Sorption of dye wastes by poly(vinyl alcohol)/poly(carboxymethyl cellulose) blend grafted through a radiation method

The instability in water of poly(vinyl alcohol) (PVA)/poly(carboxymethyl cellulose) (CMC) was improved through radiation-induced grafting with a styrene monomer. The PVA/CMC blend graft copolymer was used as a sorbent for dye wastes normally released from textile factories. The factors that may affect the sorption process such as time, temperature, weight of the blend graft copolymer, and volume of the dye waste were investigated. The sorption of dyestuffs by the blend graft copolymer was determined by a method based on spectroscopic analysis. The results showed that the blend graft copolymer has a high affinity for basic, acid, and reactive dyes. Meanwhile, it was observed that the sorption of dyes is more effective at the high temperature of 70^oC. Moreover, it was found that the sorption of dyes depends on the weight of the blend graft copolymer and does not depend on the volume of the waste solution. The sorption of the dyestuffs by a PVA/CMC graft copolymer may be considered to be a practical method to remove organic pollutants. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 136–142, 2001     

Radiation Grafting of 2-Hydroxy Ethyl Methacrylate (HEMA)/Glycidyl Methacrylate (GMA) onto Polyethylene-Coated Polypropylene Non-woven Fabric

The paper presents results of an investigation of the possibility of applying polyethylene-coated polypropylene (PE-co-PP) nonwoven fabric for treating dye wastes resulting from wastewater of the textile industry. For this purpose the radiation-induced graft copolymerization of binary mixtures of 2-hydroxy ethyl methacrylate (HEMA)/glycidyl methacrylate (GMA) onto polyethylene-coated polypropylene by the pre-irradiation method has been investigated. The effect of different factors that may affect the grafting percent such as solvent type and comonomer compositions were studied. Two solvents, dimethyl sulphoxide (DMSO) and 1-butanol were used. It was found that the degree of grafting depend upon the type of solvent and the composition of the comonomer mixture. Morphology of grafted nonwoven fabric was examined by scanning electron microscope (SEM). The hydrophilic properties in terms of swelling percent and water uptake were investigated. The higher swelling and water uptake percent were achieved at 100% HEMA diluted with 1-butanol. The use of these modified samples as absorbents for different classes of dyestuffs normally released from textile factories was achieved. The results obtained showed that the highest percentage of dye sorption was found in the case of basic dye and the lowest one in the case of reactive dye, depending on the reactive groups on the dye. Copolymers with a higher proportion of HEMA monomer diluted with 1-butanol as solvent showed the highest hydrophilic properties and higher dye uptake.     

Sorption of textile dye from aqueous solution by macroporous amino‐functionalized copolymer

Macroporous poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) (PGME) was synthesized by suspension copolymerization and functionalized with diethylene triamine (PGME‐deta). The effect of pH, contact time, and sorbent mass on sorption efficiency of initial and functionalized copolymer sample for removal of Acid Orange 10 dye from aqueous solutions was studied. No dye was sorbed by nonfunctionalized copolymer, indicating that sorption of Acid Orange 10 by PGME‐deta is specific, through amino groups. The isotherm data are best fitted by Langmuir model, indicating homogeneous distribution of active sites in PGME‐deta as well as monolayer sorption. Sorption kinetics study showed that the sorption of Acid Orange 10 by PGME‐deta obeys the pseudo‐second‐order kinetic model. It was shown that PGME‐deta selectively sorbs Acid Orange 10 from binary solution with Bezaktiv Rot reactive dye. The comparison of sorption characteristics of PGME‐deta with activated carbon showed that this functionalized copolymer might be used as an alternative sorbent for textile dyes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Dye sorption characters of gamma irradiated foamed ethylene propylene diene monomer (EPDM) rubber/clay composites

Composites based on gamma irradiated ethylene propylene diene monomer rubber in foam structure, loaded with different types of clays were used as adsorbents for different classes of dyestuffs (basic, acid, reactive and disperse) from aqueous solutions. The clays under investigation were Aswan clay (ASC) and sodium montmorillonite (Na-MMT). The effect of adsorbent composition, irradiation dose, pH and contact time on dye sorption was studied. It was found that the rubber composites loaded by Na-MMT gave maximum adsorption of the basic dye (～42%) in aqueous solution, while the rubber composites loaded by AS clay gave maximum adsorption (～28%) of the acidic dye. On the other hand, both type of clays did not show no affinity toward reactive and disperse dyes. The efficiency of dye removal was found to increase with increasing the pH and contact time. It was also observed that the irradiation dose (50 kGy) was the optimum dose for the removal of dyes for all rubber composites.     

