A novel monomer, 1‐(acryloyloxy)propan‐2‐yl phosphoryl dichloride, was synthesized and characterized in this work. Thereafter, the monomer was neutralized with sodium hydroxide and copolymerized with sodium acrylate to obtain a superabsorbent polymer. The superabsorbent polymer was then modified to improve its swelling properties (i.e., the water absorbency under load, the hydrogel strength, the resilience and the dispersion). Both single factor and orthogonal design experiments were adopted to obtain optimal conditions. The superabsorbent polymer prepared under the optimal conditions showed improved water absorbency in physiological saline [17 g · g?1 under load (P = 2 × 103 Pa) and 65 g · g?1 at atmospheric pressure] and other swelling properties, such as hydrogel strength, resilience and dispersion, also improved.
Acrylamide (AM) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS-H+) or its sodium salt (AMPS-Na+) were copolymerised by free-radical crosslinking polymerization to obtain poly(AM-co-AMPS-H+) and poly(AM-co-AMPS-Na+) superabsorbent polymers (SAPs). A maximum water absorbency in deionised water of 1200 g g−1 was achieved for poly(AM-co-AMPS-Na+) at a 85% mol of AMPS-Na+. The inclusion of mica at 5-30% (w w−1) into the preparation of poly(AM-co-AMPS-Na+) SAP leads to an intercalated structure, as detected by XRD and TEM analyses. Poly(AM-co-AMPS-Na+)/30% (w w−1) mica SAP nanocomposite showed a tap water absorbency of 593 g g−1 with a better thermal stability, compared to the pure SAP. Cone calorimetric analyses revealed that the wood specimens coated with the prepared poly(AM-co-AMPS-Na+) SAP or its 30% (w w−1) mica nanocomposite provided excellent protection in delaying the ignition time after exposure to an open flame when compared to that observed with the uncoated specimen. The maximum reduction in the peak heat release rate and the greatest extension of time at peak heat release rate were observed with the nanocomposite-coated surface, but the total heat release rate was increased. The delayed burning mechanism is brought by the intercalating structure of mica in the SAP nanocomposites, which provided a better shielding effect against external heat sources, and the capability of the SAP nanocomposite in holding a large amount of water. 相似文献
Starch-g-poly (AM-AMPS)/illite superabsorbent nanocomposite was synthesized by grafting copolymerization reaction of starch, acrylamide(AM) and 2-acrylamido-2- methyl propane sulfonic acid (APMS) in the presence of illite micropowder in deionized aqueous solution. The influence factors on water absorbency of the superabsorbent nanocoposite was optimized by single factor experiment. The synthesized superabsorbent nanocomposite exhibited the maximum water absorbency of 1320?g H2O/g in deionized water and 142?g H2O/g in 0.9?wt% sodium chloride (NaCl) solution. FTIR spectra confirmed that the grafting copolymerization between -OH groups on starch and monomers generated during the reaction. XRD analysis confirmed that crystal interlayer of illite was pulled open to 3.61?nm. TEM showed that illite slice layer randomly dispersed in the matrix of superabsorbent nanocomposite. The superabsorbent nanocomposite had a better thermal stability the corresponding superabsorbent material without illite by TGA and DSC analysis. The superabsorbent nanocomposite with excellent water absorbency and water retention could be especially useful in industry, agricultural, horticultural applications. 相似文献
A superabsorbent polymer (SAP) is a special polymer material that can absorb up to 500 times its own weight of pure water, but has a problem that it does not biodegrade itself and cause environmental pollution. Therefore, we aim to prepare a biodegradable SAP by using biomass‐based IA. The SAP must be able to retain absorbed water and absorb water under a given pressure. We have carried out studies to improve the surface hardness of the SAP to enhance absorption of water under a given pressure by surface‐crosslinking. Four types of surface‐crosslinkers, ethylene glycol diglycidyl ether (EGDGE), ethylene carbonate (EC), 1,4‐butanediol (BD), or glycerol, were used. We confirmed the water absorption capacity of the SAP by measuring its centrifuge retention capacity (CRC) and absorbency under load (AUL). The structural characteristics of the SAP were confirmed by attenuated total reflection (ATR) and X‐ray photoelectron spectroscopy (XPS), and the surface characteristics were confirmed by scanning electron microscopy (SEM). 相似文献
