Theophylline molecular imprint composite membranes prepared from poly(vinylidene fluoride) (PVDF) substrate

Theophylline molecular imprint composite membranes were prepared on the PVDF membrane substrate through the free radical polymerization method using theophylline as a template, methacrylic acid (MAA) as a functional monomer, and ethylene glycol dimethacrylate (EDMA) as a cross-linker. The binding constant (K) for the formation of monomer–template adduct was determined by means of infrared spectroscopy titration and nonlinear least-squares method. Theophylline (K=140 M^?1) can form more specific binding sites with MAA than caffeine (K=83 M^?1), therefore was chosen as the template. An effective ultrasonic cleaning method was used to remove the bound theophylline templates from the polymerized PVDF membrane. The reaction conditions were investigated to optimize the maximum binding capacity of theophylline templates to the PVDF membrane. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and contact angle measurement were used to study the surface chemistry, morphological structure and hydrophilicity of theophylline molecular imprint composite membranes. The specific binding capacities of theophylline imprint membranes were investigated by both single molecule and multi-molecule solution filtration experiments, respectively.     

Synthesis of highly selective spherical caffeine imprinted polymers via ultrasound‐assisted precipitation polymerization

A facile and efficient method for synthesis of molecularly imprinted polymers via ultrasound‐assisted precipitation polymerization was developed. Caffeine was applied as a model template in the imprinting using methacrylic acid and ethylene glycol dimethacrylate as a functional monomer and a crosslinker, respectively. Polymerization under sonochemical conditions proceeded rapidly (within 3 h at 60°C) to afford polymer microspheres with narrow size distributions in excellent yields while maintaining the binding specificity toward the template. It was found that the imprinted polymer prepared at low initial temperature (40°C) exhibited the best caffeine binding performance in terms of specificity and selectivity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Molecularly imprinted hydrogels for application in aqueous environment

Molecularly imprinted thermoresponsive hydrogels for dopamine recognition were synthesized using N-isopropylacrylamide as the temperature-sensitive element, methacrylic acid or itaconic acid as functional monomer and N,N’-methylenebisacrylamide or ethylene glycol dimethacrylate as crosslinking agent. The stoichiometry of the template–functional monomer prepolymerization complexes was determined by ¹H NMR experiments according to the Job method of continuous variation as well as signal line width analysis. It was found that dopamine hydrochloride forms complexes with methacrylic acid and itaconic acid with 1:3 and 2:3 template to functional monomer stoichiometry, respectively. Hydrogels composed of itaconic acid and with appropriate template content revealed the highest efficiency of imprinting process and relatively high selectivity of dopamine hydrochloride rebinding in water near the phase transition temperature.     

单体对分子印迹聚合物分子识别能力的影响：量子化学计算与实验研究

采用密度泛函方法计算功能单体与印迹分子的结合能,以与目标分子结合能最大的单体分子来合成分子印迹聚合物.为此,以茶碱为印迹分子,氯仿为溶剂,首先计算了茶碱与甲基丙烯酸、丙烯酰胺和三氟甲基丙烯酸的结合能,其强度顺序为：三氟甲基丙烯酸 > 甲基丙烯酸 > 丙烯酰胺.然后以茶碱为印迹分子、氯仿为溶剂、二甲基丙烯酸乙二醇酯为交联剂,分别采用上述3种单体合成分子印迹聚合物并测定了其分子识别能力,实验结果和量子化学计算结果具有一致性.最后,采用1H NMR考察了茶碱和上述3种单体之间的氢键作用,揭示出二者相互作用的内在机制.研究结果表明量子计算方法可以应用于合成分子印迹聚合物时单体的选择.     

桐油酸改性含环氧基团聚丙烯酸酯乳液的制备

摘要：以丙烯酸丁酯（BA）、甲基丙烯酸甲酯（MMA）、丙烯酸羟乙酯（HEA）为主要单体，桐油酸和甲基丙烯酸缩水甘油酯（GMA）为功能性单体，采用半连续乳液聚合法制备了一系列桐油酸改性含环氧基团聚丙烯酸酯乳液（简称改性聚丙烯酸酯乳液）。通过FTIR表征胶膜的结构，同时测定了胶膜的力学性能、耐酸耐碱性等。结果表明：当桐油酸添加量（以MMA、BA、HEA、GMA的总质量为基准）为4%时，随着GMA含量（即GMA的质量占总丙烯酸单体质量的百分数，下同）的增加，胶膜铅笔硬度增大，耐水、耐酸碱性能增强，拉伸强度增大，热稳定性增加，胶膜附着力增加。当GMA含量为12%时，胶膜铅笔硬度为4H，涂在马口铁上的胶膜在5%的盐酸溶液中浸泡144 h无变化，在5%的氢氧化钠溶液浸泡72 h无变化，24 h的吸水率为3.31%，附着力为0级。     

