Showing papers on "Acrylic acid published in 2016"
TL;DR: A very high adsorption capacity and a correlation coefficient of 0.998 calculated from isotherm equations show the high efficiency of the absorbent and thus expected to be a good candidate as an absorbent for water treatment.
281 citations
TL;DR: Fluorescence spectroscopy on a series of aqueous solutions of poly(acrylic acid) containing a luminescent label showed that polymers with molar mass, Mn < 16.5 kDa did not exhibit a pH responsive conformational change, which is typical of higher molarMass poly(Acrylic acid), while large molarmass polymers did exhibit pH-dependent diffusion.
Abstract: Fluorescence spectroscopy on a series of aqueous solutions of poly(acrylic acid) containing a luminescent label showed that polymers with molar mass, Mn < 16.5 kDa did not exhibit a pH responsive conformational change, which is typical of higher molar mass poly(acrylic acid). Below this molar mass, polymers remained in an extended conformation, regardless of pH. Above this molar mass, a pH-dependent conformational change was observed. Diffusion-ordered nuclear magnetic resonance spectroscopy confirmed that low molar mass polymers did not undergo a conformational transition, although large molar mass polymers did exhibit pH-dependent diffusion.
278 citations
TL;DR: Investigation of the effects of different binders on the cycling performance and solid electrolyte interphase (SEI) formation on silicon nanoparticle electrodes found the Lewis basic -CO2Na of CMC was found to scavenge HF in electrolyte.
Abstract: The effects of different binders, polyvinylidene difluoride (PVdF), poly(acrylic acid) (PAA), sodium carboxymethyl cellulose (CMC), and cross-linked PAA–CMC (c–PAA–CMC), on the cycling performance and solid electrolyte interphase (SEI) formation on silicon nanoparticle electrodes have been investigated. Electrodes composed of Si–PAA, Si–CMC, and Si–PAA–CMC exhibit a specific capacity ≥3000 mAh/g after 20 cycles while Si–PVdF electrodes have a rapid capacity fade to 1000 mAh/g after just 10 cycles. Infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) reveal that PAA and CMC react with the surface of the Si nanoparticles during electrode fabrication. The fresh Si–CMC electrode has a thicker surface coating of SiOx than Si–PAA and Si–PAA–CMC electrodes, due to the formation of thicker SiOx during electrode preparation, which leads to lower cyclability. The carboxylic acid functional groups of the PAA binder are reactive toward the electrolyte, causing the decomposition of LiPF6 and dissoluti...
199 citations
TL;DR: The new superabsorbent polymers fabricated via grafting polymerization of acrylic acid from chitosan (CTS/Cell) proved to be very efficient devices for controlled release of fertilizers into the soil which expands their use in agriculture and horticultural applications.
167 citations
TL;DR: The NaPAA-g-CMC based Si anode shows much better cycle stability and higher coulombic efficiency than those made with the well-known linear polymeric binders such as CMC and NaPPA.
Abstract: The design of novel binder systems is required for the high capacity silicon (Si) anodes which usually undergo huge volume change during the charge/discharge cycling. Here, we introduce a poly (acrylic acid sodium)-grafted-carboxymethyl cellulose (NaPAA-g-CMC) copolymer as an excellent binder for Si anode in lithium ion batteries (LIBs). The NaPAA-g-CMC copolymer was prepared via a free radical graft polymerization method by using CMC and acrylic acid as precursors. Unlike the linear, one-dimensional binders, the NaPAA-g-CMC copolymer binder is expected to present multi-point interaction with Si surface, resulting in enhanced binding ability with Si particles as well as with the copper (Cu) current collectors, and building a stable solid electrolyte interface (SEI) layer on the Si surface. The NaPAA-g-CMC based Si anode shows much better cycle stability and higher coulombic efficiency than those made with the well-known linear polymeric binders such as CMC and NaPPA.
151 citations
TL;DR: In this paper, a quaternized chitosan (QCh) was homogeneously synthesized by homogeneous reaction with 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) in alkali/urea aqueous solution.
