Trace metal ion retention properties of crosslinked poly(4‐vinylpyridine) and poly(acrylic acid)

The crosslinked resins poly(4‐vinylpiridine) (PVPy) and poly(acrylic acid) (PAA) were obtained by radical polymerization. PVPy shows monodentate ligands and PAA at basic pH is basically as acrylate anion, which can contain end‐carboxylates groups or form a bridge acting as mono‐ or bidentate ligands. The retention properties for trace metal ions from saline aqueous solutions and natural seawaters of these two resins were investigated by Batch equilibrium procedure. The metal ions studied were Cu(II), Pb(II), Cd(II), and Ni(II). The following effects were studied: pH, contact time, amount of the adsorbent, temperature, and salinity. The resin PVPy showed a high affinity for Cd(II) and PAA for Cu(II) and Cd(II). The metal ions were determined in the filtrate by atomic absorption spectrometry. By the treatment of the loaded resin with 4M HNO₃, it was possible to remove completely the Cu(II) ions. The retention properties of the resins were studied for trace metal ions present in the natural seawaters. Both resins showed a high affinity for Cd(II) when the natural seawater contained Cu(II) and Cd(II). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2908–2916, 2004     

The preparation and properties of acrylic and methacrylic acid grafted cellulose prepared by ceric ion initiation. II. Water retention properties

Bleached sulfite softwood pulp and the corresponding paper have been grafted with acrylic and methacrylic acids and a number of other monomers. A practical, all aqueous, ceric ion method was used as described in Part I of this series. The water and saline retention values of the grafted pulps were determined. Super water sorbency, up to 48 g/g, were obtained after suitable post treatments. A number of variables were studied including the effects of pH, counterion, crosslinking, drying, and beating. It was gratifying that drying did not affect the effeciency of water or saline water retention. Useful linear functional relationships were found between the saline water retention values and the logarithm of the percent sodium chloride in the water. The two “model” parameters of the plots also correlated well with the water retention values and with the degree of grafting expressed as the ion exchange equivalents of the pulps. The osmotic pressure approach to the water sorption as developed by Grignon and Scallan⁵ coupled with the restraining forces of the grafted polymer itself is used to interpret the process.     

聚(丙烯酸-丙烯酰胺)接枝辛基酚聚氧乙烯醚丙烯酸酯两亲性共聚物的合成及表征

以辛基酚聚氧乙烯醚丙烯酸酯(C8PhEO10Ac)为大分子单体,丙烯酸(AA)、丙烯酰胺(AM)为共聚单体,采用大分子单体接枝共聚法,制备了一种两亲性接枝共聚物(AA-AM-g-C8PhEO10Ac),用静态光散射(SLS)与GPC联用技术测得接枝共聚物的分子量为9.51×105,用FTIR、1H NMR和TG/DTA等手段对共聚物的结构及性能进行了表征。采用透射电子显微镜(TEM)对聚合物在水溶液中的自组装行为进行了初步研究。结果表明,AA-AM-g-C8PhEO10Ac在水溶液中自组装,形成球型胶束,随着浓度增大,趋向于形成更大的自组装体。     

Synthesis of amphiphilic graft copolymer with hydrophilic poly(acrylic acid) backbone and hydrophobic polystyrene side chains

A series of well-defined amphiphilic graft copolymers consisting hydrophilic poly(acrylic acid) backbones and hydrophobic polystyrene side chains were synthesized by successive atom transfer radical polymerization (ATRP) followed by hydrolysis of poly(methoxymethyl acrylate) (PMOMA) backbone. Grafting-from strategy was employed for the synthesis of graft copolymers with narrow molecular weight distribution. Hydrophobic side chains were connected to the backbone through stable C-C bonds. The backbone can be easily hydrolyzed with HCl without affecting hydrophobic side chains. This family of amphiphilic graft copolymers can form stable micelles in water. The critical micelle concentration was determined by fluorescence spectroscopy. The micellar morphologies and sizes were studied using transmission electron microscopy (TEM) and dynamic light scattering (DLS). The sizes of micelles were dependent on ionic strength, pH value and preparation conditions.     

