Synthesis and characterization of polyacrylic acid/dexy 85 and polyacrylic acid/gum arabic adducts

Polyacrylic acid/gum arabic or polyacrylic acid/dextrin (PAA/GA or PAA/D) adducts were prepared by free radical polymerization of highly concentrated, partially neutralized AA using Na₂S₂O₈/Na₂S₂O₃ redox system in the presence of GA or D. Optimum reaction conditions, viz., AA, 6.76 mol/L; Na₂S₂O₃, 26.87 × 10^?3 mol/L; Na₂S₂O₈, 34.9 × 10^?3 mol/L; degree of neutralization, 20%; temperature, 90°C; and time 30 min, were utilized in preparing two adducts of each substrate (GA or D) at two liquor ratios (LRs; 1.25/1 and 6.3/1 L/K). The four adducts formed, viz., PAA/GA₁, PAA/GA_2, PAA/D₁, and PAA/D₂ (where 1 and 2 refer to the low and high LR, respectively) were found to be water soluble at all proportions. IR spectrum of these adducts confirmed the introduction of the COOH group onto their structures. Rheological properties of 7% aqueous solutions of these adducts, including Na‐alginate (Alg), showed that all are characterized by a non‐Newtonian, shear‐thinning, thixotropic behavior. Within the range of shear rate studied, the apparent viscosities of these solutions followed the descending order: PAA/D₂ > PAA/D₁ > Alg > GA₁ = PAA/GA₂. Completing neutralization (Na form) of adducts to 100% results in a remarkable enhancement of their apparent viscosities, so that they follow the descending order, depending on the shear rate: © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4290–4300, 2006     

Alumino-silicate polyacrylic acid and related cements

The composition and setting reaction of cements formed from aluminosilicates and poly(acrylic acid), the ASPA cements, are described. Setting and hardening results from interactions between specially-formulated, complex, fluorine-containing calcium aluminosilicate glasses and aqueous solution of poly(acrylic acid) or similar poly(alkenyl carboxylic acids). Protons from the polyacid penetrate the surface of the glass decomposing the negatively charged aluminosilicate network to a siliceous hydrogel and releasing Al³⁺, Ca²⁺ and F- ions. These ions migrate, probably as complexes, such as AlF₂₊, AlF²⁺ and CaF⁺, into the polyelectrolyte phase where they cross-link polyanionic chains, by ionic and possibly chelate binding, causing the cement to gel and set. Overall the reaction may be seen as one where flexible hydrogen bonds, in the liquid, are progressively replaced by more rigid ionic ones, leading to gelation. The set cement is a composite of glass particles sheathed by a silica gel bound by a metal poly anionic matrix. ASPA cements can attain a compressive strength of 200 N/mm² in 24 h and are adhesive under oral conditions to tooth materials. They find a number of applications in conservative and preventive dentistry. Certain naturally-occurring aluminosilicate minerals react with poly(acrylic acid) to form cement but these are much weaker (not exceeding a compressive strength of 30 N/mm²) and are weakened by water.     

聚丙烯酸钠的合成及应用

综述了不同相对分子质量的聚丙烯酸钠及聚丙烯酸钠高吸水性树脂的合成方法。分别介绍了它们的应用领域。不同相对分子质量聚丙烯酸钠的合成主要采用水溶液法。根据其聚合程度的不同，分别用于石油化工、日用化工、污水处理及陶瓷制作等领域。聚丙烯酸钠高吸水性树脂的合成主要有水溶液聚合法、反应悬浮聚合法、反向乳液聚合法，微波及辐射聚合法。介绍了它在日用化工、农业、医药及建筑行业中的应用。并结合目前国内的发展状况，对今后我国聚丙烯酸钠的研制和发展作出展望。     

Low molecular weight polyacrylic acid with pendant aminomethylene phosphonic acid groups

Low molecular weight poly(acrylic acid‐co‐vinyl aminomethylene phosphonic acid)s were prepared by consecutively applying the Hofmann degradation and the Mannich reaction to polyacrylamide and poly(acrylamide‐co‐acrylic acid)s. ¹H‐NMR, ³¹P‐NMR, and microanalysis were used for structural analyses. These polymers were tested as anti‐scalent and they showed better anti‐scalent effect than commercial poly(acrylic acid)s. The scale inhibition properties of copolymers increased with increasing amount of aminomethylene phosphonic acid groups. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 870–874, 2000     

聚丙烯酸水凝胶的制备研究

以丙烯酸为单体,N,N＇-亚甲基双丙烯酰胺为交联剂,过硫酸铵为引发剂,通过自由基聚合制备了聚丙烯酸水凝胶.考察了交联剂、引发剂、单体中和度、聚合温度以及盐溶液对水凝胶溶胀性能的影响.结果表明,引发剂为单体质量的0.6％,交联剂为0.8％,单体的中和度为70％时,凝胶的溶胀性能最佳,吸水率达到了3 000％以上,聚丙烯酸水凝胶的溶胀性能随着盐溶液浓度的增大而降低.     

