Research On Perovskite Oxide/ZnO Quantum Dot/Modified Epoxidized Soybean Oil Nanocomposite Fatliquoring Agent

With the rapid development of the leather industry,white leather and light-colored leather products are becoming more and more widely used.But they are susceptible to oxidation and yellowing under the conditions of light and heat,which shortens their service life and limits their application fields.The main reason for the yellowing of white leather and light-colored leather products is the introduction chemicals containing unsaturated bonds during the leather-making process,and these unsaturated bonds are easily oxidized under the light and heat conditions.In addition,some leather collagen could also be oxidized under light and heat conditions.Therefore,designing a material that is high in saturation or/and introducing a yellow-resistant material is very necessary to improve the yellow-resistance of leather products.In this study,the asymmetric benzene sulfonate sodium Gemini surfactant(ASBGS)was prepared,and then introduced into epoxidized soybean oil to prepare an external emulsifier type fatliquoring agent.At the same time,based on the design ideas of Gemini surfactants,a self-emulsifying Gemini modified epoxidized soybean oil fatliquoring agent(GESO)was prepared by esterification and sulfite modification of epoxidized soybean oil.Next,the perovskite oxide/ZnO QDs/modified epoxidized soybean oil nano-composite fatliquoring agents were prepared by introducing the perovskite oxide(ZACT),ZnO QDs(ZQDs)and perovskite oxide/ZnO QDs(ZACT/ZQDs)nanocomposite particles into GESO,and applied to the leather fatliquoring process.The influence of the types and amounts of the three inorganic nanoparticles on the yellow-resistance of leather after fatliquoring was investigated.The main research contents are as follows:(1)4-(dodecylamide)phenol was synthesized from p-aminophenol and dodecanoic acid,and dodecanol maleic acid monoester was synthesized from maleic anhydride and dodecanol.Then the above prepared two products were used as raw materials to prepare Gemini surfactant intermediates,followed by sulfonation with NaHSO3 to prepare ASBGS.The chemical structure of ASBGS was characterized by FT-IR and 1H NMR,the properties of surface tension and emulsifying force were evaluated.The results showed that the ASBGS was successfully prepared,and its critical micelle concentration was 0.8×10-4 mol/L,the surface tension was 25.1 mN/m.The emulsification time for epoxidized soy bean oil was 283 s,and the prepared external emulsifier-type fatliquoring agent exhibited good emulsification property in cold water(R＝81.29%).(2)Soybean oil-based maleic acid monoester was prepared by using maleic anhydride and epoxidized soybean oil as raw materials.Taking the acid value as an indicator,the reaction process was optimized by a single factor test method,and the optimal preparation process of soybean oil-based maleic acid monoester was obtained.Then,4-(dodecylamide)phenol was reacted with soybean oil-based maleic acid monoester to synthesize 4-(dodecylamide)phenyl soybean oil-based maleic acid diester,followed by sulfonation with NaHSO3 to prepare GESO.The chemical structure of GESO was characterized by FT-IR,and its emulsification performance in cold water was tested.The results showed that the GESO was successfully prepared and had well emulsification property in cold water(R=91.25%).(3)ZACT was prepared by sol-gel method,and taking the crystal structure and absorbance values as the main index.The reaction process was optomized by a single factor test,and the optimal process for synthesizing ZACT was obtained.The results showed that ZACT had a complete perovskite crystal structure and the higher absorbance value(about 1.68 a.u.)when calcined at 1000℃ for 4 h.ZQDs were prepared by wet chemical method,and the fluorescence intensity and absorbance value were used as the main indicators.The reaction process was optomized by a single factor test,and the optimal preparation process for synthesizing ZQDs were obtained.The results showed that when m(Zn2+):m(OH-)=1:6,the ZQDs obtained by reacting at 25℃ for 1 h have higher absorbance(about 0.82 a.u.)and fluorescence intensity.On this basis,the ZACT/ZQDs compound nano-particels were prepared by physical blending method,and the compound ratio of the two nano-particles were optimized with absorbance and particle size as the main indicators.The results showed that the absorbance value of compound nano-particles was the highest(about 2.25 a.u.)when m(ZACT):m(ZQDs)=1:4.(4)The as-prepared ZACT,ZQDs and ZACT/ZQDs nanocomposite particles were introduced into the GESO by physical blending method,and nanocomposite fatliquoring agents with different particle doping levels were prepared and applied to the leather fatliquoring process respectively.The results showed that the introduction of ZACT,ZQDs and ZACT/ZQDs nanocomposite particles could significantly increase the absorbance value of the nano-composite fatliquoring agents.Among them,ZACT/ZQDs/GESO has the highest absorbance value and the best leather yellow-resistance after fatliquoring.When the introduction of ZACT/ZQDs was 2.5%,the yellow-resistance level could reach 5 grades.