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1.
温敏性萃取水凝胶对生物大分子的分离   总被引:4,自引:2,他引:2  
仲慧  嵇鸣  赵宜江  王锦堂  朱红军 《精细化工》2003,20(3):129-133,139
合成了均聚的聚N 异丙基丙烯酰胺(PNIPAM)水凝胶以及N 异丙基丙烯酰胺与丙烯酰胺共聚的〔P(NIPAM-AM)〕水凝胶,并研究了它们的溶胀性能及其对生物大分子的萃取分离性能。结果表明,两种温敏凝胶具有很好的溶胀性能,其低临界共溶温度(LCST)分别为30 4和31 0℃,它们对蛋白质和酶的分离效率在LCST附近发生突跃,如PNIPAM水凝胶对白蛋白的分离效率在LCST前后从96 2%降至59 8%。当交联剂N,N 次甲基双丙烯酰胺(Bis)的质量分数w(Bis)>4%时,分离效率大于90%(LCST以下)。  相似文献   

2.
温敏超细颗粒对亲水药物的吸附   总被引:4,自引:1,他引:3  
仲慧  王锦堂  朱红军  稽鸣 《精细化工》2000,17(5):265-266
用微乳液聚合方法以N 异丙基丙烯酰胺为单体合成了温敏性超细颗粒 ,研究了其对维生素B2 注射液和盐酸普鲁卡因的吸附量随温度的变化 ,结果表明 :在低温 (LCST以下 )下吸附药物 ,而在高温 (LCST以上 )下释放药物。在LCST前后 ,1g超细颗粒吸附的维生素B2 的质量分别为 2 9 59μg和 1 8 1 4μg ,吸附的盐酸普鲁卡因质量分别为 1 1 92 μg和 7 80 μg。聚 N 异丙基丙烯酰胺 (PNIPAM)超细颗粒有可能作为控制药物释放的智能载体。  相似文献   

3.
利用IPN技术合成了一种具有温度和pH双重敏感性的聚(N-异丙基丙烯酰胺)/聚丙烯酸半互穿网络微凝胶(PNIPAM/PAAc semi-IPN)。这种微凝胶在酸性条件下发生典型的体积相转变;而在弱碱性条件下,当温度低于聚(N-异丙基丙烯酰胺)(PNIPAM)微凝胶的体积相转变温度(VPTT)时,微凝胶的粒径随着温度的上升而增大,当温度达到VPTT后,粒径突然急剧减小,并随着温度的逐渐上升而减小,最终趋向平衡。  相似文献   

4.
温度对温敏性固定化酶的相对活力影响研究   总被引:1,自引:0,他引:1  
以N 异丙基丙烯酰胺 (PNIPAM)均聚凝胶和N 异丙基丙烯酰胺与丙烯酰胺 [P(NIPAM -AM) ]共聚凝胶为载体制备了四种温敏性固定化酶。其相对活力 (f)随温度的升高而降低 ,在凝胶低临界溶解温度LCST(32 0℃ )附近骤降 (均聚枯草杆菌蛋白酶的f在 32 0℃前后由 86 2 %降至 18 8% ) ,即高温下 (LCST以上 )酶从凝胶中释放出来 ,说明温敏性凝胶可用作生物固定化催化剂的功能性载体。  相似文献   

5.
通过溶液聚合法合成了丙烯酰胺(AM)与丙烯酸(AA)质量比不同的聚丙烯酰胺(PAM)与AA二元共聚水凝胶(PAM-AA),并研究了水凝胶的吸水性能和对胃蛋白酶溶液的浓缩性能。结果表明:水凝胶对蛋白质的浓缩性能与其吸水性能保持一致,单体AM与AA质量比为1∶1时具有最优浓缩倍率,为3.21倍;通过加入温敏性单体N-异丙基丙烯酰胺(NIPAM)对PAM-AA进行改性,发现NIPAM的加入会降低凝胶的吸水率,但使凝胶具有温敏性能,其低临界相转变温度(LCST)为32℃。利用温敏性凝胶的特性,在温度高于LCST时吸附蛋白质,温度低于LCST时释放蛋白质,可以实现对蛋白质较优浓缩,最高浓缩倍率可达3.72倍。PAM-AA对蛋白质浓缩通过吸水实现,而PAM-AA-NIPAM通过吸附蛋白质实现。  相似文献   