Abstract A novel hydrolysis-resistant superabsorbent composite was prepared via the solution polymerization based on acrylic acid (AA) and sodium bentonite (SBT) as monomers, tetraallylammonium bromine (TAAB) as crosslinker and ammonium persulfate (APS) as initiator. The mechanism of polymerization and the structure of the superabsorbent polymer (SAP) were studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (X-ray), and scanning electron microscopy (SEM). The reaction conditions such as different mass ratios of APS to AA, TAAB to AA, SBT to AA, neutralization degree of AA were optimized by orthogonal experiment, and the influence of each reaction condition on the capacity of water absorption at 150?°C was investigated via single-factor controlled experiment. The hydrolysis resistance and swelling kinetics of the SAP were studied in different solutions at 150?°C. Compared to traditional SAPs, the SAP synthesized with TAAB as crosslinker performed a more excellent hydrolysis resistance and water absorbency capacity at high temperatures. The water absorbency in distilled water or 0.1?mol L?1 NaCl solution could reach 392.6 and 145.2?g g?1at 150?°C, respectively. The SAP maintaining high swelling capacity in the pH range of 5–9 indicated its wide application values in the acidic or alkaline environment at high temperature. In addition, the SAP exhibited good reusability which could still retain about 73% of its initial water absorbency after reswelling six times at 150?°C. 相似文献
Recent researches focus on the synthesis of new cross‐linkers from natural resources. In the current work, functionalized tannic acid was employed as a replacement of petroleum‐based cross‐linkers because of its outstanding biochemical properties. Alkene‐ and epoxy‐functionalized tannic acids were synthesized as internal and external cross‐linkers, respectively. Cross‐linker structures were characterized with Ft‐IR and 1HNMR analysis. Different amounts, as well as different numbers of alkene functional group, were incorporated during the superabsorbent synthesis. Moreover, the internal cross‐linked superabsorbent was surface cross‐linked with different amounts of epoxy‐functionalized tannic acid and increased the absorbency under load about 10 g g?1. Free absorption properties in water and saline solution, absorbency under load, and rheological properties of superabsorbents were investigated. In addition, the antibacterial activity of the internal and external cross‐linked superabsorbent was studied against Escherichia coli and Staphylococcus aureus bacteria via different methods and compared with that of conventional superabsorbent. 相似文献
A novel kind of salt-resistant superabsorbent composite, polyacrylamide/attapulgite, from acrylamide (AM) and attapulgite (APT) was prepared by free-radical aqueous polymerization, using N,N′-methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator. The organification of APT with hexadecyltrimethyl ammonium bromide (HDTMABr) was proved by FTIR and XRD. The effects of acidified APT (H+-APT), organo-APT (HDTMABr-APT) and the content of APT in the superabsorbent composite on the water absorbency and the initial swelling rate for the superabsorbent composite in distilled water and in various saline solutions were studied. The effects of incorporated HDTMABr-APT and H+-APT on the reswelling ability of the superabsorbent composites were investigated. The results indicate that the incorporation of APT had remarkable influence on the improvement of water absorbency and swelling rate of the composites. Comparing with the composite doped with H+-APT, the water absorbency for the composite doped with 10 wt% HDTMABr-APT was enhanced from 2140 g g−1 to 2800 g g−1 in distilled water and from 100 g g−1 to 121 g g−1 in 0.9 wt% NaCl solution, respectively. The water absorbency of the composites in various saline solutions decreased with the increasing concentration, especially for the multivalent cations. In addition, the reswelling ability of the superabsorbent composites is also improved evidently by adding a small amount of HDTMABr-APT into the composite, comparing with that of incorporated with H+-APT. 相似文献
The synthesis of novel superabsorbent polymers (SAPs) based on itaconic acid (IA) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) is described for application in personal hygiene products such as disposable diapers. The AMPS is introduced to improve the low absorption performance of the existing IA-based SAPs. The salt-resistant properties of AMPS are shown to improve the absorption performance of SAP with respect to aqueous salt solutions. Further, the high ionization constant of the sulfonic acid group of AMPS contributes to the increase of the centrifugation retention capacity (CRC) of the SAP. Meanwhile, the amide group of AMPS improves the gel strength of the SAP by forming hydrogen bonds between the polymer chains. This increase in gel strength is demonstrated by the enhanced absorbency under load (AUL) and rheological analysis. The degree of neutralization affect the absorption properties of SAP, and the SAP exhibits maximum CRC and AUL of 57.3 and 14.4 g/g at 60% neutralization, respectively. As a crosslinking agent content increased, AUL increased but CRC significantly decreased. Additionally, soil pH evaluation confirms that SAP do not cause soil acidification. 相似文献