CMC-g-PAA/APT/HA复合高吸水性树脂的制备与溶胀性能

以羧甲基纤维素(CMC)为基质,丙烯酸(AA)为单体,凹凸棒黏土(APT)和腐植酸(HA)为复合组分,采用水溶液聚合法制备了羧甲基纤维素接枝聚丙烯酸/凹凸棒黏土/腐植酸(CMC-g-PAA/APT/HA)环境友好复合高吸水性树脂,用红外光谱(FTIR)进行了结构表征。考查了APT和HA含量对树脂吸水倍率和吸水速率的影响,研究了树脂在不同pH溶液中的溶胀行为以及反复吸水性能。试验结果表明,APT和HA通过其表面的活性基团参与了接枝共聚反应,在体系中引入HA和APT能够显著提高复合高吸水性树脂的吸水能力。在HA含量为5%(质量分数),APT含量为30%(质量分数)时,树脂可达到最优吸蒸馏水倍率为582g/g。该复合高吸水性树脂在pH值在4～11范围内时具有较高的吸水性能,表现出优异的pH稳定性。经过5次反复溶胀后,该复合吸水树脂仍能达到424g/g的吸水倍率,较不含APT和HA样品提高了近44%。     

冷冻-碾磨处理凹凸棒石黏土对复合高吸水性树脂性能的影响

将凹凸棒石黏土(attapulgite,ATP)经冷冻和碾磨处理后,采用羧甲基纤维素为基质,丙烯酸为单体和不同碾磨次数的ATP为无机组分,通过水溶液聚合法制备了羧甲基纤维素接枝聚丙烯酸/凹凸棒石黏土复合高吸水性树脂,考察了冷冻和碾磨处理对ATP的形貌、理化性质及对复合高吸水性树脂的吸水倍率和吸水速率的影响,评价了复合高吸水性树脂在不同pH溶液中的吸水性能。结果表明:经碾磨处理后,ATP的比表面积和孔容先降低后升高,而后趋于不变,平均孔径呈先增大后减小趋势。在相同添加量下,碾磨不同次数的ATP比表面积越大,复合树脂的吸水倍率越低,但吸水速率越快。此外,复合吸水树脂表现出优异的pH稳定性。     

AC/XG-g-PAA复合高吸水性树脂的制备及性能研究

利用溶液聚合法制备了AC/XG-g-PAA有机-无机复合高吸水性树脂。研究了丙烯酸用量、引发剂用量、丙烯酸中和度、凹凸棒黏土用量、交联剂用量和聚合反应温度等因素对合成复合高吸水性树脂性能的影响,利用傅立叶变换红外光谱仪(FTIR)、扫描电镜仪(SEM)、X射线衍射仪(XRD)和示差扫描量热仪(DSC)对产物进行表征。结果表明,丙烯酸分子与黄原胶发生接枝共聚,凹凸棒黏土与接枝共聚物发生了有机-无机复合,制备的AC/XG-g-PAA高吸水性树脂具有良好的吸水和抗盐性能,提高了高温保水性能,接枝率达137.2%,接枝效率达83.6%,最高吸水倍率达896g/g,吸盐水倍率达126.3g/g。     

AC/XG-g-PAA复合高吸水树脂的制备及性能研究

利用溶液聚合法制备了AC/XG-g-PAA有机-无机复合高吸水性树脂。研究了丙烯酸用量、引发剂用量、丙烯酸中和度、凹凸棒黏土用量、交联剂用量和聚合反应温度等因素对合成复合高吸水性树脂性能的影响,利用傅立叶变换红外光谱仪(FTIR)、扫描电镜仪(SEM)、X射线衍射仪(XRD)和示差扫描量热仪(DSC)对产物进行表征。结果表明,丙烯酸分子与黄原胶发生接枝共聚,凹凸棒黏土与接枝共聚物发生了有机-无机复合,制备的AC/XG-g-PAA高吸水性树脂具有良好的吸水和抗盐性能,提高了高温保水性能,接枝率达137.2%,接枝效率达83.6%,最高吸水倍率达896g/g,吸盐水倍率达126.3g/g。     

