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。     

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%。     

微波辐射CMC-g-PAMPS/APT高吸水树脂的制备及表征

以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体,凹凸棒黏土(APT)和羧甲基纤维素钠(CMC)为复合组分,采用微波辐射方法制备了CMC-g-PAMPS/APT环境友好复合高吸水性树脂,探讨了合成该树脂适宜的反应条件,并利用FTIR对树脂的结构进行了表征。结果表明,APT和CMC参与了接枝共聚反应;适宜的合成条件下,树脂在去离子水和生理盐水中的吸水倍率分别为834 g/g和78 g/g;树脂的吸水倍率随盐溶液浓度和金属离子价态的升高快速下降;在树脂中引入适量的APT能显著提高树脂的吸水倍率、耐盐性能和pH稳定性。     

GA-g-PAMPS/APT复合高吸水性树脂的合成和溶胀行为

以阿拉伯胶(GA)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、凹凸棒石黏土(APT)为原料,采用微波辐射法,通过接枝共聚合成生物质GA-g-PAMPS/APT高吸水性树脂。利用FTIR、XRD和TG分析了树脂的结构和热稳定性能,探讨了树脂在各种盐溶液和不同p H溶液中的溶胀行为,研究了树脂的溶胀速率和反复吸水性能。结果显示:GA、APT与AMPS之间发生了接枝共聚反应,w(GA)=7.5%、w(APT)=10%时树脂在去离子水和生理盐水中的最大吸水倍率分别为783 g/g和91 g/g。树脂在各种盐溶液和不同p H溶液中表现出良好的响应性和可逆性能。适量引入APT能显著提高树脂的热稳定性、溶胀速率、反复吸水性能和p H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。     

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。     

低成本复合高吸水性树脂的工业化研究

以丙烯酸为单体,凹凸棒黏土为复合组分,2,2-偶氮二异丁基脒二盐酸盐(V50)/过硫酸钾/抗坏血酸为引发剂,N,N′-亚甲基双丙烯酰胺为交联剂,采用水溶液自由基聚合法,在10 t反应釜内合成了速吸复合高吸水性树脂。结果表明,在w(单体)=42%(即单体质量占加入反应釜中所有物质质量的百分数)、引发温度50℃、w(发泡剂)=0.002%(以单体质量计)和w(交联剂)=0.12%(以单体质量计)的最优反应条件下,复合高吸水性树脂的吸水速率为43 s,2 kPa下吸生理盐水倍率为14.7 g/g。该工艺利用酸碱中和反应热及聚合反应热,可使胶体有效成分质量分数从42%提高到52%,降低了后续工段的蒸气耗量,与传统工艺相比,每生产1 t丙烯酸高吸水树脂总计可降低能耗达164万kJ。     

LS-g-PAMPS/AA高吸水性树脂的微波合成及吸水性能

以木质素磺酸钠(LS-Na)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酸(AA)为原料,采用微波辐射法,通过接枝共聚合成LS-g-PAMPS/AA高吸水性树脂。探讨了微波功率、辐射时间对树脂吸水倍率的影响,研究了树脂在各种pH溶液中的溶胀行为,探讨了树脂的吸水速率、保水和反复吸水性能。结果表明,引入适量的LS-Na可以显著提高树脂的吸水速率、保水和反复吸水性能。树脂具有pH敏感性,在pH值4~12之间保持较高的吸水倍率,在pH值2与7的溶液里有良好的可逆行为。     

聚丙烯酸类半互穿聚合物网络吸水树脂的合成

制备了以紫外光引发同步合成聚乙烯醇(PVA)和部分中和的丙烯酸一丙烯酰胺(AM)共聚物复合的具有半互穿聚合物网络结构的吸水树脂。分析了共聚物中AM含量、PVA的添加量及单体浓度对树脂吸水性能的影响。初步探讨了AM含量对树脂吸水量产生影响的原因,并将红外干燥的方法应用于聚合物的后处理中。实验发现,与传统的烘箱干燥相比,经红外干燥后吸水树脂的吸水速率有较大的提高,且具有干燥速度快、粉碎容易、残留单体少的优点。     

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。     

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     

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.     

