An amphoteric hydrogel: Synthesis and application as an internal curing agent of concrete

A new crosslinked amphoteric hydrogel (PAC) was synthesized and evaluated as an internal curing agent of concrete. PAC was prepared from acrylamide (AM) and 4‐(2‐((carboxylatomethyl)dimethylammonio)ethoxy)?4‐oxobut‐2‐enoate (CMD) through free‐radical polymerization by using ammonium persulfate (APS) as an initiator and methylene‐bisacrylamide (MBA) as a crosslinker. The structure of the prepared polymer was verified by the IR spectra. The effects of the polymerization variables on the swelling capacity of PAC were investigated. The water absorbency of PAC was found to increase with increasing CMD/AM ratio, reach a maximum value, and decrease afterword. Increase of either APS or MBA content decreased the water absorbency. The highest water absorbency of PAC hydrogel (P7) achieved in deionized water, 0.1M NaCl solutions and 0.1M CaCl₂ solutions, was 306 g/g, 32 g/g, and 22 g/g, respectively. Compared with a commercial acrylate‐based hydrogel 283HA, P7 was less sensitive to the existence of Ca²⁺ ions in cement pore solutions, and more effective in reducing the cracking tendency of cement pastes. Finally, mortars incorporated with proper amounts of P7 showed smaller drying shrinkage and higher compressive strength than that without hydrogel present. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42175.     

Deswelling stresses and reduced swelling of superabsorbent polymer in composites of fiber and superabsorbent polymers

The desired performance characteristics of absorbent products such as diapers include a low number of leaks, adequate liquid absorption capacity, and high skin dryness. By measuring the absorption behavior of mixtures of cellulose fluff pulp and superabsorbent polymers in nonimmersed conditions, we identify four major parameters that affect the swelling of the polymer in a composite: the Donnan ion‐exclusion effects of limiting the amount of liquid in contact with the superabsorbent polymer, the restriction of swelling by the physical constraints of the fibrous network that surrounds the polymer particles, the restriction of swelling by the capillary tension provided by the pores between the cellulose fibers, and the osmotic pressure of extracted polyelectrolytes. Swelling of the superabsorbent polymer in composites is always smaller than the value measured by immersion of the polymer followed by centrifugation. Donnan exclusion of ions from the gel phase results in about 16% less swelling than when the polymers are swollen in excess liquid. The swelling restriction imposed by the fiber network, which surrounds the granules, reduces swelling a further 10%. In addition, the presence of small pores between the fibers exerts capillary tension on the polymer and lowers the swelling by another 10%. The external compression of the composite pads does not reduce the extent of swelling of the superabsorbent polymer because the stress is supported by the fibers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2493–2507, 2005     

Novel biodegradable superabsorbent hydrogels derived from cotton cellulose and succinic anhydride: Synthesis and characterization

The synthesis of novel superabsorbent hydrogels was investigated with the reaction of cotton cellulose and succinic anhydride (SA) in the presence of 4‐dimethylaminopyridine as an esterification catalyst in a mixture of lithium chloride (LiCl) and N‐methyl‐2‐pyrrolidinone (NMP) or in a mixture of tetrabutylammonium fluoride (TBAF) and dimethyl sulfoxide (DMSO), followed by NaOH neutralization. Interestingly, a hydrogel was obtained without any crosslinking agent, and this indicated the partial formation of a diester between the cellulosic hydroxyl group and SA. The products obtained in LiCl/NMP exhibited superior absorbency to these obtained in TBAF/DMSO. The former absorbed an amount of water about 400 times its dry weight, and this was comparable to a conventional sodium polyacrylate superabsorbent hydrogel. Furthermore, in an aqueous NaCl solution, the absorbency of the product hydrogels was higher than that of the sodium polyacrylate superabsorbent hydrogel. The formed hydrogels biologically degraded almost completely after 25 days, and this showed their excellent biodegradability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3251–3256, 2006     

