pH敏感水凝胶聚甲基丙烯酸的超声合成

在超声作用下,以甲基丙烯酸为原料,N,N’-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,自由基引发聚合制备了pH敏感水凝胶聚甲基丙烯酸,采用红外光谱(FT-IR)和扫描电镜(SEM)对水凝胶分子结构与性能进行表征.在此基础上,重点研究了超声合成对于水凝胶的溶胀性能、消溶胀性能等性质的影响.实验结果表明,超声作用下合成的聚甲基丙烯酸水凝胶溶胀动力学性能以及响应灵敏性均优于常规合成方法.     

甲基丙烯酸N,N-二甲氨基乙酯与丙烯酰β-环糊精共聚水凝胶的合成及其性能研究

用不同的方法合成了两种结构不同的丙烯酰 β 环糊精酯 (β CD 3 A和 β CD 6 A) ,以此为单体与甲基丙烯酸N ,N 二甲氨基乙酯 (DMAEMA)通过氧化还原自由基引发聚合 ,合成出两类含 β 环糊精结构单元的新型水凝胶 .用核磁共振 ,红外光谱及元素分析对两种单体及共聚物的结构和组成进行了表征 .溶胀实验结果表明 ,两类水凝胶均具有较好的pH、温度及离子强度敏感性 ,且因其交联网络结构不同 ,其溶胀性能有所差异     

聚(N,N′-二乙基丙烯酰胺)水凝胶的制备及其溶胀动力学

以N,N′-二乙基丙烯酰胺(DEA)为单体,偶氮二异丁腈(AIBN)为引发剂,分别采用疏水性的1,2-二乙烯苯(DVB)和水溶性的N,N′-亚甲基双丙烯酰胺(BIS)为交联剂制备了温度敏感水凝胶聚(N,N′-二乙基丙烯酰胺)(PDEA).制得的PDEA水凝胶的低临界溶解温度(LCST)在30 ℃附近,初步讨论了交联剂的用量和性质对水凝胶性能的影响.并对其在不同温度下达到溶胀平衡时的溶胀比,去溶胀动力学及干凝胶的再溶胀动力学过程进行了研究.     

以环糊精为核的星形高分子合成及其温度、pH敏感性研究

以不同用量的氯乙酰氯与 β 环糊精反应 ,得到含有不同酰化度的氯乙酰化 β 环糊精 ,以此化合物为引发剂 ,采用原子转移自由基 (ATRP)引发甲基丙烯酸N ,N 二甲氨基乙酯 (DMAEMA)聚合 ,得到温度及pH敏感的以 β 环糊精为核的星形聚合物 .通过红外光谱、1 3C NMR、1 H NMR和氯元素滴定分析确定了酰化后的 β 环糊精的结构 ,并采用红外光谱、1 H NMR、元素分析、DSC表征了以 β 环糊精分子为核的星形聚甲基丙烯酸N ,N 二甲氨基乙酯的大分子结构 ,紫外光谱研究表明聚合物水溶液具有明显的温度和pH敏感性 .     

温度/pH敏感性接枝共聚物水凝胶P(DMAEMA-g-NIPAM)的 合成及性质研究

利用大分子单体技术, 采用自由基溶液聚合合成了温度/pH敏感性聚甲基丙烯酸-N,N-二甲氨基乙酯接枝聚N-异丙基丙烯酰胺[P(DMAEMA-g-NIPAM)]水凝胶. 用红外光谱及扫描电镜对凝胶的组成及形貌进行了表征. 凝胶的去溶胀和溶胀动力学研究表明, 所合成的凝胶具有温度和pH敏感性. 与传统的聚丙烯酸系水凝胶相比, P(DMAEMA-g- NIPAM)具有相反的pH敏感性; P(DMAEMA-g-NIPAM)凝胶在55 ℃时具有较快的去溶胀速率, 随着凝胶中接枝链PNIPAM量的增加, 凝胶的去溶胀速率加快.     