Adiabatic compressibility of polyelectrolytes: Poly(N-dimethylaminoethyl methacrylate) and its copolymer with acrylic acid

The adiabatic compressibility of poly(N-dimethylaminoethyl methacrylate) and of three copolymers of N-dimethylaminoethyl methacrylate and acrylic acid, ranging in composition from 33 to 58 mole-% amino groups, has been studied. The ?V of the polymer shows a slight decrease (2.4 cc/mole), while the ?K is found to have increased considerably (51 × 10^?4 cc bar^?1 mole^?1) compared to that of the monomer. The latter is apparently due to the more compressible nature of the polymer than that of its monomer. The experimentally observed ?K₂⁰ and ?V₂⁰ values for the three copolymers containing 58%, 43%, and 33% amino groups are ?2.5 × 10^?4 cc bar^?1 mole^?1 and 164.5 cc/mole, ?32 × 10^?4 cc bar^?1 mole^?1 and 177.5 cc/mole, and ?55 × 10^?4 cc bar^?1 mole^?1 and 211.3 cc/mole, respectively, whereas the calculated values are less by 19.4 × 10^?4 cc bar^?1 mole^?1 and 3.2 cc/mole, 49.5 × 10^?4 cc bar^?1 mole^?1 and 19.9 cc/mole, and 73 × 10^?4 cc bar^?1 mole^?1 and 16.4 cc/mole, respectively. This decrease is attributed to the interaction of acid and base groups in the molecules. The ?K₂⁰ and ?V₂⁰ values have been resolved into their ionic components ?K and ?V. Since the magnitude of electrostriction is higher in fully neutralized salt than in unneutralized salt, the ?K_2i⁰ and ?V_2i⁰ values are lower as expected. The difference in these values for the polybase and its salt is 23.7 × 10^?4 cc bar^?1 mole^?1 and 7.5 cc/mole, respectively, which may be due to the electrostrictive effect. In excess NaCl (1.0M), the magnitude of electrostriction is somewhat reduced and ?V_2i⁰ and ?V_2i⁰ approach values more or less equal to those of the unneutralized polymer. The 100% neutralized hydrochloride salt of poly(N-dimethylaminoethyl methacrylate) shows greatly increased reduced viscosity over that of the feebly basic parent polymer due to the characteristic polyelectrolytic expansion in dilute aqueous solution. The copolymer containing excess amount of amino groups (58%) shows similar behavior, while the other two copolymers containing fewer amino groups (43% and 33%) show a contraction of chains, which may be ascribed in interaction of the carboxyl ions that are freshly formed on dilution with the amino groups in the copolymer chain.     

Metal ion retention properties of poly(acrylic acid) and poly[N‐3‐(dimethylamino)propyl acrylamide‐co‐acrylic acid]

The crosslinked resins poly(acrylic acid) (PAA) and poly[N‐3‐(dimethylamino)propyl acrylamide‐co‐acrylic acid] [P(NDAPA‐co‐AA)] are obtained by radical polymerization and characterized by FTIR spectroscopy. PAA at basic pH exists basically as an acrylate anion that may contain end carboxylate groups or form bridges acting as mono‐ or bidentate ligands. P(NDAPA‐co‐AA) presents three potential ligand groups in its structure: carboxylic acid, amide, and amine. The trace metal ion retention properties of these two resins is compared by using the batch equilibrium procedure. The metal ions are contained in saline aqueous solutions and are found in natural seawater. The retention of Cu(II), Pb(II), Cd(II), and Ni(II) metal ions is studied under competitive and noncompetitive conditions. The effects on the pH, contact time, amount of adsorbent, temperature, and salinity are investigated. The PAA resin presents a high affinity (>80%) for Cu(II) and Cd(II) ions. The P(NDAPA‐co‐AA) resin shows a high affinity for Pb(II) and Cd(II) ions. With 4M HNO₃ it is possible to completely recover the PAA resin charged with Cu(II) ions and the P(NDAPA‐co‐AA) resin charged with Pb(II) ions. The two resins show a high affinity for Cd(II) ions from the seawater containing Cu(II) and Cd(II) ions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1385–1394, 2005     

Preparation of amphiphilic acrylic acid copolymer and its application in humidity‐sensitive coatings

A new kind of water‐dispersed resin, amphiphilic acrylic acid copolymer resin was prepared by hydrophilic monomer, hydrophobic monomer, and functional monomer (diacetone acrylamide). The effect of acid value and diacetone acrylamide concentration on water solubility was investigated. It showed that the acid value should be greater than 100 mg KOH/g. The coating properties of the amphiphilic acrylic acid copolymer resin and its film were measured, which showed excellent properties in hardness, gloss, and water resistance. It was applied to prepare the humidity‐sensitive coatings. The water absorption of humidity‐sensitive coatings was 260%. It could increase indoor humidity or dehumidify in dry or moist environment. On the basis of scanning electron microscopy images, the mechanism of humidity‐sensitive activity was also discussed. The humidity‐sensitive exhibited humidity sensitivity and excellent humidity retention because fillers of porous structure combined with amphiphilic copolymer. It could be widely applied in indoor coating for controlling humidity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Surface properties of polymethylenediamine-fixed styrene/acrylic acid copolymer latex

