N—异丙基甲基丙烯酰胺共聚热缩温敏水凝胶

从甲基丙烯腈与异丙醇反应制备了Ｎ－异丙基甲基丙烯酰胺（ＮＩＰＭ），研究了其以Ｎ，Ｎ＇－亚甲基双丙烯酰胺（ＭＢＡ）为交联剂在不同溶剂体系的聚合及所形成的水凝胶的性质。表明ＮＩＰＭ－ＭＢＡ凝胶具有热缩温敏性。在ＮＩＰＭ－ＭＢＡ体系引入丙烯酸钠、甲基丙烯酸钠等负离子单体时，凝胶的溶胀比明显增加，ＭＢＡ所占比例较少的体系，具有热缩、热胀双重性。     

含辣素衍生结构疏水缔合聚合物PAAH的合成、表征及溶液性质

以辣素功能结构单体N-（4-羟基-3-甲氧基-苄基）-丙烯酰胺（HMBA）为疏水单体,与丙烯酰胺（AM）和2-丙烯酰胺基-2-甲基丙磺酸钠（NaAMPS）通过自由基胶束共聚,制得三元疏水缔合聚合物P（AM-NaAMPS-HMBA）（简称PAAH）. 采用紫外-可见光谱、核磁共振氢谱、热重分析及扫描电子显微镜对共聚物的结构及形貌进行表征,利用原子力显微镜对聚合物水溶液的微观形貌进行观察,并对其溶解性、疏水缔合性、耐温性及抑菌性能进行了研究. 结果表明,所得共聚物中疏水单体含量与投料比基本一致;PAAH具有良好的速溶性,当聚合物浓度超过一定值后,溶液黏度急剧增加,且随着疏水单体含量增加,疏水缔合性能增强;原子力显微镜观察证实了聚合物水溶液中网络结构的存在. 与未改性的P（AM-NaAMPS）（简称PAA）共聚物相比,引入具有生物活性且带有刚性苯环结构的HMBA单体可使PAAH共聚物热稳定性增强,耐温性能提高,并赋予其优良的抑菌性能.     

丙烯酰胺、3-丙烯酰胺-3-甲基丁酸钠和N-烷基丙烯酰胺三元共聚物的溶液特性研究

讨论了丙烯酰胺、3-丙烯酰胺-3-甲基丁酸钠和N-烷基丙烯酰胺三元共聚物(CAANA)的水溶液特性,并与部分水解聚丙烯酰胺(HPAM)水溶液特性相比较。芘荧光光谱分析和激光光散射仪测量结果表明。CAANA由于引入了疏水性单体,在水溶液中形成了分子间的疏水缔合作用,并使得CAANA在水溶液中具有较大的均方旋转半径,相对于HPAM,CAANA具有更好的耐温抗盐性能。在一定范围内,CAANA中引入的疏水性单体形成的缔合作用愈强,愈有利于改善聚合物的耐温抗盐性能。     

离子液体中AM/AMPS/N8AM三元共聚物的合成及溶液性能

以丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为亲水单体, 以N-辛基丙烯酰胺(N8AM)为疏水单体, 在离子液体[bmim]BF4中实现了疏水缔合丙烯酰胺三元共聚物的合成.     

疏水缔合聚丙烯酰胺的合成及溶液性能研究

水溶性疏水缔合聚合物是在聚合物亲水主链上引入极少量疏水基团(一般小于2ｍｏｌ%)而形成的一种新型水溶性聚合物[1]。由于这类聚合物具有独特的流变性能,因而备受学术界和工业界关注。目前已作为涂料增稠剂[2]和流变改性剂[3]得到了应用,而通过在部分水解聚丙烯酰胺(ＨＰＡＭ)的亲水主链上引入少量疏水单体而形成的疏水缔合聚丙烯酰胺(ＨＡＰＡＭ)则可望克服ＨＰＡＭ耐温、耐盐性差的缺陷[4]而作为新一代水溶性聚合物材料用于油气开采作业[5,6]。由于亲水单体和疏水单体的不相容性,通常通过在反应溶液中加入表面活性剂使亲水单体和疏水单体…     

