共查询到18条相似文献,搜索用时 109 毫秒
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以蜡质玉米淀粉为原料,用乙醇溶剂法制备了蜡质玉米羧甲基淀粉(CMS)。考察了碱化时间、醚化反应温度、醚化反应时间、n(NaOH)/n(淀粉)、n(ClCH2COONa)/n(淀粉)对CMS粘度的影响。结果表明,在醚化反应时间2.5 h,n(NaOH)/n(淀粉)为0.4,n(ClCH2COONa)/n(淀粉)为1.2,醚化反应温度65℃,碱化时间为50 min的最佳反应条件下制得的CMS粘度为1 490 mPa.s。同时发现,随着n(ClCH2COONa)/n(淀粉)的增大,CMS粘度表现出先增大后减小再增大,最后减小的趋势,对其进行了分析。 相似文献
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马铃薯羧甲基淀粉的制备及结构分析 总被引:4,自引:0,他引:4
羧甲基淀粉是重要的变性淀粉之一,用途广泛。本文以马铃薯淀粉为原料,用乙醇溶剂法制备了马铃薯羧甲基淀粉钠,研究了氯乙酸、氢氧化钠、反应时间、反应温度、乙醇浓度、乙醇溶液体积等因素对反应的影响。以粘度为目标,用正交实验方法确定了最佳工艺条件。 相似文献
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羧甲基壳聚糖的制备及应用研究 总被引:2,自引:0,他引:2
用一氯乙酸对壳聚糖进行化学改性,制备了羧甲基壳聚糖(CMCH),探讨了影响取代度和水溶性的因素。并用红外光谱(IR)表征其结构,结果表明,制备水溶性好的CMCH的条件为;ω(NaOH)为42%,氢氧化钠与一氯乙酸的质量比为1.20:1,反应温度为55℃,测定了CMCH的保湿性,含CMCH的定型剂有较好的卷曲保持率,达到82.6%。 相似文献
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利用丝素(SF)与羧甲基壳聚糖(CMCS)共混制取不同比例的SF/CMCS共混膜。研究了CMCS诱导的丝素构象转变行为,测试了共混膜的吸湿性、透湿性和保水性。当CMCS的质量分数为5%时,共混膜中丝素的构象以β-折叠为主;当CMCS的质量分数为10%时,共混膜中丝素的构象由β-折叠向α-螺旋发生转变;当CMCS的质量分数达到15%时,共混膜中丝素的构象向无规卷曲发生转变。当CMCS质量分数小于15%时,共混膜中SF与CMCS具有良好的相容性,溶胀度较小,吸湿性随CMCS含量的增加而迅速降低。 相似文献
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《国际聚合物材料杂志》2012,61(11):548-560
Chitosan was chemically modified using monochloroacetic acid at various reaction conditions. Chemical structure was confirmed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The carboxymethyl chitosan (CM-chitosan) was prepared at different temperatures, water/isopropanol (IPA) ratios and alkali concentrations. Reaction conditions have great influence on the degree of substitution (DS) and, in turn, the solubility. The water solubility of chitosan derivatives depended upon modification conditions and degree of substitution. 相似文献
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O-carboxymethyl chitosan (CMCH) was prepared and characterized by FTIR spectroscopy and X-ray diffraction. Grafting of methacrylic
acid (MA) onto CMCH using ceric ammonium nitrate (CAN) as an initiator was carried out under nitrogen atmosphere in aqueous
solution. Evidence of grafting was confirmed by comparison of FTIR spectra of CMCH and the grafted copolymer as well as scanning
electron micrograph (SEM) and X-ray diffraction of the products. The effects of concentration of CAN, MA, reaction time and
temperature on graft copolymerization were studied by determining the grafting percentage and grafting efficiency. Keeping
other conditions constant, the optimum grafting conditions were obtained as follows: CMCH = 2 gm, CAN = 0.2 M and MAA = 0.581 mol/L,
reaction temperature = 40°C and reaction time = 4.5 hr. 相似文献
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季铵化N,O-羧甲基壳聚糖的制备及其合成条件优化 总被引:1,自引:0,他引:1
以N,O-羧甲基化度为85.6%的羧甲基壳聚糖(CM-CTS)为原料,w=0.40的NaOH水溶液为催化剂,3-氯-2-羟丙基三甲氯化铵(CTA)为接枝改性剂,在异丙醇介质中制备了具有良好水溶性的两性壳聚糖-季铵化N,O-羧甲基壳聚糖;分别以产物对模拟废水中的Cd+和Cr(Ⅵ)的絮凝去除率为基准对两性壳聚糖的合成条件进行了优化;用IR和1H NMR对产物的结构进行了表征。研究结果表明产物Cr(Ⅵ)的去除率更适宜作为合成条件的优化基准,且对应的优化条件为:季铵化反应时间为10.0 h,反应温度为60.0℃,mNaOH/mCM-CTS=0.50,mCTA/mCM-CTS=1.5;在此条件下合成产物对Cr(Ⅵ)的最大絮凝去除率为93.16%,对Cd2+的最大絮凝去除率98.52%。 相似文献
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《分离科学与技术》2012,47(8):1235-1243
Removal of Cu(II) and Ni(II) from aqueous solutions by a novel xanthated carboxymethyl chitosan (XCC) was investigated. XCC obtained was characterized by FTIR, SEM, EDX, and XRD. The adsorption ability of chitosan and XCC toward Cu(II) and Ni(II) was compared. The effect of pH (2.0–7.0), contact time (5–60 min), and adsorption isotherms on adsorption were also investigated. It was observed that the modified chitosan XCC showed a remarkable increase in Cu(II) and Ni(II) adsorption as compared to chitosan and displayed a quick adsorption performance. Further, The Langmuir isotherm was found to provide the best correlation of the experimental data and the adsorption capacity obtained from the Langmuir model was 174.2 mg/g and 128.4 mg/g for Cu(II) and Ni(II), respectively. FTIR and UV spectra suggested that the amino groups, carboxyl groups, and xanthate groups of XCC participated in the adsorption. 相似文献