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为解决羧甲基羟丙基瓜尔胶(CMHPG)合成过程中副产物多,容易糊化的问题.以丙酮为反应介质,甲醇钠为催化剂代替乙醇、异丙醇为介质,氢氧化钠为催化剂.探讨了工艺条件对产品的影响,找出了较佳工艺条件.结果表明,合成较佳工艺条件为:环氧丙烷与瓜尔胶质量比为0.2∶1、氯乙酸与瓜尔胶质量比为0.4∶1,反应时间为160 min;前者催化剂与瓜尔胶质量比为0.2∶1、反应温度为45~50℃,后者催化剂与瓜尔胶质量比为0.3∶1,反应温度为65~ 70℃.乙醇、异丙醇为介质,氢氧化钠为催化剂合成产品的羧甲基取代度为0.43,羟丙基取代度为0.36,粘度为1 120mPa·s;以丙酮为反应介质,甲醇钠为催化剂合成产品羧甲基取代度为0.48,羟丙基取代度为0.37,粘度为1 030 mPa·s. 相似文献
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瓜尔豆片为原料,经羟丙基提纯后阳离子改性,得到透明性较好的阳离子瓜尔胶(CGG)。经分析碱法水解除蛋白质最优工艺为:豆片25g,NaOH5g,98℃下反应3h:蛋白质去除率为98.24%,透光率达77%。羟丙基化较优工艺为:环氧丙烷8mL。60℃反应4h;羟丙基取代度为0.2650,透光率为89%e阳离子化最优工艺为:醚化剂10mL,60℃反应3~5h,取代度(DS)为0.1701,透光率达97%。用IR对产蹦结构进行了表征,用TG和DSC对瓜尔胶、羟丙基瓜尔胶和阳离子瓜尔胶的对比研究表明,接枝的阳离子基团对瓜尔胶的相态稳定温度有影响,阳离予瓜尔胶的水分含量和结合水含量有所降低,利于储存。此产品用于对透光率要求较高的领域。 相似文献
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丙烯酰胺-阳离子瓜尔胶接枝共聚物的絮凝性能研究 总被引:2,自引:0,他引:2
研究了低温合成的高相对分子质量的天然高分子改性絮凝剂--丙烯酰胺-阳离子瓜尔胶接枝共聚物(CGG-g-PAM)对高浊度烟草废水的絮凝效果,以及PAC投加量、CGG-g-PAM投加量、pH和不同相对分子质量CGG-g-PAM等对浊度(》4 500 NTU)、COD和色度去除率的影响.结果表明,在pH 5,PAC投加质量浓度为120 mg/L,CGG-g-PAM投加质量浓度为3.6 ms/L时,去浊率达98%,COD去除率达24%,色度去除率达20%,且絮凝性能优于阳离子瓜尔胶(CGG)和阳离子聚丙烯酰胺(CPAM).实验研究表明,产品具有良好的絮凝效果,在工业废水处理中具有一定的应用前景. 相似文献
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以瓜尔胶(GG)为原料、3-氯-2-羟丙基二甲铵基乙酸盐(CCDH)为两性醚化剂,在碱催化剂作用下半干法合成了不同取代度的ZGG,并通过IR对CCDH和ZGG进行了表征。同时考察了体系中碱用量、反应温度、反应时间对产品取代度的影响。结果表明,当瓜尔胶用量为8 g,CCDH为4 g,NaOH为0.06 g,温度为65℃,反应时间为5 h,取代度为0.544。 相似文献
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研制出一步水媒法合成羧甲基羟丙基瓜尔胶工艺,改性反应针对胚乳片进行,直接加工得到成品。考察了合成过程中氢氧化钠、环氧丙烷、氯乙酸、反应温度、反应时间等因素对产品粘度和水不溶物含量的影响,得到比较适宜的工艺条件:氢氧化钠、环氧丙烷、氯乙酸与胚乳片质量比分别为0.30∶1,0.20∶1,0.40∶1,反应温度为80~85℃,反应时间为100~110 min。合成的羧甲基羟丙基瓜尔胶,水不溶物为2%~3%,粘度为110~120 mPa.s,在粘度比瓜尔原粉略微下降的情况下,水不溶物由20%~25%大幅下降到2%~3%,水溶性得到明显改善。 相似文献
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以可生物降解和生物相容的羧甲基纤维素钠(NaCMC)与阳离子瓜尔胶(GG)为原料,制得系列不同配比的多糖共混膜。以此共混膜作为药物布洛芬的载体,考察了共混比、药物浓度以及pH值对药物释放的影响,并研究了其药物释放机理。结果发现,对布洛芬药物释放影响最大的是介质的pH值,其次是共混膜的共混比例,药物含量在弱碱介质中有一定的影响,在酸性介质中基本无影响。大部分的药物释放n>0.89,为非Fick扩散(骨架溶蚀机制),药物以零级进行释放。共混膜对疏水性药物布洛芬具有较好的缓释性能。 相似文献
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The synthesis of two polysaccharide‐based graft copolymers with acrylamide, guar gum grafted polyacrylamide (GG‐g‐PAM) and hydroxypropyl guar gum grafted polyacrylamide (HPG‐g‐PAM) is described. The graft copolymers have been characterized by viscometry, infrared spectroscopy and thermal analysis. The flocculation characteristics of the graft copolymers have been studied in kaolin, iron ore, and silica suspensions. For the base polysaccharides guar gum (GG) and hydroxypropyl guar gum (HPG), it is observed that GG exhibits better performance than HPG in all three suspensions. For the graft copolymers, HPG‐g‐PAM shows better performance than GG‐g‐PAM. The flocculation characteristics of the best performing graft copolymer (HPG‐g‐PAM) are compared with various commercially available flocculants in the three suspensions mentioned above. © 2001 Society of Chemical Industry 相似文献
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Graft copolymers of carboxymethyl guar gum (CMGG) and polyacrylamide (PAM) have been synthesized by grafting polyacrylamide chains onto carboxymethyl guar gum backbone using a ceric‐ion‐induced solution polymerization technique. By varying the amount of initiator, three different grades of graft copolymers are synthesized. The characterization of graft copolymer is carried out by FTIR, NMR, intrinsic viscosity measurement, SEM, SLS, DTG, and rheology. A comparison of flocculation efficiency of CMGG and its graft copolymer shows that the graft copolymer exhibits better flocculation performance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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The effect of different reaction conditions on the grafting of methyl methacrylate (MMA) onto guar gum (GG) has been studied in detail. The grafting efficiency was optimal under the following conditions: MMA at 1.13 mol/L; ceric ammonium sulfate at 6.32 × 10?3 mol/L; dextrose monohydrate at 2.428 × 10?3 mol/L; GG at 4 g/L; temperature at 50°C; and time at 210 min. Fourier transform infrared spectroscopy was used for the confirmation of copolymer formation. Thermogravimetric analysis of GG and a representative graft copolymer were studied. A probable mechanism of grafting has been suggested. The biodegradability of the resulted copolymer was evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3520–3525, 2001 相似文献
