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1.
研究了壳聚糖-丝心蛋白半互穿透合物网络型膜对pH值和离子的敏感性,发现该膜在pH〈3.3时溶胀度剧烈增加;在pH=2时,是否出现溶胀极大值与膜组分的含量及交联剂的含量有关;膜在不同pH值溶液中可交替溶胀和收缩,且这种溶胀-收缩行为重复可逆,同时,该膜在不同离子溶液中的溶胀度亦不同,在相同离子强度的溶液中,此膜在3价离了了中的溶胀度最大。  相似文献   

2.
研究了壳聚糖-丝心蛋白半互穿聚合物网络型膜对pH值和离子的敏感性,发现该膜在pH<3.3时溶胀度剧烈增加;在pH=2时,是否出现溶胀极大值与膜组分的含量及交联剂的含量有关;膜在不同pH值溶液中可交替溶胀和收缩,且这种溶胀-收缩行为重复可逆。同时,该膜在不同离子溶液中的溶胀度亦不同;在相同离子强度的溶液中,此膜在3价离子中的溶胀度最大。  相似文献   

3.
丝素蛋白膜上5-氟尿嘧啶的包埋及其释放   总被引:12,自引:0,他引:12  
讨论了包埋在丝素膜中的5-氟脲嘧啶(5-FU)的固定状况,在不同PH值下测定了丝素5-FU复合膜中药物的释放,实验结果表明:5-FU均匀地被包埋在丝素膜中,即丝素膜可以作为5-FU载体,经过比涂层保护,丝素5-FU复合膜中的5-FU溶解释放速率变慢,释放时间延长;经涂层的 素5-FU复合膜在接近丝素蛋白等电点(PH=4.5)时,5-FU在溶液中释放速度较慢,释放时间较长,表明用调节外部溶液PH值的  相似文献   

4.
采用简便环保的方法制备了具有低溶胀、高离子交换容量(IEC)的交联型季铵聚芳醚砜阴离子交换膜.随着交联度的提高,膜的吸水率和溶胀率降低,说明交联可以抑制膜的溶胀.20℃时所有交联膜的离子传导率均达0.045 S/cm以上,拉伸强度在50.1 MPa以上,表明在高IEC值下,交联膜仍具有良好的力学性能和较高的离子传导能力.同时,交联度提高会加强膜的甲醇阻隔性能.  相似文献   

5.
智能性共聚物水凝胶P(AM—NaA)相转变的研究   总被引:1,自引:0,他引:1  
本文用^60Co-γ射线辐射合成了聚(丙烯酰胺-丙烯酸钠)P(AM-NaA)智能性共聚物水凝胶,并用FTIR对共聚物进行了表征。着重研究了水凝胶在丙酮-水介质中的溶胀和收缩速率、溶胀平衡时间及体积相转变特性。  相似文献   

6.
本文用 ̄(60)Co-y射线辐射合成了聚(丙烯酰胺-丙烯酸钠)P(AM-NaA)智能性共聚物水凝胶,并用FTIR对共聚物进行了表征。着重研究了水凝胶在丙酮-水介质中的溶胀和收缩速率、溶胀平衡时间及体积相转变特性。  相似文献   

7.
曹汉瑾  褚莹 《应用化学》1995,12(1):99-100
消除夹带溶胀的新液膜操作法曹汉瑾,褚莹,何彦涛,吴子生,严忠(东北师范大学化学系长春130024)关键词液膜,油/水乳液,溶胀,夹带,包裹消除液膜操作中的夹带溶胀对液膜的工业化具有重要意义,夹带溶胀分为包裹溶胀和再液化溶胀。前者是乳状液滴上浮时将水相...  相似文献   

8.
溶剂及pH值对1,1-二苯基-2-苦肼基自由基分析法的影响   总被引:4,自引:0,他引:4  
研究了水和多种有机溶以及PH值对1,1-二苯基-2-若肼基自由基(DPPH.)分析法的影响。结果表明,所试溶剂对该测定体系的影响不大,通过扣除溶剂的影响后,同一种抗氧化剂在不同溶剂中的抗氧化活性相近,表明该分析体系可用于水及多种有多种氧化性质的研究。PH值对该分析的影响较大,强权、强碱使DPPH.溶液迅速失效,在PH2~10范围内物质的抗氧化活性随PH值的升高而降低。  相似文献   