Abstract: Quaternized chitosan (QCh) was homogeneously synthesized by reacting chitosan with 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) in alkali/urea aqueous solution for the first time. The structure and solution properties of QCh were characterized by using element analysis, FT-IR, 13C NMR, SEC-LLS, rheology, viscometer, and ξ-potential measurements. Subsequently, polyelectrolyte complex (PEC) hydrogels were constructed by in situ polymerization of acrylic acid (AA) monomers in the concentrated QCh solution. The structure and mechanical behavior of the prepared hydrogels were systematic studied. Because of the high charge density and solubility of QCh, strong electrostatic interactions were formed in the hydrogels and endowed them tough with self-recovery properties. The mechanical behavior of the hydrogels was accurately tuned from stiff and viscoelastic to soft and elastic by changing the poly(acrylic acid) (PAA) content. The regulation mechanism relied on the remarkable difference in the chai...
138 citations
TL;DR: In this paper, a serial of crosslinked sodium acrylate and acrylamide copolymer/graphene oxide (P(AANa-co-AM)/GO) hydrogels with different mass ratios of acrylic acid (AA) to acrylamide (AM) and different contents of N,N-methylenebis(acrylamides) (MBA) were prepared via dispersive polymerization.
Abstract: A serial of cross-linked sodium acrylate and acrylamide copolymer/graphene oxide (P(AANa-co-AM)/GO) hydrogels with different mass ratios of acrylic acid (AA) to acrylamide (AM) and different contents of N,N-methylenebis(acrylamide) (MBA) were prepared via dispersive polymerization. The prepared hydrogels were characterized by XRD, FT-IR, TGA, SEM, and BET in detail. The removal efficiency of Pb2+ and Cd2+ on the P(AANa-co-AM)/GO hydrogel have been improved significantly due to the addition of 1.0 wt % of GO. The P(AANa-co-AM)/GO hydrogel with AA/AM = 1 and 0.8 wt % of MBA has the highest removal efficiency for Pb2+ and Cd2+ and a suitable swelling ratio, which was selected as the adsorbent for systematic adsorption of Pb2+ and Cd2+ from aqueous solutions. The adsorption capacity and removal efficiency of Pb2+ and Cd2+ on the P(AANa-co-AM)/GO hydrogel were dependent on pH, initial heavy metal ion concentration, and adsorbent dosage. The presence of 0.01–0.05 M Mg2+ or Ca2+ has an obvious effect on the adso...
124 citations
TL;DR: Benefiting from the unique features of Ln(3+), the PAA-S HNFs simultaneously exhibited versatile advantages including good photoluminescent performance, tunable emission color, and excellent flexibility and processability, which also hold great potential for applications in luminescent patterning, underwater fluorescent devices, sensors, and biomaterials.
Abstract: Combined with the features of electrospun nanofibers and the nature of hydrogel, a novel choreographed poly(acrylic acid)–silica hydrogel nanofibers (PAA-S HNFs) scaffold with excellent rare earth elements (REEs) recovery performance was fabricated by a facile route consisting of colloid-electrospinning of PAA/SiO2 precursor solution, moderate thermal cross-linking of PAA-S nanofiber matrix, and full swelling in water. The resultant PAA-S HNFs with a loose and spongy porous network structure exhibited a remarkable adsorption capacity of lanthanide ions (Ln3+) triggered by the penetration of Ln3+ from the nanofiber surface to interior through the abundant water channels, which took full advantage of the internal adsorption sites of nanofibers. The effects of initial solution pH, concentration, and contact time on adsorption of Ln3+ have been investigated comprehensively. The maximum equilibrium adsorption capacities for La3+, Eu3+, and Tb3+ were 232.6, 268.8, and 250.0 mg/g, respectively, at pH 6, and the ...
83 citations
TL;DR: In this paper, a random poly(methyl methacrylate- co -butyl acrylate co -acrylic acid) was synthesized via emulsion polymerization utilizing thermally-activated persulfate radicals.
78 citations
TL;DR: In this paper, two groups of comb-like polycarboxylate ether (PCE) polymers were synthesized by aqueous free radical polymerization from acrylic acid (AA), methacrylic acid (MAA), and poly(ethylene glycol) monomethyl ether methacrylate.
78 citations
TL;DR: In this article, the carboxylic acid groups introduced by grafting acrylic acid, significantly enhanced the absorption capacity of LS- g -AA hydrogels, and the equilibrium absorption of MB reached 2013mg·g − 1 while pH, absorption time, and initial MB concentration affected the overall absorption capacity.
