Synthesis and properties of carboxymethyl cellulose‐graft‐poly(acrylic acid‐co‐acrylamide) as a novel cellulose‐based superabsorbent

A new cellulose‐based superabsorbent polymer, carboxymethyl cellulose‐graft‐poly(acrylic acid‐co‐acrylamide), was prepared by the free‐radical grafting solution polymerization of acrylic acid (AA) and acrylamide (AM) monomers onto carboxymethyl cellulose (CMC) in the presence of N,N′‐methylenebisacrylamide as a crosslinker with a redox couple of potassium persulfate and sodium metabisulfite as an initiator. The influences of reaction variables such as the initiator content, crosslinker content, bath temperature, molar ratio of AA to AM, and weight ratio of the monomers to CMC on the water absorbency of the carboxymethylcellulose‐graft‐poly(acrylic acid‐co‐acrylamide) copolymer were investigated. The copolymer's structures were characterized with Fourier transform infrared spectroscopy. The optimum reaction conditions were obtained as follows: the bath temperature was 50°C; the molar ratio of AA to AM was 3 : 1; the mass ratio of the monomers to CMC was 4 : 1; and the weight percentages of the crosslinker and initiator with respect to the monomers were 0.75 and 1%, respectively. The maximum water absorbency of the optimized product was 920 g/g for distilled water and 85 g/g for a 0.9 wt % aqueous NaCl solution. In addition, the superabsorbent possessed good water retention and salt resistance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1382–1388, 2007     

丙烯酸类共聚物超吸水树脂的合成研究

用丙烯酸（AA）和丙烯酰胺（AM）作原料,以氢氧化铝为交联剂,过硫酸盐为引发剂,通过溶液聚合法,合成了高吸水性树脂聚（丙烯酸-丙烯酰胺）（P（AA-AM））共聚物。讨论了其在蒸馏水和NaCl水溶液中的吸液性能,考察了单体配比、丙烯酸中和度、交联剂用量、反应温度、引发剂用量等条件对树脂吸水性能的影响。结果表明,最佳合成丁艺为：n（AM）：n（AA）为O．3-0．4,AA的中和度为70％,过硫酸钾和单体的质量比为0．2％-0．3％,氢氧化铝和单体的质量比为0．03％-0．05％,聚合温度为55-60℃。测得的吸水倍率为1050g／g。     

Utilization of starch and montmorrilonite for the preparation of superabsorbent nanocomposite

Starch and montmorrilonite (MMT) were used as raw materials for synthesizing starch‐graft‐poly[acrylamide (AM)–acrylic acid (AA)]/MMT superabsorbent nanocomposite by graft and intercalation copolymerization reaction of starch, AM, and AA in the presence of organic MMT micropowder in aqueous solution. Major factors affecting water absorbency such as weight ratio of monomers to starch, weight ratio of AM to AA, neutralization degree of AA, amount of crosslinker, initiator, and MMT were investigated. The superabsorbent nanocomposite synthesized under optimal synthesis conditions exhibits absorption of 1120 g H₂O/g sample and 128 g H₂O/g sample in deionized water and in 0.9 wt % NaCl solution, respectively. IR spectra showed that the graft copolymerization between  OH groups on MMT and monomers took place during the reaction, and that crystal interlayer was pulled open in the superabsorbent nanocomposite. X‐ray diffraction analysis showed that the crystal interlayer of MMT was pulled open to 2.73 nm, and thus formed nanometer exfoliation composite material. Thermogravimetric analysis showed that starch‐graft‐poly (AM–AA) superabsorbent nanocomposite (8 wt % MMT) has good thermal stability. This superabsorbent nanocomposite with excellent water absorbency and water retention, being biodegradable in nature, economical and environment friendly, could be especially useful in industry, agricultural, and horticultural applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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     

玉米秸秆接枝丙烯酸-丙烯酰胺树脂的制备与吸水性能

以醚化预处理玉米秸秆(PTCS)为基体,丙烯酸(AA)和丙烯酰胺(AM)为单体,过硫酸钾为引发剂,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PTCS接枝AA、AM共聚物[PTCS-g-P(AA-co-AM)]。研究了合成条件对树脂吸水率的影响,考察了树脂重复吸水和保水性能,并用红外光谱(FTIR)、电子扫描电镜(SEM)表征了产物的结构和形貌。结果表明,在m(PTCS):m(AA):m(AM)= 1:5:2,丙烯酸中和度为70%,K₂S₂O₈为0.6%,MBA为0.2%,60℃反应3h条件下,制备高吸水性树脂的吸水率最大,对蒸馏水和0.9% NaCl水溶液的吸水率分别为144.04g/g、30.60g/g,且重复吸水和保水性能良好。     

