壳聚糖接枝丙烯酰胺/二甲基二烯丙基氯化铵水凝胶的辐射合成及溶胀性能

采用γ射线辐照法,以壳聚糖(CTS),丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDACC)为原料,N,N-亚甲基双丙烯酰胺(MBA)为交联剂,制备了壳聚糖-丙烯酰胺-二甲基二烯丙基氯化铵(CTS-AM-DMDAAC)水凝胶。研究了吸收剂量、单体配比、交联剂用量等因素对水凝胶溶胀性能的影响,并考察了水凝胶的环境响应性。结果表明,制备水凝胶的适宜条件为吸收剂量为4kGy,总单体AM和DMDAAC中AM与DMDAAC质量比为2.33∶1,总单体与CTS质量比2.67∶1、MBA用量为总单体质量的2.5%,在此条件下,制得的水凝胶溶胀度最高;CTS-AM-DMDAAC水凝胶对pH值和离子强度具有良好的敏感性。     

智能聚氨酯水凝胶的合成及性能研究

以聚乙二醇(PEG-200、400、600)、二羟甲基丙酸(DMPA)、2,4-甲苯二异氰酸酯(TDI)及N,N'-二乙基丙烯酰胺(DEAAm)等为原料合成了3种对pH值、温度、离子强度等敏感的智能聚氨酯水凝胶,研究了智能聚氨酯水凝胶溶胀率(SR)受pH值、温度、离子强度等因素的影响.结果表明,合成的聚氨酯水凝胶具有良好的pH、温度、离子强度敏感性,并具有良好的溶胀-退胀可逆性.     

壳聚糖接枝丙烯酸/丙烯酰胺水凝胶的制备及性能

以丙烯酸(AA)、丙烯酰胺(AM)两种单体同时对壳聚糖(CTS)进行接枝改性,合成了具有环境响应性的壳聚糖水凝胶,讨论了各合成因素对凝胶溶胀性能的影响及凝胶对pH值、离子强度和温度的响应性。结果表明,当反应时间为2h~2.5 h、单体与CTS质量比为8∶1、反应温度在60℃左右、引发剂用量为0.35%(占单体和CTS总量的百分比,下同)、交联剂用量为0.125%时,制得的水凝胶最高溶胀度可达224 g/g,而且该凝胶同时具有pH值、离子强度和温度敏感性。     

高强度/多功能氧化石墨烯纳米复合智能水凝胶的制备

以甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)和丙烯酸(AA)为单体,N,N-亚甲基双丙烯酰胺(MBA)为交联剂,过硫酸铵(APS)和亚硫酸氢钠(NaHSO3)为引发剂,在氧化石墨烯(GO)水分散液中合成了高强度GO纳米复合智能水凝胶。研究了GO和交联剂MBA含量对高强度GO纳米复合智能水凝胶力学性能、热稳定性的影响。研究表明,GO纳米复合智能水凝胶的热稳定性、力学性能,随GO或MBA含量的增加其强度增加;当pH6或pH8时,GO纳米复合智能水凝胶具有pH敏感性;GO纳米复合智能水凝胶的低临界溶解温度(LCST)约为30℃;当NaCl浓度小于0.4mol/L时GO纳米复合智能水凝胶具有明显的离子强度敏感性。     

新型环境敏感性β-环糊精水凝胶的合成及性能研究

通过单6-对甲基苯磺酰β-环糊精酯(β-CD-6-OTs)与乙二胺反应引入活泼的氨基后,进一步与丙烯酸作用进行酰胺化反应,得到单乙烯基修饰β-环糊精(β-CD-6-EA),并以此为单体在交联剂N,N′-亚甲基双(丙烯酰胺)存在下,分别与丙烯酸和甲基丙烯酸-N,N-二甲氨基乙酯共聚,合成两类分子中含悬挂式β-环糊精结构的水凝胶(CEA和CED).通过红外光谱表征了水凝胶的结构,溶胀实验结果表明该水凝胶具有较好的pH,温度及离子强度敏感性.     