6.
将自由基聚合法合成的聚N-异丙基丙烯酰胺(PNIPAM)微凝胶和聚偏氟乙烯(PVDF)共混,制备出了具有温度响应性的复合膜。采用FTIR、SEM对PNIPAM微凝胶/PVDF温敏膜的组成及结构进行分析,可以发现PNIPAM微凝胶被成功包裹在PVDF膜孔中,并使膜的孔径增大。PNIPAM微凝胶对温度具有较好的响应性,可以通过改变温度调节微凝胶的溶胀和收缩,进而调控复合膜的水通量。  相似文献   

7.
用羟丙基纤维素(HPC)接枝的多链转移官能基大分子链转移剂,通过可逆加成断裂链转移(RAFT)聚合制备了羟丙基纤维素接枝聚(N-异丙基丙烯酰胺)(PNIPAM)水凝胶(HPC-g-PNIPAM hydrogel),研究了HPC相对分子质量、RAFT分子接枝密度以及HPC和NIPAM质量比对水凝胶微观形貌、低临界溶解温度(LCST)以及溶胀性能和机械性能的影响。结果表明,HPC大分子RAFT聚合PNIPAM能获得具有高溶胀比和快速响应性能的水凝胶;HPC的引入能提高水凝胶机械强度。RAFT聚合方法和少量大分子纤维素RAFT分子的引入会略微降低LCST,但当HPC组分增加到一定量,又会使LCST升高。  相似文献   

8.
设计合成了一种包含氧化石墨烯(GO)片层、聚(N-异丙基丙烯酰胺)(PNIPAM)微凝胶球体和PNIPAM链段的复合结构水凝胶。通过控制聚合时间得到负载双键且粒径不同的PNIPAM微凝胶,将其作为交联点与N-异丙基丙烯酰胺(NIPAM)聚合,GO作为纳米填料掺入水凝胶体系,GO片层上的含氧基团与NIPAM上的胺基产生氢键物理交联。此方法制备的复合水凝胶同时具有温度敏感和近红外光敏感特性,通过改变GO浓度、微凝胶的合成时间、NIPAM浓度等条件,水凝胶的光敏感性和温度敏感性得到提升。相比于传统PNIPAM水凝胶,此种复合水凝胶能够对光响应,实现非接触式控制形变,且响应速率快、响应程度高,可应用于光控开关等领域。  相似文献   

9.
张宁  单国荣 《化工学报》2018,69(11):4862-4868
设计合成了一种包含氧化石墨烯(GO)片层、聚(N-异丙基丙烯酰胺)(PNIPAM)微凝胶球体和PNIPAM链段的复合结构水凝胶。通过控制聚合时间得到负载双键且粒径不同的PNIPAM微凝胶,将其作为交联点与N-异丙基丙烯酰胺(NIPAM)聚合,GO作为纳米填料掺入水凝胶体系,GO片层上的含氧基团与NIPAM上的胺基产生氢键物理交联。此方法制备的复合水凝胶同时具有温度敏感和近红外光敏感特性,通过改变GO浓度、微凝胶的合成时间、NIPAM浓度等条件,水凝胶的光敏感性和温度敏感性得到提升。相比于传统PNIPAM水凝胶,此种复合水凝胶能够对光响应,实现非接触式控制形变,且响应速率快、响应程度高,可应用于光控开关等领域。  相似文献   

10.
分散聚合法合成聚(N-异丙基丙烯酰胺)温敏性微凝胶   总被引:1,自引:0,他引:1  
以PVP为稳定剂,在水或醇/水介质中通过分散聚合法合成出聚(N-异丙基丙烯酰胺)(PNIPAM)温敏性微凝胶。研究结果表明,可通过改变稳定剂用量和分散介质极性来控制PNIPAM微凝胶的大小,这两种因素对PNIPAM微凝胶的溶胀比有明显的影响,而对其相转变行为影响不大;交联剂用量对PNIPAM微凝胶的粒径、溶胀比和相转变行为都有比较明显的影响。PNIPAM微凝胶可能主要通过接枝共聚物聚结机理成核,通过初级粒子之间的聚并完成粒子增长过程。  相似文献   