Design and synthesis of superabsorbent polymers

A series of novel copolymer superabsorbents based on the monomers acrylamide (AM), acrylic acid (AA), acrylonitrile, methacrylic acid, sodium acrylate (SA), and 2‐hydroxyethyl methacrylate (HEMA) were prepared by copolymerization using ammonium persulfate as an initiator and N,N‐methylenebisacrylamide as a crosslinking agent. The experimental results of superabsorbent polymers (SAPs) show that the absorbency in water and NaCl solutions is maximum for AM, SA, HEMA and AM, AA, SA combinations. The copolymers were characterized by IR spectroscopy. The water retention of soil was also enhanced using the above superabsorbents. Use of SAPs for the growth of the croton plant was also investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2635–2639, 2001     

聚丙烯酸树脂吸液性能的条件探讨

本实验采用溶液聚合法,以丙烯酸（AA）和丙烯酰胺（AM）为单体,氢氧化铝作为交联剂,过硫酸钾为引发剂合成高吸水性树脂,并探讨了单体丙烯酰胺与丙烯酸的配比率、丙烯酸的中和度、交联剂用量、聚合温度、引发剂对高吸水树脂吸液性能的影响.结果显示当丙烯酰胺和丙烯酸单体的配比率0.3～0.4,丙烯酸的中和度60 ％～70％,交联剂的用量约占单体0.03 ％～0.05％,引发剂用量约占单体的0.2％加.3％,聚合温度为55～60℃时,合成树脂的吸水倍率达最大,为995.35 g/g.     

丙烯酸/马来酸酐高吸水树脂的合成

以丙烯酸(AA)、丙烯酸盐和马来酸酐(MA)为原料,过硫酸铵(APS)为引发剂,N,N-亚甲基双丙烯酰胺(MBA)和甘油为交联剂,采用水溶液聚合法合成了一种新型的高吸水树脂. 考察了交联剂用量、引发剂用量以及马来酸酐氨化程度对高吸水树脂吸水性能的影响,并通过正交实验优化了条件,使合成的高吸水树脂对去离子水和0.9%的NaCl水溶液的吸收能力分别达到1689 g/g和115 g/g.     

丙烯酸-丙烯酰胺高吸水树脂溶液共聚与吸液性能研究

以丙烯酸(AA)和丙烯酰胺(AM)为原料,过硫酸钾为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,采用水溶液聚合对丙烯酸-丙烯酸胺(PAAAM)高吸水树脂的合成条件进行了优化。结果表明,在室温下最大吸蒸馏水倍率为2710g/g,在w(NaCl)=0.9%的水溶液中吸水倍率为133g/g。考察了单体质量分数、交联剂质量分数以及引发剂质量分数对PAAAM在蒸馏水及w(NaCl)=0.9%溶液中吸液性能的影响,并对实验结果进行了回归分析。     

Synthesis and Swelling Behavior of Superabsorbents Cross-Linked with N-Maleyl Chitosan

A kind of superabsorbent based on the monomers maleic anhydride (MA) and acrylic acid (AA) was prepared by solution polymerization using ammonium peroxodisulfate (AP) and sodium bisulfite (NaHSO₃) as initiator, and N-maleyl chitosan (N-MACH) as cross-linker. Effects of process parameters such as the amount of cross-linker, mass ratio of MA to AA, and neutralization degree of AA on the water absorbency of superabsorbents are discussed. The results indicated the water absorbency of superabsorbents increased and then decreased with the increase of MA content, the amount of the N-MACH cross-linker, and the neutralization degree of AA. Under the optimal conditions, the water absorbency of superabsorbents could reach l560.42 g/g and 83.7 g/g in distilled water and in 0.9% NaCl solution, respectively. In addition, to enhance the water absorbency of superabsorbents in 0.9% NaCl solution, polyvinyl alcohol (PVA) was introduced as interpenetrating polymer in the network and 2-acrylamido-2-methyl propane sulfonic acid (AMPS) was introduced as comonomer. It was proved that PVA and AMPS could effectively improve the water absorbency of superabsorbents both in distilled water and 0.9% NaCl solution.     

