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魔芋葡甘聚糖/聚乙烯吡咯烷酮水凝胶的制备及缓释性能研究 总被引：2，自引：0，他引：2
以魔芋葡甘聚糖（KGM）和聚乙烯吡咯烷酮（PVP）为原料,戊二醛（GA）为交联剂,合成了KGM／PVP半互穿网络水凝胶。通过红外光谱、X-衍射、SEM扫描电镜对水凝胶的结构进行了袁征,并且研究了KGM与PVP质量比、交联剂含量对水凝胶的溶胀度影响。在p14=2．2和pH=7．4条件下分别研究了交联度对溶胀动力学特性的影响,以及载药凝胶的体外释放行为。实验结果表明,KGM与PVP质量比对该凝胶的溶胀性能有一定的影响：KGM：PVP为1：1时,凝胶的溶胀度最大;随着交联剂含量的增加,凝胶的溶胀度、溶胀速率、药物的释放速率均逐渐降低;凝胶在pH=2．2时的溶胀度较高,溶胀速率、药物的释放速率均较快。 相似文献
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以壳聚糖为原料,三聚磷酸钠(TPP)为交联剂,乙酸乙酯为油相,司班80和吐温80为分散剂的乳液交联法制备壳聚糖微凝胶.FTIR表征微凝胶结构.研究结果发现,当醋酸浓度为0.13mol/L,壳聚糖溶液浓度为2.5%,交联剂与壳聚糖的质量比为0.15,油水比为1.20:1时,壳聚糖微凝胶的溶胀能力最大.此条件下制得不同分子量壳聚糖的微凝胶,其溶胀能力随壳聚糖的分子量减小而增大,且微凝胶具有pH值和盐敏感性. 相似文献
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《考试周刊》2018,(23):147-149
以羧甲基壳聚糖和N-异丙基丙烯酰胺为原料,N,N′-亚甲基双丙基酰胺为交联剂,过硫酸钾为引发剂合成了羧甲基壳聚糖/聚(N-异丙基丙烯酰胺)(CMCS/PNIPAAm)复合水凝胶。考查了温度、pH、离子浓度等对复合水凝胶溶胀度的影响。研究表明,在25~75℃温度范围内,pH=5-10范围内,CMCS/PNIPAAm复合水凝胶的溶胀度大于羧甲基壳聚糖;在NaCl浓度为0.30-0.60mol/L,CaCl2的浓度为0.10-0.60mol/L时,CMCS/PNIPAAm复合水凝胶溶胀度明显大于羧甲基壳聚糖水凝胶。结果表明,合成的羧甲基壳聚糖/聚(N-异丙基丙烯酰胺)复合水凝胶有较好的温度、pH、离子强度敏感性。 相似文献
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合成了N—肉桂酰氧甲基丙烯酰胺(CMMAM)与丙烯酰胺(AM)的共聚物(CMMAM—AM)，通过光交联法制备了水凝胶．测定了水凝胶的DSC，并对水凝胶的溶胀性能进行了初步研究、热分析实验表明：随共聚物中CMMAM含量的增加，水凝胶的Tg值下降． 相似文献
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pH敏感型水凝胶是指水凝胶的体积随外界环境如pH值、离子强度变化而变化的一类高分子凝胶,可方便地调节和控制凝胶内药物的释放和扩散速率,目前常用于缓控释药物载体.本文利用明胶与壳聚糖为原料,采用化学交联法制备了一种pH响应性水凝胶,探讨原料用量、反应温度及交联剂用量对凝胶溶胀性能的影响,获得了一种对pH敏感的智能水凝胶. 相似文献
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研究了温度、NaCl浓度以及溶液的pH值等环境因素对WDH36NF油船货油舱内底板用钢腐蚀速率、腐蚀形貌的影响。结果表明:油船货油舱内底板用钢的腐蚀速率随温度升高而增加。NaCl浓度由5%增大到10%,内底板用钢的腐蚀速率随浓度增大而增加,NaCl浓度由10%增大到15%,内底板用钢的腐蚀速率减小。pH值由0.5增大到0.85,内底板用钢的腐蚀速率随pH值增大而增加,pH值由0.85增大到1.2,内底板用钢的腐蚀速率减小,并趋于平缓。 相似文献
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在比较电解质溶液中离子浓度大小时,人们常常会遇到一个问题“等物质的量的NaCl和CH3COONa晶体各溶于水配成同体积的溶液,溶液中阴离子的浓度是否相等?对这个问题,存在两种截然相反的说法:说法一:两溶液中阴离子浓度不相等,NaCl溶液中阴离子浓度比CH3COONa溶液大。理由:在电解质溶液中存在下列浓度关系NaCl溶液:c(Na+ ) +c(H+ ) =c(OH- ) +c(Cl- ) ;CH3COONa溶液:c(Na+ ) +c(H+ ) =c(OH- )+c(CH3COO- ) ;NaCl不水解,溶液pH =7,CH3COONa水解,溶液pH >7,可知NaCl溶液的H+ 浓度大于CH3COONa溶液的H+ 浓度。由于两溶液… 相似文献
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一、问题的提出例1.下列装置的线路接通后,经过一段时间,溶液的pH值明显下降的是(D)(86年高考题)例2.用石墨作电极电解1摩/升的下列物质的溶液,溶液的pH值保持不变的是(C)A HCl B NaOH C Na_2SO_4 D NaCl(92年高考题)例3.串联电解分装在两个烧杯里的200毫升0.3摩/升NaCl溶液和300毫升0.1摩/升AgNO_3溶液,用pt作电极,过一段时间后取出电极,将两怀溶液混和后其pH值(D)(95年湖南省竞赛题)A大于7 B小于7C 等于7 D 大于或等于7显然,电解过程中溶液pH值大小变化这一知识点是高考、竞赛之热点.怎样快速解答这类试题,笔者以为,同学们必须牢牢掌握:(1)电镀过程中溶液pH值基本保持不.变. 相似文献
