真空制备木薯淀粉超吸水材料

采用真空技术成功制备了一种木薯淀粉（CS）-g-丙烯酸（AA）超吸水材料。在AA与cS质量比2．5：l,过硫酸钾0．07g,30％wt氢氧化钠水溶液中和度（摩尔比）20％,N,N’-弧甲基双丙烯酰胺0．14％（占AA重）条件下,65℃真空恒温反应3h,干燥后得超吸水材料（cs．SAP）。一定温度湿度条件下,不同形状CS—SAP吸液能力及保水性能有一定差别,保留4％凝胶残重的材料保水时间最长可达28d：材料吸去离予水倍率高达1316．8（g／g）、自来水673．1（g／g）、0．9％NaCI水溶液54．8（g／g）、人工尿液63．0（g／g）。接枝反应及材料吸水结构经FTIR．SEM,PM表征。     

膨润土复合保水材料凝胶微波干燥及其吸水性能研究

膨润土复合保水材料凝胶块的干燥通用干燥方式是烘箱干燥或沸腾流化床干燥,现分别采用105℃烘箱鼓风、40%微波输出将含水60%的凝胶干燥至含水分8%,其干燥时间分别为6h和8min;且微波干燥有利于保水材料用膨润土含蒙脱石片层的快速膨胀解离,干燥后的成品具有更好的吸水、保水通道和更大的吸水倍数,含膨润土45%的保水材料成品采用微波干燥凝胶块,其吸收纯水、0.9%Na Cl水溶液能力分别达810 g/g、58 g/g,较常规烘箱鼓风干燥样品吸纯水、0.9%Na Cl水溶液倍数提高率分别为62.0%、31.8%;膨润土复合保水剂凝胶微波干燥具有较好的干燥节能、提高成品吸收纯水、吸盐水性能效果。     

AA/AMPS共聚物水凝胶的吸液性能

研究了采用溶液聚合法制备的AA/AMPS共聚物Poly(AA-co-AMPS)水凝胶的吸液性能,结果表明:合成的凝胶材料在0.9%生理盐水中的吸液能力达到125 g/g以上;在溶液的pH值5～9时,水凝胶的吸水倍率与最大吸液率的比值(Q/Qmax)最大;水凝胶对NaBr溶液的吸收能力要好于对NaCl溶液的吸收能力;水凝胶对乙醇、氨水溶液的吸收能力随溶液浓度的增高而增大,对尿素水溶液的吸收能力随溶液浓度的增高而减小。     

粘土-高吸水复合树脂的制备和吸水性能研究

具有层状结构的粘土矿物可以与有机单体进行插层处理,制备粘土-高吸水复合树脂,可降低高分子高吸水树脂的成本、提高吸水后凝胶强度、提高凝胶的耐盐性。本文综述了粘土-高吸水复合树脂的制备工艺,以及影响其性能的主要因素,探讨了该材料的吸水机理,对其应用前景提出几点建议。     

超吸水树脂的发展难点及解决与发展趋势

超吸水树脂是一类新型的功能高分子材料,具有较低交联密度和良好的亲水性,与传统吸水材料相比吸水倍率更高,吸水速度更快,保水性能更好,因此在实际生产生活中应用非常广泛,并且发展迅速。但当前超吸水树脂的发展正在经历瓶颈,本文对当前超吸水树脂发展存在的问题如理论与开发进程不统一、生产工艺优化与开发进程不统一、实际应用方式与开发进程不统一等进行了分析,并提出了初步的解决建议,对今后研究发展的趋势进行了展望。     

高吸水性树脂的吸水机理及制备方法

高吸水性树脂是一种新型的功能高分子材料，由于它能吸收自身质量几百至上千倍的水，且吸水膨胀后生成的凝胶具有优良的保水性。因而在生理卫生用品、土木建筑、食品、农业、医药等方面具有广阔的应用前景。本文介绍了高吸水性树脂的研究状况，吸水机理以及制备方法，并对高吸水性树脂的发展前景作了展望。     

在EVM中通过原位生成丙烯酸钠制备吸水膨胀橡胶

NaAA(丙烯酸钠)用于制备超吸附性材料。超吸附性的聚丙烯酸钠(PNaAA)可以吸附大量的水，即使在一定的压力下吸附的水分也很难被除去。PNaAA在许多产品中可得到有价值的应用，例如一次性尿布，农业及园艺土壤及用于医疗及保健系统。近年来出现了许多有关PNaAA的研究报道。制备方法不同，PNaAA的吸水特性也不同。为了提高吸水后的亲水性和力学性能，以及降低PNaAA的成本，常用其他亲水性的单体与NaAA进行共聚。     