Abstract: Lignosulfonate- g -acrylic acid (LS- g -AA) hydrogels that possess superabsorbent capacity were synthesized by grafting acrylic acid (AA) on the backbone of lignosulfonate (LS) in the presence of N , N ′-methylene- bis -acrylamide (MBA) as initiated by laccase/ t -BHP(tert-butyl hydroperoxide). Specifically, the carboxylic acid groups introduced by grafting acrylic acid, significantly enhanced the absorption capacity of LS- g -AA hydrogels. In this case, methylene blue (MB) was the representative dye substrate to study absorption dynamics. It was found that the equilibrium absorption of MB reached 2013 mg·g − 1 while pH, absorption time, and initial MB concentration affected the overall absorption capacity. The absorption isotherms and kinetics obeyed standard Freundlich and pseudo-2nd-order models, respectively. Furthermore, preliminary desorption experiments were conducted in weak acid solution and showed that ~ 50% of the original MB could be removed over one rinse cycle.
TL;DR: In this paper, a modified H-ZSM-5 catalysts with NaOH and Na2HPO4 were used in the catalytic dehydration of lactic acid to acrylic acid.
TL;DR: The grafting from approach was used to prepare pH-responsive polyacid brushes using poly(itaconic acid) and poly(acrylic acid) (PAA) at the amine functional groups of chitosan and the products were structurally characterized and displayed reversible pH- responsive behavior and controlled adsorption/desorption of methylene blue.
Abstract: The grafting from approach was used to prepare pH-responsive polyacid brushes using poly(itaconic acid) (PIA) and poly(acrylic acid) (PAA) at the amine functional groups of chitosan. Hybrid materials consisting of polymer brushes and magnetite nanoparticles (MNPs) were also prepared. The products were structurally characterized and displayed reversible pH-responsive behavior and controlled adsorption/desorption of methylene blue (MB). Switchable binding of MB involves cooperative effects due to conformational changes of brushes and swelling phenomena in solution which arise from response to changes in pH. Above the pKa, magnetic nanocomposites (MNCs) are deprotonated and display enhanced electrostatic interactions with high MB removal efficiency (>99%). Below the pKa, MNCs undergo self-assembly and release the cationic dye. The switchable binding of MB and the structure of the polymer brush between collapsed and extended forms relate to changes in osmotic pressure due to reversible ionization of acid grou...
TL;DR: In this work, poly(acrylic acid) chains at extremely high grafting densities and confined in nanoscale pores displayed a unique long-lived hysteretic behavior caused by their ability to form a metastable hydrogen bond network.
Abstract: Stimuli-responsive soft materials are a highly studied field due to their wide-ranging applications; however, only a small group of these materials display hysteretic responses to stimuli. Moreover, previous reports of this behavior have typically shown it to be short-lived. In this work, poly(acrylic acid) (PAA) chains at extremely high grafting densities and confined in nanoscale pores displayed a unique long-lived hysteretic behavior caused by their ability to form a metastable hydrogen bond network. Hydraulic permeability measurements demonstrated that the conformation of the PAA chains exhibited a hysteretic dependence on pH, where different effective pore diameters arose in a pH range of 3 to 8, as determined by the pH of the previous environment. Further studies using Fourier transform infrared (FTIR) spectroscopy demonstrated that the fraction of ionized PAA moieties depended on the thin film history; this was corroborated by metal adsorption capacity, which demonstrated the same pH dependence. Th...
TL;DR: In this paper, the thermal behavior of polyelectrolyte complexes (PECs) containing weak PECs containing poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) as influenced by water content and complexation pH was investigated.
Abstract: Here, we present the thermal behavior of polyelectrolyte complexes (PECs) containing weak polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) as influenced by water content and complexation pH. Modulated differential scanning calorimetry (MDSC) reveals a glass-transition-like thermal transition (Ttr) that decreases in value with increasing hydration and with decreasing complexation pH. We show the collapse of all Ttr values into a single master curve when plotted against the ratio of water molecules per intrinsic (PAH+–PAA–) ion pair for all pH values explored. Remarkably, this master curve is linear when the natural log of the water to intrinsic ion pair ratio is plotted against the inverse of Ttr. This strongly indicates that the thermal transition is heavily influenced by water at the intrinsic ion pair site. Other water–solvent mixtures are also explored, for which Ttr appears to depend only on water content, regardless of the added solvent. These results suggest that wa...
TL;DR: In this article, a two-step protocol for the conversion of glycerol to acrylic acid is presented, where the first stage uses formic acid to allyl alcohol and the second stage uses Mo-V-W-O multiple-metal oxide catalysts.