Reactive electrospinning of poly(vinyl alcohol) nanofibers

We aim to couple the electrospinning in‐line with solution chemistry to fabricate novel crosslinked polymer nanofibers. Poly(vinyl alcohol) (PVA) was used as a model polymer due to its high amount of hydroxyl groups. To obtain ideal parameters for electrospinning, pure PVA was explored primarily. To gain crosslinked fibers, PVA was first crosslinked partially with glutaraldehyde (GA) followed by transferring this precursor to a long hot tube which was used as reactor and then electrospun right before gelation. The preheating time and tube‐passing time were determined with viscometer and rheometer. The reactive as‐spun fibers could maintain their original morphology after water immersion due to their high crosslinking degree. The thermal stability and mechanical property of reactive as‐spun fibers were improved drastically compared with pure and GA vapor crosslinked PVA fibers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Network characterization and swelling behavior of chemical hydrogels based on acid‐containing poly(vinyl alcohol)

Poly(vinyl alcohol) (PVA) was modified with phthalic and succinic anhydrides to give vinyl alcohol–vinyl ester copolymers that contain carboxylate groups. These half‐esters were then crosslinked by using the poly‐ (ethylene glycol) (PEG) 400 diglycidylether. Low crosslinker/carboxylate ratios were used to obtain low degrees of crosslinking, so the capacity of the resulting hydrogel to absorb water was high. Water absorption was determined gravimetrically as a function of time at room temperature. The equilibrium swelling ratio and compressive modulus were characterized for all the resulting PVA hydrogels and related to the network structure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3026–3031, 2003     

Swollen behavior of crosslinked network hydrogels based on poly(vinyl alcohol) and polydimethylsiloxane

Poly(vinyl alcohol) (PVA) was dissolved in the water to make a 10 wt % aqueous solution, and polydimethylsiloxane (PDMS) was mixed with 1 wt % 2,2‐dimethyl‐2‐phenylacetophenone (DMPAP) and 0.5 mol % methylenebisacrylamide (MBAAm) in isopropyl alcohol. This mixture was added to a PVA aqueous solution and heated at 90°C for 7 h. Various crosslinked networks were prepared at different molar ratios of PVA/PDMS (1:1, 1:3, and 3:1). The characterization of PVA/PDMS crosslinked networks was determined by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), a universal testing machine (UTM), and the equilibrium water content (EWC). The DSC melting endotherms showed, at 219.49°C, a sharp endothermic peak of PVA, and PVA/PDMS crosslinked networks had melting peaks close to this point. The value of EWC increased with the content of PVA in the crosslinked networks, simultaneously depending on the temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 957–964, 2002     

The interactions of ionic dye permeants with poly(vinyl alcohol) membranes

The well-known interaction between Congo Red and poly(vinyl alcohol), PVA, was studied by equilibrium dialysis. The diffusion of Congo Red into PVA membranes was much more rapid in 0.1N NaCl solution than in water. The dye appeared to be practically immobilized by the membranes in both solvents. A short survey of the dialytic behavior of various classes of ionic dyes through PVA membranes with water as solvent was undertaken. Anionic dyes permeated the membranes only very slowly, whereas cationic dyes permeated the membranes relatively rapidly and dyed them considerably. The existence of negative charges on the PVA membranes was demonstrated by performing dialysis experiments with the anionic dye Orange II and the cationic dye Acridine Orange in water and in excess electrolyte (1N NaCl).     

