细菌聚γ-谷氨酸溶液流变性能的研究

STUDIES ON RHEOLOGICAL CHARACTERISTICS OF γ-POLY(GLUTAMIC ACID) PRODUCED BY BACTERIA

用分散聚合法制备了苯乙烯 甲基丙烯酸甲酯微米级单分散共聚物微球 ,粒径为 5 4 μm .将分散聚合体系与乳液聚合体系进行了比较 ,并对共聚物微球的形貌。

The rheological characteristics γ poly(glutamic acid) ( γ PGA) solution have been investigated.The solution is a typical non Newtonian shear thinning fluid with a characteristic n parameter lower than l.With temperature raised,the viscosity of γ PGA solution shows the trend of decreasing.Over the angular frequency( ω) range 0 01～100 rad·s 1 ,the storage modulus ( G′ ) of 5% (W/V) γ PGA gels is much higher than its loss modulus ( G″ ) and loss dependent on frequency which showed that γ PGA has fine elasticity.1% is close to the threshold concentration needed for gelation. γ PGA is dispersible in cold water to form weak gel.Continuous heating at high temperature treatment changed the network of γ PGA gel.Similar results are observed for γ PGA gels prepared under pH 4 and 12 Addition of 1%～10% NaCl,7%KCl,MgSO 4,ZnSO 4 and CaCl 2 decrease the G′ of 2% γ PGA gel at low frequency and increased G″ over the frequency rang 0 01～100 rad·s -1 which indicated that the formation of elastic network is hindered.However,addition of 1 7% PbNO 3 of 1 7% AgNO 3 makes total loss of viscoelasticity of the 2% γ PGA system.