超吸水纤维吸水倍率的测试方法研究

以超吸水纤维吸水倍率测试的企业标准为基础,分析超吸水纤维吸水倍率的影响因素。结果表明：超吸水纤维的吸水倍率测试受非织造布布袋尺寸、水温、离子浓度、pH值、浸泡时间、切断长度的影响较大,受水体积的影响较小。据此提出了适合超吸水纤维吸水倍率的测试方法。     

淀粉接枝衣康酸/丙烯酸高吸水材料制备与性能

旨在为降低吸水材料成本、拓宽原料来源、提高生物降解性、减少对石油化工产品的依赖提供指导,以水溶液接枝共聚法制备了淀粉接枝衣康酸/丙烯酸高吸水材料（S/IA/AA）,讨论了淀粉糊化条件、中和度、单体含量、反应温度等因素对材料吸水性能的影响,采用FTIR、SEM、EDX等对吸水材料进行表征。研究表明：淀粉糊化最佳条件为糊化温度80℃,糊化比为10 g•g^-1,糊化时间30 min;吸水材料合成最佳条件为中和度50%,衣康酸40%,淀粉20%,引发剂为4×10^-3 mol•L^-1,交联剂0.075%,反应温度50℃;利用40％衣康酸替代丙烯酸所制S/IA/AA同S/AA相比,其吸水性能有一定提高且保水性能优良。     

XG-g-PAA/OMMT有机-无机杂化复合高吸水性材料

利用溶液聚合法制备了黄原胶-g-聚丙烯酸/有机蒙脱土(XG-g-PAA/OMMT)有机-无机杂化复合高吸水性材料。当蒙脱土用量为丙烯酸质量的6%时,XG-g-PAA/OMMT的吸水倍率高达882 g/g,吸w(NaCl)=0.9%的水溶液倍率达到106.5 g/g。借助红外光谱仪、X射线衍射仪、扫描电镜、差示扫描量热仪和热重分析仪对合成产物进行了研究。结果表明,黄原胶分子与丙烯酸发生接枝共聚,蒙脱土的加入改变了XG-g-PAA的晶态结构,使复合高吸水性材料形成的网络空间增大,吸水抗盐性能和热稳定性能提高。通过研究复合高吸水性材料的吸水溶胀过程探讨其吸水动力学机理,表明XG-g-PAA/OMMT的吸水动力学扩散模型主要为non-Fickon扩散。     

GG-g-PAA/LOESS复合高吸水性树脂的制备与性能

以瓜尔胶(GG)、丙烯酸(AA)和黄土(LOESS)为原料,过硫酸铵(APS)为引发剂,N,N'-亚甲基双丙烯酰胺(MBA)为交联剂,采用水溶液聚合法制备了瓜尔胶接枝聚丙烯酸/黄土(GG-g-PAA/LOESS)复合高吸水性树脂。采用FTIR和SEM对其结构进行了表征,研究了LOESS的添加量对复合高吸水性树脂的溶胀能力和溶胀动力学的影响,考察了复合高吸水性树脂的保水性能、反复溶胀性以及在不同pH溶液中的吸水性能。结果表明,瓜尔胶、丙烯酸和LOESS发生了接枝共聚,体系中引入LOESS能够显著提高复合高吸水性树脂的吸水性能。当LOESS的质量分数为2%时,该树脂最高吸水倍率可达602 g/g,室温下6 d后,其保水率仍达28%,5次反复溶胀,吸水倍率仍能保持初始时的49%。此外,该复合高吸水性树脂还表现出优异的pH稳定性。     

海泡石接枝P(AMPS-co-AM)高吸水树脂的合成和性能

以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)和海泡石黏土(ST)为原料,采用微波辐射方法制备了ST接枝P(AMPS-co-AM)耐盐性高吸水性树脂,考察了海泡石用量、无机盐溶液金属离子价态和浓度对树脂吸水倍率的影响,研究了树脂的吸水速率和保水性能。用FTIR、XRD、SEM对吸水性树脂进行了表征。结果表明,树脂的吸水倍率随着无机盐溶液浓度的增加而减小,在不同价态金属离子盐溶液中,树脂的吸水倍率顺序为NaCl>CaCl2>FeCl3,在体系中适量地引入ST能显著提高树脂的吸水能力,树脂具有较快的吸水速率和良好的保水性能。FTIR和XRD表明,ST和有机单体之间发生了接枝共聚反应,部分单体插入到ST的层间形成插层型复合高吸水性树脂,SEM显示树脂具有多孔的层状结构。     