9.
以P507-煤油HCl-Sm为实验体系,在两种聚偏氟乙烯中空纤维膜器中研究了溶胀性能、反萃酸度对基于水相的总传质系数及中空纤维膜孔径的影响,考察了料液酸度、萃取剂浓度、钐离子浓度与萃取速率的关系。获得了相应的反应级数。根据界面反应动力学,得到了速率常数值和动力学方程。  相似文献   

10.
模拟混凝土孔溶液中钢筋钝化膜的光电化学方法研究   总被引:6,自引:0,他引:6  
储炜  杨勇 《电化学》1995,1(3):291-297
利用光电化学方法研究了钢筋在模拟混凝土孔溶液中钝化膜的电子性质,结果表明,钢筋在该溶液中形成的钝化膜是一种无定形的n-型半导体成相膜,膜由多种铁氧化物组成,其组成受溶液中的离子、PH值、成膜电位影响,腐蚀抑制NaNO2影响钝化膜的组成和生长过程,从而提高钢筋的抗氯离子点蚀能力。  相似文献   

11.
以海藻酸钠 (SA)和N 异丙基丙烯酰胺 (NIPAM)为原料 ,制备出具有温度敏感性的半互穿网络水凝胶 (SA PNIPAMsemi IPN) .主要研究了海藻酸钠用量、水介质温度及pH值对该凝胶溶胀速率的影响 .结果表明 ,在PNIPAM最低临界溶解温度 (LCST)以下 ,该凝胶的溶胀速率随着凝胶网络中SA组分的增加而增大 ,且溶胀速率取决于高分子链的松弛速率 ;pH对凝胶溶胀速率的影响与温度有关 ,温度对溶胀速率的影响与pH有关 .  相似文献   

12.
Thermo- and pH-responsive semi-IPN polyampholyte hydrogels were prepared by using carboxymethyl chitosan and P(2-(dimethylamino) ethyl methacrylate) with N N'-Methylenebisacrylamide (BIS) as crosslinking agent. It was found that the semi-IPN hydrogel shrunk most at the isoelectric point (IEP) and swelled when pH deviated from the IEP. Its swelling ratio dramatically decreased between 30 and 50 °C at pH 6.8 buffer solution. It also showed good reversibility. The UV results showed that when the pH values of drug release medium were 3.7, 6.8, and 9 at 25 °C, the cumulative release rates reached 83.1, 51.5, and 72.2%, respectively. The release rate of coenzyme A (CoA) was higher at 50 °C than 37 and 25 °C at pH 6.8 solution. The release rate decreased with increasing the content of carboxymethyl chitosan at 25 °C in pH 6.8 solution. The results showed that semi-IPN hydrogel seems to be of great promise in pH/temperature drug delivery systems.  相似文献   

13.
为制备具有较高机械性能的壳聚糖凝胶, 设计将壳聚糖-碳纳米管复合物引入壳聚糖凝胶网络. 以戊二醛为交联剂, 采用冷冻干燥的方法制备了一系列壳聚糖-碳纳米管/壳聚糖半互穿网络凝胶. 测试了凝胶的机械性能, 考察了凝胶在不同pH值缓冲溶液中的去溶胀和溶胀行为. 实验结果表明, 添加壳聚糖-碳纳米管复合物的凝胶与普通壳聚糖凝胶相比机械强度明显增加, 而凝胶本身的pH敏感性不受影响.  相似文献   

14.
Anion exchange membranes with semi-interpenetrating polymer network (semi-IPN) were prepared based on quaternized chitosan (QCS) and polystyrene (PS). The PS was synthesized by polymerization of styrene monomers in the emulsion of the QCS in an acetic acid aqueous solution under nitrogen atmosphere at elevated temperatures. The semi-IPN system was formed by post-cross-linking of the QCS. A hydroxyl ionic conductivity of 2.80×10(-2) S cm(-1) at 80°C and a tensile stress at break of 20.0 MPa at room temperature were reached, respectively, by the semi-IPN membrane containing 21 wt.% of the PS. The durability of the semi-IPN membrane in alkaline solutions was tested by monitoring the variation of the conductivity and the mechanical strength. The degradation of the conductivity at 80°C was about 5% by immersing the membrane in a 1 mol L(-1) KOH solution at room temperature for 72 h and at 60°C for 50 h, respectively. The tensile stress at break at room temperature could maintain about 20.0 MPa for the membrane soaking in a 10 mol L(-1) KOH solution at ambient temperature for more than 70 h. The water swelling of the semi-IPN membranes was discussed based on the stress relaxation model of polymer chains, and it obeyed the Schott's second-order swelling kinetics.  相似文献   