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用分步法合成了交联聚丙烯酸甲酯(PMA)-交联聚苯乙烯(PS)互穿树脂,然后用二乙烯三胺对其胺解,得到由交联聚丙烯酰胺-交联聚苯乙烯组成的亲水-疏水互穿树脂.利用疏水部分(PS)来调整亲水部分(PAM)的溶胀,来分离具有不同体积的酸. 相似文献
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采用分步聚合法合成了两网质量比不同,第二网交联度均为30%的聚二乙烯基苯/聚丙烯酸甲酯互穿聚合物网络（PDVB-PMA IPN）,将它们分别用20%的NaOH/甲醇溶液碱解,合成了一网疏水、一网亲水的聚二乙烯基苯/聚丙烯酸互穿聚合物网络（PDVB-PAA IPN）。测定了两网质量比对树脂的比表面积、平均孔容、孔径以及弱酸交换量的影响。比较了不同树脂对水溶液中苯酚的吸附性能差别,测定了此类树脂的热力学数据,探讨了此类树脂的吸附机理,建立了一种通过溶胀致孔合成吸附树脂的方法。 相似文献
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采用1/2浓度Hoagland营养液培育法中不同浓度(0.000、0.050、0.075、0.100和0.125 mol/L)的Na Cl溶液处理V2期苗期大豆,待大豆生长至V3期,分析不同浓度盐胁迫对大豆生长以及POD、SOD和CAT同工酶的影响。结果表明:Na Cl浓度越高,大豆生长受到的抑制越大,而POD、SOD和CAT的活性在Na Cl浓度在0.050 mol/L有一定的增加,但增加到0.075 mol/L后,酶的活性降低。在0.075和0.100mol/L的Na Cl浓度诱导出了新的POD同工酶谱带,而0.125 mol/L Na Cl使SOD同工酶的2条谱带消失。 相似文献
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Interaction of salinity and cadmium stresses on mineral nutrients,sodium, and cadmium accumulation in four barley genotypes 总被引：1，自引：0，他引：1
Interaction of salinity （NaCI） and cadmium （Cd） on growth, mineral nutrients, Na and Cd accumulation in four barley genotypes differing in salt tolerance was studied in a hydroponic experiment. Cd, NaCI and their combined stresses reduced Ca and Mg concentrations in roots and shoots, K concentration in shoots, increased K and Cu concentrations in roots relative to control, but had non-significant effect on micronutrients Cu, Fe and Mn concentrations in shoot. The three stresses reduced accumulation of most tested nutrients in both roots and shoots, except NaCI and NaCl＋Cd stresses for root K and shoot Cu accumulation in salt tolerant genotypes. The salt tolerant genotypes did not have higher nutrient concentration and accumulation than the sensitive ones when exposed to Cd and NaCI stresses. In conclusion, the affecting mechanism of Cd stress on nutrients was to some extent different from salinity stress, and the NaCl＋Cd stress was not equal to additional Cd and NaCI stresses, probably due to the different valence and competitive site of Na^＋ and Cd^2＋. NaCI addition in the Cd-containing medium caused remarkable reductions in both Cd concentration and accumulation, with the extent of reduction being also dependent on genotypes. The salt-tolerant genotypes had lower Na concentration than sensitive ones. 相似文献
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超声光栅测量液体体积弹性模量实验研究 总被引：1，自引：0，他引：1
在利用超声光栅测液体声速的基础上,针对不同浓度的食盐(NaCl)溶液,研究超声波声速与溶液浓度的关系,并由此得出液体体积弹性模量与浓度的关系。实验结果表明,食盐(NaCl)溶液浓度与其体积弹性模量成近似线性关系。 相似文献