Preparation and characterization of spongy cryogels of poly(vinyl alcohol)–casein system: water sorption and blood compatibility study

Polyvinyl alcohol (PVA) and casein are biocompatible and biodegradable macromolecules, which have been widely applied in biomedical fields. In this paper, novel physically crosslinked hydrogels composed of PVA and casein were prepared by repeated freezing–thawing treatment of aqueous solutions of PVA and casein and characterized by IR, differential scanning calorimetry and scanning electron microscopy techniques. The prepared so‐called ‘cryogels’ were evaluated for their water uptake, and the influences of various factors, such as their chemical architecture and the pH and temperature of the swelling bath, were investigated in terms of water sorption. The effect of salt and various simulated biological fluids on the swelling of cryogels was investigated. The in vitro biocompatibility of the prepared cryogels was also judged by methods such as protein (bovine serum albumin) adsorption, blood clot formation and percentage haemolysis measurements. Copyright © 2005 Society of Chemical Industry     

Water and temperature response of semi‐IPN hydrogels composed of chitosan and polyacrylonitrile

Temperature‐responsive semi‐interpenetrating polymer networks (semi‐IPNs) constructed with chitosan and polyacrylonitrile (PAN) were crosslinked with glutaraldehyde. The semi‐IPN determined the sorption behavior of water at several temperatures and at a relative humidity (RH) of 95% using a dynamic vapor sorption (DVS) system. Water diffusion coefficients of semi‐IPNs were calculated according to the Fickian Law at several temperatures and exhibited a relatively water uptake, 0.1–0.4 at room temperature. The water uptake of hydrogels depended on temperature. The apparent activation energy was dependent of the composition of the semi‐IPN with value of 32.8–34.8 kJmol^?1. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2721–2724, 2003     

Preparation of poly (acrylic acid) containing core‐shell type resin for removal of basic dyes

BACKGROUND: A core‐shell type carboxylic acid modified resin was prepared and dye sorption characteristics of the resin were investigated. The resulting grafted resin material has been shown to be an efficient sorbent for removal of basic dyes from water as a result of the carboxylic acid group's affinity towards basic dye molecules. RESULTS: The resin was characterized using Fourier transform infrared spectroscopy (FT‐IR) and titrimetric methods. The basic dyes (methylene blue and crystal violet) were removed by contacting the swollen resin with aqueous dye solutions at room temperature. The adsorption capacities of resin were determined by colorimetric analysis of the residual dye content in the adsorption medium, which gave capacities for methylene blue and crystal violet of 300 and 250 mg g^?1 resin, respectively. The prepared resin is also able to remove basic dyes completely from dilute aqueous dye solutions. Batch kinetic sorption experiments determined that a pseudo‐second‐order rate kinetic model was applicable. CONCLUSION: Flexibility of the polymer side chains is expected to provide pseudo‐homogeneous reaction conditions and easy accessibility of the functional groups involved. The adsorbents are expected to have the advantage of mobility of the grafted chains in the removal of basic dyes from aqueous mixtures. The resin has potential as an adsorbent for removal of basic dyes for use over a wide pH range. Copyright © 2011 Society of Chemical Industry     

Crosslinked poly(vinyl alcohol) supports for the immobilization of a lipolytic enzyme

Different esters of crosslinked poly(vinyl alcohol) (PVA) were synthetized. They were developed for protein fractionation and immobilization. PVA was crosslinked with epichlorohydrin (CL‐PVA) and esterified with linear fatty acids of different length (Cn‐CL‐PVA). A characterization of the obtained products was made. The swelling behavior, the solubility, and the percentage of esterification were examined. Values of equilibrium water content of about 81% were reached for CL‐PVA samples. The polymers' stability and morpholgy were also investigated. Thermal analysis showed an increase in matrices stability, while SEM data showed the superficial development due to crosslinking and esterification reactions. Moreover, evident morphological inhomogeneities, mainly in the commercial and crosslinked products rather than in the final polymer, were present. Finally, immobilization experiments with a commercial crude of Candida rugosa were performed. Experiments showed a greater affinity of the protein for carbon chain length ranging from 8 to 12. Data indicated that compared to Celite 545, C8‐CL‐PVA was a better support for enzyme immobilization by physical adsorption, confirming the fact that microbial lipases prefer hydrophobic supports. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1881–1889, 1999     

Properties and pervaporation performance of poly(vinyl alcohol) membranes crosslinked with various dianhydrides