Novel superabsorbent materials from bacterial cellulose

A novel process for the production of superabsorbent materials (hydrogels) from bacterial cellulose (BC) was developed. Prior to crosslinking with a water‐soluble polyethylene glycol diacrylate (PEGDA), BC was first carboxymethylated and functionalized with glycidyl methacrylate. The degree of crosslinking influenced the swelling properties of the hydrogels. The use of greater amounts of PEGDA enhanced the formation of a thicker macromolecular network containing fewer capillary spaces in the crosslinked gel. The maximum water retention value of the hydrogels containing 2.5–3.5 mmol of carboxyl groups per gram of gel reached 125 g g^?1 in distilled water, and 29 g g^?1 in saline (0.9% NaCl solution). The highly porous hydrogel architecture with a pore size of 350–600 µm created a high specific surface area. This enables rapid mass penetration in superabsorbent applications. The superabsorbent hydrogels reached 80% of their maximum water absorption capacity in 30 min. © 2018 Society of Chemical Industry     

VMT/P(AMPS-co-AA)复合高吸水树脂的性能测试

研究了溶液pH、盐浓度对辉光放电电解等离子体引发合成的蛭石/聚(2-丙烯酰胺-2-甲基丙磺酸-co-丙烯酸) (VMT/P(AMPS-co-AA)) 复合高吸水树脂的溶胀行为的影响,考察了染料pH、吸附时间、染料浓度等因素对复合高吸水树脂吸附量的影响,同时对树脂的吸附-解吸性能进行了研究。结果表明, VMT/P(AMPS-co-AA)具有高吸水性、pH敏感性、盐敏感性以及高吸附性。该树脂在蒸馏水中的最大溶胀率达到822.4 g/g,对阳离子染料亚甲基蓝(MB)、结晶紫(CV)和孔雀石绿(MG)的吸附量分别可达2027.8, 2171.8和883.2 mg/g。在pH=6.5和25℃下,其对染料的吸附行为符合动力学准二级模型,该树脂还具有一定的吸附-解吸性能和重复利用性能。     

Studies on poly(acrylic acid)/attapulgite superabsorbent composite. I. Synthesis and characterization

A novel poly(acrylic acid)/attapulgite superabsorbent composite was synthesized by graft copolymerization reaction of acrylic acid (AA) on attapulgite micropowder using N,N′‐methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator in aqueous solution. The effects on water absorbency of such factors as reaction temperature, initial monomer concentration, degree of neutralization of AA, amount of crosslinker, initiator, and attapulgite were investigated. These crosslinked superabsorbent composites were characterized by thermogravimetetric analysis and scanning electron microscopy. The graft copolymerization reaction of AA on attapulgite micropowder was characterized by FTIR. The water absorbencies for these superabsorbent composites in water and saline solutions were investigated and water‐retention tests were carried out. Results obtained from this study show that the water absorbency of the superabsorbent composite synthesized under optimal synthesis conditions with an attapulgite content of 10% exhibited an absorption of 1017 g H₂O/g sample and 77 g H₂O/g sample in distilled water and in 0.9 wt % NaCl solution, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1596–1603, 2004     

Synthesis of poly(acrylic acid)/sodium humate superabsorbent composite for agricultural use

A novel poly (acrylic acid)/sodium humate superabsorbent composite was synthesized by graft copolymerization reaction of acrylic acid (AA) on sodium humate micropowder using N,N′‐methylenebisacrylamide (MBA) as a crosslinker and potassium peroxydisulfate (KPS) as an initiator in aqueous solution. The effects on water absorbency of factors such as reaction temperature, initial monomer concentration, and degree of neutralization of AA, amount of crosslinker, initiator, and sodium humate were investigated. The superabsorbent composite was characterized by scanning electron microscopy, and the graft copolymerization reaction of AA on sodium humate micropowder was characterized by IR spectroscopy. Results obtained from this study show that the water absorbency of the superabsorbent composite synthesized under optimal conditions for synthesis with a sodium humate content of 5.3% exhibited absorption of 684 g H₂O/g sample in distilled water. Water‐retention in soil is enhanced by the use of the superabsorbent composite. The effect of superabsorbent composite on the growth of corn is reported. The superabsorbent composite may be of use as water management materials for agriculture purposes in desert and drought‐prone areas. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5137–5143, 2006     

