| Nonionic surfactants have high stability in aqueous solution,and are not easily affected by strong electrolytes and pH.Nonionic surfactants have better properties than general ionic surfactants,such as emulsification,solubilization and dispersion.In this paper,the preparation of rosin modified hydroxypropyl chitosan from regenerable disproportionated rosin and chitosan was studied,and the properties of the products were investigated,including the following three aspects:?1?preparation and optimization of hydroxypropyl chitosan?HPCS?;?2?preparation and properties of hydroxypropyl chitosan grafted with dehydroabietyl glycidyl ether?DAGE-g-HPCS?;?3?preparation and properties of hydroxypropyl chitosan grafted with glycidyl dehydroabietic acid?GDHA-g-HPCS?.In the part of preparation and optimization of HPCS,the preparation process of HPCS by the reaction of alkalized chitosan with propylene oxide and its influencing factors were investigated.The structure of the product was characterized by FT-IR and1H NMR,and the degree of substitution?DS?of HPCS was determined by elemental analysis.At the same time,the preparation conditions of HPCS were optimized by four-factor and three-level orthogonal experiment,and the relationship between the water solubility of HPCS and DS was studied.The results showed that DS of HPCS can be affected by the concentration of NaOH solution,the material ratio of propylene oxide to sugar unit,the temperature and time of hydroxypropylation reaction,and the influence order is as follows:the concentration of NaOH solution during chitosan alkalization>the hydroxypropylation reaction temperature>the material ratio of propylene oxide to sugar unit>the hydroxypropylation reaction time.The optimized conditions are as follows:the concentration of NaOH solution during chitosan alkalization is 30.0%,the material ratio of propylene oxide to sugar unit is 20,the hydroxypropylation reaction time is 36.0 h,and the hydroxypropylation reaction temperature is 50.0°C.Confirmatory experiments were carried out,and it was found that DS of the product was 110.6%.The water solubility of HPCS increased with the increase of DS,and the HPCS with DS?58.04%could be completely dissolved in water under neutral conditions.At the same time,HPCS were degraded by sodium nitrite degradation,and the low molecular weight HPCS with characteristic viscosity of 17.832,16.339,12.964,11.569 and 9.621 were obtained.In the part of preparation and properties of dehydroabietyl glycidyl ether grafted hydroxypropyl chitosan,the preparation process of DAGE-g-HPCS by the grafting reaction of water soluble HPCS and DAGE was studied,and the effect of the ratio of DAGE to HPCS on the grafting degree?DG?was investigated.The structure of the product was characterized by FT-IR and 1H NMR.The DG of the product was determined by elemental analysis.The emulsifying ability of the product was evaluated by measuring the stabilization time of benzene-water emulsion.The surface activity of the product was analyzed by surface tension method.The foam properties of the products were evaluated by oscillatory method.The results showed that the DG of DAGE-g-HPCS increased from 5.38%to 16.54%,the corresponding critical micelle concentration?cmc?decreased from 0.7436 g·L-1 to 0.2226 g·L-1,while the emulsifying ability and foam stability increased gradually.the stability time of benzene-water emulsion increased from 4505s to 7813s,and the foam stability increased from 81.05%to 91.46%.At the same time,the performance of DAGE and low molecular weight HPCS graft products was also studied,the results showed that as the intrinsic viscosity of HPCS decreased from 17.832 to 9.621,the cmc of DAGE-g-HPCS aqueous solution increased from 0.5090 to 0.8474 g·L-1,the stability time of benzene-water emulsion increased from 2078s to 4320s,and the foam retention of DAGE-g-HPCS aqueous solution increased from 74.42%to 83.65%.In the part of preparation and properties of dehydroabietic acid glycidyl ester grafted hydroxypropyl chitosan.The preparation process of GDHA-g-HPCS by the grafting reaction of water-soluble HPCS and GDHA was studied,and the effect of the material ratio of GDHA to HPCS on DG was investigated.The structure of the product was characterized by FT-IR and 1H NMR.The DG of the product was determined by elemental analysis.The emulsifying ability of the product was evaluated by measuring the stabilization time of benzene-water emulsion.The surface activity of the product was analyzed by surface tension method.The foam stability of the product was evaluated by oscillation method,and the gelation time of GDHA-g-HPCS was studied by pour bottle method.The results showed that the DG of GDHA-g-HPCS increased from 0.72%to 10.54%,the corresponding cmc decreased from 0.7619 g·L-11 to 0.1894g·L-1,the stability time of benzene-water emulsion increased from 2846.0 s to 18063.0s and then decreased to 2612.0s,and the foam retention of GDHA-g-HPCS decreased to 79.68%after increasing from 80.32%to 97.46%.At the same time,the performance of GDHA and low molecular weight HPCS graft products was also studied,the results showed that as the intrinsic viscosity of HPCS decreased from 17.832 to 9.621,the cmc of GDHA-g-HPCS aqueous solution increased from 0.4318 g·L-1 to 0.7342 g·L-1,the stability time of benzene-aqueous emulsion increased from 607.0 s to 2064.0 s,and the foam retention of GDHA-g-HPCS increased from 66.28%to 80.31%.The GDHA-g-HPCS solution with DG of 2.81%and a concentration of 30.0g·L-1 was cross-linked by sodium?-glycerophosphate,the gel of GDHA-g-HPCS was formed at a constant temperature at 37.0°C for 26.0 min,and converted into sol after 42.0 min at 4.0°C. |
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