凹凸棒黏土/黄原胶接枝改性高吸水性树脂的制备

以丙烯酸(AA)、丙烯酰胺(AM)为单体对黄原胶(XG)进行接枝改性,再以N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,过硫酸铵(APS)为引发剂,加入凹凸棒黏土,采用溶液聚合法合成了一种新型复合高吸水性树脂。通过单因素试验研究了AA中和度、交联剂用量、引发剂用量、反应温度和凹凸棒黏土用量等因素对该树脂吸水(吸盐水)性能的影响,利用傅里叶红外光谱(FT-IR)仪、热重分析(TGA)仪对其结构和热性能进行了表征。结果表明:制备高吸水性树脂的最佳工艺条件为AA中和度70%,反应温度70℃,w(交联剂)=0.06%,w(APS)=1.0%,w(凹凸棒黏土)=5%;在最佳工艺条件下制备的高吸水性树脂,其最大吸水倍率、吸盐水倍率分别为827、109 g/g。     

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。     

微波辐射APT–g-PAMPS高吸水性树脂的制备及性能

以凹凸棒黏土(APT)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为原料,过硫酸钾(KPS)为引发剂,N,N'-亚甲基双丙烯酰胺(NMBA)为交联剂,采用微波辐射法接枝共聚合成了APT-g-PAMPS耐盐性复合高吸水性树脂,用FTIR和XRD对复合吸水性树脂的结构进行了表征。考察了微波功率和时间及APT用量对树脂吸水倍率的影响,测定了不同APT用量高吸水性树脂的吸水速率、保水性能及反复吸水性能。FTIR和XRD结果显示,APT和有机单体之间发生了接枝共聚反应,其反应仅在APT的表面进行,单体并没有插入到APT的层间。结果表明,微波功率为195 W,辐射时间为2.5 min,w(APT)=5%时,树脂在去离子水和生理盐水中的吸水倍率分别为987g/g和102 g/g。该复合高吸水性树脂具有较快的吸水速率、较强的保水性能和较好的反复吸水性能。在体系中引入适量APT能够显著提高复合吸水树脂的吸水能力和耐盐性能,同时能明显加快树脂的吸水速率和提高树脂的保水性能。     

淀粉和纤维素基高吸水性树脂的制备与性能

对以淀粉或羧甲基纤维素为原料,用丙烯酸进行接枝共聚得到高吸水性树脂作了介绍。将丙烯酸用氢 氧化钠部分中和,然后与淀粉或羧甲基纤维素共混,用水溶性的过硫酸铵做引发剂,Ｎ,Ｎ－亚甲基双丙烯酰胺做交联 剂,在一定的反应温度下得到了不同吸水能力的高吸水性树脂;找到了吸水能力与天然高分子加入量之间的关系。 以淀粉和羧甲基纤维素为原料的产物的最高吸水能力分别为 １０８ｇ·ｇ－１及 １５２ｇ·ｇ－１,是一种良好的吸水剂。     

有机改性凹凸棒土复合P (AA-co-AM)高吸水性树脂的制备及性能研究

以过硫酸铵为引发剂,表面丙烯酰基化的凹凸棒土(AT-MPS)为交联剂,采用水溶液聚合法制备了丙烯酰基化凹凸棒土复合聚(丙烯酸-co-丙烯酰胺)高吸水性树脂[AT-MPS/P (AA-co-AM)].考察了中和度、丙烯酸与丙烯酰胺的单体比、引发剂用量以及凹凸棒土用量对复合吸水树脂吸液性能的影响.采用红外光谱(FTIR)、热失重分析(TGA)以及扫描电镜(SEM)等方法对复合吸水树脂进行了表征.结果表明,丙烯酸中和度为75％、m(AA)∶m(AM) =4∶1、引发剂用量为0.8％、AT-MPS用量为8％时,复合吸水树脂的最大吸水倍率为347.7 g/g,最大吸盐水倍率为43.5 g/g.红外光谱分析结果表明,凹凸棒土参与了聚合交联反应;SEM表明,凹凸棒土在复合吸水树脂中具有良好的分散性.     

不同高吸水性树脂吸附金属离子的研究

本文共制备两种吸水树脂:一种以丙烯酸(AA)为单体,采用过硫酸钾(KSP),硝酸铈铵(CAN)为复合引发剂,N-N′-亚甲基双丙烯酰胺(MBA)为交联剂,加入羧甲基纤维素(CMC)接枝共聚制备纤维素类吸水树脂;另一种则用相同浓度的单体,引发剂,交联剂,反应条件下制备聚丙烯酸类吸水树脂。通过对两种吸水树脂吸附重金属离子如Na+、Li+、Ca2+、Zn2+、Co2+、Fe3+溶液,以及对尿素的吸附能力,吸水速率,保水能力的测试比较,结果表明:在相同的反应条件下纤维素类吸水树脂对离子的吸附能力强于聚丙烯酸类吸水树脂。     

