葡聚糖接枝型高载量金属螯合介质的制备与性能

对琼脂糖凝胶微球进行烯丙基活化,再接枝葡聚糖分子,考察葡聚糖分子量等因素对葡聚糖接枝过程的影响;以葡聚糖接枝琼脂糖凝胶微球为基质,制备亚氨基二乙酸型金属螯合介质,考察葡聚糖接枝过程对金属螯合介质的孔道结构、流通性能和载量等的影响. 结果表明,分子量20~500 kDa的葡聚糖都能均匀分布于琼脂糖凝胶微球内,葡聚糖接枝量随分子量增加而增大,所制的金属螯合介质形貌、粒径及其分布基本不受影响,且具有更好的流通性能,孔道结构比商品介质Ni Sepharose 6FF更丰富. 葡聚糖接枝的金属螯合介质对带组氨酸标签的乳酸脱氢酶和睫状神经营养因子的载量分别达到19和27 mg/mL,较Ni Sepharose 6FF的载量分别提高26.6%和42.0%.     

共聚物接枝蛋白离子交换色谱介质制备及性能

高容量蛋白质色谱介质是色谱过程高效化的材料基础和重要前提。采用原子转移自由基聚合（ATRP）技术,以甲基丙烯酸3-磺酸丙酯钾和甲基丙烯酸甲酯（MMA）为单体化合物合成了多种无规共聚物接枝离子交换色谱介质,并对其蛋白质吸附性能进行研究。单体总浓度一定情况下共聚物接枝色谱介质孔道半径（r_pore）随MMA浓度升高而增大,反映出接枝共聚物链渐趋塌陷的特征。蛋白质吸附结果表明,溶菌酶吸附容量取决于介质的离子交换容量;而抗体吸附容量则与rpore及相应的聚合物层厚度变化密切相关。随着聚合物层厚度的增大,聚合物层对抗体的空间排阻作用增强,抗体吸附容量下降。此外,引入MMA优化共聚物分子链可显著提高蛋白质吸附量,在SEP-gS30/M30介质中抗体和溶菌酶的饱和吸附量分别达到237 mg·g^-1和380 mg·g^-1。无规共聚物接枝离子交换色谱介质孔道内聚合物层厚度和蛋白质吸附也受无机盐浓度调控。     

氯化接枝法制备高性能氯化聚乙烯

报道了在氯化聚合物大分子链上进行接枝及引进各种官能团的方法——氯化接枝法。该方法可以有效地制备特殊性能或含有官能团的含氯聚合物，并可进行分子结构和材料结构的设计。     

葡聚糖接枝型耐碱Protein A介质的层析性能提升研究

Sepharose 4FF微球经环氧活化后与葡聚糖溶液反应,得葡聚糖接枝型琼脂糖微球,再经环氧活化和偶联耐碱型Protein A配基,得葡聚糖接枝型高载量Protein A介质,测定了介质在线清洗稳定性能,并进行了热力学研究. 结果表明,与常规Protein A介质相比,葡聚糖接枝型Protein A介质的最高流速提高约32%,对抗体hIgG的动态载量为60.6 mg/mL,分别为常规介质和MabSelect SuRe介质载量的123%和95%;经40次清洗后,葡聚糖接枝型Protein A介质动态载量为原始载量的92%,远高于常规介质的84%,与MabSelect SuRe稳定性基本一致. 3种介质对抗体的结合均为熵驱动过程,葡聚糖接枝型Protein A介质的吸附热介于MabSelect SuRe和常规Protein A介质之间.     

反离子对牛血清白蛋白在荷电葡聚糖接枝介质中色谱行为的影响

从前期开发的具有极高的吸附容量及传质速率的二乙氨乙基葡聚糖接枝离子交换介质中选取FF-D50-DexD100和FF-DexD100为典型代表,利用Cl^-、SCN^-、SO₄^2-、HPO₄^2-为模型反离子,以牛血清白蛋白（BSA）为模型蛋白,以商品化介质（Q Sepharose FF、Q Sepharose XL、DEAE Sepharose FF）为对照,在离子强度为0.06mol/L下,系统研究反离子对二乙氨乙基葡聚糖接枝介质的蛋白质吸附与洗脱行为的影响。结果表明,二乙氨乙基葡聚糖接枝介质对不同反离子的偏好性存在差异,且该偏好性差异与基团所处位置（接枝链配基或表面配基）无关。同时,介质偏好性弱的反离子会通过促进二乙氨乙基葡聚糖接枝介质的“链传递”效应加快蛋白质的传质速率,从而提高动态吸附容量。因此,在使用二乙氨乙基葡聚糖接枝介质进行蛋白质色谱柱分离过程中,可在吸附操作中使用HPO₄^2-,在洗脱操作中使用SCN^-来优化分离效果。     