11.
B.H. Tan  K.C. Tam 《Polymer》2010,51(14):3238-3243
The microstructure and rheological properties of thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) microgels cross-linked with methylenebis-acrylamide (BA) were examined by dynamic light scattering and rheological techniques. As the temperature was increased from 10 to 50 °C, the particles diameter decreased by approximately two times near the volume phase transition temperature, Tv of between 30 and 35 °C. The addition of salt to the microgel dispersion provides competition for the water molecules hydrating the PNIPAM chains thus weakening the PNIPAM-H2O hydrogen bonds and the microgel progressively deswelled. The validity and limitation of the semi-empirical approach to model charged soft microgel particles developed previously were tested on this thermo-responsive system. A variable specific volume, k was introduced to convert the mass concentration to effective volume fraction. With increasing concentration, inter-particle repulsive force was enhanced, which overcame the osmotic force inside the soft particle, resulting in the expulsion of solvent from the swollen particles, and the particle shrank. The viscosity data for PNIPAM microgels at varying solution temperatures and ionic strength showed excellent agreement with the modified Krieger-Dougherty (K-D) model.  相似文献   

12.
采用无皂乳液聚合法制备聚(N-异丙基丙烯酰胺)/壳聚糖微凝胶(PNIPAM/CS),透射电镜和动态光散射研究了微凝胶外貌形态及刺激响应性。结果显示,微凝胶颗粒呈球形,具有核、壳结构形态。加入壳聚糖对PNIPAM的体积相转变温度(VPTT)有影响,微凝胶VPTT随壳聚糖用量的增加向高温迁移,此结果与示差量热法(DSC)测定一致。不同pH条件下微凝胶粒径变化表明,颗粒直径随pH增大逐渐减小,至碱性又增大,显示明显的pH敏感性;相应颗粒Zeta电位逐渐减小,接近中性达到等电点,至碱性反转为负值,这一变化能对微凝胶pH敏感性进行合理解释。  相似文献   

13.
Yuriko Matsumura  Kaoru Iwai 《Polymer》2005,46(23):10027-10034
Poly(N-isopropylacrylamide) (PNIPAM) microgel particles labeled with 3-(2-propenyl)-9-(4-N,N-dimethylaminophenyl)phenanthrene (VDP) as an intramolecular fluorescent probe were prepared by emulsion polymerization. The thermo-responsive behavior of the VDP-labeled PNIPAM microgel particles dispersed in water was studied by turbidimetric and fluorescence analyses. The transition temperature of the VDP-labeled PNIPAM microgel particles in water determined by turbidimetric analysis was ca. 32.5 °C. The wavelength at the maximum fluorescence intensity of the VDP units linked directly to the microgel particles dramatically blue-shifted around the transition temperature. In addition it gradually blue-shifted even below the transition temperature where there was no change observed in the turbidity. These findings suggest that the gradual shrinking of microgel particles occurs with increasing temperature and the subsequent dramatic shrinking results in the increasing in the turbidity. The transition temperatures of VDP-labeled poly(N-n-propylacrylamide) and poly(N-isopropylmethacrylamide) microgel particles determined by turbidimetric analysis were ca. 23 and ca. 42.5 °C, respectively, and their thermo-responsive behavior was similar to that for the VDP-labeled PNIPAM system. In these three systems the microenvironments around the fluorescent probes above the transition temperatures became more hydrophobic than those below the transition temperature, and the estimated values of microenvionmental polarity around the VDP units on their collapsed states were almost the same.  相似文献   

14.
The response to temperature and glucose, high salt tolerance and self‐regulated drug delivery are simultaneously probable by applying a multifunctional microgel in a rational design by a colloid chemistry method. Such smart microgels were fabricated with thermoresponsive N‐isopropylacrylamide, glucose‐sensitive (2‐phenylboronic esters‐1,3‐dioxane‐5‐ethyl)methyl acrylate (PBDEMA) and water‐soluble crosslinker poly(ethylene glycol) diacrylate through a precipitation emulsion method. These colloidal nanoparticles exhibited PBDEMA‐composition‐dependent responsive behavior with changing temperature and ionic strength. Amongst them, the microgel with 20.7 mol% PBDEMA with a narrow size distribution is suitable for diabetes treatment because it can adapt to the surrounding medium of different glucose concentrations over a clinically relevant range (0–2.0 mg mL?1), control the release of preloaded insulin and is highly stable under normal physiological conditions. Preliminary experiments suggest these highly stable microgels have the potential to be used for self‐regulated therapy and monitoring the response to treatment. © 2018 Society of Chemical Industry  相似文献   