Synthesis,characterization and swelling behaviors of hydroxyethyl cellulose‐g‐poly(acrylic acid)/attapulgite superabsorbent composite

In this work, a series of novel hydroxyethyl cellulose‐ g‐poly(acrylic acid)/attapulgite (HEC‐g‐PAA/APT) superabsorbent composites were prepared through the graft polymerization of hydroxyethyl cellulose (HEC), partially neutralized acrylic acid (AA), and attapulgite (APT) in aqueous solution, and the composites were characterized by means of Fourier‐transform spectroscopy, scanning electron microscopy, and transmission electronmicroscopy. The effects of polymerization variables including concentrations of the initiator and crosslinker and APT content on water absorbency were studied, and the swelling properties in various pH solutions as well as the swelling kinetics in various saline solutions were also systematically evaluated. Results showed that the introduction of 5 wt% APT into HEC‐g‐PAA polymeric network could improve both water absorbency and water absorption rate of the superabsorbent composites. In addition, the superabsorbent composites retained high water absorbency over a wide pH range of 4–10, and the swelling kinetics of the superabsorbent composites in CaCl₂ and FeCl₃ solutions exhibited a remarkable overshooting phenomenon. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

魔芋接枝丙烯酸-丙烯酰胺共聚物/凹凸棒石复合材料的制备与表征

以水溶液聚合法制备了魔芋接枝丙烯酸-丙烯酰胺共聚物/凹凸棒石复合材料。考察了魔芋用量、凹凸棒石用量、中和度、丙烯酰胺用量等因素对复合材料吸液倍率的影响,并采用FTIR,SEM对复合材料进行表征。结果表明,凹凸棒石的适量加入可以提高复合材料的吸液倍率。当魔芋用量为丙烯酸单体质量的4%、凹凸棒石用量为6%、中和度为90%、丙烯酰胺用量为20%时,制备的复合材料的吸液倍率最高。红外光谱(FTIR)表明魔芋葡甘聚糖、丙烯酸、丙烯酰胺和凹凸棒石共同参与了接枝聚合反应;扫描电子显微镜(SEM)分析表明凹凸棒石与高分子复合效果良好。     

Study on superabsorbent composite. XI. Effect of thermal treatment and acid activation of attapulgite on water absorbency of poly(acrylic acid)/attapulgite superabsorbent composite

The effect of acid activation and thermal treatment of attapulgite on water absorbency of superabsorbent composite were investigated. Under the same preparation conditions, superabsorbent composite prepared with natural attapulgite exhibited a water absorbency of 639 g/g and it merely kept 71% of its initial water absorbency after 5 times of swelling–deswelling–reswelling test. However, superabsorbent composites prepared with 2–10 M hydrochloric acid acidified attapulgite and 100–400°C thermal treated attapulgite respectively exhibited the water absorbency of 884–1,241 g/g and 701–1,515 g/g. Also, those superabsorbent composites can keep 87% and 85% of their initial water absorbency after 5 times of swelling–deswelling–reswelling test, respectively. These results showed that, compared with superabsorbent composite prepared with natural attapulgite, the comprehensive water‐absorbing properties of poly(acrylic acid)/ attapulgite superabsorbent composites were improved effectively by acid activation and thermal treatment of attapulgite. This improvement of water absorbencies and gel strength of superabsorbent composite may be due to synthetical factors such as changes in the crystalline structure and the specific surface area and improvement of the number and the activity of hydroxyl groups of attapulgite, which in turn influence the grafting efficiency of monomer, crosslinking density, and the structure of superabsorbent composite network. POLYM. COMPOS., 28:397–404, 2007. © 2007 Society of Plastics Engineers     

合成聚丙烯酸/凹凸棒复合保水剂的中试放大实验

在100 L的中试设备上,用水溶液聚合法,以丙烯酸和凹凸棒黏土为主要原料,以N,N-亚甲基双丙烯酰胺为交联剂,V-50和过硫酸钾复配作为引发体系,进行了聚丙烯酸/凹凸棒复合保水剂的中试放大实验。考察了各种制备条件对产品性能的影响,得到的最佳工艺条件为:引发温度22℃;丙烯酸的中和度为60%;w(凹凸棒)=30%~45%;w(丙烯酸)=30%~35%;w(N,N-亚甲基双丙烯酰胺)=0.2%;w(复合引发剂)=0.5%;m(V-50)∶m(过硫酸钾)=2∶3;w(十二烷基硫酸钠)<0.2%。最佳制备条件下中试产品在蒸馏水及w(NaC l)=0.9%的水溶液中的吸水倍数分别为550~700和55~75。中试实验表明,该工艺生产的产品性能稳定,为工业化生产提供了参考。     