具有灵敏pH响应的高强度聚丙烯酰胺/聚丙烯酸钠双网络水凝胶的合成

采用二步法,以锂藻土(Laponite)交联聚丙烯酰胺(PAM),N,N-亚甲基双丙烯酰胺(BIS)交联聚丙烯酸(PAA),通过自由基聚合制备了PAM/PAA双网络水凝胶。该水凝胶的拉伸强度可达137 k Pa,在酸性缓冲液中收缩,碱性缓冲液中溶胀,具有灵敏的pH响应性。通过调节丙烯酸(AA)单体的中和度和2种网络交联剂的用量及单体配比,可控制双网络水凝胶的拉伸性能和响应性能。结果表明,AA中和度为125%,m(AM)∶m(Laponite)=1∶0.6,m(AA)∶m(BIS)=1∶0.0002,m(AM)∶m(AA)=7∶1时,水凝胶的拉伸强度最佳,可达137 k Pa;该条件下制备的双网络水凝胶同时具有灵敏可逆的pH响应性,在pH=3的缓冲液中溶胀度达5.26,在pH=7的缓冲液中溶胀度可达16.98。     

微波快速合成响应型增韧水凝胶

以N-异丙基丙烯酰胺(NIP)、丙烯酰胺(AM)和聚乙二醇-马来酸酐双酯(PEG-MAH)为单体,采用微波聚合法快速合成了三元共聚智能型、增韧水凝胶。利用红外光谱和扫描电子显微镜表征了水凝胶的结构和形貌;同时对水凝胶的热稳定性、温敏性、pH敏感性、盐敏性和增韧性等进行了测试分析。实验结果表明:水凝胶的LCST在40℃时,平衡溶胀比随溶液pH值的增加而增加,随盐浓度的增加而减小。水凝胶内单体的摩尔比n(NIP)∶n(AM)∶n(PEGMAH)=1∶8∶2时,凝胶的韧性最好。     

聚丙烯酰胺/聚甲基丙烯酸(2-甲基氨基)乙酯高强度双网络水凝胶的制备及pH响应性

利用两步法合成了聚丙烯酰胺(PAM)/聚甲基丙烯酸(2-甲基氨基)乙酯(PDMAEMA)双网络水凝胶,第一网络为锂藻土(Laponite)物理交联的PAM纳米复合水凝胶,第二网络为化学交联剂N,N-亚甲基双丙烯酰胺(BIS)交联PDMAEMA。研究了2种网络相对含量、纳米黏土Laponite用量、化学交联剂BIS用量对水凝胶强度和pH响应性的影响。研究结果表明,PAM/PDMAEMA双网络水凝胶具有高强度,改变单体AM和DMAEMA的配比、交联剂的用量,其拉伸强度在36～91.9 kPa范围内可调。PAM/PDMAEMA双网络水凝胶还具有灵敏的pH刺激响应性,在pH=4时双网络水凝胶溶胀度急剧下降。     

pH敏感P(MAA-co-AM)水凝胶的制备及溶胀行为研究

以甲基丙烯酸(MAA)、丙烯酰胺(AM)为单体,N,N-亚甲基双丙烯酰胺作交联剂(BIS),过硫酸铵为引发剂(APS),用溶液聚合的方法合成水凝胶P(MAA-co-AM),研究了单体配比及干燥方式对水凝胶表面形貌以及对水、不同pH溶液及盐溶液的溶胀行为的影响。结果表明,P(MAA-co-AM)16凝胶(MAA/AM摩尔比为16∶100)冻干处理后具有均匀的大孔;与PAM和PMAA凝胶相比,P(MAA-co-AM)16凝胶的吸水溶胀速率快(1h溶胀平衡)、平衡溶胀比大(ESR=250)、pH体积响应变化大(pH为4.01、6.86、9.18时的ESR分别为20、60、141),吸盐率比PMAA有所提高。     

聚丙烯酸钾／羧甲基纤维素钠半互穿网络水凝胶的两步水溶液合成及其药物释放

以N,N’-亚甲基双丙烯酰胺为交联剂、过硫酸铵和焦亚硫酸钠为氧化还原引发剂，采用新型两步水溶液聚合法制备了聚丙烯酸钾／羧甲基纤维素钠（PAA／CMC-Na）半互穿网络水凝胶．对其溶胀动力学、离子强度敏感性和pH敏感性进行了研究．探讨了PAA／CMC-Na半互穿网络水凝胶对荼碱的释放行为，实验结果表明所吸收的茶碱在盐溶液中90min内释放率可达90％，释放规律遵循Fiekian扩散机制。     