聚（N，N＇-二乙基丙烯酰胺）水凝胶的制备及其溶胀动力学

以N,N’-二乙基丙烯酰胺（DEA）为单体,偶氮二异丁腈（AIBN）为引发剂,分别采用疏水性的1,2-二乙烯苯（DVB）和水溶性的N,N’-亚甲基双丙烯酰胺（BIS）为交联剂制备了温度敏感水凝胶聚（N,N’-二乙基丙烯酰胺）（PDEA）。制得的PDEA水凝胶的低临界溶解温度（LCST）在30℃附近,初步讨论了交联剂的用量和性质对水凝胶性能的影响。并对其在不同温度下达到溶胀平衡时的溶胀比,去溶胀动力学及干凝胶的再溶胀动力学过程进行了研究。     

半互穿网络淀粉水凝胶的制备及溶胀性研究

以玉米淀粉和丙烯酸为主要原料,过硫酸铵为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,采用新型两步水溶液聚合法合成聚丙烯酸/玉米淀粉半互穿网络水凝胶,并对凝胶的结构和研究淀粉的用量、pH值对水凝胶溶胀性能的影响。研究表明:水凝胶具优越的溶胀性、pH敏感性和膨胀可逆性,使其可以应用于很多领域。     

光化学合成P(DMAA-co-MMA)/Nano-SiO2复合水凝胶及其性能研究

以N,N-二甲基丙烯酰胺(DMAA)及甲基丙烯酸甲酯(MMA)为单体,Irgacure 2959为光引发剂,N,N′-二甲基双丙烯酰胺(Bis)为交联剂,利用紫外光引发自由基聚合制备了聚N,N′-二甲基丙烯酰胺(PDMAA)及P(DMAA-co-MMA)水凝胶,并通过加入少量表面改性后的纳米SiO₂对该水凝胶进行改性,制得了P(DMAA-co-MMA)/纳米SiO₂复合水凝胶,用FT-IR和SEM对产物进行了表征,同时研究该复合凝胶的溶胀动力学、消溶胀动力学、pH值响应性、离子强度等.该方法简便、快捷,大大缩短了聚合时间,合成过程仅需2-3 min.     

甲基丙烯酸烷基酯为疏水成分的溶剂改性pH-敏感凝胶的溶胀行为

以不同酯烷基链长的甲基丙烯酸烷基酯为疏水成分，甲基丙烯酸二乙氨基乙酯(DEA)为可离子化单体，及以二甲基丙烯酸乙二醇酯(EGDM)或二乙烯苯(DVB)为交联剂，合成了数个系列甲苯改性的不同交联度的疏水阳离子凝胶，研究了这些凝胶以pH-敏感溶胀为主的容胀行为．发现以甲基丙烯酸正丁酶(BMA)，EGDM及DEA合成的改性凝胶，与以苯乙烯(St)，DVB及DEA合成的溶剂改性凝胶具有十分相似的平衡溶胀和动力学溶胀性质．研究结果为增加疏水阳离子凝胶的载药种类，拓宽由pH改变而触发释药的控释体系的应用范围提供了新的途径．     

pH响应性阳离子型微凝胶的制备及性质研究

以甲基丙烯酸-(N,N-二甲氨基)乙酯(DMAEMA)和丙烯酸乙酯(EA)为共聚单体, 二甲基丙烯酸乙二醇酯(EGDMA)为交联剂, 采用半连续乳液聚合法, 制备了具有pH响应性的阳离子型微凝胶, 并研究不同聚合条件对所合成的微凝胶性质的影响. 利用透射电子显微镜(TEM)、激光粒度分析仪和流变仪对微凝胶进行一系列表征. 研究了介质pH值对微凝胶的形态、平均粒径、zeta电位、溶液浊度(透光率)的影响, 以及NaCl盐溶液对微凝胶分散体系稳定性的影响. 结果表明, 这类阳离子型微凝胶体系具有良好的pH响应性, 在pH＝7左右发生相转变. 此外, 研究表明不同浓度NaCl溶液对微凝胶的稳定性有一定影响, 临界絮凝浓度约为1.3 mol•L－1.     