Studies on poly(acrylic acid)/attapulgite superabsorbent composites. II. Swelling behaviors of superabsorbent composites in saline solutions and hydrophilic solvent–water mixtures

The effect of the attapulgite content on the swelling for a series of poly(acrylic acid)/attapulgite superabsorbent composites in water was studied. The effects of the temperature and pH values on the water absorbency of the superabsorbent composites were investigated. The swelling behavior of the superabsorbent composites in various saline solutions was also investigated. The water absorbency in various salt solutions decreased with an increase in the ionic strength of the solutions. At a high ionic strength (>1 × 10^?3M), the water absorbency in monovalent cationic solutions was higher than that in multivalent cation solutions. This dramatic reduction of the water absorbency in multivalent cationic solutions of high ionic strength may have been due to the complexing ability of the carboxylate groups inducing the formation of intramolecular and intermolecular complexes, which resulted in an increased crosslink density of the network. The swelling behavior of the superabsorbent composites in mixtures of water and hydrophilic solvents, including methanol, acetone, ethanol, and dimethyl sulfoxide (DMSO), was also investigated. The water absorbency decreased with an increase in the concentration of any of the four organic solvents, and two transitions were observed in the superabsorbent composite/hydrophilic solvent–water mixture systems. The main transition for the four hydrophilic solvent–water mixtures was a collapse of the swollen gel (at 50–80% methanol, 30–80% acetone, 50–80% ethanol, and 50–80% DMSO). For the methanol–water system, the magnitudes of the first and second transitions for the poly(acrylic acid)/attapulgite superabsorbent composites containing lower proportions of attapulgite were larger than those for the superabsorbent composites with higher attapulgite contents. The effect of the mixture temperature on the water absorbency of the superabsorbent composites in 10 min was also reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1869–1876, 2004     

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     

Superabsorbent composite XXII: Effects of modified sepiolite on water absorbency and swelling behavior of chitosan‐g‐poly(acrylic acid)/sepiolite superabsorbent composite

In this work, a series of chitosan‐g‐poly(acrylic acid)/sepiolite (CTS‐g‐PAA/ST) superabsorbent composites containing raw sepiolite, acid‐activated sepiolite, and cation‐exchanged sepiolite were synthesized by free‐radical graft polymerization in aqueous solution, using N,N′‐methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. The effects of raw sepiolite, acid‐activated sepiolite, and cation‐exchanged sepoilite on equilibrium water absorbency, swelling rate, and swelling behavior in different pH value solution of superabsorbent composites were systematically investigated. The results from FTIR spectra showed that chitosan and sepiolite participated in graft polymerization reaction with acrylic acid. The introduction of acid‐activated and cation‐exchanged sepiolite into chitosan‐g‐poly(acrylic acid) polymeric network could improve water absorbency and swelling rate compared with that of the raw sepiolite. All prepared samples have similar swelling behavior in different pH solutions and the equilibrium water absorbencies of samples keep roughly constant in the pH range from 4 to 12. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Superabsorbent composite. XIII. Effects of Al3+‐attapulgite on hydrogel strength and swelling behaviors of poly(acrylic acid)/Al3+‐attapulgite superabsorbent composites

Al³⁺‐attapulgite (Al³⁺‐APT) was prepared by treating attapulgite (APT) with AlCl₃ aqueous solution of various concentrations. The poly(acrylic acid)/Al³⁺‐attapulgite (PAA/Al³⁺‐APT) superabsorbent composite was prepared by reaction of partly neutralized acrylic acid, and Al³⁺‐APT in aqueous solution using N, N′‐methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. The surface morphology of the composite was investigated by SEM, and the Al³⁺‐APT composite generated a relatively planar surface comparing the nature APT. The effects of Al³⁺‐APT on hydrogel strength and swelling behaviors, such as equilibrium water absorbency, swelling rate, and reswelling capability, of the superabsorbent composites were also studied. The hydrogel strength and reswelling capability were improved, however, the equilibrium water absorbency and swelling rate decreased with increasing AlCl₃ solution concentration. The equilibrium water absorbency firstly increased, and then decreased with increasing Al³⁺‐APT content. The results indicate that Al³⁺‐APT acts as an assistant crosslinker in the polymeric network, which has great influences on hydrogel strength and swelling behaviors of the PAA/Al³⁺‐APT superabsorbent composites. POLYM. ENG. SCI., 47:619–624, 2007. © 2007 Society of Plastics Engineers.