Study On Preparation Technology Of Modified Starch Green Based On Ozone Oxidation And Supercritical

Modified starch is one of the widely used textile size, it is very important in the field of environmental protection green textile size. To explore new green modified starch technology, the research uses the oxidized starch as raw material, it is studied that the application of supercritical fluid in the grafted starch. Its main contents are as follows:1. Firstly, the research uses ozone as oxidant, using ozone gas phase to oxidize corn starch. Through the orthogonal experiment system,1 researched effect of various process parameters on the gelatinization properties and carboxyl content of oxidized starch,then optimized the oxidation process. Through orthogonal experiment design optimization, I found that change rule of carboxyl content, stable viscosity, breakdown and setback conforms to a rule. In order to improve the degree of oxidation, the largest influence factor is time. Through the single factor experiments of time, I found that the the change rules of oxidation degree. Oxidized starch detected by the scanning electron microscope, XRD, XPS,analysis results show morphology and crystallization of oxidized starch does not change too much.2.Then, using the technology of supercritical carbon dioxide in solid grafting. Carried by supercritical carbon dioxide,Making monomer and initiator swell into oxidized starch granules.Then,directly heating up to the reaction temperature. Under the low pressure gas of CO2 protection, starch and BA take place grafting reaction. After the reaction, release the gas of CO2. Grafted starches are characterized by infrared analysis,thermal analysis, scanning electron microscope, DSC,XRD ect, the results of analysis show that the oxidized starch and butyl acrylate happened copolymerization reaction. I studied the influences of the swelling time, swelling temperature, swelling pressure, reaction time, reaction temperature, monomer dosage, initiator dosage, carboxyl content on the graft rate. The optimal technological condition is 9.6g BA,0.55g BPO,20g oxidized starch, swelling time 25 min, swelling temperature 42 ℃, swelling pressure 8 MPa, reaction temperature 65 ℃, reaction time 1 h, maximum grafting rate was 26%.