聚羧酸系超塑化剂研究进展

回顾了聚羧酸系超塑化剂的发展历程,着重介绍了近年来的研究热点。早期研究主要集中于聚羧酸系超塑化剂分子结构对其分散作用的影响,后期更侧重于聚羧酸系超塑化剂与水泥的吸附、分散作用等机理的研究。目前,随着研究的深入及聚羧酸系超塑化剂发展的细化,许多研究者更专注于聚羧酸系超塑化剂在复杂体系中实现特定功能的研究,高保坍型、黏土抵抗型和早强型聚羧酸系超塑化剂亦因此成为近年来研究的热点和前沿课题。     

羧酸系混凝土超塑化剂的作用机理及分子结构模型设计

简要讨论了羧酸系混凝土超塑化剂的作用机理和分子设计原理,并详细分析了各种不同超塑化剂分子结构模型与分散和保坍性能之间的关系,提出了新型超塑化剂的分子设计原则,设计了一种集大减水、高保坍、低掺量的分子结构模型,对模型进行了试验验证,结果证实了其分子设计原则的可行性。     

全氟庚烷端基聚丙烯酸的制备及其水溶液的表面张力

高分子聚电解质既不同于简单的电解质,也不同于无离解基团的高聚物,表现出特殊的物理化学性能,其研究在理论上有重大的意义．同时,聚电解质具有重要的实用价值,如在污水处理、土壤改良、三次采油、钻井液添加剂、制药等领域有广泛的应用．在生命科学中,高分子聚电解质的研究对于正确理解生物大分子的作用（如蛋白质和脂类在生命体中的作用）是十分重要的［１］．聚丙烯酸（ＰＡＡ）是研究较多的合成聚电解质,其分子链在水溶液中离解而带有大量羧酸阴离子［２］,Ｉｓｈｉｍｕｒｏ等［３,４］较详细研究了ＰＡＡ水溶液的表面张力随其…     

水体系中含卟啉基团的两亲高分子的自组装行为和性质的研究

在文中合成了两种不同的卟啉单体5-(4-acryloyloxyphenyl)-10,15,20-tris(4-carboxylphenyl)porphyrinate zinc(Ⅱ)(ZnAOTCPP)和5-(4-acrylo-yloxyphenyl)-10,15,20-tris(4-methoxycarboxylphenyl)porphyrinate zinc(Ⅱ)(ZnMeAOTCPP),它们分别与丙烯酰胺(Acrylamide,AM)聚合得到含有卟啉基团的两亲高分子.与对应的单体相比,含有三羧酸卟啉基团的高分子在水中形成了一个新的紫外吸收峰和一个新的荧光发射峰,而含有三羧酸甲酯卟啉基团的高分子除此之外在更长波的方向上还另外出现了一个新的紫外吸收峰和一个新的荧光发射峰.随着高分子水溶液浓度的提高,高分子中卟啉基团的光谱性质的变化趋势显示高分子在水中的自组装行为可以分为分子间缔合和分子内缔合的两种情况.此外,实验结果显示含有三羧酸甲酯卟啉基团的高分子相对于含有三羧酸卟啉基团的高分子更加有利于卟啉缔合物的形成.     

聚羧酸共聚物侧链结构对水泥分散性的研究

通过“分子设计”,研制出一类带有不同侧链的聚醚基团,羧酸基团的聚羧酸共聚物减水剂,着重讨论了侧链长度对分散性能的影响。实验结果表明：通过调整聚羧酸共聚物中不同侧链的比例使其具有最佳的分散性。本实验合成的聚乙二醇侧链分子量为600：400=1：1（摩尔比）时,聚羧酸共聚物的分散效果最好,水泥浆体的流动度及分散力最佳,分别为289mm和10．36。     

水溶性高负责担载二茂铁希夫碱与DNA的作用

利用荧光探针技术和凝胶电泳等分析方法，对水溶性高分子聚丙烯酸-N-乙烯 基吡咯烷酮和聚甲基丙烯酸-N-乙烯基吡咯烷酮担载的二茂铁希夫碱与DNA的作用进 行了初步研究。实验结果表明：所合成的高分子二茂铁希夫碱在同DNA作用时存在 有静电作用和嵌入模式，由于水性基团的引入和高分子链的协同效应，促进了配合 物同DNA的这种作用．     