淀粉接枝聚丙烯酸高吸水树脂吸附CuS04的行为和动力学

以淀粉和丙烯酸为原料,用水溶液聚合法制备淀粉接枝聚丙烯酸高吸水树脂(St-g-PAA),在20～40℃研究St-g-PAA对CuSO.的吸附行为.结果表明,St-g-PAA对CuSO4的室温吸附行为符合Freundlish关系,等温吸附表达式为:Te=0.06 c0.3(g/g),其吸附过程具有一级反应特征,反应速率常数为:k=6.92×10-9×exp(35.418 4 kJ/Rr),吸附过程的表观活化能Ea=-35.418 4 kJ/mol,具有反应温度低、吸附速度快的特点.     

淀粉接枝聚丙烯酸高吸水树脂吸附CuSO_4的行为和动力学

以淀粉和丙烯酸为原料,用水溶液聚合法制备淀粉接枝聚丙烯酸高吸水树脂（St-g-PAA）,在20～40℃研究St-g-PAA对CuSO4的吸附行为。结果表明,St-g-PAA对CuSO4的室温吸附行为符合Freundlish关系,等温吸附表达式为：Γe=0.06c0.3（g/g）,其吸附过程具有一级反应特征,反应速率常数为：k=6.92×10-9×exp（35.418 4 kJ/RT）,吸附过程的表观活化能Ea=-35.418 4 kJ/mol,具有反应温度低、吸附速度快的特点。     

磷酸亚基聚丙烯酸的合成及性能研究

以丙烯酸、次磷酸钠为单体，在过氧化氢一次磷酸钠引发体系下反应，合成了一种新型绿色水处理剂磷酸亚基聚丙烯酸。运用正交试验法确定了最佳合成条件，并运用红外光谱对合成产物进行了结构鉴定。对合成产物进行了阻垢与缓蚀性能研究，并与常用水处理药剂HEDP和PAA进行了比较。     

聚丙烯酸系增稠剂的合成及性能研究

以丙烯酸单体为原料,N-马来酰化壳聚糖为交联剂,过硫酸铵为引发剂,采用溶液聚合法制备聚丙烯酸系增稠剂。研究了交联剂浓度、中和度、温度、不同电解质对聚丙烯酸系增稠剂粘度的影响。实验结果表明:交联剂为0.4wt%,中和度为80mol%,0.5wt%该增稠剂凝胶溶液粘度可达54 200 mPa.s,但在温度升高或电解质存在的情况下,体系粘度降低。     

Grafting of polypropylene and its potential use as metal ion adsorption resin

Polypropylene (PP) was modified by radical grafting of acrylic acid (AA) in the melt by using dicumyl peroxide (DCP) as initiator. To reach a high grafting degree (GD) without substantially modifying PP‐chain structure, a few runs were carried out by employing butyl 3‐(2‐furanyl)propenoate (BFA), which is a coagent able to preserve the molecular weight (MW) of PP macromolecules in the presence of radical grafting reagents. All the samples were extracted with selective solvents to remove unreacted chemicals and free poly(acrylic acid) (PAA), and the GD was accurately determined by using the FTIR methodology. The GD ranged from 1.51 to 4.67 mol %. High‐temperature size permeation chromatography analysis was used to evaluate MW behavior, confirming the control exerted by the presence of BFA on the degradation reactions. DSC, TGA, and SEM analyses were performed to analyze the chemical modification effects on the polymer products' thermal and morphological properties. Finally, selected samples, with a particle size distribution in the range 100–850 μm, were tested as metal ion adsorption resins. Al(III), Cr(III), Zn(II), Cd(II), Pb(II), and Hg(II) were studied, and the highest adsorption efficiency values (in percentage) were obtained for Al(III) (15–20%) and Hg(II) (25–30%). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

N—水杨醛缩天冬氨酸与锌的荧光反应及其应用

在10%～25%的乙醇-水溶液中锌与 SASP 反应形成1:1的螯合物。适宜的 pH 范围是7.8～8.2,螫合物的最大激发和最大发射波长分别为λ_(cx)=271nm 和λ_(cm)=448nm。在0～2.5μg/25mL 的范围内荧光强度与锌的浓度成直线关系.其检测限是2.0ng/mL。本法用于水样、面粉、人发中锌的测定,结果满意。     

Controlled conversion of polyacrylamide into polyacrylic acid

Interaction of nitrous acid with aqua solution of poly(acrylamide) gives poly(acrylic acid) in quantitative conversion yields. The reaction proceeds smoothly, with simultaneous evolution of nitrogen, provided that the temperature below 5 °C. The procedure presented provides a versatile route to prepare acrylic acid-acrylamide copolymers in any desired composition, by adjusting molar ratio of nitrous acid. Received: 29 January 1997/Revised: 24 July 1997/Accepted: 6 August 1997     

甲酸生产工艺技术及应用

甲酸是甲醇深加工的重要下游产品之一。本文对甲酸钠法、丁烷液相氧化法、甲酰胺法、甲酸甲酯水解法制甲酸生产工艺进行了对比分析,同时简要介绍了甲酸生产与消费情况。     

Preparation of hydrophilic polysulfone membrane using polyacrylic acid with polyvinyl pyrrolidone