Abstract: The conversion of glycerol, the main byproduct of the biodiesel industry, to acrylic acid is one of the most attractive biomass to biochemical processes. It represents millions of tons of market demand. The previous tandem reaction protocol for the conversion of glycerol to acrylic acid via an acrolein intermediate always suffers from fast catalyst deactivation and thus cannot be commercialized. Herein, a novel two-step protocol for the conversion of glycerol to acrylic acid is presented: glycerol deoxydehydration (DODH) by formic acid to allyl alcohol, followed by oxidation to acrylic acid in the gas phase over Mo–V–W–O catalysts. In the second step, supported and unsupported Mo–V–W–O multiple-metal oxide catalysts were used for the transformation of allyl alcohol to acrylic acid and excellent activity as well as selectivity was achieved. Remarkably, the mesoporous silica-supported Mo–V–W–O catalysts showed superb stability on time stream under the optimal reaction conditions with an overall acrylic acid...
TL;DR: In this article, a graft copolymerization of ANI onto Gg-co-poly(AA) chains, in the presence of N,N’-methylene-bis-acrylamide (MBA) and ammonium persulphate (APS) as a crosslinker-initiator system in an aqueous solution, was performed.
TL;DR: Results from the ATR-FTIR characterization of the membranes, solubility tests, turbidimetry, and TEM suggest that the reaction occurs already at 80 °C, leading mostly to graft samples, while at higher curing temperatures (120 or 150 °C) insoluble cross-linked samples are usually obtained.
Abstract: In the present work, reactive blending of copolymers with complementary functional groups was applied to control their antimicrobial activity and antifouling action in real conditions. For this purpose, two series of copolymers, poly(4-vinylbenzyl chloride-co-acrylic acid), P(VBC-co-AAx), and poly(sodium 4-styrenesulfonate-co-glycidyl methacrylate), P(SSNa-co-GMAx), were synthesized via free radical copolymerization and further modified by the incorporation of biocidal units either covalently (4-vinyl benzyl dimethylhexadecylammonium chloride, VBCHAM) or electrostatically bound (cetyltrimethylammonium 4-styrenesulfonate, SSAmC16). The cross-linking reaction of the carboxylic group of acrylic acid (AA) with the epoxide group of glycidyl methacrylate (GMA) of these two series of reactive antimicrobial copolymers was explored in blends obtained through solution casting after curing at various temperatures. The combined results from the ATR-FTIR characterization of the membranes, solubility tests, turbidimetr...
TL;DR: The novel bilayer coated mesoporous silica nanoparticle would be a good candidate for tumor therapy due to its biocompatibility, controlled release and pH responsive behavior.
TL;DR: Composite hydrogels prepared by in situ incorporation of a natural macromolecule guar gum and nano sized bentonite clay in an acrylic network during copolymerization of acrylic acid, N,N-methylenebisacrylamide and hydroxyethyl methacrlylate in water showed the best results in mechanical and swelling properties.
TL;DR: In this paper, the sequence of monomers in polycarboxylate superplasticizers (PCEs) synthesized from acrylic acid and isoprenyloxy polyethylene glycol (IPEG) macromonomer was characterized by 13C nuclear magnetic resonance (NMR) spectroscopy.
TL;DR: Characterization of the adsorbents indicated that the increase in uranium adsorption capacity with each acid monomer was related to higher grafting of AN and therefore a higher conversion to amidoxime (AO).
Abstract: Uranium is dissolved in the ocean at a uniform concentration of 3.34 ppb, which translates to approximately 4-5 billion tons of uranium. The development of adsorbents that can extract uranium from seawater has been a long term goal, but the extremely dilute uranium concentration along with the competition of other metal salts (which are at higher concentrations) has hindered the development of an economical adsorption process. Several acid monomers were co-grafted with acrylonitrile (AN) to help increase the hydrophilicity of the adsorbent to improve access to the metal adsorption sites. Grafting various acid monomers on PE fibers was found to significantly affect the uranium adsorption in simulated seawater in the following order: acrylic acid (AA) < vinyl sulfonic acid (VSA) < methacrylic acid (MAA) < itaconic acid (ITA) < vinyl phosphonic acid (VPA). Interestingly, the uranium adsorption capacity significantly increased when Mohr's salt was added with acrylic acid, most likely due to the reduction of co-polymerization of the monomers. When testing under more realistic conditions, the acid-grafted PE fiber adsorbents were exposed to natural seawater (more dilute uranium), the uranium adsorption capacity increased in the following order: MAA < AA (Mohr's salt) < VSA < ITA (Mohr's salt) < ITA < VPA, which agreed well with the simulated seawater results. Characterization of the adsorbents indicated that the increase in uranium adsorption capacity with each acid monomer was related to higher grafting of AN and therefore a higher conversion to amidoxime (AO).