智能型AMPS/DMAEMA水凝胶的电敏感性能

以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)和甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)为单体,N,N′-亚甲基双丙烯酰胺为交联剂,过硫酸铵和亚硫酸氢钠为氧化还原引发剂,采用水溶液聚合法制备了AMPS/DMAEMA水凝胶,考察了样品水凝胶在外加直流电场刺激下的消溶胀动力学和弯曲行为.结果表明,DMAEMA单体含量和施加电压大小对水凝胶的电敏感性能有着显著影响.用一级动力学方程能够较好地描述水凝胶在接触电压刺激下的消溶胀过程.在非接触电压刺激下,单体摩尔比,n(AMPS):n(DMAEMA)=9:1的水凝胶向负极弯曲;单体摩尔比n(AMPS):n(DMAEMA)=5:5的水凝胶向正极弯曲;单体摩尔比n(AMPS):n(DMAEMA)=7:3的水凝胶随着非接触电压的增大,出现先向负极弯曲,后向正极弯曲的现象.     

UV-radiation curing of simultaneous interpenetrating polymer network hydrogels for enhanced heavy metal ion removal

Simultaneous interpenetrating polymer network (IPN) hydrogels have been prepared by UV-initiated polymerization of a mixture of acrylamide (AM) and triethylene glycol divinyl ether (DVE-3). The consumption of each monomer upon UV-irradiation was monitored in situ by real-time infrared (RTIR) spectroscopy. The acrylamide monomer AM was shown to polymerize faster and more extensively than the vinyl ether monomer DVE-3, which was further consumed upon storage of the sample in the dark, due to the living character of the cationic polymerization. The IPN hydrogels were used to remove heavy metal ions from aqueous solution under the non-competitive condition. The effects of pH values of the feed solution and the DVE-3 content in the formulation on the adsorption capacity were investigated. The results indicated that the adsorption capacity of the IPN hydrogels increased with the pH values and DVE-3 content in the formulation. Furthermore, the synergistic complexation of metal ions with two polymer networks in the IPN was found in the adsorption studies. Adsorption kinetics and regeneration studies suggested that the IPN hydrogels could be used as fast-responsive and renewable sorbent materials in heavy metal removing processes.     

PVA/P(AA-AM)复合水凝胶的制备及性能

采用水溶液聚合方法合成了不同组成的丙烯酸-丙烯酰胺共聚物(P(AA-AM))。将聚乙烯醇(PVA)与所合成的P(AA-AM)共混,以戊二醛为交联剂,制备出了不同结构的PVA/P(AA-AM)复合水凝胶。采用扫描电镜观察了凝胶形貌,研究了复合水凝胶的结构与性能关系。结果表明,复合水凝胶溶胀性能与所用交联剂加量有关,复合水凝胶的溶胀度随着交联剂加量增加先增大后减小,在交联剂加量为0.5%时水凝胶溶胀度达到最大值。复合凝胶中的聚合物组成对溶胀度影响显著,随着P(AA-AM)含量提高,水凝胶的溶胀度逐渐增大。适当结构的复合水凝胶具有pH敏感性,敏感程度随着凝胶中P(AA-AM)含量的增加而增强。     

Stimulus-responsive "smart" hydrogels as novel drug delivery systems

Recently, there has been a great deal of research activity in the development of stimulus-responsive polymeric hydrogels. These hydrogels are responsive to external or internal stimuli and the response can be observed through abrupt changes in the physical nature of the network. This property can be favorable in many drug delivery applications. The external stimuli can be temperature, pH, ionic strength, ultrasonic sound, electric current, etc. A majority of the literature related to the development of stimulus-responsive drug delivery systems deals with temperature-sensitive poly(N-isopropyl acrylamide)(pNIPAAm) and its various derivatives. However, acrylic-based pH-sensitive systems with weakly acidic/basic functional groups have also been widely studied. Quite recently, glucose-sensitive hydrogels that are responsive to glucose concentration have been developed to monitor the release of insulin. The present article provides a brief introduction and recent developments in the area of stimulus-responsive hydrogels, particularly those that respond to temperature and pH, and their applications in drug delivery.     