Characterization and Evaluation of Acrylic Acid Co-2-acrylamido-2-methylpropane-1-sulfonic Acid Hydrogels for Uranium Recovery

Crosslinked 2-acrylamido-2-methyl-1-propane sulfonic acid -co- acrylic acid (AMPS/AA) hydrogels were synthesized by radical polymerization in the presence of N,N′-methylenebisacrylamide (MBA) as the crosslinking agent using potassium persulfate (KPS) as initiator. Hydrogels with different compositions and crosslinker concentrations were prepared. The structures of hydrogels were characterized by FTIR analysis. Thermal stabilities of the hydrogels were investigated using TGA and DSC analysis. Swelling kinetics and the equilibrium water content (EWC) of the hydrogels were studied. The swelling behavior of these hydrogels was investigated at different pHs at room temperature. Also the swelling behavior of these hydrogels was investigated at different ionic strength. The ability of the prepared hydrogels to bind uranium(VI) was tested under noncompetitive conditions by batch equilibrium procedure. Experimental work using uranyl nitrate hexahydrate bought from the local market was carried out in the safeguards destructive analysis laboratory (KMP-I) in the National Center for Nuclear Safety and Radiation Control.     

PAMPS/SiO_2杂化水凝胶的合成及电场敏感性研究

以2-丙烯酰胺-2-甲基丙磺酸(AMPS)为有机原料,正硅酸乙酯(TEOS)为无机原料,过硫酸钾为引发剂,N,N'-亚甲基双丙烯酰胺为交联剂,通过原位-凝胶水溶液聚合法合成了一系列不同二氧化硅含量和不同聚离子浓度的聚(2-丙烯酰胺-2-甲基丙磺酸)/二氧化硅杂化电场敏感性水凝胶.通过扫描电子显微镜(SEM)表征凝胶的结构,研究水凝胶在去离子水以及氯化钠溶液中的溶胀和消溶胀行为.结果表明,系列凝胶的平衡溶胀度介于224.9至325.6之间,复合凝胶的溶胀速率随TEOS用量的增加而降低;除理想杂化凝胶外,随着聚离子浓度的升高,凝胶在氯化钠溶液中的消溶胀速率逐渐减小.对凝胶的电场敏感性研究表明,当聚离子浓度大于氯化钠溶液浓度时,凝胶进一步溶胀,反之则消溶胀,其中杂化凝胶的再溶胀性能减弱,而消溶胀行为变得更为明显.同时制得的理想杂化凝胶,较纯有机凝胶具有更为理想的力学性能,最大抗压缩强度可达23.4 MPa.     

二乙烯基砜交联的可德胶化学水凝胶的制备与表征

以二乙烯基砜(DVS)作为交联剂通过亲电加成反应制备了可德胶化学水凝胶。采用傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)和质构分析手段表征了所得凝胶的结构与性能,并对其形貌、溶胀率以及水凝胶的力学性质与制备条件的关系进行了研究。结果表明:所得凝胶网络结构较为致密均匀,溶胀率依赖于交联度。可德胶化学水凝胶的强度和韧性可以通过DVS的用量、可德胶的浓度和碱溶液的浓度进行调控。     

pH and temperature responsive hydrogels of poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-methacrylic acid): Synthesis and swelling characteristics

Temperature and pH sensitive 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and methacrylic acid (MAA) homopolymer and copolymer hydrogels have been prepared using N,N′-methylenebisacrylamide (MBA) and ethylene glycol dimethacrylate (EGDMA) as crosslinkers. Swelling of these hydrogels has been studied in terms of monomer ratio, type and concentration of the crosslinkers and in various concentrations of mono, di and trivalent salt solutions. Though swelling of the EGDMA crosslinked poly(AMPS-co-MAA) hydrogels is found to be higher than those based on MBA crosslinker, strength of the latter system has been found to be better. Swelling behavior of these hydrogels in different salt solutions at different concentrations has shown a drop in swelling from monovalent to trivalent cations and also at higher salt concentrations. The results have indicated the possibilities of developing tailor made hydrogels combining optimum swelling with better strength characteristics that will suit different physiological and biological environments.     