TL;DR: In this paper, a new molecularly imprinted adsorbents based on poly(methacrylic acid) and poly(acrylic acyclic acid) have been synthesized, characterized and evaluated as selective materials for the adsorption of diuron.
Abstract: In the present study new molecularly imprinted adsorbents based on poly(methacrylic acid) and poly(acrylic acid) have been synthesized, characterized and evaluated as selective materials for the adsorption of diuron. Morphological, textural data and the presence of functional groups in the polymer have been evaluated by means of SEM, nitrogen adsorption–desorption assays and FT-IR, respectively. Two functional monomers were evaluated for the MIP synthesis, methacrylic acid (MIP MAA ) and acrylic acid (MIP AA ), and the first one showed higher selectivity and better adsorption towards diuron in the presence of competitor molecules, carbofuran and 2,4-D. The experimental adsorption isotherm of diuron has been obtained at pH 7.0 in phosphate buffer (0.05 mol L − 1 ):acetonitrile (1:2, v / v ) medium and equilibrium time of 180 min. The respective maximum adsorption capacities (MAC) of MIP MAA and MIP AA were found to be 14.58 and 7.32 mg g − 1 . One should note that MAC of MIP AA and its respective blank polymer (NIP AA ) was very similar to each other, while for the MIP MAA its MAC was significantly higher (14.58 mg g − 1 ) than the MAC of NIP MAA (6.12 mg g − 1 ). Such result demonstrates the great influence of monomer on the adsorption and selectivity of MIP. Adsorption kinetic data were well fitted to pseudo-first-order and intraparticle diffusion models, while the adsorption isotherms showed good fit to the isotherm of Langmuir–Freundlich for two sites (LF-2) and one site (LF-1), but the former one allowed insight into the adsorption mechanism with more details.
TL;DR: In this article, the dynamics of supramolecular networks made up of partially hydrolyzed poly(n-butyl acrylate) [PnBA] is investigated.
Abstract: The dynamics of supramolecular networks made up of partially hydrolyzed poly(n-butyl acrylate) [PnBA] is investigated. These linear entangled random copolymers [PnBA-AA] self-assemble via hydrogen bonding interactions between carboxylic acid groups. Two types of supramolecular assemblies are revealed, i.e., binary assembly of carboxylic acid dimers and collective assembly of dimers into distinct poly(acrylic acid) [PAA] domains. The latter is proved by emergence of new relaxation processes in broadband dielectric spectroscopy while the former is evident by an increase of the glass transition temperature as well as retardation of segmental mobility observed by rheology. Therefore, a “sea–island” morphology containing geometrically confined PAA nanodomains embedded in a PnBA-rich matrix is suggested for the supramolecular network. Thermodynamic theories are employed to rationalize the existence of an interlayer with restricted mobility between the two phases. A fraction of PnBA-AA segments that are trapped ...
TL;DR: The results showed that the rate of degradation was about 10 times higher at acidic condition than that at alkaline condition in the first 1 min when 1mg L(-1) of ozone solution was added into 1 mg L(- 1) of salicylic acid solution.
TL;DR: The utilization of lignin based synthetic drug-loaded hydrogel is one of the prospective ways to recycle the pulping waste lignosulphonate.
Abstract: A novel method (ultrasound synthesis) has been applied to prepare a sodium lignosulphonate-grafted poly(acrylic acid-co-poly(vinyl pyrrolidone)) hydrogel (SLS-g-P(AA-co-PVP)), and the products were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetry analysis (TGA). The swelling behavior and pH sensitivity of SLS-g-P(AA-co-PVP) hydrogel were investigated. Amoxicillin was used as model drug to study the release properties in enzyme-free simulated gastrointestinal fluids and it exhibited favorable pH-sensitivity and controllable release behavior in vitro. By adjusting the pH value of medium, the release behavior could be controlled. In simulated gastric fluids (SGF) (pH = 1.2 ± 0.2), the cumulative release rate was up to 51.5% in 24 h and about 32% for 2 h. But for the simulated intestinal fluids (SIF) (pH = 7.4 ± 0.1), the cumulative release rate reached 84.5% in 24 h and 63.3% after digestion and absorption for 5 h. The amoxicillin encapsulated with SLS-g-P(AA-co-PVP) hydrogel show a better release effect in the simulated intestinal fluids than that in simulated gastric fluids. In a word, the utilization of lignin based synthetic drug-loaded hydrogel is one of the prospective ways to recycle the pulping waste lignosulphonate.
