羧甲基罗望子胶的制备与表征

将罗望子胶(TKP)和氯乙酸钠(SMCA)在碱性异丙醇水溶液中反应,制备一系列不同取代度的羧甲基罗望子胶(CMTKP)。研究NaOH与SMCA的物质的量比、SMCA加入量、反应温度及反应时间对CMTKP取代度、反应效率及水溶液的透光率和表观黏度的影响,确定合理的工艺条件及配方,制得了取代度为0.92,反应效率为77%的CMTKP。与TKP原粉相比,CMTKP的冷水可溶性和冻融稳定性明显提高,质量分数为2%的CMTKP水溶液透光率达到97%。TGA表明了CMTKP的热稳定性下降,XRD表明了CMTKP的结晶区随着取代度的增大而减少。并用FTIR和13C NMR对其结构进行了表征。

Synthesis and characterization of carboxymethyl tamarind

Series of carboxymethyl tamarind kernel polysaccharide (CMTKP) with different degree of substitution (DS) were prepared by the reactions of tamarind kernel polysaccharide (TKP) and sodium monochloroacetic acid (SMCA) in alkaline aqueous isopropanol. The influence of mole ratio of NaOH to SMCA, SMCA concentration, reaction temperature and time on DS, reaction efficiency (RE) as well as the transmittance and apparent viscosity of CMTKP aqueous solution was investigated. The maximum DS of 0.92 and the RE of 77% were obtained. The solubility of CMTKP in cold water and the freeze-thaw stability were apparently improved and the transmittance of the mass fraction of 2% CMTKP aqueous solution could be up to 97%. Thermal stability decreased showed by TGA, and crystalline region reduced with the increasing of DS after carboxymethylation showed by XRD. The structure was characterized by FT-IR and solid-state ¹³C NMR.