含不同基团的聚丙烯酰胺改性毛细管柱的制备及应用

在丙烯酰胺、N,N-亚甲基双丙烯酰胺的混合溶液添加烯丙基胺或乙烯基磺酸钠,得到混合单体溶液,引入毛细管中,经热自由基引发原位聚合并键合到管壁上,制得化学改性的毛细管柱。通过调节烯丙基胺、乙烯基磺酸钠的加入量,得到荷电不同的聚合物。共制备了5根改性柱,发现带有氨基的聚合物涂层优于磺酸基及中性聚合物涂层。进一步比较3根氨基柱的分离效果,单体混合液中含有0.15 mol/L丙烯酰胺、0.03 mol/LN,N-亚甲基双丙烯酰胺及>1 mol/L的烯丙基胺时,制得的改性柱效果最好,可以方便地调节电渗流,并能有效抑制蛋白质的吸附,用其对鸡卵清蛋白进行区带电泳,显示出良好的分离度及重现性。     

丙烯酰胺和表面活性大单体共聚物的合成及其性能研究

首先合成表面活性大分子单体丙烯酸聚氧乙烯（２３）－十二烷基酯（ＡＡ－ＰＯＥＬＥ）,再通过与丙烯酰胺共聚合的方法得到在水溶性聚合物聚丙烯酰胺分子结构中引入疏水基团的共聚物改性ＰＡＭ。因ＡＡ－ＯＰＥＬＥ单体具有表面活性,所以共聚合时无需添加乳化剂。当改性ＰＡＭ中疏水基团含量为１．１０ｍｏｌ％时,其水溶液表现出独特的流变性和增稠性,着重讨论了改性ＰＡＭ作为乳胶增稠剂的性能。     

AM/AA/DMDAAC/OAM疏水缔合的两性共聚物的合成及性能研究

以十八醇为原料,制备长链疏水单体N-十八烷基丙烯酰胺(OAM)。以丙烯酰胺(AM)、丙烯酸(AA)、二甲基二烯丙基氯化铵(DMDAAC)、N-十八烷基丙烯酰胺(OAM)为单体,通过胶束聚合法合成了水溶性疏水缔合两性四元共聚物。利用FT-IR、1HNMR、DTA-TG对聚合物的结构和热稳定性进行分析,考察了疏水基团摩尔分数、聚合物浓度对聚合物溶液表观粘度、储能模量、耗能模量等流变性能的影响,并对四元共聚物溶液的性能进行评价。结果表明,疏水两性共聚物具有很好的耐温、抗盐、耐剪切等优异性能。     

SET-LRP法制备星型疏水缔合水溶性聚合物

采用丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸钠(NaAMPS)以及N-叔丁基丙烯酰胺(NtBA)为共聚单体,以Cu~0粉/三(2-二甲氨基乙基)胺(Me_6-TREN)为催化体系,四氯化碳(CCl_4)为引发剂,利用单电子转移自由基聚合(SET-LRP)方法合成星型疏水缔合水溶性聚合物P(AM/NtBA/NaAMPS)。采用控制变量法分别考察了引发温度、疏水单体含量、AMPS含量、引发剂用量、催化剂铜、单体浓度等因素对聚合物相对分子质量的影响,确定了最佳聚合条件并考察了聚合物的耐温抗盐性能。结果表明,当单体浓度为35%,引发温度为25℃,AM、AMPS、NtBA分别占单体总量的93.6%、5%、1.4%(摩尔比),引发剂质量分数为0.4942%,催化剂铜的质量分数为0.0848%,钝化剂的质量分数为0.1192%时,所得星型疏水缔合水溶性聚合物P(AM/NtBA/NaAMPS)的相对分子质量出现最高值为267万,同时具有一定的耐温抗盐性,其溶液性能与线型化的P(AM/NtBA/NaAMPS)相似,且在相同浓度下CaCl_2对聚合物表观粘度的影响比NaCl大。     

水溶性疏水缔合聚合物-膨润土纳米复合材料的研究

以有机改性膨润土、2-丙烯酰胺-2-甲基丙磺酸（AMPS）、 N,N-二甲基丙烯酰胺（DMAA）和季铵盐单体D-C₁₆Br为原料，通过原位聚合制备了一种新型水溶性疏水缔合聚合物-膨润土纳米复合材料。利用红外光谱、X-射线衍射仪对产物结构进行表征，并通过与纯共聚物AMPS/DMAA/D-C₁₆Br相比，研究了纳米黏土材料的引入对共聚物性能的影响。结果表明：在膨润土促进聚合物分子形成疏水缔合结构的作用下，具有复合插层结构的复合材料在热稳定性、耐温性、抗剪切性和黏弹性方面均优于纯聚合物，表明该纳米复合材料较纯共聚物具有良好的应用前景。     