Saline solution absorbency and structure study of poly (AA-AM) water superabsorbent by inverse microemulsion polymerization

A series of novel copolymer superabsorbents based on acrylamide (AM), acrylic acid(AA) were prepared by inverse microemulsion copolymerization using ammonium persulfate (APS) as the initiator and N,N-methylenebisacrylamide (MBA) as the crosslinking agent and OP-10 and SDS as complex surfactants. The synthetic variables (amount of crosslinking agent and initiator, water/oil ratio, monomer/surfactant ratio and AA/ Am ratio) and their effects on the absorbencies of the synthesized superabsorbents were investigated. The experimental results of superabsorbent polymers (SAPs) showed the maximum saline solution absorbency of 130 g/g within 75 min, and the saline solution absorbency of 111 g/g within 30 min. FTIR indicated the structure of the acrylic acid and acrylamide copolymer. SEM indicated that the particles prepared with higher crosslinker content (0.03%) showed smaller pore sizes and less porous structures compared with those with less crosslinker content (0.01%) and the number of the micropores largely decreased with the water/oil ratio increasing from 8% to 14%.     

Utilization of waste polystyrene and starch for superabsorbent composite preparation

A superabsorbent composed of waste polystyrene, starch, and acrylic acid was prepared through emulsion polymerization. The effects of major factors such as starch, acrylic acid, initiator, crosslinker, and bentonite contents and the neutralization degree of acrylic acid on water absorbency were investigated to obtain optimum conditions with high swelling capacity. The superabsorbent hydrogel was characterized by scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The FTIR results confirmed that the grafting polymerization took place among the polystyrene, acrylic acid, starch, and bentonite. The introduction of bentonite particles into the polystyrene‐g‐poly (acrylic acid)‐co‐starch system could increase the water absorbency. The superabsorbent composite containing 3 wt % bentonite had the highest water absorbency (500 g/g in distilled water and 49 g/g in 0.9 wt % NaCl solution). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

PVA/PAA-AM共混高吸水纤维的微观结构与吸液能力

丙烯酸(AA)、丙烯酰胺(AM)为单体,在聚乙烯醇(PVA)溶液中共聚,由聚合物溶液纺丝制备高吸水纤维。用扫描电子显微镜(SEM)观察了纤维微观结构,结果表明,高吸水纤维具有微相分离结构,纤维表面形貌和横截面形状随纤维组成变化。从吸水溶胀后经液氮冷阱干燥的纤维干凝胶的SEM照片,可以观察到纤维内部存在原纤间交联网络和大量各向异性分布的长形孔洞,证实纤维具有三维网络结构并且吸收过大量的水。随AM加入量的增加,纤维的吸液能力先上升后下降, w〔AM/(AA+AM+PVA)〕=3%时,纤维吸蒸馏水倍率为 243,吸ρ(NaCl) =9g/L的盐水溶液倍率为 58。研究表明,较多的AM会导致共混结构不相容性增加,吸水能力下降。     

耐盐型丙烯酸-丙烯酰胺接枝共聚高吸水树脂的合成及其性能研究

采用溶液聚合法,以丙烯酸(AA)和丙烯酰胺(AM)为单体,N,N＇-亚甲基双丙烯酰胺(NMBA)为交联剂,过硫酸钾(KPS)为引发剂.合成出丙烯酸-丙烯酰胺接枝共聚高吸水树脂.探讨了单体比[m(丙烯酸):m(丙烯酰胺)]、交联剂和引发荆用量、单体中和度及聚合温度对树脂吸水率的影响.IR光谱表明,丙烯酸和丙烯酰胺发生了接...     

P(AA-AM-VAc)/OMMT复合高吸水性树脂的制备

采用水溶液聚合法,以丙烯酸(AA)、丙烯酰胺(AM)、乙酸乙烯酯(VAc)为单体,有机膨润土(OMMT)为复合微粒,反应得到了P(AA-AM-VAc)/OMMT复合高吸水性树脂。通过单因素实验考察了聚合温度、单体组成、引发剂用量、交联剂用量、丙烯酸中和度、有机膨润土掺入量对复合树脂吸液率的影响,获得了最佳工艺条件。结果表明,在最佳工艺条件下制备的复合高吸水性树脂对纯净水和w(NaC l)=0.9%水溶液的吸收倍率分别为695 g/g和113 g/g。     