Hydrogels of sodium alginate based copolymers grafted with sodium-2-acrylamido-2-methyl-1-propane sulfonate and methacrylic acid for controlled drug delivery applications

Novel sodium alginate based hydrogels were prepared by grafting the binary mixture of methacrylic acid and sodium-2-acrylamido-2-methyl-1-propane sulfonate on to sodium alginate (SA) with N,N'-methylenebisacrylamide (MBA) and ammonium persulfate (APS) as crosslinker and initiator respectively. The resultant SA-g-poly(AMPSNa-co-MAA) hydrogels were characterized using Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Thermo Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD). The results indicated that an increase in the amount of sodium-2-acrylamido-2-methyl-1-propane sulfonate, swelling capacity was found to increase. The effects of temperature, pH and inorganic salt on the swelling behavior of the hydrogels were investigated. The pH reversibility behavior at pH levels of 1.0 and 9.0 indicated great potential of this hydrogel as a candidate system for controlled drug delivery.     

Poly(N,N‐diethylacrylamide) microspheres by dispersion polymerization

Poly(N,N‐diethylacrylamide)‐based microspheres were prepared by ammonium persulfate (APS)‐initiated and poly(vinylpyrrolidone) (PVP)‐stabilized dispersion polymerization. The effects of various polymerization parameters, including concentration of N,N′‐methylenebisacrylamide (MBAAm) crosslinker, monomer, initiator, stabilizer and polymerization temperature on their properties were elucidated. The hydrogel microspheres were described in terms of their size and size distribution and morphological and temperature‐induced swelling properties. While scanning electron microscopy was used to characterize the morphology of the microspheres, the temperature sensitivity of the microspheres was demonstrated by dynamic light scattering. The hydrodynamic particle diameter decreased sharply as the temperature reached a critical temperature ～ 30 °C. A decrease in the particle size was observed with increasing concentration of both the APS initiator and the PVP stabilizer. The microspheres crosslinked with 2–15 wt % of MBAAm had a fairly narrow size distribution. It was found that the higher the content of the crosslinking agent, the lower the swelling ratio. High concentration of the crosslinker gave unstable dispersions. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6263–6271, 2008     

Synthesis and thermal properties of a novel lactose‐containing poly(N‐isopropylacrylamide‐co‐acrylamidolactamine) hydrogel

An improved, simple, and efficient method for the synthesis of lactose‐containing monomer acrylamidolactamine (LAM) has been reported. Free radical copolymerization of this monomer with N‐isopropylacrylamide (NIPAM) in the presence of the crosslinking reagent N,N′‐methylenebisacrylamide (BisA) (1.2 mol %) proceeded smoothly in an aqueous solution using potassium persulfate (KPS) and N,N,N′,N′‐tetramethylethylenediamine (TMEDA) as the initiating system and gave transparent hydrogels. Reactivity ratios were estimated from copolymerization reactions carried out in solution without BisA crosslinker and at low conversion, by using both linearization and nonlinearization methods. They were found to be r_LAM = 0.75 and r_NIPAM = 1.22. The swelling behavior of the hydrogels was studied by immersion of the hydrogels in deionized water at different temperatures. Equilibrium water uptake was increased when the LAM content was higher than 47 mol %, and reached ≈ 44‐fold with 100 mol % LAM at room temperature. Depending on the composition, the gels showed sharp swelling transitions with small changes in temperature. Differential scanning calorimetry (DSC) was used to characterize the swelling transition and the organization of water in the copolymer hydrogels. The amounts of freezable water in these hydrogels ranged from 81 to 89%, and was not correlated to the content of the sugar monomer. These gels have potential applications as biocompatible materials. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1393–1402, 1999     