Optimization of binary porogen solvent composition for preparation of butyl methacrylate monoliths in capillary liquid chromatography

Butyl methacrylate monolithic columns in 320 microm i.d. fused silica capillaries for reversed-phase capillary liquid chromatography were prepared by radical polymerization initiated thermally with azobisisobutyronitrile (AIBN). Polymerization mixture contained butyl methacrylate (BMA) as the function monomer and ethylene dimethacrylate (EDMA) as the crosslinking agent with 1,4-butanediol and 1-propanol as a binary porogen solvent. Ratio of 1,4-butanediol to 1-propanol in the porogen solvent was optimized regarding the monolithic column efficiency and performance. Total porosity, column permeability, separation impedance, Walters hydrophobicity index, retention factors, peak asymmetry factors, height equivalents to a theoretical plate and peak resolutions were used for characterization of the prepared monolithic columns. The polymerization mixture consisting of 17.8% of BMA, 21.8% of EDMA, 18.0% of 1,4-butanediol, 42.0% of 1-propanol and 0.4% AIBN generated monolithic columns of the best performance having a sufficient permeability and the lowest separation impedance. It was also demonstrated that monolithic columns of this composition exhibited good preparation reproducibility and an excellent pressure resistance when applied in capillary liquid chromatography.     

Polymer-based monolithic microcolumns for hydrophobic interaction chromatography of proteins

Monolithic capillary columns for hydrophobic interaction chromatography (HIC) have been prepared by thermally initiated, single-step in situ polymerization of mixtures of monovinyl monomers including butyl methacrylate and/or 2-hydroxyethyl methacrylate, with a divinyl crosslinker glycerol dimethacrylate or 1,4-butanediol dimethacrylate using two different porogen systems. Two porogenic solvent mixtures were used; one "hydrophilic", consisting of water, butanediol, and propanol, and one "hydrophobic," comprising dodecanol and cyclohexanol. The porous structures of the monoliths were characterized and their performance was demonstrated with a separation of a mixture of myoglobin, ribonuclease A, and lysozyme under conditions typical of HIC.     

Cation exchange/hydrophobic interaction monolithic chromatography of small molecules and proteins by nano liquid chromatography†

In this study, vinyl phenyl boronic acid modified lauryl methacrylate‐based monolithic column was successfully prepared for cation exchange/hydrophobic interaction monolithic chromatography of small molecules and proteins in nano LC. The polymeric mixture consisted of lauryl methacrylate, vinyl phenyl boronic acid as cation exchanger, ethylene dimethacrylate as cross‐linker, polyethylene glycol and methanol as binary porogenic solvent, and azobisisobutyronitrile as initiator. The resulting monolith showed good permeability and mechanical stability. Different ratios of monomer and porogens were used for optimizing the properties of the column. The monolithic column performance with respect to hydrophobic and cation exchange interactions was assessed by the separation a series of alkyl benzenes and anilines, respectively. cis‐Diol‐containing compounds such as phenols were also utilized to evaluate the retention behaviors of the vinyl phenyl boronic acid modified monolithic column. The monolithic column showed cation exchange interactions in the separation of aniline compounds. Theoretical plate number up to 52 000 plates/m was successfully achieved. The prepared monolith was further applied to the proteins with different acetonitrile content.     

Aqueous chromatographic system for separation of biomolecules using thermoresponsive polymer modified stationary phase

We have investigated a new method for HPLC using packing materials modified with a functional polymer, such as thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm). PNIPAAm-modified silica exhibits temperature-controlled hydrophilic-hydrophobic surface property changes in aqueous systems. Temperature-responsive chromatography is performed with an aqueous mobile phase without using an organic solvent. We designed ternary copolymers of NIPAAm introduced 2-(dimethyl-amino) ethyl methacrylate (DMAEMA) as a cationic monomer and butyl methacrylate (BMA) as a hydrophobic monomer. A cationic thermoresponsive hydrogel grafted surface would produce an alterable stationary phase with both thermally regulated hydrophobicity and charge density for separation of bioactive compounds. In this study, we achieved successful separation of lysozyme without the loss of bioactivity by temperature-responsive chromatography. The electrostatic and hydrophobic interactions could be modulated simultaneously with the temperature in an aqueous mobile phase, thus the separation system would have potential applications in the separation of biomolecules.     