十字型微通道制备粒径均一的纤维素层析介质

为了满足层析介质对粒径单分散的要求,利用十字型微通道的聚焦效应,形成粒径均一的纤维素微液滴,经固化成纤维素微球,再偶联配基制成了纤维素层析介质。以离子液体1-乙基-3-甲基咪唑甲基磷酸直接溶解微晶纤维素为水相,葵花籽油为油相,考察了微通道内微液滴的形成条件,优化了纤维素浓度、分散剂浓度、油水两相流速等因素,得到粒径约100 μm的纤维素微液滴,CV值小于0.2。微液滴固化再生,得到球形度良好的纤维素微球,湿真密度1.019 g·ml^-1,孔度94.6%,体均粒径105.5 μm;进一步偶联DEAE配基,制得了离子交换层析介质,离子交换容量为123.3 μmol·g^-1,牛血清白蛋白的饱和吸附容量Q_m达到220 mg·g^-1,有效扩散系数D_e为1.8×10^-11m²·s^-1,体现出较好的蛋白质吸附性能。     

甘蔗渣接枝技术研究进展

甘蔗渣（SCB）作为一种重要的植物纤维,是可再生资源,其接枝技术日益受到重视。本文先介绍了SCB的结构、物理化学性质以及接枝机理,再重点评述了预处理方式、不同的接枝单体和溶剂、引发方式对SCB接枝的影响。预处理破坏了SCB的超分子结构从而提高SCB的反应可及性;一般溶剂不能破坏SCB的多相结构,反应在SCB表面进行,纤维素溶剂和一些二元体系溶剂可溶解SCB而实现分子水平上的接枝;引发剂浓度对接枝率的提高有一个最佳范围;接枝单体用量直接影响接枝率。最后指出SCB接枝物在离子交换、重金属离子吸附、吸油和吸水保水等方面的应用前景,并建议SCB接枝技术应向着接枝效率高、接枝物性能稳定、工艺绿色环保和开发成本低等方向发展。     

高性能化CPE接枝共聚物的制备与表征

以高密度聚乙烯(HDPE)为原料,甲基丙烯酸缩水甘油酯(GMA)为接枝单体,采用氯化原位接枝法,得到官能化氯化聚乙烯接枝聚合物(CPE-cg-GMA)。实验通过红外光谱(IR)、差示扫描量热(DSC)分析、扫描电镜(SEM)分析等表征手段对接枝共聚物的结构进行了初步探讨。结果表明,HDPE与GMA单体氯化原位接枝过程,接枝到HDPE骨架上的环氧基团水解形成了羟基,与其它大分子之间形成了氢键。此外,由于接枝链的存在,使大分子的结晶度与CPE相比显著降低,同时CPE-cg-GMA的综合力学性能大幅度提高。     

辐射接枝法生产离子交换纤维的进展

介绍了辐射接枝生产离子交换纤维的主要方法 :共辐射接枝法、无氧预辐射接枝法和有氧预辐射接枝法。比较了这些方法的优缺点 ,指出有氧预辐射接枝更适合于工业化生产。对今后辐射接枝生产离子交换纤维的发展进行了展望     

化学接枝技术

化学接枝技术费用较低,所得涂层较薄,并且在稳定性,使用寿命和性能上均优于常规的涂层方式,是一种在化工领域中应用前景广泛的高新技术。     

三聚氰胺改性木质素的制备及银离子吸附性能

以酶解木质素、三聚氰胺和甲醛为原料,通过接枝反应制备三聚氰胺改性酶解木质素(MEHL),并研究MEHL对银离子的吸附性能。接枝反应的研究结果表明,三聚氰胺和甲醛的添加量对产率有很大影响。酶解木质素、三聚氰胺、甲醛质量比为10:6:6,于90℃下反应4 h,所制得的MEHL的产率可达83.7%。红外光谱、热重和元素分析的结果表明,三聚氰胺成功接枝到酶解木质素分子上。MEHL的含氮量由酶解木质素的0.81%提高到18.55%。银离子的吸附研究表明,MEHL对银离子表现出很好的吸附性能。在银离子初始浓度为0.16 mol·L^-1,在MEHL用量为50 mg,吸附温度为30℃时吸附36 h,MEHL对银离子的吸附容量为944.1 mg·g^-1。     

Adsorption of Hg2+ on a novel chelating fiber prepared by preirradiation grafting and amination