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介绍了官能团衍生化、接枝共聚、交联等瓜胶衍生物的制备方法及影响因素、瓜胶及其衍生物在药物控制释放领域的应用现状,并指出改性瓜胶具有比原粉更好的药物控制释放效果,因此经过配方设计,瓜胶及其衍生物有望成为药物控制释放尤其是靶向结肠给药领域的理想载体。 相似文献
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Synthesis of novel superabsorbent hydrogels has been investigated with the reaction of guar gum and succinic anhydride (SA), using of 4‐dimethylaminopyridine as esterification promoter and water or dimethylsulfoxide (DMSO) as reaction solvent, followed by NaOH neutralization. Hydrogels prepared in water exhibited somewhat higher water absorbency than those prepared in DMSO; its maximum water absorbency in pure water and aqueous 0.9% NaCl solution was ca. 200 g/g and 80 g/g, respectively. These values were considerably higher than those of hydrogels obtained from starch in a similar way. The products in this study biologically degraded up to 70–80% after 10 days in activated sludge, which shows their excellent biodegradability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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In an attempt to modify the sodium salt of partially carboxymethylated guar gum (Na‐PCMGG; degree of substitution = 0.291), we studied the ultraviolet‐radiation‐induced graft copolymerization of methyl acrylate with ceric ammonium nitrate as a photoinitiator. The influence of the grafting yield was studied as a function of the different reaction parameters, and the optimum reaction conditions for photografting were determined. The various reaction parameters included the photoinitiator, nitric acid, and monomer (methyl acrylate) concentrations, the reaction time, the temperature, and the amount of the substrate. A kinetic scheme for photografting copolymerization was proposed, and the results were in good agreement with the kinetic scheme. The graft copolymerization of methyl acrylate onto Na‐PCMGG (degree of substitution = 0291) in the presence and absence of ultraviolet radiation was also carried out for the study of the efficiency of the photoinitiator. The influence of carboxymethyl groups added to the guar gum molecule on its behavior toward ultraviolet‐radiation‐induced grafting with methyl acrylate was also investigated. The evidence of photografting was ascertained with IR spectroscopy and scanning electron microscopy techniques. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1977–1986, 2005 相似文献
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Etherification optimization for preparing partially hydrolized hydroxypropylated guar gum and its properties
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The partially hydrolized hydroxypropylated guar gum (PHHGG) was prepared using GG as the raw material, hydrochloric acid as the hydrolysis agent, epoxy propane as the etherifying agent, ethanol as the solvent to obtain better property combination. The effect of the reaction temperature, reaction time, and amounts of sodium hydroxide, ethanol, and epoxy propane on the substitution degree of the partially hydrolized hydroxypropylated GG was investigated. These process parameters were optimized by the orthogonal test. Using polarized light microscopy, infrared spectrometer, differential scanning calorimetry, and thermogravimetric analyzer, the appearance, structure, and thermal property of the partially hydrolized hydroxypropylated GG (PHHGG) were observed and measured. The results indicated that the best process conditions for preparing the PHHGG were: reaction temperature = 60°C, reaction time = 12 h, amount of sodium hydroxide = 1.2%, amount of ethanol = 60%. The acid resistance and alkali resistance of GG were obviously improved by the acidolysis and hydroxypropylation. The particle appearance of GG was a thin strip after it was hydrolized by acid and hydroxypropylated by epoxy propane. The acidolysis increased the melting onset temperature, peak temperature, and end temperature of GG but the hydroxypropylation decreased them. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40489. 相似文献
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两性离子型瓜尔胶的制备及稀溶液性质 总被引:1,自引:0,他引:1
以瓜尔胶(GG)为原料,2,3-环氧丙基二甲铵基乙酸盐(ECDH)为两性醚化剂,在碱催化剂作用下干法合成了新型两性离子型瓜尔胶(ZGG)。采用酸碱滴定法测定了ZGG的等电点,并借助乌氏黏度计研究了等电点范围内ZGG的稀溶液性质,考察了外加盐浓度和不同外加盐对ZGG的影响。结果发现,随着氯化钠溶液浓度的增大,其特性黏度增大,表现出明显的反聚电解质溶液行为,二价金属离子对ZGG的影响大于一价金属离子对其的影响,即CaCl2>MgCl2>NaCl。 相似文献