基团转移聚合合成PMMA—PEA—PAN嵌段共聚物的研究

丙烯酸系橡胶的综合性能仅次于氟橡胶,成本较低,若制成可重复加工的热塑性弹性体则更有价值。前人曾用阴离子聚合法进行过合成试验,均因副反应太多等原因而未能获得满意的结果。基团转移聚合(GTP)是八十年代建立的合成高分子新方法,在室温下进行“活性聚合”是其重要特征。本文利用GTP方法、单官能团引发剂,仅通过适当控制加料次序和时机就合成了软段居中的三元共聚物,为合成全丙烯酸系热塑弹性体奠定了基础。     

叠氮聚合物的合成

叠氮基团不仅是高含能基团和高反应性基团,而且也可以被转化为其他官能基团。叠氮聚合物可用作高能黏合剂、交联材料以及表面改性材料等,还可以作为合成功能高分子的前体,因此叠氮聚合物的合成研究引起了高分子科学家的广泛关注。到目前为止,叠氮聚合物的合成方法研究取得了新的进展,主要包括: 高分子化学改性法、环醚类叠氮单体阳离子开环聚合法和不饱和叠氮单体自由基聚合法。本文综述了近些年来叠氮聚合物的合成研究方面取得的主要成果和进展,其中包括本课题组的一些研究工作。     

季铵盐、季膦盐类高分子抗菌剂的研究进展

综述了季铵盐、季膦盐类高分子抗菌剂的研究进展,包括该类抗菌剂的合成、性能及抗菌机理。现有的研究结果表明,含有多种杀菌基团高分子抗菌剂的抗菌作用可能与杀菌基团的种类、杀菌基团的固载量、载体与杀菌基的结合位置、杀菌基团的分布、载体的表面亲水性能、聚合物的交联度、链结构等有关。若能在分子结构中同时有序引入季铵盐或季膦盐、海因类杀菌基团,有可能存在杀菌基团的协同效应,并且可能形成一个新的高分子抗菌材料的研究分支。     

两性高分子与小分子及大分子的相互作用（上）

两性高分子是分子链上同时含有正负电荷基团的一类高聚物,具有独特的性质.本文就合成两性高分子与小分子物质(金属离子、表面活性剂、染料、有机探针等)及大分子化合物(聚电解质、蛋白质)的络合过程及影响络合的因素进行了综述.     

Thermal and Pore Structural Characteristics of Polymer-impregnated and Superplasticized Cement Pastes

Two sets of hardened cement pastes were prepared by (a) impregnation with polymethyl methacrylate and polystyrene or (b) admixing with water-soluble condensates(superplasticizers) such as Na-phenol sulphonate formaldehyde, Na-polystyrene sulphonateand Na-β-naphthol sulphonate formaldehyde. The pastes were hydrated for 180 days. The results of nitrogen adsorption indicated that polymer impregnation strongly affected the specific surface areas and the total pore volumes of the hardened cement pastes. XRD analysis, DTA and TG demonstrated (a) the formation of new phases as a result of the interactions involving the polymer within the pore system of the hydrated products of the impregnated cement pastes, and (b) no change in the phase composition of the hydrated products of the cement pastes admixed with superplasticizers. This revised version was published online in July 2006 with corrections to the Cover Date.     

Insights into electrodeposition of an inhibitor film and its inhibitive effects on calcium carbonate deposition

Polycarboxylic acid (PAA), a common scale inhibitor has demonstrated adsorption properties on stainless steel surfaces. An electrochemically based technique has been used to assess the extent of film formation. The presence of calcium and magnesium ions in the solution and the cathodic electrochemical activity at the metal surface have been shown to enhance the inhibitor film formation by promoting the transport of the inhibitor from the solution to the metal surface. The effect of the inhibitor film in retarding scale deposition is assessed using measurement of the deposition onto metal electrodes immersed in a supersaturated solution of CaCO(3). The practical implications of these findings are discussed.     