Synthesis of superabsorbent polymers by irradiation and their applications in agriculture

The superabsorbent polymers (SAPs) were synthesized by grafting copolymerization of acrylic acid and acrylamide onto starch by using γ‐ray radiation technique and poly(ethylene glycol) (PEG) as a crosslinker. The samples were characterized by IR spectroscopy. The effect of various synthetic parameters such as irradiation dose, irradiation dose rate, monomer concentration, monomer/starch ratio, and PEG content were studied. The effects of different drying methods on water absorbency of the SAPs were also studied. The experimental results showed that the water absorbency of the SAPs depends largely on the specific conductance of water when the specific conductance is below 500 μs/cm. The water retention of sand and soil was enhanced by using the SAPs. Effects of the SAPs on the germination of seeds and growth of young plants were investigated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1748–1755, 2004     

新型含醛基两性聚氨酯乳液的制备与表征

以异佛尔酮二异氰酸酯(IPDI)、聚四氢呋喃醚二醇(PTMG)、2,4-二羟基苯甲醛(DDBA)、2,2-二羟甲基丙酸(DMPA)和N-甲基二乙醇胺(N-MDEA)为原料,通过加成反应制备了含醛基两性聚氨酯乳液(AAPU)。考察了r值(IPDI中的—NCO与其他原料中总羟基的物质的量的比值)以及亲水扩链剂(DMPA)用量对乳液粒径及稳定性的影响。利用紫外光谱(UV)、红外光谱(FTIR)对AAPU进行了结构表征,通过纳米粒度仪、透射电镜和Zeta电位分析仪对乳胶粒的粒径大小、形貌和带电情况进行了测定。结果表明:产物具有预期的结构。r值控制为1.20,DMPA用量为5%(以原料的总质量为基准,下同)时,所合成AAPU的平均粒径为42.6 nm,等电点为5.16,乳胶粒外形呈较规则球形;由于AAPU表现为两性,它可在非金属鞣制体系的复鞣加工中作为复鞣剂,有望提高皮革与阴离子湿整饰材料的结合能力。     

Effects of hydrolysis treatment on the structure and properties of semi-interpenetrating superabsorbent polymers

A semi-interpenetrating polymer network superabsorbent polymer based on sodium lignosulfonate-graft-poly(acrylic acid-acrylamide)/potassium dihydrogen phosphate and polyvinyl alcohol (PVA/SL-g-P[AA-AM]/KDP) was synthesized by using solution polymerization. The PVA/SL-g-P(AA-AM)/KDP was further hydrolyzed in NaOH solution. The structure, thermal stability, and morphologies of samples were examined by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results of FTIR, TGA, and DSC showed that PVA interpenetration through SL-g-P(AA-AM)/KDP network has occurred, and PVA/SL-g-P(AA-AM)/KDP was successfully alkaline hydrolyzed. From the SEM images, the high porous and loose surface structure of polymers was formed after hydrolysis, which greatly increased the specific surface area. Samples after hydrolysis exhibited higher equilibrium swelling capacity (1963 g/g) compared to the nonhydrolyzed samples (866 g/g). The swelling kinetics of all samples well complied with the pseudo-second order swelling kinetics model. Simple hydrolysis treatment not only improved the swelling capacity of PVA/SL-g-P(AA-AM)/KDP but also induced an enhancement on its water retention performance, which made it potentially useful as a water retention agent in the revegetation of abandoned mines or slope wasteland.     