TL;DR: Results from circular dichroism (CD) analysis and catalytic activity tests reveal an increase in the β-sheet content of lipase molecules upon immobilization, along with an enhancement in their activities and stabilities.
Abstract: A facile approach for the preparation of core–shell structured poly(acrylic acid) (PAA)-coated Fe3O4 cluster@SiO2 nanocomposite particles as the support materials for the lipase immobilization is reported. Low- or high-molecular-weight (1800 and 100 000, respectively) PAA molecules were covalently attached onto the surface of amine-functionalized magnetic silica nanoacomposite particles. The successful preparation of particles were verified by scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential measurement, and Fourier-transform infrared (FTIR) techniques. Once lipase is covalently immobilized onto the particles with an average diameter of 210 ± 50 nm, resulting from high binding sites concentrations on the low- and high-molecular-weight PAA-coated particles, high lipase immobilization efficiencies (86.2% and 89.9%, respectively), and loading capacities (786 and 816 mg g–1, respectively) are obtain...
TL;DR: Electrochemical performances of fabricated EDLCs are studied through cyclic voltammetry (CV) and galvanostatic charge-discharge studies and the complexation between PAA, LiTFSI and TiO2 is discussed in Attenuated total reflectance-Fourier Transform Infrared studies.
Abstract: Nanocomposite polymer electrolyte membranes (NCPEMs) based on poly(acrylic acid)(PAA) and titania (TiO2) are prepared by a solution casting technique. The ionic conductivity of NCPEMs increases with the weight ratio of TiO2.The highest ionic conductivity of (8.36 ± 0.01) × 10−4 S·cm−1 is obtained with addition of 6 wt % of TiO2 at ambient temperature. The complexation between PAA, LiTFSI and TiO2 is discussed in Attenuated total reflectance-Fourier Transform Infrared (ATR-FTIR) studies. Electrical double layer capacitors (EDLCs) are fabricated using the filler-free polymer electrolyte or the most conducting NCPEM and carbon-based electrodes. The electrochemical performances of fabricated EDLCs are studied through cyclic voltammetry (CV) and galvanostatic charge-discharge studies. EDLC comprising NCPEM shows the specific capacitance of 28.56 F·g−1 (or equivalent to 29.54 mF·cm−2) with excellent electrochemical stability.
TL;DR: In this article, the effect of composition ratio on the properties for PVA/PAA blend membrane was investigated by using molecular dynamics (MD) simulation, and the analysis of binding energy and pair correlation function reveal the reason why the mechanical properties of systems decrease with the additional of PAA.
TL;DR: In this article, a novel hydrogel composite was prepared via inverse suspension polymerization using starch, acrylic acid and organo-mordenite micropowder with the crosslinker, N,N′-methylenebisacrylamide and the initiator, potassium persulfate.
Abstract: A novel hydrogel composite was prepared via inverse suspension polymerization using starch, acrylic acid and organo-mordenite micropowder with the cross-linker, N,N′-methylenebisacrylamide and the initiator, potassium persulfate. Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy confirmed that the acrylic acid was grafted onto the backbone of the corn starch, that the organo-mordenite participated in the polymerization, and that the addition of organo-mordenite improved the surface morphology of the hydrogel composite. The swelling capacity of the hydrogel composite was evaluated in distilled water, and solutions with different pH values, and various salt solutions. It was found that the incorporation of 10 wt-% organo-mordenite enhanced the water absorbency by 144% (from 268 to 655 g∙g–1) and swelling was extremely sensitive to the pH values, the concentration of the salt solution and cation type. Swelling kinetics and water diffusion mechanism of the hydrogel composite in distilled water were also discussed. Moreover, the hydrogel composite showed excellent reversibility of water absorption even after five repetitive cycles and the hydrogel composite exhibited significant environmental-responsiveness by changing the swelling medium from distilled water to 0.1 mol∙L–1 NaCl solution. In addition, the loading and release of urea by the hydrogel composite were tested and the nutrient-slowrelease capability of this material was found to be suitable for many potential applications.