Synthesis, characterization and evaluation of sulfonic resins as catalysts

Ion-exchange resins have been often used as catalysts especially those based on styrene-divinylbenzene copolymers with sulfonic acid groups in the aromatic rings of polymer chains. That is due to the advantages of heterogenous catalysis over the homogeneous acid catalysis. Moreover, resin catalysts can often lead to high selectivity in organic reactions due to the matrix effects. Therefore, the study of copolymers synthesis conditions to determine the type of polymer structure produced as well as the characterization of sulfonic resins obtained thereof are of great interest. The current paper describes the synthesis, characterization and evaluation as catalysts of sulfonic resins derived from polymer supports synthesized by aqueous suspension polymerization of styrene and divinylbenzene. The reaction conditions were varied and polymer supports with different physical properties and morphological characteristics were obtained. The polymer supports were chemically modified by sulfonation. The resultant sulfonic resins had their catalyst activity evaluated in the esterification of acetic acid with n-butanol.     

Intercalation of Sulfanilic Acid‐Phenol‐Formaldehyde Polycondensate into Hydrocalumite Type Layered Double ­Hydroxide

Polycondensates containing sulfonate groups, referred to as concrete superplasticizers, are widely used in the construction industry. A sulfanilic acid–phenol–formaldehyde polycondensate (SPF) with M_w ≈ 100.000 g · mol^–1 was synthesized from sulfanilic acid, phenol and formaldehyde by polycondensation reaction, and its intercalation into hydrocalumite type Layered Double Hydroxide (LDH) was investigated. Preparation was done by rehydration of tricalcium aluminate, a cement constituent, in the presence of the polymer. According to the XRD pattern, SPF was successfully intercalated. A d value of approx. 2.6 nm was found. Elemental composition of the new organo‐mineral phase reveals charge balancing of the cationic LDH main layers by the polycondensate. Thermogravimetry indicates that thermal degradation of intercalated SPF occurs at higher temperature, compared to non‐intercalated SPF. According to SEM imaging, the novel Ca‐Al‐LDH phase exhibits the morphology of intergrown platelets. Ultra‐thin nanosheets (foils) with approx. 50 nm thickness were obtained. The layered structure and d value obtained from diffraction analysis were confirmed by TEM imaging. The new hydride can be used as cement and concrete additive.     

Infrared spectroscopy studies of the cyclic anhydride as the intermediate for the ester crosslinking of cotton cellulose by polycarboxylic acids. III. Molecular weight of a crosslinking agent

Polycarboxylic acids have been used as nonformaldehyde crosslinking agents for cotton fabrics to replace the traditional N-methylol reagents. In this research, we compared 1,2,3,4-butanetetracarboxylic acid (BTCA) with poly(maleic acid) (PMA) as crosslinking agents for cotton cellulose. BTCA and PMA have similar molecular structures with carboxyl groups bonded to their molecular backbones, and both form five-membered cyclic anhydride intermediates during a curing process. However, BTCA is a more effective crosslinking agent for cotton cellulose than PMA. This is mainly attributed to the differences in the mobility of the anhydride intermediates to access the cellulosic hydroxyl groups during a curing process. The mobility of the anhydride intermediate of PMA is reduced due to its molecular size and multiple bonding between a PMA molecule and cellulose. Consequently, more anhydride and less ester are detected on the cotton fabric treated with PMA than on the fabric treated with BTCA. The amount of the unreacted anhydride intermediate on the fabric treated with PMA is reduced whereas the amount of ester is increased when another hydroxyl-containing compound of low molecular weight is present. Thus, the infrared spectroscopy data show a clear link between the molecular weight of a polycarboxylic acid and its effectiveness for crosslinking cotton cellulose. © 1997 John Wiley & Sons, Inc.     