Purification of antibody heteropolymers using hydrophobic interaction chromatography

A heteropolymer (HP) is a unique dual antibody conjugate composed of specific, chemically cross-linked monoclonal antibodies (mAbs). In this study we have demonstrated that HPs can be purified using hydrophobic interaction chromatography (HIC). Two propyl HIC resins; [PolyPropyl A and EMD Fractogel Propyl (S)] were evaluated in this study. Phosphate buffers, pH 6.5 containing ammonium sulfate or sodium sulfate were used to bind the HP to the column. A descending sulfate gradient or step gradient was used to elute the bound HP species from the column. The HP reaction mixture typically contains multiple conjugated HP species, as well as unreacted monomer mAbs. Conjugated HP product was successfully separated from unreacted antibody monomers with both propyl resins using buffers with ammonium sulfate. There was no monomer separation from HP using buffers with sodium sulfate. The purification processes, presented in this study allows the non-cross-linked antibodies to pass through the column without being bound to the resin, while the cross-linked antibodies (the HP product) bound to the column were subsequently eluted by decreasing the ammonium sulfate concentration in the running buffer. HP product was efficiently separated from free mAbs using Propyl HIC resins at both analytical and preparative scales.     

疏水层析蛋白质动力学与平衡过程的考察

疏水层析是分离生物大分子的常用技术之一，但对疏水层析中蛋白质吸附动力学和平衡过程的研究并不多见．本文对蛋白质疏水吸附动力学和平衡过程作了基本假设，并用实验进行了验证。制备了两种不同丁基密度的疏水琼脂糖介质，用其吸附牛血清白蛋白(BSA)以验证对疏水吸附动力学与平衡过程作的假设，考察了盐浓度及配基密度对蛋白质疏水吸附的影响．还对三种疏水性不同的蛋白质：核糖核酸酶、卵清蛋白和牛血清白蛋白的混合体系进行了分离性能的研究，获得了满意的分离效果．实验表明，蛋白质在疏水介质上的吸附动力学和平衡过程与所作假设相符，在实验条件下等温吸附线符合Langmuir吸附等温方程：研制的丁基琼脂糖疏水介质具有优良的使用性能。     

Separation of basic, acidic and neutral compounds by capillary electrochromatography using uncharged monolithic capillary columns modified with anionic and cationic surfactants

A mode of capillary electrochromatography (CEC), based on the dynamical adsorption of surfactants on the uncharged monolithic stationary phases has been developed. The monolithic stationary phase, obtained by the in situ polymerization of butyl methacrylate with ethylene dimethacrylate, was dynamically modified with an ionic surfactant such as the long-chain quaternary ammonium salt of cetyltrimethylammonium bromide (CTAB) and long-chain sodium sulfate of sodium dodecyl sulfate (SDS). The ionic surfactant was adsorbed on the surface of polymeric monolith by hydrophobic interaction, and the ionic groups used to generate the electroosmotic flow (EOF). The electroosmotic mobility through these capillary columns increased with increasing the content of ionic surfactants in the mobile phase. In this way, the synthesis of the monolithic stationary phase with binary monomers can be controlled more easily than that with ternary monomers, one of which should be an ionic monomer to generate EOF. Furthermore, it is more convenient to change the direction and magnitude of EOF by changing the concentration of cationic or anionic surfactants in this system. An efficiency of monolithic capillary columns with more than 140000 plates per meter for neutral compounds has been obtained, and the relative standard deviations observed for to and retention factors of neutral solutes were about 0.22% and less than 0.56% for ten consecutive runs, respectively. Effects of mobile phase composition on the EOF of the column and the retention values of the neutral solutes were investigated. Simultaneous separation of basic, neutral and acidic compounds has been achieved.     