高吸水性树脂的结构设计与性能改善

利用Flory凝胶理论阐明了高吸水性树脂的吸水机理 ,并解释了高分子链上的电荷密度、外界溶液离子强度以及交联度对树脂吸水倍数和吸水速率的影响。介绍了利用分子设计和颗粒形状设计对高吸水性树脂进行结构设计以改善树脂综合性能的方法。指出今后高吸水性树脂的研究重点应集中在高性能化、材料复合化、智能性凝胶、生物可降解性的研究等几个方面     

Effect of hydrophobic monomer on the synthesis and swelling behaviour of a collagen‐graft‐poly[(acrylic acid)‐co‐(sodium acrylate)] hydrogel

BACKGROUND: Graft polymerization of vinylic monomers onto natural backbones is an efficient approach for the synthesis of natural‐based superabsorbents. The nature of the monomers will affect the swelling behaviour of the superabsorbents. Here, a novel superabsorbent was synthesized through grafting of acrylic acid onto collagen in the presence of hydrophobic styrene as co‐monomer. Subsequently, the effect of styrene on the swelling behaviour of the superabsorbent was studied. RESULTS: The highly swelling superabsorbent was prepared by introducing styrene into a collagen‐graft‐poly(acrylic acid) hydrogel. By inclusion of styrene monomer, the swelling capacity of the hydrogel was increased; this is discussed according to the network composition. The effect of swelling media (salt solutions and various pH values) was investigated. The results of absorbency under load showed that hydrogels containing phenyl groups exhibit better behaviour; however, by introducing styrene, the rate of water uptake and resistance to water holding under heating was reduced. Scanning electron micrographs of hydrogels revealed a decrease in porosity on using styrene. CONCLUSION: Inclusion of styrene monomer in the ionic superabsorbent caused high swelling capacity with better absorbency under load. This can be used to prepare highly swelling superabsorbents with good mechanical properties. The pH reversibility of the synthesized superabsorbent makes it a candidate for use in the controlled release of drugs and in agrochemicals. Copyright © 2008 Society of Chemical Industry     

Effect of aggregate size on liquid absorption characteristics of konjac glucomannan superabsorbent

In this article, four kinds of konjac glucomannan based superabsorbent polymers (KSAPs) with different aggregate sizes were obtained by sieving the KSAP powders manually. They were characterized by scanning electronic microscopy (SEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and optical contact angle (OCA), and the effects of aggregate size on liquid absorption characteristics of KSAP were studied in detail. The results show that the coarse KSAP particles were aggregated by many microspheres, while the fine particles were well dispersed with 50–150 µm particle size. OCA dynamic images showed the enhanced hydrophilicity for the finer particles. The liquid absorption measurements demonstrated that water and physiological saline absorption velocity of KSAP increased for the finer particles, while their ultimate water holding capacity decreased accordingly. The liquid absorption capacity of the finest sample (75 µm) could reach its maximum value (332.5 ± 5.6 g/g) in 0.5 min, while the coarsest sample (850 µm) reached the maximum value (532.5 ± 1.2 g/g) in 16 min. The reason for this phenomenon was discussed, and a new model was proposed to explain it. We believe that the results of this article would be meaningful in application of KSAP as superabsorbent materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45416.     

Preparation and Swelling Behavior of a pH-Responsive Psyllium-g-Poly(acrylic acid)/Attapulgite Superabsorbent Nanocomposite

In this study, a series of psyllium-g-poly(acrylic acid)/attapulgite (PSY-g-PAA/APT) superabsorbent nanocomposites were prepared. The effects of the content of APT on equilibrium water absorption, swelling rate, and the swelling behaviors of the nanocomposites in various cationic saline solutions and different pH solutions were also systematically investigated. The nanocomposite containing 10 wt% APT gives the best water absorption of 568 g/g in distilled water and 64 g/g in 0.9 wt% NaCl solution. The excellent responsive properties and reversible On-Off switching characteristics can be observed in various pH buffer solutions.