Surface charge density, ζ-potential, and dispersion stability of polymethylenediamine (PMD)-fixed styrene/acrylic acid copolymer [P(St/AA)] latex were investigated. PMD-fixed P(St/AA) latices are amphoteric and have isoelectric points at pH 4–7. Though the flocculations were observed at neutral pH, the pHs where the flocculation rates were maximum are slightly higher than were the isoelectric points. This result suggests the influence of the expansion of PMD-fixed polymer layer surrounding the particles on the flocculation. The fixation of PMD to the surface of P(St/AA) latex lowers the dispersion stability for high electrolyte concentration.     

Preparation of superabsorbent based on the graft copolymerization of acrylic acid and acrylamide onto konjac glucomannan and its application in the water retention in soils

A new konjac glucomannan (KGM)-based superabsorbent polymer, KGM-g-poly(acrylic acid-co-acrylamide), was prepared by the free radical grafting solution polymerization of acrylic acid (AA) and acrylamide (AM) monomers onto KGM in the presence of N,N′-methylenebisacrylamide as a crosslinker with potassium persulfate as an initiator. The effects of reaction parameters, including the amount of crosslinking agent and initiator, the weight ratio of both (AA + AM) to KGM and AM to (AA + AM), neutralization degree of AA, bath temperature, and reaction time, on the water absorbency of the superabsorbent were investigated. The Fourier transform infrared spectroscopy was used to characterize the structures of the copolymer. The maximum water absorbency of the optimized product was 650 g/g for distilled water and 70 g/g for a 0.9 wt % aqueous NaCl solution. Furthermore, the water retention of the copolymer in soils was studied. The effect of the copolymers on the aggregate distribution of soils was also evaluated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Studies on chitosan and poly(acrylic acid) interpolymer complex. II. Solution behaviors of the mixture of water-soluble chitosan and poly(acrylic acid)

Water-soluble chitosan with a 50% deacetylation degree was prepared according to the literature. The mixtures of water-soluble chitosan and poly(acrylic acid) (PAA) in water was studied by various experimental techniques, such as viscometry, potentiometry, and transmittance measurements. The results showed that water-soluble chitosan may complex with PAA through electrostatic attraction. This polyelectrolyte complex exists steadily at about an equimolar unit composition. © 1996 John Wiley & Sons, Inc.     

Preparation and characterization of silanized silica gel‐supported poly(acrylic acid) network polymer and study of its analytical application as selective extractor for lead ion

A novel silanized silica gel (SSG)‐supported poly(acrylic acid) network polymer (ion exchanger) has been synthesized and characterized for the study of its analytical applications. The chemical nature of the ion exchanger has been elucidated with the help of FTIR, NMR, TGA, DSC, and SEM. The immobilization of the polymer network on SSG has been studied. The optimum pH range for quantitative extraction of lead was found to be 4.5–6.0. The effects of pH and stripping agent on extraction and elution of Pb(II), respectively, have been investigated. Ion exchange and break through capacity of the exchanger have been determined at room temperature. Pb(II) has been extracted quantitatively from various environmental samples. A plausible mechanism for lead ion exchange has been suggested. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of an amphiphilic graft copolymer with a poly(acrylic acid) backbone and n-octylphenyl polyoxyethylene side chains

A novel, well-defined, amphiphilic graft copolymer was synthesized by the free-radical copolymerization of acrylic acid and an amphiphilic macromonomer, n-octylphenyl polyoxyethylene acrylate. This acrylic copolymer was characterized by IR and ¹H-NMR. The number-average molecular weight was determined by gel permeation chromatography to be 4.37 × 10⁴ (weight-average molecular weight/number-average molecular weight = 1.23). The graft copolymer exhibited good solubility in water and high surface activity at much lower concentrations. The molecules of the AA–C₈PhEO₁₀Ac copolymer formed polymolecular micelles at 3.0 × 10⁻⁴ g/mL. The aggregation of the copolymer was examined in aqueous solution by measurement of the fluorescence of 2-p- toluidinylnaphthalene 6-sulfonate as a fluorescent probe. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of poly(acrylic acid)-g-polystyrene copolymer by successive ATRP

A series of well-defined amphiphilic graft copolymers consisting of hydrophilic poly(acrylic acid) backbone and hydrophobic polystyrene side chains were synthesized by hydrolysis of poly(methyl acrylate)-g-polystyrene under basic condition. The backbone and the side chains were synthesized by atom transfer radical polymerization (ATRP), so the molecular weight could be tuned by the variation of the feed ratio or monomer conversion, and the molecular weight distributions of amphiphilic graft copolymers were kept low (PDI < 1.35). The products were characterized by FT-IR, ¹H NMR, ¹³C NMR, and gel permeation chromatography (GPC). The study of self-assembly behavior can benefit the formation of the well-defined structures of the products.     