Study on superabsorbent composites. XVIII. Preparation,characterization, and property evaluation of poly(acrylic acid‐co‐acrylamide)/organomontmorillonite/sodium humate superabsorbent composites

A series of novel multifunctional poly (acrylic acid‐co‐acrylamide) (PAA‐AM)/organomontmorillonite (O‐MMT)/sodium humate (SH) superabsorbent composites were synthesized by the graft copolymerization reaction of partially neutralized acrylic acid and acrylamide on O‐MMT micropowder and SH with N,N′‐methylene bisacrylamide as a crosslinker and ammonium persulfate as an initiator in an aqueous solution. The superabsorbent composites were characterized by means of Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The effect of the relative weight ratio of SH to O‐MMT on the water absorbency was studied, and the results indicated that the best water absorbency of 591 g/g in distilled water was obtained when an O‐MMT content of 20 wt % and an SH content of 30 wt % were incorporated. The superabsorbent composite possessed a good capacity for water retention; even after 30 days, 24.4 wt % of water could still be saved by the sand soil containing 1.0 wt % superabsorbent composite. The results from this study show that the water absorbency of a superabsorbent composite is improved by the simultaneous introduction of O‐MMT and SH into a PAA‐AM network in comparison with the incorporation of only O‐MMT or SH. Also, in comparison with PAA‐AM/MMT/SH, an appropriate amount of O‐MMT can benefit the developed composites with respect to their water absorbency, salt resistance, and capacity for water retention in sand soil. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

黄原胶改性制备高吸水性树脂的研究

以丙烯酸(AA)和丙烯酰胺(AM)为黄原胶(XG)的接枝改性剂,采用反向悬浮聚合法制备了高吸水性树脂——接枝改性共聚物(XG-g-AA/AM)。采用U*10(104)均匀设计法对XG-g-AA/AM的合成工艺进行了优化。结果表明:XG-g-AA/AM的最佳合成条件为m(AA)=10.0 g、w(引发剂)=0.5%(相对于单体总质量而言)、AA中和度80%和反应温度60℃,此时XG-g-AA/AM的吸水倍率为890.1 g/g、吸盐水倍率为172.2 g/g;热失重分析(TGA)结果显示,XG-g-AA/AM的热稳定性优于XG;扫描电镜(SEM)观测结果显示,XG-g-AA/AM表面形成的多孔网络结构,有利于其对水分子的接触与吸附。     

Swelling study of superabsorbent PAA‐co‐PAM/clay nanohydrogel

A series of superabsorbent composites were prepared from acrylic acid (AA), acrylamide (AM), and Cloisite® 30B by aqueous solution polymerization technique using ammonium peroxodisulfate (APS) as initiator. The interaction of the organically modified nanoclay with PAA‐co‐PAM copolymer was verified by FTIR, whereas the morphology of the composite was studied by Scanning Electron Microscopy (SEM). The water absorbency in deionized water and saline water of the synthesized nanohydrogels was measured by calculating their percentage swelling ratio. The effects of copolymerization, monomer ratio, clay content, and temperature on the water absorbency were studied. The results indicated a considerable increase in swelling ratio by proper monomer proportion and incorporation of optimum clay percentage into the copolymer matrix. It was found that the nanohydrogel acquired highest water absorbency with 2% clay loading. The reswelling ability and water retention capacity of the PAA‐co‐PAM hydrogel and PAA‐co‐PAM/clay nanohydrogel were also measured. The water absorbency was found to increase after each reswelling for which it may be useful as recyclable superabsorbent material. The results of water retention capacity of the nanohydrogel were also encouraging and find application in agriculture, especially in drought‐prone areas. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of AA‐based superabsorbent interpenetrated with sodium PVA sulfate

An interpenetrating network of acrylic acid (AA)‐based superabsorbents and sodium PVA sulfate (SPS) were prepared by copolymerizing AA and N,N′‐methylene bisacrylamide as a crosslinking monomer in a solution of SPS with KPS, a radical initiator. The SPS was prepared through the sulfation of the hydroxyl groups of PVA with DMF‐SO₃ complex in DMSO. The AA‐based superabsorbent interpenetrated with SPS (SA‐IP‐SPS) showed superior properties such as higher water and saline absorbency, absorbency under load (AUL), and water retention value (WRV) compared with AA‐based superabsorbent due to the interpenetrated SPS. The maximum water and saline absorbency of SA‐IP‐SPS was 1753 and 125.6 g/g, respectively. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2525–2532, 2000