In this work, three dianhydrides with similar chemical structures, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA), 4,4′‐oxydiphthalic anhydride (ODPA), and pyromellitic dianhydride (PMDA), are employed for the crosslinking modification of poly(vinyl alcohol) (PVA) membranes for ethanol dehydration via pervaporation. The changes in crosslinking degree, surface hydrophilicity, and glass‐transition temperature are investigated and compared. Compared to the pure PVA membrane, all crosslinked membranes show higher fluxes but lower separation factors, because of the higher fractional free volume and the lower hydrophilicity by the crosslinking of the PVA matrix, respectively. In addition, all crosslinked PVA membranes exhibit similar flux, and the separation factor presents a decreasing order of PVA/PMDA‐2 > PVA/ODPA‐2 > PVA/BTDA‐2, which is in the reverse order of their hydrophilicity, probably because of the reduction in the swelling resistance. With the PMDA content increasing from 0.01 to 0.04 mol/(kg PVA) in the PVA/PMDA crosslinked membranes, the crosslinking degree is enhanced and the hydrogen bonding is weakened, resulting in a flux increase from 120.2 to 190.8 g m^?2 h^?1, but the separation factor declines from 306 to 58. This work is believed to provide useful insight on the chemical modification of PVA membranes for pervaporation and other membrane‐based separation applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46159.     

Diffusion and sorption studies of dyes through PVA cryogel membranes

The capacity of poly(vinyl alcohol) (PVA) to crosslink through freeze/thaw method was used to obtain PVA hydrogel membranes (HG) that were subjected to sorption and diffusion experiments using three dyes: Congo red (CR), methylthymol blue (MTB), and crystal violet (CV). To study the sorption of dyes into the cryogenic membrane, dye solutions at different concentrations were used. After sorption, desorption of dyes from the PVA membrane was monitored to quantify the possible regeneration of the membrane (PVA HG). To have a deep insight on the mechanism behind the desorption process, dye‐release kinetics were studied. The diffusion experiments reveal the fact that CR and MTB do not permeate the PVA HG membrane making it a promising candidate in the advanced purification processes of wastewaters. The effect of the incorporation of dyes (CV, CR, and MTB) on the chemical properties of PVA cryogel matrices has been studied by using several techniques such as: differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Silicon‐containing anionic water‐borne polyurethane with covalently bonded reactive dye

A silicon‐containing water‐borne polyurethane (PU) polymer with hydroxyl side groups was synthesized that was stable in basic conditions and also capable of reacting with a reactive dye to form a covalently bonded dye molecule. The silicon‐containing anionic water‐borne PU prepolymer was synthesized from H₁₂‐4,4′‐diphenylmethane diisocyanate (H₁₂‐MDI), polytetramethylene glycol, polydimethylsiloxane (PDMS), 2,2′‐bis(hydroxymethyl), propionic acid (anionic centers), and triethyleneamine using the prepolymer mixing method. Water was then added to emulsify and disperse the resin to form an anionic water‐borne PU prepolymer. N‐(2‐Hydroxyethyl ethylene diamine) (HEDA) was used to extend the prepolymer to form a water‐borne PU polymer with a side chain of hydroxyl groups, which can further react with the reactive dye to form a dyed PU. The reactive dye of chlorosulfuric acid esters of sulfatoethyl sulfones can react with the water‐borne PU polymer. Behaviors of alkali resistance and dyeing properties were observed. In consideration of thermal properties, the dye‐grafted PU polymers exhibited lower glass‐transition temperatures for soft segments and hard segments than those without dye. Concerning mechanical properties, it was found that the modulus and the strength of the dyed PU polymers decreased with grafting of the dye molecule, but elongation at break was increased. The alkali resistance increased with PDMS content. For dye‐uptake properties, the percentage of dye grafting was over 90%. Also, the dye‐grafted PU exhibited a lower percentage of dye migration than that of polymers with ethylene diamine instead of HEDA as a chain extender, and showed greater colorfastness to light. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2045–2052, 2003     

Preparation and characteristics of polymer-based large adsorbent particles

Using polyvinyl alcohol (PVA) crosslinked with glutaric dialdehyde (c-PVA) as matrix and activated carbon (AC) or crosslinked polyacrylic acid (PAA) as the adsorptive constituent, large beads of c-PVA-AC and c-PVA-PAA composites were prepared via the sedimentation polymerization method. In this method, an aqueous solution of PVA, glutaric dialdehyde, and a catalyst for crosslinking (hydrochloric acid), containing activated carbon or the precursors of the crosslinked polyacrylic acid was injected dropwise with a syringe into hot mineral oil (about 80–90°C) located in a cylindrical reactor fit with a stirrer near its bottom. Partial gelation took place during the sedimentation process. This ensured that the particles arrived at the bottom of the column, where they were kept about 30–60 min to complete their polymerization, maintained their individuality without aggregation. The particle size was as large as about 3 mm. The adsorption characteristics of the two types of adsorbents were dependent on their AC or PAA content. Their adsorption capacity for four dyes was investigated. The c-PVA-AC and c-PVA-PAA had, at room temperature, saturation adsorption capacities as large as 84 and 104 mg/g for the basic Chrysoidin dye, and 70 and 72 mg/g for the basic Bismarck brown Y dye. © 1996 John Wiley & Sons, Inc.     