A novel chelating fiber was prepared by the irradiation‐induced grafting copolymerization of glycidyl methacrylate on polypropylene fiber and consequent amination with diethylenetriamine. The effects of the reaction conditions, such as reaction time, temperature, and monomer concentration, on the degree of grafting were investigated. The optimal conditions for grafting were found to be 3 h, 100°C, and a 50% (v/v) glycidyl methacrylate concentration in tetrahydrofuran solution. This fiber showed good adsorption performance at different concentrations of Hg²⁺, in particular for trace Hg²⁺. Under the adsorption conditions of pH = 4, initial concentration = 1000 mg/L, and time = 20 h, the adsorption capacity of the chelating fiber for Hg²⁺ reached 785.28 mg/g. It completely adsorbed the Hg²⁺ ions in solution within a short contact time, showing a very high adsorption rate for Hg²⁺. Furthermore, the chelating fiber also had a high selectivity for mercury, whereas Cu²⁺ coexisted in different concentrations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Fractionation of dextran using repetitive batch chromatography

The fractionation of broad dextran fractions using preparative scale gel permeation chromatography has been carried out. A batch system was used, consisting of ten borosilicate columns, each of 5.1 cm i.d. and 70 cm long and packed with Spherosil XOB075 porous silica beads. The repetitive injection technique was employed and the effects of feed, charge volume and concentration on the molecular weight distribution of the products were evaluated.     

Preparation of an anion‐exchange adsorbent by the radiation‐induced grafting of vinylbenzyltrimethylammonium chloride onto cotton cellulose and its application for protein adsorption

Poly(vinylbenzyltrimethylammonium chloride)‐graft‐cotton cellulose, an anion‐exchange matrix, was synthesized by a mutual radiation‐induced grafting technique with a ⁶⁰Co γ‐radiation source. The grafted matrix was characterized by grafting yield estimation, elemental analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The grafting yield decreased with the increase in the dose rate. However, the grafting yield and nitrogen content of grafted samples increased almost linearly with an increase in the total irradiation dose. To evaluate the performance of the grafted anion‐exchange matrix, the protein adsorption and elution behavior were investigated in a continuous column process under various experimental conditions, with bovine serum albumin used as a model protein. The binding and elution behavior of the anion‐exchange matrix depended on different experimental parameters, such as the grafting yield, ionic strength, pH of the medium, and amount of protein loaded. From a breakthrough curve, the equilibrium binding capacity and elution percentage of the grafted anion‐exchange matrix were estimated to be 40 mg/g and 94%, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5512–5521, 2006     

Preparation of ion exchange membranes by preirradiation induced grafting of styrene/divinylbenzene into crosslinked PTFE films and successive sulfonation

Ion exchange membranes (IEMs) were prepared by preirradiation induced grafting of styrene with or without divinylbenzene (DVB) into crosslinked polytetrafluoroethylene (RX‐PTFE) films and successively sulfonated by chlorosulfonic acid. The effects of the DVB concentration and solvent on the kinetic of the graft polymerization were studied. The ion exchange capacity (IEC) values of the prepared membranes ranging from 1.5 to 2.8 mequiv/g were obtained. The degree of swelling increased with the increase in the degree of grafting, while higher crosslinking density of both the RX‐PTFE matrices and the grafts suppressed the degree of swelling. The chemical stabilities of the IEMs were tested by recording the weight of the membranes being soaked in hot H₂O₂ solutions. The weight‐time curves of the prepared membranes showed one‐step quick decrease due to the decomposition of the poly(styrene‐sulfonic acid) (PSSA) grafts. Higher crosslinking density in both the RX‐PTFE matrices and the grafts improved the chemical stability of the IEMs. The ionic conductivity of the IEMs increases with the increase in the IEC values. The IEMs with IEC values higher than 2.2 mequiv/g hold the higher ionic conductivity than that of Nafion® 112 membrane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3587–3599, 2006     

Protein adsorption onto diethylaminoethyl dextran modified anion exchanger: Effect of ionic strength and column behavior

