| Glutaric acid starch ester was obtained by the reaction of native maize starch(M),waxy corn starch(W),cassava starch(C)and potato starch(P)with glutaric anhydride in aqueous phase and alcohol phase,respectively.Furthermore,hydroxypropyl cassava starch ester was also prepared in alcohol phase with propylene oxide,The physical and chemical properties of different starch esters and application of composite modified starch in acidic printing paste were investigated.The detailed research results were showed as follows:1.The results of study on aqueous glutaric acid starch ester(AGAM)and alcohol phase glutaric acid starch ester(EGAM)physicochemical properties indicated that two new absorption peaks appeared at 1731 cm-1and 1557 cm-1,respectively,which were attributed to the stretching vibration on C=O and antisymmetric stretching vibration on –COO-in GA starch.It illustrated that ester carbonyl group was inserted into starch molecules.Brabender showed that the peak viscosity of AGAM samples was increased by 4.6 times,the maximum reduced the gelatinization temperature was 25°C,hot paste viscosity increased by 2.1 times,the stability of hot paste was not improved,EGAM samples paste time shortened,pasting temperature decreased,and the stability of hot paste was improved significantly.It can be inferred that some crosslinking reactions may have occurred in alcohol phase system.2.After exploring the aqueous glutaric acid of waxy corn starch ester(AGAW)and glutaric alcohol phase of waxy corn starch ester(EGAW)on the physicochemical properties:FTIR showed that the glutaric acid groups were successfully bonded with starch.Brabender indicated that the maximum temperature reduction of AGAW samples was 20°C,peak viscosity increased by 2.9 times,the maximum thermal paste viscosity increased by 3.4 times,but the stability of hot paste showed no obvious improvement,the maximum temperature reduction of EGAW samples was 15°C,peak viscosity increased by 2.3 times,the maximum thermal paste viscosity increased by 3.5 times,but the stability of hot paste showed no obvious improvement,which was different from native starch because the cross-linking reaction characteristics was not very clear.3.In terms of physicochemical properties of AGAC and EGAC in the aqueous phase of glutaric acid,FTIR showed that the new absorption peaks were obtained at 1732 cm-1 and1557 cm-1.However,Brabender showed that the peak viscosity of AGAC samples increased by 1.89 times,while gelatinization temperature decreased obviously,and EGAC samples only to form a single ester,reduced gelatinization temperature,peak viscosity greatly,but no increase in viscosity stability.Paste transparency,freeze-thaw stability and anti shearing forceof AGAC samples were stronger than the native starch,while salt resistance of AGAC and EGAC were lower than that of native starch.4.We studied physicochemical properties of glutaric acidpotatostarch ester in aqueous and alcohol-phase,respectively,AGAP and EGAP samples showed that the potato starch ester of glutaric acid appeared a new absorption peak at 1732 cm-1 and 1555 cm-1 by infrared spectroscopy and structure characterization contrast.XRD analysis showed that the modified starch the intensity of the peak decreased and the crystallization became smaller.With the increase of the degree of substitution,the relative crystallinity of AGAP and EGAP decreased and the gelatinization enthalpy decreased.Brabender showed that the esterification occurred in both aqueous systems and crosslinked two kinds of reactions,gelatinization temperature decreased,peak viscosity were lower than the native potato starch;alcohol phase of gelatinization temperature of potato starch decreased,the maximum only decreased by 13.1°C,the peak viscosity decreased first then increased and became wider and peak viscosity stability increased,showing that the esterification occurred simultaneously with crosslinking.However,the peak viscosity of hot paste stability has been significantly improved.AGAP's paste freeze-thaw stability,salt resistance and shear resistance were stronger than native starch.5.We prepared dual-modified starch which was hydroxypropylated by 1.2-epoxy propane and esterified by glutaric anhydride and properties of it were investigated.The results of FTIR indicating the attachment of ester carbonyl group and hydroxypropyl group to the native starch.Compound modification of esterification was carried out by glutaric anhydride to improve the paste viscosity and rheology of CHP.When DS was 0.0362,the paste viscosity increased from the original 1800 mPa·s to 12100 mPa·s which is 6.72 times higher than that of the CHP.When the composite modified starch paste applied in textile printing.The results implied that various indexes(MS=0.439,DS=0.0362 and MS=0.439,DS=0.0391)of composite modified starch samples conformed to the requirements of printing paste in acid dye printing paste.In order to reduce production costs and increase production efficiency,the original paste can be used in acid dye paste printing fine pattern to substitute the guar gum paste. |
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