Preparation of water‐compatible molecularly imprinted polymers for caffeine with a novel ionic liquid as a functional monomer

Water‐compatible molecularly imprinted polymers (MIPs) for caffeine were synthesized in aqueous medium with a new functional monomer, 1‐(α‐methyl acrylate)‐3‐methylimidazolium bromide (1‐MA‐3MI‐Br), which had π–π and hydrogen‐bonding interactions. Caffeine‐imprinted polymers were prepared in suspension polymerization with 1‐MA‐3MI‐Br and methacrylic acid (MAA), which only had hydrogen bonding, as a functional monomer. For the specific binding characteristics of the new functional monomer 1‐MA‐3MI‐Br, the adsorption capacity and relative separation factor (β) of MIPs for caffeine were significantly enhanced. The maximum adsorption capacities of 1‐MA‐3MI‐Br–MIP and MAA–MIP imprinted microspheres for caffeine were 53.80 and 28.90 μmol/g, respectively. Moreover, the relative separation factors were measured by comparison of the separation characteristics under competitive adsorption conditions. The results showed that the β of MAA–MIP for caffeine relative to theophylline was only 1.65; this showed a very poor recognition selectivity for caffeine, but β of 1‐MA‐3MI‐Br–MIP for caffeine with respect to theophylline was remarkably enhanced to 3.19; this showed an excellent recognition selectivity and binding affinity toward caffeine molecules in an aqueous environment. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

不同功能单体制备的S-萘普生印迹聚合物材料的性能

以S-萘普生为模板,分别采用丙烯酰胺(AM)、N-乙烯基吡咯烷酮(NVP)和甲基丙烯酸(MAA)3种功能单体,合成了印迹聚合物P1、P2和P3。用UV和Chem 3D计算模拟,研究了功能单体与模板分子之间的相互作用,经PM3半经验方法计算得到AM、NVP、MAA与模板分子之间的相互作用能分别为-32.06、-21.01和-1.55kJ/mol。平衡结合实验测得当底物浓度为0.1 mmol/L时,P1、P2和P3的吸附量分别为0.360、0.305和0.150μmol;在浓度为0.1~4 mmol/L时,3种分子印迹聚合物对S-萘普生的吸附量大小关系为P1>P2>P3,这与计算出的功能单体与模板分子之间的相互作用能大小关系一致。     

咖啡因分子印迹物的制备及其性能研究

采用分子印迹技术，以咖啡因为模板分子，丙烯酰胺为功能单体，二甲基丙烯酸乙二醇酯为交联剂，偶氮二异丁腈为引发剂，在氯仿中本体聚合方式制备了咖啡因分子印迹聚合物。紫外分光光度法对功能单体与模板分子之间聚合进行考察，结果表明，通过咖啡因分子印迹聚合物的制备，可实现咖啡因与结构类似物的分离和精制。     

红霉素分子印迹聚合物纳米微球的制备及其吸附特性

以红霉素为模板分子、甲基丙烯酸为功能单体、乙二醇二甲基丙烯酸酯为交联剂,采用沉淀聚合法制备了粒径均一的红霉素纳米分子印迹聚合物微球,优化了分子印迹聚合物的合成条件,确定了模板分子与功能单体的最佳摩尔比为1:3,对其进行了表征. 结果表明,所制聚合物对红霉素的实际最大吸附量可达202.12 mg/g,吸附约200 min达到平衡,对红霉素具有良好的选择性吸附能力.     

以乙烯基吡咯烷酮为功能单体的金属配合印迹聚合物的制备及水相识别

Using nickel（II） acetate.-2,2＇-dipyridyl complex as template and N-vinyl-2-pyrrolidone （NVP） as coordinate functional monomer,.a new kind of metal-compiexing template molecularly impnnted polymer （MIP） was prepared..The results of equilibri.um binding experiments in. aqueous solution showed that the MIP had higher＇binding capacity for nickel（ II ）-2,2＇-dipyridyl than the non-imprinted polymer with the same chemical composition. Theinfluences of metal ions and pHof solution on the recognition performance of MIP were investigated. The bindingcharacteristics of MIP were evaluated by the Scatchard analysis with one-site and two-site binding equations, respectively. The results on substrate selectivity of imprinted polymer revealed that MIP had better binding affinityfor template among thetested compounds.     