Controlled release of aspirin from pH‐sensitive chitosan/poly(vinyl alcohol) hydrogel

The aim of this study was to develop a cheap, pH‐sensitive enteric coating of aspirin with biocompatible polymers. A novel approach was used to develop enteric coating from chitosan (CS) and poly(vinyl alcohol) (PVA). Solutions of CS and PVA (5 : 1 mol ratio) were mixed and selectively crosslinked with tetraethoxysilane. IR analysis confirmed the presence of the incorporated components and the existence of siloxane linkages between CS and PVA. The crosslinking percentage and thermal stability increased with increasing amount of crosslinker. The response of the developed coating in different media, such as water, pH (nonbuffer and buffer), and ionic media showed hydrogel properties. All hydrogels showed low swelling in acidic and basic pH media, whereas maximum swelling was exhibited at neutral pH. This pH sensitivity of the hydrogel has been exploited as enteric coating for commercial aspirin tablets. The dissolution test of enteric‐coated aspirin tablet in simulated gastric fluid (pH 1.2) showed 7.11% aspirin release over a period of 2 h, whereas a sustained release of remaining aspirin (83.25%) was observed in simulated intestinal fluid (pH 6.8). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Role of molecular weight of atactic poly(vinyl alcohol) (PVA) in the polarizing efficiency of PVA/azo dye complex film with high durability

To precisely identify the effect of molecular weight of atactic poly(vinyl alcohol) (a‐PVA) on the durability and polarizing efficiency (PE) of a‐PVA/dye polarizing film, we prepared two (a‐PVA)s with similar syndiotactic diad contents of 54.0%, degrees of saponification of 99.9%, and with different number‐average degrees of polymerization [(P_n)s] of 1700 and 4000, respectively. Through a series of experiments, it was found that molecular weight of a‐PVA had a significant influence on the durability of a‐PVA/dye film in heat and humidity conditions (relative humidity of 80% and temperature of 90°C). That is, both desorption of dye in a‐PVA/dye film and transmittance of film decreased with increasing molecular weight of PVA. The change of PE (durability) of a‐PVA/dye film in heat and humidity conditions was limited to about below 5%. The change of PE of PVA/dye film having P_n of 4000 especially was limited to 1%, whereas that of a‐PVA/iodine film with P_n of 4000, was almost 80% under the same condition. Also, transmittance of the drawn a‐PVA/dye film was far higher than that of the undrawn one. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 967–974, 2005     

蓝色活性染料的合成及拼混增效

本文设计合成了22只含复合双活性基的蓝色活性染料。测定了活性染料的四个特征参数S、E、R和F值,考察了染料结构与直接性的关系。测定了染料的提升力,根据染料的相容性和染料的结构特征选择拼混染料;不同类活性染料的拼混和同类活性染料的拼混都得到染深性很好的混合染料。测定了活性染料的耐碱性,耐碱性好的染料与耐碱性差的染料通过适当比例混合后,混合染料具有优异的耐碱性。     

Water sorption of poly(vinyl alcohol)/ poly(diallyldimethylammonium chloride) interpenetrating polymer network hydrogels

Temperature‐responsive interpenetrating polymer network (IPN) hydrogels constructed with poly(vinyl alcohol) and poly(diallyldimethylammonium chloride) using the sequential IPN method were studied. The characteristics of IPN hydrogels were investigated using the dynamic vapor sorption system. IPN hydrogels exhibited a relatively high sorption ratio, 180–360% at room temperature. The sorption ratio of hydrogels depended on temperature. Diffusion coefficients were calculated according to the Fickian Law at several temperatures. The apparent activation energy was 5.43 kJ mol^?1, which corresponds to typical diffusion processes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1389–1392, 2003