聚丙烯酰胺在炭黑粒子表面的功能修饰及其在传感领域的应用

考察了不同结构的醇羟基和不同反应条件对丙烯酰胺在炭黑表面接枝聚合反应的影响;在聚丙烯酰胺接枝炭黑（PAAm-g-CB）存在下,通过异丙醇铝（AIP）的溶胶-凝胶化反应,制得了一种新颖的具有智能响应性的PAAm-g-CB/Al2O3凝胶杂合材料,研究了其气敏性能.结果发现,随反应时间和反应温度提高,单体转化率和接枝率提高;不同醇羟基结构对引入到炭黑表面的醇羟基含量有一定影响,并按（CH3）2CH-OH＞CH3-OH＞CH3CH2-OH＞CH3（CH2）6CH2-OH＞CH3（CH2）3CH2-OH顺序递增.由PAAm-g-CB/Al2O3凝胶杂合材料可制得对丙酮蒸气响应能力强的负蒸气系数传感材料,该传感材料具有良好的响应重复性及对丙酮等强极性溶剂良好的选择性.     

超高分子量抗盐型聚合物的合成及性能评价

以丙烯酰胺(AM)和衣康酸(IA)为原料,采用自由基溶液聚合法合成了共聚物(IAPAM),用FTIR、~1HNMR、元素分析和GPC对其结构进行表征,并对其抗一价、二价阳离子降黏性能及抗氧化还原物质能力进行评价。结果表明,IAPAM黏均相对分子质量高达1.716×10~7。与部分水解聚丙烯酰胺(HPAM)相比,IAPAM有较好的抗一价和二价阳离子降黏的能力,当Na~+/Ca~(2+)质量浓度分别为30000、500 mg/L时,IAPAM水溶液的黏度分别为196.8、161.56 m Pa·s,降黏率(均指与未加盐或还原性物质相比,下同)分别为21.44%、35.52%。抗氧化还原物质评价结果表明,IAPAM具有较好的抗Fe~(2+)和S~(2–)降解的能力,当Fe~(2+)/S~(2–)质量浓度均为10 mg/L时,降黏率分别为23.67%、0.56%。然而,IAPAM对Fe~(2+)的络合稳定作用需要耗费一定时间,未达到络合稳定状态时,Fe~(2+)对聚合物的氧化降解仍然能够进行。     

水溶性单体分散聚合的研究进展

综述了丙烯酰胺等六类水溶性单体分散聚合的研究现状。     

HPLC法测定医用聚丙烯酰胺水凝胶中AM的含量

目的:建立一种定量测定医用聚丙烯酰胺水凝胶产品中丙烯酰胺含量的方法。方法利用高效液相色谱法检测医用聚丙烯酰胺水凝胶产品中丙烯酰胺的含量。结果:三种不同流动相体系测定的结果分别为:1.72x10-5g/g(0.9%NS,pH=3.7),2.65x10-5g/g(0.9%NS,pH=7.0),6.43x10-6g/g(100%甲醇)。结论:本法灵敏、准确、快速;所有测定结果均符合国家质量标准。     

Phosphorylation of Native Porcine Olfactory Binding Proteins

The identification of various isoforms of olfactory binding proteins is of major importance to elucidate their involvement in detection of pheromones and other odors. Here, we report the characterization of the phosphorylation of OBP (odorant binding protein) and Von Ebner’s gland protein (VEG) from the pig, Sus scrofa. After labeling with specific antibodies raised against the three types of phosphorylation (Ser, Thr, Tyr), the phosphate-modified residues were mapped by using the beta-elimination followed by Michael addition of dithiothreitol (BEMAD) method. Eleven phosphorylation sites were localized in the pOBP sequence and nine sites in the VEG sequence. OBPs are secreted by Bowman’s gland cells in the extracellular mucus lining the nasal cavity. After tracking the secretion pathway in the rough endoplasmic reticulum of these cells, we hypothesize that these proteins may be phosphorylated by ectokinases that remain to be characterized. The existence of such a regulatory mechanism theoretically increases the number of OBP variants, and it suggests a more specific role for OBPs in odorant coding than the one of odorant solubilizer and transporter. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Chrystelle Le Danvic and Fanny Brimau contributed equally to the work.     

