【摘要】 用巯基乙胺为链转移剂,过硫酸铵为引发剂合成了氨基封端的聚2-丙烯酰胺基-2-甲基丙磺酸(H2N-PAMPS).再用1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC)和N-羟基琥珀酰亚胺(NHS)在室温下催化H2N-PAMPS的端氨基与大豆分离蛋白(SPI)的羧基反应形成酰胺键,得到接枝物SPI-g-NH-PAMPS.用1H-NMR、傅利叶红外光谱、13C-NMR对H2N-PAMPS和接枝物SPI-g-NH-PAMPS进行结构表征.用zeta电位仪、紫外可见光光谱,荧光光谱,动态激光光散射对SPI及其接枝物SPI-g-NH-PAMPS的水溶液性质进行了研究.结果表明,与SPI相比,SPI-g-NH-PAMPS的溶解性、表面疏水性、乳化性等有所改善,接枝物SPI-g-NH-PAMPS聚集体粒径增大,形成独特的核壳结构.更多还原

【Abstract】 Graft copolymers（SPI-g-NH-PAMPS）were prepared by a graft reaction between the free carboxylic acid groups of soy protein isolate（SPI）and the amino groups of poly（2-acrylanmido-2-methyl propane sulfonic acid）（H₂N-PAMPS）using 1-（3-（dimethylamino）propyl）-3-ethyl-carbodiimide hydrochloride/N-hydroxysuccinimide as the condensing agents in a buffer solution.H₂N-PAMPS and SPI-g-NH-PAMPS were fully characterized by 1H-NMR,FTIR and 13C-NMR spectroscopies.The aqueous solution properties of SPI and SPI-g-NH-PAMPS were studied by zeta potentiometer,UV-Visible spectroscopy,fluorescence spectrometer,dynamic laser light scattering（DLS）.The charge of SPI-g-NH-PAMPS measured by zeta potentiometer was negative within the whole pH range studied,which was due to the ionization of sulfonic groups of grafted chains.UV-Visible spectroscopy measurements demonstrated that the solubility of SPI was improved after the graft reaction,especially around the isoelectric point of SPI where it was increased by about 40%,because of the grafted hydrophilic H₂N-PAMPS chains.Fluorescence probing studies with 1-anilinonaphthalene-8-sulfonic acid（ANS）in aqueous solution revealed that the surface hydrophobicity of SPI-g-NH-PAMPS was much weaker than that of SPI.The average hydrodynamic radius（<R_h>）of SPI aggregates measured by dynamic laser light scattering（DLS）was increased from about 140 nm to about 200 nm.TEM studies indicated that SPI-g-NH-PAMPS aggregates presented a unique core-shell structure because hydrophilic PAMPS long chains surrounded on the surface of SPI globulins,and formed more hydrophilic shell,and the average size of SPI-g-NH-PAMPS aggregates was also bigger than that of SPI aggregates.The graft reaction using EDC provides a new method to modify SPI and expands the application fields of SPI.更多还原