Methacrylate monolithic capillary columns for gradient peptide separations

For the separation of peptides with gradient-elution liquid chromatography a poly(butyl methacrylate-co-ethylene dimethacrylate) (BMA) monolithic capillary column was prepared and tested. The conditional peak capacity was used as a metric for the performance of this column, which was compared with a capillary column packed with C18-modified silica particles. The retention of the peptides was found to be smaller on the BMA column than on the particulate C18 column. To obtain the same retention in isocratic elution an approximately 15% (v/v) lower acetonitrile concentration had to be used in the mobile phase. The retention window in gradient elution was correspondingly smaller with the BMA column. The relation between peak width and retention under gradient conditions was studied in detail. It was found that in shallow gradients, with gradient times of 30min and more, the peak widths of the least retained compounds are strongly increased with the BMA column. This was attributed to the fact that these compounds migrate and elute with an unfavorable high retention factor. More retained compounds are eluted later in the gradient, but with a lower effective retention factor. With shallow gradients the peak capacity of the BMA column ( approximately 90) was clearly lower than that of a conventional packed column ( approximately 150). On the other hand, with steep gradients, when components elute with a low effective retention factor, the performance of the BMA column is relatively good. With a gradient time of 15min similar peak widths and thus similar peak capacities ( approximately 75) were found for the packed and the monolithic column. Two strategies were investigated to obtain higher peak capacities with methacrylate monolithic columns. The use of lauryl methacrylate (LMA) instead of butyl methacrylate (BMA) gave an increase in retention and narrower peaks for early eluting peptides. The peak capacity of the LMA column was approximately 125 in a 60min gradient. Another approach was to use a longer BMA column which resulted in a peak capacity of approximately 135 could be obtained in 60min.     

Optimization of the porous structure and polarity of polymethacrylate-based monolithic capillary columns for the LC-MS separation of enzymatic digests

The porous structure as well as the polarity of methacrylate ester-based monolithic stationary phases has been optimized to achieve the separation of various peptides originating from enzymatic digestion. The porous structure, determined by the size of both pores and microglobules, was varied through changes in the composition of porogenic solvents in the polymerization mixture, while the polarity was controlled through the incorporation of butyl, lauryl, or octadecyl methacrylate in the polymer backbone. Both the morphology and the chemistry of the monoliths had a significant effect on the retention and efficiency of the capillary columns. The best resolution of peptidic fragments obtained by digestion of Cytochrome c with trypsin in solution was obtained in a gradient LC-MS mode using a monolithic capillary column of poly(lauryl methacrylate-co-ethylene dimethacrylate) featuring small pores and small microglobules. Raising the temperature from 25 to 60 degrees C enabled separations to be carried out at 40% higher flow rates. Separations carried out at 60 degrees C with a steeper gradient proceeded without loss of performance in half the time required for a comparable separation at room temperature. Our preparation technique affords monolithic columns with excellent column-to-column and run-to-run repeatability of retention times and pressure drops.     

Methacrylate monolithic columns for capillary liquid chromatography polymerized using ammonium peroxodisulfate as initiator

Four methacrylate ester‐based monolithic columns for capillary liquid chromatography (CLC) were prepared by radical polymerization with ammonium peroxodisulfate (3 columns) and by thermal initiation (1 column). The polymerization mixture consisted of butyl methacrylate (BMA) and ethylene glycol dimethacrylate (EDMA), propan‐1‐ol, butane‐1,4‐diol, water, and ammonium peroxodisulfate as initiator. It was necessary to add N,N,N′,N ′‐tetramethylethylenediamine (TEMED) to the polymerization mixture to activate the reaction. The amount of initiator and activator was optimized to attain quantitative polymerization. The reproducibility of three columns prepared at ambient temperature was studied. The most efficient column with HETP of 29 μm for uracil was compared to the monolithic column prepared by thermal initiation with α,α′‐azobisisobutyronitrile (AIBN). The efficiencies of all the test columns were characterized by van Deemter curves. Their total porosities were calculated from the retention time of uracil. Walters indices of hydrophobicity (HI) were calculated from the retention factors of anthracene and benzene. The columns prepared by both methods are comparable in their selectivities and efficiencies. They show the same characteristics because their total porosities and Walters indices of hydrophobicity are consistent. However, the preparation of monoliths using ammonium peroxodisulfate was less demanding, because polymerization was possible at ambient temperature.