Fast‐swelling superabsorbent polymers with polymerizable macromolecular surfactant as crosslinker

Fast‐swelling superabsorbent polymers (SAPs) have been prepared by micellar cross‐linking copolymerization of acrylic acid and acrylamide using polymerizable macromolecular surfactants (PMSs) as multifunctional crosslinkers, with a foaming technique. Sodium bicarbonate (NaHCO₃)/acetone and Pluronic F127 were used as foam (or porosity) generators and stabilizer, respectively. It has been found that the PMSs with different polyethylene glycol (PEG) chain length have little effect on the swelling rate of the SAPs, while the foam generators are crucial. In addition, the monomer concentration and the concentration of the PMS are important to the fast swelling rate of the SAPs. For a balance of a relatively fast‐swelling rate, high water absorbency under load and low cost in drying, a monomer concentration of above 50%, 0.08% PMS, and 5% NaHCO₃ are preferable. The water absorbency of SAP prepared under optimal conditions could reach half of equilibrium water absorbency in 30 seconds and the saline water absorbency under load could reach 18.4 g/g. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44173.     

Characterization of a superabsorbent polymer

We studied an amorphous polymer superabsorbent, able to absorb until 1000 times its weight of water. It is consisted of macromolecular chains, dependent between them by chemical bonds. The swelling of the product in the presence of water gives rise to a polyelectrolytic gel. The chemical analysis of polymer by energy dispersive spectrometry and photoelectrons spectroscopy with a microsounder X showed that the product is homogeneous. It contains carbon, oxygen, and sodium. The measurements of specific surface of the product show that the polymer is nonporous and present a weak surface of about 2.1 m²/g. The thermal study of polymer showed that, under the effect of the temperature and with atmospheric pressure, the polymer is degraded only at temperatures higher than 200°C and becomes porous. When the material is heated at higher temperature of 200°C, its surface becomes increasingly porous with also an increase in the size of the pores. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 782–786, 2007     

Peroxide macro‐initiators for improving biodegradability of polymers

Modification of dextrin by tert‐butylperoxy methanol or its acylation with cyclic anhydride containing a peroxide group resulted in macro‐initiators with randomly located peroxide fragments in the polysaccharide. When dextran was oxidized with iodic acid, dialdehydedextran was obtained. Its aldehyde groups reacted with tert‐butyl hydroperoxide to give functional peroxide groups. The content of peroxide fragments depended directly on the ratio of reagents. The resulting macro‐initiators may be used for synthesizing graft copolymers with polystyrene on poly(butyl acrylate) containing polysaccharide. © 2001 Society of Chemical Industry     

新型两性吸附树脂PSN的合成

以苯胺、浓硫酸、苯酚和甲醛为原料 ,经磺化、预聚、交联三步反应制得两性吸附树脂PSN。考察了反应物配比、反应温度、反应时间和催化剂对各步反应的影响 ,得到最佳反应条件 :苯胺和浓硫酸在 1 85～ 1 90℃磺化 5h ,产率可达 75 7% ,未纯化产物可直接与甲醛在硫酸催化下进行预缩聚。通过改变反应物的用量 ,可制备具有不同阴、阳离子功能团比值的树脂     

Preparation,water absorbency,and enzyme degradability of novel chitin‐ and cellulose/chitin‐based superabsorbent hydrogels

Superabsorbent hydrogels were prepared from chitin dissolved in lithium chloride and N‐methyl‐2‐pyrrolidinone by esterification crosslinking with 1,2,3,4‐butanetetracarboxylic dianhydride (BTCA). The absorbency of the chitin hydrogel was strongly dependent on the ratio of BTCA feed to chitin. The hydrogel prepared at the feed ratio of 5 showed the highest absorbency (345 g/g‐polymer), and the hydrogel was composed of 0.65 molecules of BTCA per monomer unit of chitin. The hydrogels exhibited good biodegradability by chitinase with a maximum degradation of 91% within 7 days. This method for obtaining the chitin hydrogel was also applicable to cellulose and chitin mixtures, and 1 : 1 cellulose/chitin hybrid hydrogels could be obtained by the esterification crosslinking of a mixture with a 1 : 1 molar ratio of cellulose and chitin. The optimal BTCA feed ratio of 5 resulted in the cellulose/chitin hydrogel with the highest water absorbency (329 g/g‐polymer), and the hydrogel contained 0.65 molecules of BTCA per polysaccharide monomer unit. In addition, the hybrid hydrogels were degraded by cellulase as well as chitinase. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of graft copolymer (guar gum–g–N‐vinyl‐2‐pyrrolidone) and investigation of metal ion sorption and swelling behavior

