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.
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) ( H2 N-PAMPS ) using 1- ( 3- ( dimethylamino ) propyl ) -3-ethyl-carbodiimide hydrochloride/N-hydroxysuecinimide 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 ( 〈 Rh 〉 ) 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.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2009年第5期430-436,共7页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号20374025,50673038)
复旦大学聚合物分子工程教育部重点实验室开放基金资助项目