牺牲硅胶法制备烟酸分子印迹聚合物及其性能研究

选用薄层层析硅胶作为牺牲载体,以烟酸为模板分子,丙烯酰胺为功能单体,乙二醇二甲基丙烯酸酯为交联剂,合成了烟酸分子印迹聚合物(MIPs).通过考察功能单体种类及用量、交联剂用量及硅胶用量确定了制备MIPs的最佳工艺条件,制备得到的MIPs吸附容量达到78.5 μmol·g-1.以烟酰胺作为竞争底物考察MIPs的特异吸附性...     

硫丹分子印迹聚合物的合成及吸附特性分析

采用分子印迹技术,以α-甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,乙腈为致孔剂,合成以硫丹为模板的印迹聚合物微球。首先利用紫外光谱方法研究了模板与功能单体相互作用情况,采用平衡吸附试验对印迹聚合物吸附效率进行了表征,与化学组成相同的空白聚合物相比,印迹聚合物微球对模板分子具有更高的吸附效率,按最佳合成条件得到的印迹聚合物最大表观吸附量达42.56 mmol/g。     

自交联型改性苯丙乳液的制备及其用于防水涂料的性能研究

以丙烯酸（AA）、丙烯酸丁酯（ BA）和苯乙烯（St）为基础单体,通过调控功能单体甲基丙烯酸缩水甘油酯（ GMA）的用量制备了一种自交联型改性苯丙乳液（ PGSA）对乳液粒径大小与分布、形态与形貌以及乳液涂膜吸水性能进行了表征。以 PGSA乳液为液料辅以无,机水泥等填料制备了双组分聚合物水泥防水涂料,对其抗渗及力学性能进行了研究。结果表明：当 GMA用量为 7%时（以单体 AA、BA和 St的总质量计）,PGSA乳液的粒径为 210 nm、粒径分布（PDI）为 0. 17~0. 21,且放置 6个月后乳液的粒径及分布基本保持不变。此外,随着 GMA用量的增加, PGSA乳液涂膜的吸水率呈下降趋势。 PGSA基防水涂料的抗渗性、抗拉强度及断裂伸长率都符合 GB/T 23445—2009《聚合物水泥防水涂料》标准的要求,应用前景广阔。     

甲基对硫磷分子印迹聚合物制备中溶剂和功能单体的影响

为了有效的分离富集水样中的有机磷农药,以甲基对硫磷为模板、二甲基丙烯酸乙二酯为交联剂,采用传统方法制备了甲基对硫磷分子印迹聚合物(MIPs).考察了三种溶剂和三种功能单体及其用量对MIPs吸附性能的影响.结果表明,以氯仿为溶剂制得的MIP特异性最强,溶剂用量对MIPs比表面积和溶胀比的影响显著.氯仿用量为35 mL时MIP性能最理想;~1H-NMR研究显示,4-乙烯基吡啶(4VP)与模板分子通过π-π堆积作用形成稳定的复合物,按4VP与模板分子摩尔比4:1制得的MIP特异性和亲和性较理想.测定了该MIP的吸附等温线,利用Langmuir等温式分析结果,得出其饱和吸附量为625.5 μmol·g~(-1),明显高于非印迹聚合物的饱和吸附量285.7 μmol·g~(-1).利用该MIP对模拟海水样品进行研究,结果显示,MIP对不同有机磷农药的吸附能力表现出一定的差异.通过进一步优化,提高MIPs的选择性,该材料有望用于水样中甲基对硫磷的分离富集和分析.     

Effects of water on the long‐term properties of Bis‐GMA and silylated‐(Bis‐GMA) polymers

Bis‐GMA (2,2‐bis‐[4‐(2‐hydroxy‐3‐methacryloxypropoxy)phenyl]propane) is a viscous hygroscopic monomer which is used with triethyleneglycol‐dimethacrylate (TEGDMA) for dental restorations. Bis‐GMA was silylated with dimethyl‐isopropyl‐siloxane and further polymerized in order to increase water resistance and viscosity. The viscosity of the silylated monomer, Sil·Bis‐GMA, was 50 times lower than that of the parent monomer. After 1 month in water, poly(Bis‐GMA/TEGDMA) absorbed 2.6% water and the silylated polymer, poly(Sil·Bis‐GMA), only 0.56%. During this process water extracted residual monomer from each polymer. The behavior of water sorption and desorption as a function of time in poly(Sil·Bis‐GMA) was completely different from that shown by poly(Bis‐GMA/TEGDMA). The difference is discussed in terms of diffusion coefficients. Initially, water advancing contact angles (θ_ADV) were 75° and 95°, respectively. After 1 month in water both polymers showed a reduction of about 20° in θ_ADV. In poly(Bis‐GMA/TEGDMA), the reduction in θ_ADV obey to water absorption and bulk plasticization; it showed a reduction of 15°C in glass transition temperature, T_g. In contrast, the reduction in θ_ADV in poly (Sil·Bis‐GMA) obeyed to water adsorption and reorientation of the molecules at the surface in contact with the water phase; it only showed a change of 2°C in T_g. Contact angle hysteresis provided further evidence about plasticization. According to our results poly(Sil·Bis‐GMA) is more stable in water than poly(Bis‐GMA/TEGDMA). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

