the vinyl acetate graft sweet potato starch composite, discusses the optimum conditions of graft copolymerization, get the best reaction time was 2h, the optimal reaction temperature of 70℃, popular potato residue amount of 3.5 g, vinyl ester content for 8ml, the amount of ammonium sulfate is 0.4g, polymerization and grafting rate was the highest.Through the infrared spectroscopy and scanning electron microscopy and other tests on the graft copolymers were characterized by infrared spectra obvious absorption peak ester group, a vinyl acetate showed active bond successfully grafted onto the sweet potato slag, and effective at 1740cm-1 improve the smoothness of the surface of sweet potato residue.Using ammonium persulfate(APS) as initiator, vinyl acetate graft monomer, initiator concentration by examining the graft copolymerization, the monomer concentration, sweet potato residue concentration Polymerization reaction rate of the graft, the sweet potato research vinyl acetate residue graft reaction kinetics, reaction mechanism was discussed graft copolymerization reaction, the reaction to give a theoretical reaction rate equation, And deduces the apparent kinetic equation of the reaction, associated with the low concentration of initiator, the graft polymerization reaction rate equation is apparent: Rg=K [M]0.37[AGU]0.57[APS]0.28. The reaction rate of sweet potato residue experiments and ammonium persulfate reaction rate and theoretical analysis is consistent, indicating sweet potato slag graft copolymerization mainly double-terminated reaction as the main form of termination, sweet potato residue can be considered consistent with contact with vinyl acetate graft copolymerization reaction mechanism, monomer grafted onto the starch molecular chain to form a graft copolymer composites, and the results of theoretical and experimental error are analyzed.The torque rheometer modified sweet potato residue and the polylactic acid melt blended to prepare a new type of cheap modified sweet potato residue / polylactic acid composite. According torque rheometer torque curve and the time to explore the blending process to give plasticizing properties and processing properties of composite materials, the results showed that when the temperature at 140 ℃, speed 35 r / min, and PLA modified sweet potato residue ratio of 1:3, the degree of mixing more uniform, to improve the processing properties of the composites. By IR, DSC test and scanning electron microscopy of composite materials were characterized, The results showed that, after the vinyl acetate-modified sweet potato residue and the polylactic acid interface compatibility than pure sweet potato residue / polylactic acid composite.