Graft copolymer of N‐vinyl‐2‐pyrrolidone with guar gum was synthesized and its reaction conditions were optimized for better yield using potassium peroxymonosulfate (PMS) and glycolic acid (GA) as a redox initiator. The effect of PMS, GA, hydrogen ions, guar gum, and N‐vinyl‐2‐pyrrolidone (NVP) along with reaction time and temperature were studied by determining the grafting parameters: grafting ratio, efficiency, conversion, add‐on, homopolymer, and rate of grafting. It was observed that the maximum yield occurred at with a time of 120 min at a temperature of 45°C and a guar gum concentration of 0.4 g/L concentration. The graft copolymer was characterized by infrared spectroscopy and thermal analysis. The activation energy for the grafted and ungrafted gum was calculated. It was observed that the graft copolymer was thermally more stable than the pure gum. The swelling and metal ion sorption behavior of guar gum and guar gum‐g‐N‐vinyl‐2‐pyrrolidone also were studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2480–2489, 2006     

两性聚丙烯酰胺的合成及应用

主要研究两部分的内容，第一部分两性聚丙烯酰胺的合成，通过曼尼希反应改性阴离子型的聚丙烯酰胺制备了两性的聚丙烯酰胺，并讨论了反应时间，反应温度，反应物的浓度对胺化度的影响。第二部分为将合成的产品应用于不同废水，进行絮凝实验，研究了无机絮凝剂单独使用和同有机絮弹簧剂配合使用的效果。采用测上清液透过率方法，并和改性前的阴离子型，非离子型聚丙烯酰胺对比，结果发现，两性聚丙烯酰胺有很好的絮凝效果。优于同类的其他絮凝剂。     

两性高分子絮凝剂的研究现状

简要介绍了国内外两性高分子絮凝剂研究进展;结合作者的研究,提出了无毒或低毒,易于生物降解,无二次污染,原材料广泛,易于合成加工的絮凝剂是今后的发展方向;同时加强两性高分子的结构与应用性能关系的研究。     

两性聚合物絮凝剂的合成和性能测试

研究了两性聚合物AANa—MATMC的合成和它的性能。首先合成阳离子聚合物AM—MATMC,其合成优化条件：n（AM）：n（MATMC）：9：1;温度55℃;引发剂的用量为单体总质量的0．05％：聚合时间为7h。阳离子聚合物AM—MATMC部分水解得到两性聚合物AANa—MATMC,部分水解条件是温度60℃,时间90min,n（碳酸钠）：n（丙烯酰胺基团）=1：8,产物的收率为98．2％。性能测试结果发现：经其处理过的污水的化学需氧量、透光率及污泥滤饼含水量等指标优于国内同类产品,与进口阳离子聚丙烯酰胺比较其污泥滤饼含水量小,显示出优良的絮凝性能。     

Characterization by thermal analysis of PP with enhanced biodegradability

Samples of polypropylene (PP) filled with a biodegradable additive marketed under the Bioefect trademark, were subjected to an outdoor soil burial test for 21 months. Samples were initially characterized by thermogravimetry. The kynetics of the thermal degradation of both the carbonated chains of PP and the additive have been studied by means of the Hirata differential method and the Broido integral method. Such analysis reveals that the additive is more affected by the degradation process than the PP matrix. Changes in the morphology of the samples with the exposure time have been analyzed by Differential Scanning Calorimetry, in terms of the crystalline content of PP and its lamellar thickness distribution. The β‐ and α‐relaxation zones of the dynamic mechanical relaxation spectra of both PP and pure Bioefect have been characterized using the Fuoss‐Kirkwood equation and a deconvolution method. The analysis of the relaxation spectra shows that the interfacial and crystalline regions of the PP matrix are quite affected by the degradation process. On the other hand, it has also been found that changes in the crystallinity and the mechanical behavior of the samples take place in different stages. Such an evolution can be adequately represented by polynomial equations. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2174–2184, 2001     