15.
将聚氨酯(PU)与聚N-异丙基丙烯酰胺(PNIPAM)半互穿网络聚合物(semi-IPN)通过浸入沉淀相转化方法制备成微孔膜,并从亲水性、吸水溶胀性以及透湿性等方面对其温度响应性进行了讨论.PNIPAM的引入使膜的亲水性、吸水性和透湿性大为改善,并显著提高了膜的温度响应能力;但与此同时也使得膜的韧性降低.当PU/PNIPAM为3/1时,可获得最好的综合性能.同传统无孔致密膜相比,PU/PNIPAM semi-IPN微孔膜的透湿机理是基于微孔的开闭,在维持显著的温敏透湿性的同时可实现较高的高温透湿量.  相似文献   

16.
以甲基丙烯酸(MAA)、N-异丙基丙烯酰胺(NIPAAm)、丙烯酰胺(AM)为原料,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,利用IPN技术并结合磁性的γ-Fe2O3增强剂,在水溶液中制备了半互穿网络水凝胶(PMAA/PAM-NIPAAm/γ-Fe2O3),研究了水凝胶的溶胀性﹑热稳定性和电磁性。实验表明,水凝胶形成稳定的IPN互穿网络结构且该水凝胶具温度、pH双重敏感性和顺电磁性。所合成的水凝胶在低临界溶解温度31℃以下,具有明显正向温敏性,高于此温度,水凝胶的温度敏感性会逐渐减弱。产品成功克服了NIPAAm类水凝胶的温缩性。  相似文献   

17.
将线性聚(N-异丙基丙烯酰胺)(PNIPAAm)和海藻酸钠(SA)分子同时引入到PNIPAAm凝胶中,制备了交联聚(N-异丙基丙烯酰胺)/(海藻酸钠/聚(N-异丙基丙烯酰胺))半互穿网络(Cr-PNIPAAm/(SA/PNIPAAm)semi-IPN)水凝胶。在弱碱性条件下(pH=7.4),改变SA与线性PNIPAAm的质量比对Cr-PNIPAAm/(SA/PNIPAAm)semi-IPN水凝胶的溶胀度没有太大的影响。在酸性条件下(pH=1.0),其溶胀度随着SA与线性PNIPAAm质量比的减小而增大。由于亲水性SA与线性PNIPAAm的协同作用,Cr-PNIPAAm/(SA/PNIPAAm)semi-IPN水凝胶的消溶胀速率得到很大提高。  相似文献   

18.
The aqueous swelling kinetics of a series of crosslinked chitosan (cr-CS) with glutaraldehyde (GA) interpenetrating polyether hydrogels have been studied as functions of pH, the N-deacetylation degree of chitosan, the amount of crosslinking agent, the electrolyte composition in solution, temperature, and gel composition. Based on these results, the swelling mechanism of the hydrogels was discussed. The release profiles of chlorhexidini acetas from the semi-IPN were also investigated. © 1994 John Wiley & Sons, Inc.  相似文献   

19.
Amphoteric superabsorbent composite with semi-interpenetrating polymer networks (semi-IPN) composed of poly(acrylic acid) (PAA)/Ca-bentonite/poly(dimethyldiallylammonium chloride) (PDMDAAC) was prepared by a combination of intercalative polymerization and a sequential IPN method and the effects of reaction parameters on the swelling capacity were studied. PDMDAAC was used as a polycation to modify bentonite and form semi-IPN with lightly crosslinked PAA. FTIR and TG were used to characterize the amphoteric superabsorbent composites with semi-IPN. The thermal stability of the product was not degraded as in the case of using small molecular surfactant to modify bentonite. The contents of carboxylic groups and nitrogen had been determined. This indicated that the product with certain content of carboxylic groups and nitrogen is inclined to exhibit excellent swelling capacity. The presence of PDMDAAC improved the swelling capacity. The resulting amphoteric superabsorbent composite showed excellent swelling capacity of 1578 g/g in distilled water and 136 g/g in 0.9 wt% NaCl solution. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

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