15.
A series of temperature‐sensitive microgels based on N‐isopropylacrylamide as the main monomer, tert‐butyl acrylate (tBA) as the comonomer, and N,N′‐methylene‐bis(acrylamide) as the crosslinker were synthesized with a modified surfactant‐free emulsion polymerization method. The chemical structure and global shape with an excellent monodispersity of the microgels were confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The temperature‐sensitive behavior of the microgels was investigated by dynamic light scattering and ultraviolet–visible spectrophotometric analysis. The results show that the volume phase‐transition temperature of the poly(N‐isopropylacrylamide‐cotert‐butyl acrylate) [poly(NIPAM‐co‐tBA)] microgels were tuned over a broad range by the incorporated amount of tBA comonomer and their temperature sensitivity decreased with increasing content of tBA units incorporated into the microgel network. Furthermore, the swelling ratios of the poly (NIPAM‐co‐tBA) microgels were lowered gradually with increasing tBA unit content within the microgel network. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2962–2967, 2007  相似文献   

16.
Poly(N‐isopropylacrylamide) (PNIPAM) microgels were prepared through soap‐free emulsion polymerization using 2, 2′‐ azobisobutyronitrile and potassium persulfate as initiator respectively. The thermal response of microgels was researched by measuring the transmittance and the hydrodynamic diameter of the microgels at different temperatures. The result shows that the different structure of the end groups of polymer that come from residues of initiator result in the different thermal response of PNIPAM microgels. The LCST (lower critical solution temperature) of AIBN‐initiator microgels is 5°C lower than that of the KPS‐initiator microgels, whereas the AIBN‐initiated PNIPAM microgels have better thermal response sensitivity. The scanning electron microscope characterization shows that the morphology of AIBN‐initiated PNIPAM microgels is more regular than that of KPS‐initiated. Furthermore, the Tg of the microgels was measured by differential scanning calorimeter and the result indicates that the end groups influences the Tg of microgels severely. This work demonstrated that the hydrophobic end group coming from initiators can decreases the LCST of PNIPAM microgels and increases the thermal response sensitivity, which providing a newly simple but effective method to regulate the thermal response of PNIPAM microgels. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1164‐1171, 2013  相似文献   

17.
“Single‐chain” microgels were synthesized successfully from the cross‐linkable poly(N‐isopropylacrylamide) (PNIPAM) copolymer. This type of microgel has the exact chemical structure, molecular weight and molecular weight distribution of its precursor. It provides a direct way to compare the properties of linear polymers with those of their networks. The viscosity properties show that the microgels have lower critical solution temperatures (LCST) that are even higher than those of the corresponding linear copolymers. This can be attributed to the crosslinking points, which retard the change of the conformation of the network chains. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2179–2183, 2003  相似文献   

18.
焦炭及其改性吸附预处理焦化废水的试验研究   总被引:3,自引:1,他引:2  
采用经化学改性前后的焦炭对焦化废水进行吸附预处理,并对其吸附性能进行了检测.结果表明,焦炭对焦化废水中的COD、挥发酚、氨氮和氰化物均有一定的去除效果,分别为相同条件下活性炭对上述污染物去除率的15.48%、16.41%、39.47%和172.84%.化学改性可使焦炭对焦化废水中氨氮和氰化物的吸附性能明显的提高,其中HNO,改性对焦炭吸附废水中氨氮和氰化物能力的增加效果显著,对氨氮的吸附常数从未改性前的0.009 7 L·mg-1增加为0.077 L·mg-1;对氰化物的吸附常数从未改性前的0.002 4 L·mg-1增加为0.073 9 L·mg-1.KOH改性对焦炭吸附废水中氰化物能力的增加效果明显,对氰化物的吸附常数从未改性前的0.002 4 L·mg-1增加为0.095 5 L·mg-1.  相似文献   

19.
用沉淀聚合法,以N-乙烯基己内酰胺(VCL)和N-乙烯基吡咯烷酮(NVP)为共聚单体、N,N-亚甲基双丙烯酰胺(MBA)为交联剂,通过改变交联剂的量制备了-系列不同粒径的温敏型微凝胶。用纳米颗粒力度分析仪(DLS)和原子粒显微镜(AFM)对凝胶进行了表征。结果表明:粒子为球型单分散;在15—55℃范围内凝胶粒径随温度升高而减小,具有温度敏感性,最低临界转变温度(LCST)为35℃;交联剂的量不改变最低临界转变温度,只改变粒子大小。  相似文献   

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