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Rong-fang GUO Gao-feng YUAN Qiao-mei WANG 《Journal of Zhejiang University. Science. B》2013,14(2):124-131
To understand the regulation mechanism of NaCl on glucosinolate metabolism in broccoli sprouts,the germination rate,fresh weight,contents of glucosinolates and sulforaphane,as well as myrosinase activity of broccoli sprouts germinated under 0,20,40,60,80,and 100 mmol/L of NaCl were investigated in our experiment.The results showed that glucoerucin,glucobrassicin,and 4-hydroxy glucobrassicin in 7-d-old broccoli sprouts were significantly enhanced and the activity of myrosinase was inhibited by 100 mmol/L of NaCl.However,the total glucosinolate content in 7-d-old broccoli sprouts was markedly decreased although the fresh weight was significantly increased after treatment with NaCl at relatively low concentrations(20,40,and 60 mmol/L).NaCl treatment at the concentration of 60 mmol/L for 5 d maintained higher biomass and comparatively higher content of glucosinolates in sprouts of broccoli with decreased myrosinase activity.A relatively high level of NaCl treatment(100 mmol/L) significantly increased the content of sulforaphane in 7-d-old broccoli sprouts compared with the control.These results indicate that broccoli sprouts grown under a suitable concentration of NaCl could be desirable for human nutrition. 相似文献
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研究了圆叶牵牛种子在6种浓度（0,50,100,150,250和400 mmol.L-1）NaCl胁迫及6种温度（15,20,25,30,35,40℃）条件下的发芽率.结果表明,NaCl浓度低于50 mmol.L-1对种子萌发的影响不大,但高于100 mmol.L-1时随NaCl浓度的升高,相对发芽率显著降低,直至0,浓度为150 mmol.L-1时,对种子萌发抑制作用最大;圆叶牵牛种子萌发的最适温度为15~20℃,高于25℃时,温度越高,发芽率越低,35℃以上不能萌发. 相似文献
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With N-vinyl-2-pyrrolidone (NVP) and itaconic acid ( IA ), poly ( N-vinyl-2-pyrrolidone/itaconic acid) [ P(NVP/IA) ] hydrogel was synthesized by free radical solution polymerization. The structure of this P(NVP/IA) was characterized by IR. Effects of concentration of itaconic acid, amount of cross-link agent,N, N‘-methylene-bis-acrylamide, reaction temperature, and time on properties of swelling ratio (SR) of the hydrogel were investigated. The results show that the best swelling property of the hydrogel is obtained at 50 ℃ and 1.5 h. pH sensitivity increases as the concentration of itaconic acid in the hydrogel system increases.Swelling ratio of the hydrogel decreases as the amount of cross-link agent increases. 相似文献