二甲基二烯丙基氯化铵与丙烯酰胺的共聚动力学

采用膨胀计法研究了以过硫酸铵-亚硫酸氢钠为引发剂的二甲基二烯丙基氯化铵(DMDAAC)和丙烯酰胺(AM)的水溶液共聚合动力学,测定了相应的聚合速率方程、聚合表观活化能和单体竞聚率。结果表明,聚合反应温度为45℃,当DMDAAC与AM物质的量比分别为1∶9,2∶8和3∶7时,共聚速率方程分别为Rp1=k[M]2.61[IO]0.51[IR]0.52,Rp2=k[M]2.70[IO]0.50[IR]0.53和Rp3=k[M]2.73[IO]0.50[IR]0.56,表观活化能分别为Ea1=79.10 kJ/mol,Ea2=81.39 kJ/mol和Ea3=85.15 kJ/mol,两单体的竞聚率分别为rDMDAAC=0.14,rAM=6.11。上述实验结果可从动力学角度为不同阳离子度PDA聚合速率差别及产物特征黏度值差异进行解释。     

Stimulus-Responsive “Smart” Hydrogels as Novel Drug Delivery Systems

ABSTRACT

Recently, there has been a great deal of research activity in the development of stimulus-responsive polymeric hydrogels. These hydrogels are responsive to external or internal stimuli and the response can be observed through abrupt changes in the physical nature of the network. This property can be favorable in many drug delivery applications. The external stimuli can be temperature, pH, ionic strength, ultrasonic sound, electric current, etc. A majority of the literature related to the development of stimulus-responsive drug delivery systems deals with temperature-sensitive poly(N-isopropyl acrylamide)(pNIPAAm) and its various derivatives. However, acrylic-based pH-sensitive systems with weakly acidic/basic functional groups have also been widely studied. Quite recently, glucose-sensitive hydrogels that are responsive to glucose concentration have been developed to monitor the release of insulin. The present article provides a brief introduction and recent developments in the area of stimulus-responsive hydrogels, particularly those that respond to temperature and pH, and their applications in drug delivery.     

数字图像相关法在稀土掺杂水凝胶电响应行为测量中的应用

基于放大成像技术、高速摄像技术与数字图像相关方法,研究了稀土掺杂水凝胶在非接触直流电场作用下的电刺激响应行为,并对相关的机理进行了探讨。实验结果表明,在非接触直流电场作用下,掺入稀土后的Sm/Gel/P(AA/AM)、Eu/Gel/P(AA/AM)水凝胶与Gel/P(AA/AM)水凝胶相比,对电场的响应更为敏感;稀土掺杂水凝胶均随着电场的增大,形变位移增大;水凝胶在掺杂稀土后沿着电场方向产生形变,在掺杂稀土前逆着电场方向产生形变。文中测试方法具有实验装置简单、全场非接触、无附加质量、无附加阻尼、测量变形范围可调等优点。数字图像相关方法用于此类材料力学性能的研究是一种行之有效的方法。     

P(NIPA-co-AM)超大孔水凝胶的制备及其性能

以N-异丙基丙烯酰胺(NIPA)、丙烯酰胺(AM)为单体,过硫酸铵为引发剂,N,N'-亚甲基双丙烯酰胺为交联剂,采用泡沫分散聚合法制备N-异丙基丙烯酰胺与丙烯酰胺共聚物[P(NIPA-co-AM)]超大孔水凝胶,研究了丙烯酰胺、引发剂、交联剂、盐酸、碳酸氢钠用量对水凝胶溶胀、退溶胀性能的影响,通过DSC、SEM、FTI...     

温度/pH敏感性Semi-IPN水凝胶的制备与性能

以N-乙烯基乙酰胺（NVA）、醋酸乙烯酯（VAc）和甲基丙烯酸-N,N′-二甲氨基乙酯（DMAEMA）为原料,通过自由基聚合制备了PDMAEMA/P（NVA-co-VAc）半互穿网络（Sem-iIPN）水凝胶。实验结果表明,该水凝胶具有较好的温度敏感性、pH敏感性、溶胀-退胀可逆性。随着温度的逐渐升高,凝胶的溶胀率随之...     

温度敏感性聚甲基丙烯酸N,N-二甲基氨基乙酯(PDMAEMA)水凝胶的合成及性能研究

采用热化学聚合法制备了聚甲基丙烯酸N,N-二甲基氨基乙酯(PDMAEMA)水凝胶,并对其溶胀性能进行了研究.研究结果表明,PDMAEMA水凝胶具有温度敏感性,在去离子水中其ICST约为50℃;水凝胶的温度敏感性与介质的pH值有关,在碱性溶液中凝胶表现出典型的温度敏感性,而在酸性溶液中凝胶的溶胀率受温度的影响很小,没有温度敏感性.