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     

Study on superabsorbent composites. IX: Synthesis,characterization and swelling behaviors of polyacrylamide/clay composites based on various clays

A series of clay-based superabsorbent composite from acrylamide (AM) and various clays, such as attapulgite, kaolinite, mica, vermiculate and Na⁺-montmorillonite, was prepared by free-radical aqueous polymerization, using N,N′-methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator, and then saponified with sodium hydroxide solution. In this paper, the reaction mechanism and thermal stability of the superabsorbent composites incorporated with various clays were characterized by FTIR, XRD and TGA, respectively. The effects of clay kind and clay content on equilibrium water absorbency of these composites were also investigated and compared. In addition, the influences of clay kind on comprehensive swelling behaviors of the PAM/clay superabsorbent composites were studied. The results indicated that the introduced clays could influence physicochemical properties of obtained superabsorbent composites. Mica could improve thermal stability of corresponding superabsorbent composites to the highest degree comparing with the other clays. The PAM/clay superabsorbent composites incorporated with 10 wt% clay of various kinds were all endowed with equilibrium water absorbency of more than 1300 g g⁻¹. The equilibrium water absorbency decreases with increasing clay content and correlates with the kind of clay. Attapulgite-based superabsorbent composite was endowed with higher water absorbency in univalent cationic saline solution, however, the vermiculite- and the kaolinite-based ones acquired the highest water absorbency in CaCl₂ and FeCl₃ aqueous solution, respectively. Moreover, the superabsorbent composites incorporated with Na⁺-montmorillonite have higher swelling rate and that of doped with mica was endowed with higher reswelling capability.     

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     

AA-AMPS共聚物陶瓷分散剂的制备及分散性能

以丙烯酸和2-丙烯酰胺基-2-甲基-丙烷磺酸(AMPS)为单体,过硫酸铵(NH4)2S2O8作为引发剂,次亚磷酸氢钠作为链转移剂,通过自由基聚合反应合成共聚物PAA-AMPS。探讨了不同反应条件对共聚物分散性能的影响,共聚物分散剂PAA-AMPS的最佳合成条件为:丙烯酸(AA)与2-丙烯酰胺基-2-甲基-丙烷磺酸(AMPS)的摩尔比为8∶1;引发剂(NH4)2S2O8用量为单体总质量的1%;链转移剂次亚磷酸氢钠的用量为单体总质量的10%;单体质量分数为24%;反应温度85℃。通过FTIR、GPC及1HNMR等手段对共聚物的结构及相对分子质量及其分布进行了表征,并对添加不同量分散剂的料浆的黏度进行研究。结果表明,聚合物质量分数为0.3%,料浆的黏度最低,与进口产品PC-67(PAA-Na)相比,共聚物PAA-AMPS的分散效果更好。     

Study on superabsorbent composite. XV. Effects of ion‐exchanged attapulgite on water absorbency of superabsorbent composites

A series of superabsorbent composite, polyacrylamide/attapulgite, from acrylamide (AM) and ion‐exchanged attapulgite (APT) was prepared by aqueous polymerization, using N,N′‐methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator. The effects of ion‐exchanged APT on water absorbency of superabsorbent composites in distilled water and in 0.9 wt% NaCl solution were studied. The result indicates that higher cation‐exchange capacity (CEC) and lower specific surface area (SSA) of APT treated with various anions are of benefit for improving water absorbency in distilled water. The effects of AlCl₃ solution concentration and Al³⁺‐exchanged APT content on water absorbency of the composite were also investigated. The concentration of AlCl₃ solution has a great influence on water absorbency of the superabsorbent composite. Al³⁺‐exchange of APT could also enhance reswelling ability of the corresponding composite, which indicates that Al³⁺‐exchange of APT could improve gel strength and gives a direct evidence for its acting as an inorganic assistant crosslinker in the polymeric network. POLYM. COMPOS., 28:208–213, 2007. © 2007 Society of Plastics Engineers