聚羧酸系高性能减水剂分子在稀溶液中尺寸及其在体积排除色谱表征中表观分子量的模型研究

针对被称为"第一代聚羧酸高性能减水剂"(以下简称为MPEG-type PCE)的甲基丙烯酸(MAA)/烯酸甲酯(MAA-MPEG)梳状共聚物分子,从高分子物理基础理论出发,构建等效自由连接链模型,结合前人的理论结果和实验数据,得到了MPEG-type PCE分子的回转半径、流体力学半径及其相应的支化参数的数学表达式.在此基础上,报道了以下三方面的工作:首先,将计算结果与文献中的实验结果进行比较,检验模型的合理性;其次,利用所建立的数学模型考察主链分子量、侧链分子量和侧链接枝密度对PCE分子的回转半径和流体力学半径的影响;最后,结合近年来发展的体积排除色谱分离理论,对PCE分子的真实分子量与其常规体积排除色谱"表观分子量"(又被称为GPC分子量)两者之间的差异进行了分析.本文所提出的计算模型和数学表达式没有不确定的指前因子,可用来估算MPEG-type PCE分子在稀水溶液中的尺寸以及根据其GPC分子量估算真实分子量.     

A new method to analyze copolymer based superplasticizer traces in cement leachates

Enhancing the flowing properties of fresh concrete is a crucial step for cement based materials users. This is done by adding polymeric admixtures. Such additives have enabled to improve final mechanicals properties and the development of new materials like high performance or self compacting concrete. Like this, the superplasticizers are used in almost cement based materials, in particular for concrete structures that can have a potential interaction with drinking water. It is then essential to have suitable detection techniques to assess whether these organic compounds are dissolved in water after a leaching process or not. The main constituent of the last generation superplasticizer is a PolyCarboxylate-Ester copolymer (PCE), in addition this organic admixture contains polyethylene oxide (free PEO) which constitutes a synthesis residue. Numerous analytical methods are available to characterize superplasticizer content. Although these techniques work well, they do not bring suitable detection threshold to analyze superplasticizer traces in solution with high mineral content such as leachates of hardened cement based materials formulated with superplasticizers. Moreover those techniques do not enable to distinguish free PEO from PCE in the superplasticizer.Here we discuss two highly sensitive analytical methods based on mass spectrometry suitable to perform a rapid detection of superplasticizer compounds traces in CEM I cement paste leachates: MALDI-TOF mass spectrometry, is used to determine the free PEO content in the leachate. However, industrial copolymers (such as PCE) are characterized by high molecular weight and polymolecular index. These two parameters lead to limitation concerning analysis of copolymers by MALDI-TOFMS. In this study, we demonstrate how pyrolysis and a Thermally assisted Hydrolysis/Methylation coupled with a triple-quadrupole mass spectrometer, provides good results for the detection of PCE copolymer traces in CEM I cement paste leachates.     

HPLC determination of domoic acid in shellfish based on magnetic molecularly imprinting polymers

A magnetic molecularly imprinting polymer for domoic acid was fabricated. Synthesis conditions were optimized. The polymer particles have high magnetization for rapid magnetic separation. The apparent maximum absorption amount and dissociation constant of the polymer were 1,600?µg?g^?1 and 20.6?µg?mL^?1, respectively. The polymer retained 90% of adsorption amount after 5 times of repeated use. It was used as an adsorbent for purification and HPLC detection of domoic acid in shellfish with a detection limit of 0.050?µg?g^?1. Thus, the polymer could be applied to the sample pretreatment of aquatic products.     

水杨酸分子印迹分离介质的水相制备及色谱行为

以水杨酸为模板分子,2-乙烯基吡啶为功能单体,在甲醇/水体系中制备了水杨酸分子印迹聚合物,并将其作为高效液色谱分离介质研究了其对水杨酸及水杨酸的位置异物体———对羟基苯甲酸的色谱行为。结果表明,该聚合物固定相表现出良好的分离选择性,能够使水杨酸与对羟基苯甲酸快速基线分离。通过对流动相组成与色谱分离效果关系的探讨,证实溶质与印迹固定相的疏水相互作用是分子识别的主要作用力。