丙烯酸接枝改性PET纤维的结构与性能

采用丙烯酸接枝改性聚对苯二甲酸乙二酯(PET)纤维,探讨了接枝率对PET纤维结构、回潮率、染色性能以及力学性能的影响。结果表明:随着接枝率的增加,PET纤维密度变化不大,双折射率略为下降,纤维的吸湿性、抗静电性和染色性能提高,拉伸性能有所下降。当接枝率为10.78%时,PET纤维经0.03 mol/L的Na_2CO_3溶液处理后,其质量比电阻为1.34×10~6Ω·g/cm~2,回潮率为5.05%,纤维拉伸强度为3.31 cN/dtex,上染率达93.8%。     

Influence of ultrasonic parameters on degradation of acrylic acid/acrylamide copolymer based superabsorbent hydrogels cross-linked with NMBA

Continuous exposure to high-energy ultrasonic waves depolymerizes macromolecules in solutions and produces a permanent reduction in viscosity. Different factors affect the efficiency of this process. In this study, ultrasonic degradation of one commercially important hydrogel based on acrylic acid and acrylamide cross-linked with N,N-methylenebisacrylamide (NMBA) was carried out in aqueous solution at room temperature (25?°C). The purpose of this study was to present new experimental data for this ultrasonic degradation. In this respect, the effect of sonication parameters (power and pulse) on the rate of degradation was investigated. Granule disintegration was determined using a method to measure the swelling power of hydrogel. A method of viscometry was used to study the degradation behavior of the hydrogel and a first-order kinetic equation was employed to calculate the degradation rate constants. The experimental results indicated that the rate of ultrasonic degradation increased with increasing ultrasonic power and pulse. FTIR and UV spectrometry measurements confirmed that the degradation proceeded by mechanical forces. A detailed degradation mechanism has been proposed including chain scission. The present study has enabled us to understand the role of the ultrasonic parameters in deciding the extent of viscosity reduction in hydrogel systems.     

Unconventional ion exchange resins and their retention properties for Hg2+ ions

Synthesis of two unconventional ion exchange resins and their behaviour on the mercury sorption experiments were investigated.The ion exchange resins were obtained by the quaternization reaction of 4-vinylpyridine:divinylbenzene copolymer, gel-type, by two ways namely, the nucleophilic substitution of the pyridine matrix with 2-chloroacetamide and the nucleophilic addition of protonated copolymer to acrylamide.Comparative sorptions of Hg²⁺ ions on the synthesized pyridine resins by batch experiments in mono- and binary system were analyzed. Mercury retention experiments aimed to study the influence of the solution concentration, contact time and solution pH. The removal of Hg²⁺ ions from aqueous solutions depends on the pH values, the amount of the retained mercury increased with the pH value.The studied strong base pyridine anion exchange resins presented a good selectivity for the Hg²⁺ ions during the competitive sorption of Hg²⁺/Cu²⁺, Hg²⁺/Zn²⁺ and Hg²⁺/Fe³⁺ at metal cations ratio of 1:1.     

氧化条件对淀粉/丙烯酸共聚物粘接性能的影响

以双氧水(H2O2)为氧化剂、硫酸铜(CuSO4)为氧化催化剂,玉米淀粉经氧化、糊化和AA(丙烯酸)接枝改性后,制得淀粉/AA接枝共聚物;然后以此为瓦楞纸板生产用淀粉胶粘剂的载体,以淀粉氧化过程中的pH、催化剂含量、氧化剂含量、氧化时间和氧化温度为试验因素,以接枝淀粉胶粘剂/瓦楞纸板的粘接强度和边压强度为考核指标,采用单因素试验法优选出制备该胶粘剂的最佳工艺条件。结果表明:当pH=10、V(0.1 mol/L CuSO4)=0.6 mL、w(H2O2)=0.6%、氧化时间为20 min和氧化温度为30℃时,接枝淀粉胶粘剂具有相对最好的粘接性能,相应接枝淀粉胶粘剂/瓦楞纸板的粘接强度和边压强度相对最大。