D-对羟基苯甘氨酸分子印迹聚合物的制备及分子识别能力

以D-对羟基苯甘氨酸（D-HPG）为模板分子,以丙烯酰胺（AM）和α-甲基丙烯酸（MAA）为功能单体,乙二醇二甲基丙烯酸酯为交联剂,合成了D-HPG分子印迹聚合物,并测定其对D-HPG的识别能力。静态吸附实验表明,以MAA为功能单体制备的分子印迹聚合物具有更强的分子识别能力,其饱和吸附量达43.9 μmol•g^-1,印迹因子α为3.6。分子力学计算表明,MAA与D-HPG形成复合物的结合能较大,且MAA在乙醇和水中的溶剂化能较小,因此与AM比较,MAA和模板分子D-HPG在乙醇和水中能形成更加稳定的复合物。紫外光谱分析表明,MAA与D-HPG之间的结合力比AM与D-HPG之间的结合力要强,与分子力学计算以及静态吸附实验得到的结果相一致。     

Computer simulation and synthesis of stimuli‐responsive polymer by sol‐gel for selective recognition of (4‐chloro‐2‐methylphenoxy)acetic acid

A novel photoresponsive functional monomer bearing a siloxane polymerizable group and azobenzene moieties was synthesized, and then photoresponsive molecularly imprinted sol‐gel polymers were successfully fabricated from the synthesized functional monomer, using (4‐chloro‐2‐methylphenoxy)acetic acid (MCPA) as a molecular template. The photoisomerization properties of the functional monomer are retained after incorporation into the rigid three‐dimensional crosslinked polymer matrix. The template is then removed from the resulting polymer to generate pores, which are complementary to the template in shape, size and functionality. The substrate affinity of the molecularly imprinted polymer (MIP) receptor sites is photoswitchable. This can be attributed to the photoisomerization of azobenzene chromophores within the MIP receptors, resulting in alteration of their geometry and the spatial arrangement of their binding functionalities. The binding affinity of the imprinted recognition sites was switchable by alternate irradiation with UV and visible light, suggesting that azobenzene groups located inside the binding sites could be used as chemical sensors and the trans–cis isomerization could regulate the affinity for MCPA. To study the hydrogen bond interactions between template molecules and functional monomer, computational molecular modeling was employed. The data indicate that the design of the MIP is rational. Copyright © 2012 Society of Chemical Industry     

分子印迹杂化材料的溶胶-凝胶法制备及选择性固相萃取牛奶中洛美沙星

以兽药洛美沙星为模板分子,3-氨基丙基三乙氧基硅烷为功能单体,甲基三甲氧基硅烷为交联剂,采用溶胶-凝胶分子印迹技术,以离子对及疏水作用方式,在水相体系中合成了具有分子识别作用的的新型有机-无机杂化分子印迹聚合物。静态吸附和Scatchard分析实验结果表明,此印迹材料对洛美沙星的结合存在两个结合位点,最大吸附容量分别为95.65与127.45μmol/g。以此印迹材料作为固相萃取剂,优化萃取条件,成功应用于牛奶中洛美沙星测定。     

Molecularly Imprinted Polymers Based on Chitosan for 2,4-Dichlorophenoxyacetic Acid Removal

The development of low-cost and eco-friendly materials for the removal of pollutants from water is one of the main modern challenges. For this purpose, molecularly imprinted polymers were prepared under optimized conditions starting from chitosan (CS), chemically or ionically modified with glycidyl methacrylate (GMA) or itaconic acid (ITA), respectively. 2,4-Dichlorophenoxyacetic acid (2,4-D) was used as a template, obtaining the CS_GMA and CS_ITA series. The influence of the template concentration on the MIPs’ (molecularly imprinted polymers) morphology, thermal behaviour and swelling ability, as well as on the 2,4-D removal capacity, were analyzed. The amount of the template used for the imprinting, together with the different permeability of the matrices, were the key factors driving the analyte uptake process. Despite the good performance shown by the non-imprinted CS_GMA sample, the best results were obtained when CS_GMA was imprinted with the highest amount (5%) of template (CS_GMA_5). This system was also more efficient when consecutive adsorption experiments were carried out. In addition, CS_GMA_5 had a desorption efficiency of 90–100% when a low pesticide concentration was used. These findings suggest that the presence of imprinted cavities could be useful in improving the performance of sorbent materials making CS_GMA_5 a possible candidate for 2,4-D removal.