Gelation theory for solutions of polymers with loci of strong interaction

This paper presents a statistical mechanical analysis of gelation in certain solutions ofA/B copolymers. Repeat unitsA, the major units, must constitute about 90 mole% or more of the copolymer, and are compatible with the solvent. Repeat unitsB, the minor units, must be totally incompatible with the solvent and represent loci of strong interaction between the macromolecular chains. If these interactions are sufficiently strong they can lead to gelation of the mixture. The following simplifications of the model afford results that can be expressed in simple, closed form: (1) TheB units are uniformly distributed along the chain backbone. (2) Polymer concentration must be greater then that for chain overlap. (3)B–B interactions lead to dimerization ofB units only. Examples include: (1) Any aqueous polymer solution where theA repeat units are hydrophilic and theB repeat units are hydrophobic;B–B interactions are thus by hydrophobic bonding. (2) Neutralized acrylic acid/acrylamide copolymers where theB are acrylamide repeat units which associate by hydrogen bonds. (3) Ionomer solutions whereB–B bonding is by dipole-dipole interaction. The results show that there is a critical copolymer concentration for gel formation, C _c . It turns out that C _c decreases withB content for low dimerization energies and increases withB content for higher dimerization energies. At intermediate dimerization energies, C _c is insensitive to theB content. The two extreme regimes of behavior are similar to contradictory predictions of previously published theories. Received: 18 September 2000 / Reviewed and accepted: 20 September 2000     

Synthesis and antimicrobial activities of acrylamide polymers containing quaternary ammonium salts on bacteria and phytopathogenic fungi

Three series of acrylamide monomers/polymers containing quaternary ammonium salts (QASs), i.e., acrylamide QAS monomers (QDs), homopolymers of QDs (PQDs) and copolymers of QDs with acrylate monomer (PQDCs), were synthesized and employed in antimicrobial tests against both bacteria (Escherichia coli (E. coli) and Staphylococcus albus (S. albus)) and phytopathogenic fungi (Rhizoctonia solani (R. solani) and Fusarium oxysporum f. sp. cubense race 4 (Foc4)). The antibacterial activity of the QASs was evaluated by determining the minimum inhibitory concentration (MIC) against E. coli and S. albus by the TTC coloration method, and the antifungal activity was measured by mycelia growth inhibition as well as MIC and the minimum fungicidal concentration (MFC) values. The results indicated that PQD homopolymers and PQDC copolymers showed far better antimicrobial activities than QD monomers. PQDC copolymers by incorporating hydrophobic acrylate units into the main chain of polyacrylamide backbone displayed even better antimicrobial activities, depending on QAS structure and hydrophobic content. Moreover, polymers with benzyl group attached to nitrogen atom showed better inhibitory effect on bacteria and phytopathogenic fungi. The results could assist understanding and development of future design of antimicrobial polymers as potential fungicide agents to control plant disease.     

Stereospecific preparation of polyacrylamide with low polydispersity by ATRP in the presence of Lewis acid

The stereospecific atom transfer radical polymerizations of acrylamide were achieved in the presence of the Lewis acid Y(OTf)₃ or AlCl₃ as stereospecific catalyst using chloroacetic acid/CuCl/N,N,N′,N′-tetramethyl-ethylenediamine (TMEDA) as initiating system. The addition of Lewis acid Y(OTf)₃ in the ATRP of acrylamide led to an increased polymerization rate and an improved tacticity of polyacrylamide (m ∼ 71%) at the expense of controllability of the molecular weight distribution. In the case of AlCl₃, the polymerizations were committed to afford the resultant polyacrylamide with lower polydispersity index ranging from 1.03 to 1.42 and well-controlled tacticity with meso content ranging from 57 to 76% depending on the different reaction conditions used. Lower temperature or higher concentration of the feeding Lewis acid helped to obtain the polyacrylamide with increased tacticity which revealed a decreased glass transition temperature (T_g).     

NaOH/PAM催化剂对合成生物柴油的影响

大麻籽油和甲醇经NaOH/PAM催化合成生物柴油,本实验在醇油比固定的情况下考察了催化剂的碱含量、催化剂用量对酯交换转化率的影响、碱量及反应时间分别对转化率和皂化百分数的影响,采用红外光谱技术对催化剂进行分析,确定了较适宜的反应条件.结果表明:实际碱量随NaOH添加量的增加而增加；催化剂用量增加,原料油转化率增加；反应时间的增加,原料油转化率曲线增加到一定水平后趋于平缓；较适宜的反应条件为PN-4催化剂用量3％,反应时间为60 min.     

印刷电路板厂工业废水中含锡废渣回收探讨

将已沉淀下来的含锡废渣(下简称锡泥)为处理对象,主要探讨使用有机高分子絮凝剂(聚丙烯酰胺)提炼工业废液中锡离子的工艺。与一般的无机凝聚剂相比较,高分子絮凝剂处理含锡废水具有投加药量少,最佳适用pH低,污染低,形成絮体快而且个体较大,絮体沉降性能好等特点。