Our previous studies on bovine serum albumin(BSA) adsorption to diethylaminoethyl dextran(DEAE dextran,DexD, grafting-ligand) and DEAE(D, surface-ligand) modified Sepharose FF resins found that all the grafted resins(FF-DexD and FF-D-DexD) exhibited extremely fast uptake rate(effective diffusivity, D_e, D_e/D_O 1.4),which was six times greater than the ungrafted resins(D_e/D_O 0.3). In this work, the influence of ionic strength(IS) on 6 typical DEAE dextran-grafted resins was investigated. Bath adsorption equilibria and kinetics, breakthrough, and linear gradient elution experiments were conducted. Commercial DEAE Sepharose FF was used for comparison. It is found that protein adsorption capacities on DEAE dextran-FF resins and the commercial resin decreased with increasing IS, but DEAE dextran-FF resins exhibited much higher capacity sensitivity to salt concentration. Besides, steeper decrease of adsorption capacities could be obtained at higher graftingligand or surface-ligand density. It is worth noting that the facilitating role of surface-ligand to the "chain delivery" effect was weakened after adding salt, leading to the less improvement in uptake rate by increasing surface-ligand density at higher IS. Although the uptake rates of the DEAE dextran-FF resins increased first and then decreased with increasing IS, they kept the extremely high level of De values(D_e/D_O 1.1) at the their working/binding IS range. Moreover, the DEAE dextran-FF resin displayed much higher adsorption capacities and De values than commercial ungrafted resin in their working condition. Furthermore, the column results of DEAE dextran-FF resins presented higher dynamic binding capacities than and similar elution ISs with DEAE Sepharose FF to achieve similar(or even higher) recoveries suggest the excellent chromatographic column performance of the DEAE dextran-FF resins. Finally, both high recovery and purity of BSA and γ-globulin could be easily achieved using the typical DEAE dextran-FF column, FF-D60-DexD160, to separate their binary mixtures,by step gradient elution. The research has provided new insights into the practical application of the series of DEAE-dextran grafted resins in protein chromatography and proved their superiority.     

Preparation of acrylic acid grafted polypropylene nonwoven fabric by photoinduced graft polymerization with preabsorption of monomer solution

We improved photoinduced graft polymerization by absorbing the monomer solution onto the substrate (Ab‐type) instead of immersing the substrate in the monomer solution (Im‐type) before photoirradiation to yield a more practical and effective grafting system. With this system, acrylic acid (AA) was effectively grafted onto polypropylene (PP) nonwoven fabric. The maximum degree of grafting obtainable was restricted by the amount of monomer preabsorbed onto the PP fabric. However, we effectively enhanced the degree of grafting by increasing the monomer concentration, adding trimethylolpropane triacrylate (TMPTA) to the monomer solution, and repeating the photoirradiation with supplementation of the monomer solution. The net availability of the monomer for graft polymerization was 50% or greater; this increased to 90% or greater with the addition of TMPTA and was much higher than for conventional Im‐type photografting (≤13%). Fourier transform infrared spectra, scanning electron microscopy morphology observations, and the adsorption–regeneration properties confirmed that the PP‐g‐AA fabric prepared by the improved Ab‐type photografting method had comparable qualities to those of fabric prepared by conventional Im‐type photografting. Thus, the improved Ab‐type photografting system provides potential for the preparation of graft adsorbents on a large scale at a competitive cost with a continuous reactor, such as a conveyer belt system, instead of a batch reactor. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

共价接枝蛋白分子改善聚苯乙烯生物填料表面性能

采用氧化和接枝蛋白分子的方法,在聚苯乙烯生物填料表面提高了原有亲水性基团的比例,同时引入了新的亲水基团和细胞识别位点.对比氧化、未氧化直接接枝、氧化后接枝3种处理方法,发现表面能分别从42 mJ·m^-2提高到74.77、119.5、172.3 mJ·m^-2;C—C键比例分别下降了26.56%、18.64%和32.21%,C—O键比例分别提高了17.78%、16.35%和25.56%,并且新增加了—(C=O)—O—、—(C=O)—NH等有亲水性质的化学键;利用配制模拟废水对氧化后接枝蛋白分子填料进行动态培养生物挂膜试验,结果表明改性后的填料生物膜初期附着速率和增长量明显高于未经改性的生物填料.     

离子交换法脱除磷酸中锰离子的动态吸附研究

近年来离子交换技术在湿法磷酸净化领域得到了广泛的发展与应用。采用Sinco-430型阳离子交换树脂脱除磷酸中的锰离子,考察了流量、磷酸溶液初始锰浓度、温度对吸附效果的影响。结果表明：增大进液流量、提高溶液初始锰浓度以及升高温度均有利于缩短树脂饱和时间,但进液流量的增大会降低树脂的吸附率,而温度的升高则会降低树脂的饱和吸附量。在进液流量为4.0 mL/min、溶液初始锰质量浓度为10.22 mg/mL、体系温度为35 ℃的条件下,树脂对锰离子的饱和吸附量为64.76 mg/g、吸附效率为63.55%。采用Thomas,Yoon-Nelson和Yan 3种吸附模型对动态吸附过程数据进行拟合,发现Yan模型的拟合效果最佳,而且由其计算得出的饱和吸附量与实验测定值的相对偏差在6.93%~10.91%。