This study examined the consequences of the addition of polyvinyl pyrrolidone (PVP) of different molecular weights with constant molecular weight of polyacrylic acid (PAA) on the morphology and permeation properties of polysulfone (PSF) membranes. The asymmetric polymeric membranes were prepared by phase inversion process using PSF in N‐methyl‐2‐pyrrolidone (NMP) as a solvent. The surface structure and morphology of the prepared membranes were analyzed by field‐emission scanning electron microscope (FESEM) and atomic force microscopy (AFM). The pore number, average pore size and area of pores for all the membranes were determined by permeability method. These ultrafiltration membranes were subjected to characterizations such as measurement of pure water flux (PWF), compaction factor (CF), bovine serum albumin (BSA) rejection for finding the permeability performance, whereas equilibrium water content, contact angle, porosity, hydraulic resistance, and ion exchange capacity (IEC) are measured for evaluating the hydrophilicity. Results demonstrate that the flux performance of the membranes and morphological parameters own a crucial inter‐relationship with the molecular weight of PVP. The membrane pore area and pore number were found to be increased by increasing molecular weight of PVP with constant molecular weight of PAA. A detailed comparative study was done with Chakrabarty et al. (J. Membr. Sci. 2008, 309, 209) and found better in almost all the aspects. All the resulting parameters were compared and concluded with the fact that addition of small amount of PAA in PSF/PVP/NMP casting solution can be better than addition of PVP alone. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41964.     

Photoluminescent and tough hydrogels from silk fibroin and polyacrylic acid complexed with europium

Biocompatible, tough, and photoluminescent hydrogels are highly desirable for biomedical applications in vivo. Herein, hybrid hydrogels prepared from silk fibroin (SF) and polyacrylic acid (PAA) and complexed with europium, named as SF-PAA-Eu³⁺ hydrogels, exhibit good comprehensive properties. Owing to the intensive molecular interactions among SF, PAA, and Eu³⁺, SF-PAA-Eu³⁺ hydrogels show a greatest tensile strength of 0.58 MPa, elongation of 443%, and work of fracture of 1.65 MJ/m. In vivo imaging experiment in a mouse subcutaneous implantation model revealed excellent and sustained photoluminescence of the SF-PAA-Eu³⁺ hydrogels for 24 h. The work provides a strategy for designing functional SF-based hydrogels for imaging applications in vivo.     

乳液聚合法聚丙烯酸树脂的制备研究

介绍了以丙烯酸、苯乙烯、丙烯酸丁酯、丙烯酸羟丙酯为单体,采用过硫酸铵作为引发剂,以非离子乳化剂聚氧乙烯醚(OP-10)和阴离子乳化剂十二烷基硫酸钠(SDS)作为复合乳化剂,经过乳液聚合,制得了一种水性涂料用缔合型增稠剂.考察了丙烯酸单体含量、乳化剂用量对乳液性能和增稠剂黏度的影响.优化了反应条件,反应过程和最终乳液都很...     

Grafting of poly(acrylic acid) onto polyethylene filament and its distribution

Radiation-induced simultaneous grafting of acrylic acid onto high density polyethylene filament is carried out with aqueous solution of acrylic acid in the absence and presence of ethylene dichloride. Distribution of grafted poly(acrylic acid) is studied by two methods. One is optical microscopic investigation of cross sections of dyed filament, and the other is electron probe microscopy of acrylic acid graft filament after conversion to calcium acrylate. Qualitative study with WAXS is also carried out. Grafting begins from the surface or periphery and proceeds, with sharp boundary, to the core. The reaction takes place only in the amorphous part of polyethylene. The percent graft in the grafted part is homogeneous and rather high from the beginning of the reaction; it is true that additional grafting to the already grafted part takes place, but it is not so noticeable.     

Characterization of a chromium-rich tannery waste and its potential use in ceramics

Leather industries which promote hide stabilization by the conventional chrome-tanning process are a major source of pollution because of the resultant chromium-rich wastes. In this work, an extensive characterization of such a chromium-rich waste sludge is presented, regarding its chemical composition (XRF), crystalline phase contents (XRD), organic carbon content (TOC), thermal behavior by thermogravimetry (TG) and differential scanning calorimetry (DSC), as well as its stability under chemical attack (the concentration of important ions in the leachates being determined by capillary electrophoresis) and when submitted to temperatures as high as 1100 °C, in air. The material showed the tendency to produce some undesirable, and previously non-detected hexavalent chromium when exposed to high temperatures, but after washing off the soluble salts and the elimination of the organic matter by firing, the resultant material was succesfully tested as a ceramic pigment in a conventional glaze composition usually employed in the ceramic tile industry.     

茶树油的性质及其应用

简述了茶树油的来源、提取方法、性质以及标准等。主要介绍了茶树油应用于化妆品的天然防腐杀菌、护肤嫩肤功能；应用于日用化学品的舒缓镇定、渗透力强、温和不刺激等特性；应用于医疗中作为强抗菌剂以及食品中作为香味剂等，从而为国内进一步深入开展茶树油的开发利用研究提供了一些有益信息。