疏水改性智能水凝胶P(NIPA-co-DiAB)的合成及其温敏行为

以N-异丙基丙烯酰胺(NIPA)和N,N-双烯丙基苄胺(DiAB)为共聚单体、N,N-亚甲基双丙烯酰胺(BIS)为交联剂、十二烷基硫酸钠(SDS)为表面活性剂、过硫酸铵(APS)-四甲基乙二胺(TMEDA)为氧化还原引发体系,采用自由胶束交联共聚法合成了疏水基团为芳香基的疏水改性温敏性智能水凝胶P(NIPA-co-DiAB)。研究了DiAB摩尔分数(x(DiAB))对水凝胶溶胀性能的影响。 在初始溶胀阶段,随着x(DiAB)由0增大至3%,P(NIPA-co-DiAB)水凝胶的溶胀行为由Fickian扩散转变为non-Fickian扩散。x(DiAB)分别为0、1%、2%和3%时,P(NIPA-co-DiAB)水凝胶的平衡溶胀率SR0在蒸馏水中分别为63.6、93.5、141.6和167.4,在0.01 mol/L SDS溶液中分别为63.1、71.0、59.0和77.5,在CTAB溶液中分别为37.6、42.2、44.1和60.0,在Triton X-100溶液中分别为30.9、49.4、68.5和88.3。 结果表明,P(NIPA-co-DiAB)水凝胶的(SR0)大于PNIPA水凝胶,且在蒸馏中比在0.01 mol/L表面活性剂溶液中要大。 加入0.01 mol/L Triton X-100、CTAB或SDS后,PNIPA水凝胶的体积相变温度或较低临界溶解温度(LCST)由32.5 ℃分别增加至35.4、45.6和80 ℃。P(NIPA-co-DiAB)水凝胶的LCST由32.0～32.5 ℃分别增加至34.7～35.6 ℃、45.8~46.2 ℃和80 ℃。 加入表面活性剂能增加P(NIPA-co-DiAB)水凝胶的体积相变温度,高的体积相变温度与DiAB含量无关。     

腐植酸钠/聚N-异丙基丙烯酰胺/粘土杂化水凝胶的合成及脱色性能

以N-异丙基丙烯酰胺单体、粘土和腐植酸钠为原料合成了温敏腐植酸钠/聚N-异丙基丙烯酰胺/粘土（SH/PNIPA/clay）系列水凝胶。用红外光谱分析仪对其内部相互作用进行了研究,并用紫外可见分光光度计对水凝胶吸附-解吸亚甲基蓝的性能进行了测试。实验结果表明凝胶中SH与PNIPA形成了氢键;凝胶对亚甲基蓝（MB）的吸附和解吸能力受腐植酸钠的含量、粘土含量、亚甲基蓝的起始浓度和温度的影响。２％粘土含量和低温条件有利于凝胶吸附和解吸。     

Modeling of Swelling Behaviors of Acrylamide-Based Polymeric Hydrogels by Intelligent System

Hydrogels based on acrylamide (AAm) were synthesized by free radical polymerization in an aqueous solution using N,N’-methylenebisacrylamide (MBAAm) as crosslinker. To obtain anionic hydrogels, 2-acrylamido-2-methylpropanesulfonic acid sodium salt (AMPS) and acrylic acid (AAc) were used as comonomers. The swelling behaviors of all hydrogel systems were modeled using an artificial neural network (ANN) and compared with a multivariable least squares regression (MLSR) model and phenomenal model. The predictions from the ANN model, which associated input parameters, including the amounts of crosslinker (MBA) and comonomer, and swelling values with time, produce results that show excellent correlation with experimental data. The parameters of swelling kinetics and water diffusion mechanisms of the hydrogels were calculated using the obtained experimental data. Model analysis indicated that the ANN models could accurately describe complex swelling behaviors of highly swellable hydrogels.