两性表面活性剂的合成路线概述

重点介绍了国内新型两性表面活性剂的合成研究概况。咪唑啉型表面活性剂的合成主要是利用了咪唑啉中间体羟基的反应活性,通过酯化或磺化合成出了硼酸酯、硫酸酯和磺酸盐型咪唑啉两性表面活性剂;以二乙醇胺为原料合成两性表面活性剂时,先与脂肪酸或卤代烷反应合成出叔胺,叔胺再与各种季铵化剂反应制备各种两性表面活性剂;甜菜碱型两性表面活性剂的原料可以是脂肪酸、脂肪醇或脂肪伯胺。氨基酸型两性表面活性剂以伯胺为原料,合成出分子中引入了其他原子或基团。对这些两性表面活性剂的性能测定表明,它们的性能优良。     

蓖麻油改性两性聚氨酯复鞣剂的制备及应用

以异氟尔酮二异氰酸酯和聚四氢呋喃二醚醇为原料、2,2-二羟甲基丙酸为阴离子扩链剂、N-甲基二乙醇胺为阳离子扩链剂,制备了两性聚氨酯乳液,接着使用蓖麻油改性两性聚氨酯得到产物(COWPU).通过FTIR对其进行了表征,采用纳米粒度及zeta电位仪对COWPU乳液的粒径及等电点进行了测试,采用TG对COWPU膜进行了热性能...     

Performance of a novel,eco-friendly,cellulose-based superabsorbent polymer (Cellulo-SAP): Absorbency,stability, reusability,and biodegradability

Superabsorbent polymers (SAPs) have attracted tremendous attention recently, with researchers noting that their high water absorbability is valuable for various applications, especially in agricultural contexts. Two types of materials can be used to produce SAPs: Fossil-based (which are harmful to the environment) and bio-based (which are significantly more environmentally friendly, given their biodegradability and minimal toxic side effects). Although bio-based SAPs are preferable for environmental reasons, their synthesis tends to be time consuming and labour intensive, while their absorption capacity (AC) can be far below expectations. To address these problems, a novel, eco-friendly, cellulose-based superabsorbent polymer (Cellulo-SAP) was developed in this study through facile preparation via free radical synthesis using modified cellulose. Then, the absorbency, thermal/pH stability, reusability, and biodegradability of Cellulo-SAP were evaluated. This new polymer demonstrated reusability as a water reservoir, in addition to high thermal and pH stability. More importantly, Cellulo-SAP achieved an AC of 475 g/g and exhibited superior biodegradability compared to a commercial, fossil-based SAP. Accordingly, these results prove that Cellulo-SAP can be used in agriculture as an effective alternative to fossil-based SAPs.     

一种两性葡萄糖胺表面活性剂的合成与性能研究

在乙醇介质中,用KOH对葡萄糖胺盐酸盐(GAH)脱酸生成葡萄糖胺(GA),再与氯乙酸反应制得羧甲基氨基葡萄糖(CM-GluN),CM-GluN进一步与环氧丙基十二烷基二甲基氯化铵(DTGA)反应合成了两性氨基葡萄糖表面活性剂(2-羟基-3-十二烷基二甲基季铵基)丙基-6-O-羧甲基氨基葡萄糖(QA-CM-GluN)。采用IR和N元素分析对QA-CM-GluN进行了结构表征,并测试了其表面性能。结果表明,25℃下,QA-CM-GluN的cmc为0.001 mol.L-1,γcmc为25.78 mN.m-1,Γmax为3.78×10-10mol.cm-2,Amin为0.44 nm2;并表现出一定的乳化性和泡沫性能;与十二烷基二甲基甜菜碱(BS-12),Tween 80和十六烷基三甲基氯化铵(1631)配伍良好,无分层现象。