The effect of polymer surface modification via interfacial polymerization on polymer–protein interaction

Membrane separation is an important processing technology used for separating food ingredients and fractionating value‐added components from food processing byproducts. Long‐term performance of polymeric membranes in food protein processing is impeded by the formation of fouled layers on the membrane surface as a result of protein adsorption onto the membrane surface. Surface modification of synthetic membranes, i.e., changing surface characteristics to reduce protein adsorption permanently, is one of the innovative ways of reducing the fouling of membrane surfaces. In this study, surface modification of flat‐sheet ultrafiltration membrane, polyethersulfone (PES), was investigated in improving the hydrophilicity of PES surfaces, thereby reducing adsorption of the protein caused by hydrophobic–hydrophobic interaction between the protein and the membrane. Hydrophilic polymer grafting through thin‐film composite using interfacial polymerization was employed to improve the hydrophilicity of the commercial PES membranes. Poly(vinyl alcohol), poly(ethylene glycol), and chitosan were chosen as hydrophilic polymers to graft on PES membrane because of their excellent hydrophilic property. Modified PES membranes were characterized by contact angle, FTIR, XPS, and AFM. Contact angles of modified PES membranes were reduced by 25 to 40% of that of the virgin PES membrane. XPS spectrum supported that the PES membranes were successfully modified by interfacial polymerization. Tapping‐mode AFM was used to examine the changes in surface topography of modified PES membranes. The PES membranes modified by interfacial polymerization showed lower roughness (from 1.2 to 2.0 nm) than that of virgin PES membrane (2.1 nm). The results of these instrumental analyses indicated that the PES membranes were successfully enhanced hydrophilically through interfacial polymerization. The protein adsorption on the modified membranes was reduced by 30 to 35% as a result of surface modification of the PES membranes using interfacial polymerization technique. Published 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Combined EIS and FTIR–ATR study of water uptake and diffusion in polymer films on semiconducting electrodes

Electrochemical impedance spectroscopy (EIS) and Fourier Transform Infrared Attenuated Total Reflection (FTIR–ATR) Spectroscopy were combined as a spectroelectrochemical method to analyze water uptake of thin polymer films on semiconducting optical crystals.

An oxide covered n-doped silicon crystal was used as optical crystal and an epoxy-amine adhesive was used as polymer film. The combined in-situ analytical approach allowed the analysis of diffusion coefficients of water with two independent measurement techniques, the quantification of the water uptake and its influence on the interphasial composition. The analytical approach is shown to be suitable for defect free polymer films and for defect containing polymer films. The corresponding semiconductor electrochemistry of silicon was evaluated to analyze the film capacitance in series with the semiconductor space charge capacitance.     

Utilization of emulsion polymer for preparing bagasse fibers polymer–cement composites

Sugarcane‐bagasse fiber–polymer cement composites were prepared using three lattices namely, styrene butadiene, vinyl ester, and styrene acrylic. The lattices percentages ranged between 3 and 21% from the weight of the mixture. The pressed samples were irradiated at different irradiation doses by using electron beam (EB) accelerator. Comparative studies have been made for physicomechanical properties of unirradiated and irradiated samples. The results indicated that the flexural strength, modulus of elasticity, and impact toughness of the composites increase with the increasing polymer content up to 9.9 and 15% of styrene butadiene, vinyl ester, and acrylic styrene, and then decrease. It was also observed that the maximum values of flexural strength and modulus of elasticity obtained at EB‐irradiation dose 45, 40, and 25 kGy for styrene butadiene, acrylic ester, and vinyl ester, respectively. The impact strength of the composites did not significantly improve above 10 kGy. The average values of hardness of irradiated composites were higher than that those of unirradiated and control composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Bulk surface photografting process and its application. III. Photolamination of polymer films

This paper introduces a set of new concepts related to the macromolecular design and to the practice in the realm of lamination by photografting, with experimental studies of the synthesis, structure, and performance of various systems, including valence bond adhesion of the organic polymeric materials, hyperbranched macromolecules rooted to the surface of organic substrates, macromolecular networks rooted on and bridged between two organic substrates, and a synthetic route combining primary and secondary photografting processes for the preparation of supermolecular architectures. In successful photolamination experiments based on these ideas, hyperbranched macromolecules of large size (10–20 μm) were obtained after initiation with aromatic ketones, which undergo a photoreduction reaction. A range of different organic polymeric films have been laminated. T-peel tests show most of the laminates broke inside the substrates and not at the interface between adhesive and substrate. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1723–1732, 1997     

Effect of polymer properties on bubble growth in polymer–paperboard composites

Foamed paperboard is a composite material used in thermally insulated food packaging and beverage containers. The paperboard is sandwiched between a layer of low‐density polyethylene and a barrier layer, and the low‐density film is foamed through heating. The moisture inside the paperboard vaporizes and serves as the driving force for creating the foam. The bubble growth on the paper surface has been tracked with high‐speed photography. The number of generated bubbles has been found to depend on the number of pores on the surface of the paperboard; there is little or no dependence on the properties of the polymer, at least across the range of properties studied. In contrast, the thickness of the foam is relatively insensitive to the paperboard properties but has a strong dependence on the thickness of the initial polymer film, the nature of the polymer, and the speed at which it is extruded onto the paperboard. It is believed that some of these variations arise from differences in the degree of adhesion between the polymer and the paperboard. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Interactions between dyes and polyelectrolytes: Effect of polymer–polymer interactions

The competition between methyl orange dye and various polymers [gelatin, poly(vinyl alcohol), polyacrylamide, etc.] for the binding sites on quaternized poly(1-vinylimidazole) in aqueous solutions was studied. The method used was based on a well-known effect of dissolved polyelectrolytes on the rate of diffusion of solutes through semipermeable membranes. The final results are expressed as the ratio of C₁^″(bound)/C₁^′(bound), where C₁^″(bound) is the amount of the solute adsorbed to a mixture of two polymers and C₁(bound) is the amount of solute bound to a single polymer. In the case of quaternized poly(1-vinylimidazole) it was found that as much as 15% of the solute bound to the polymer can be replaced by another, “nonadsorbing” polymer.     

Slow release polymer–iodine tablets for disinfection of untreated surface water

Simple water treatment devices are designed to treat small amounts of drinking water for home use. This study was undertaken to develop an iodine‐releasing polymeric formulation and examine its potential as a domestic water purifier for untreated surface water. The antimicrobial tablet formulation was made from gum arabic (GA), poly(vinylalcohol) (PVA), ethyl cellulose (EC), and poly(vinylpyrrolidone)‐iodine (PVP‐I). The formulation consisted of a dispersible core tablet surrounded by a hydrophilic coating of EC and poly(ethylene glycol) mixture. These stable, non‐vaporizing, and water‐insoluble tablets slowly release iodine through diffusion over 48 h when suspended in water. The swelling behavior and release were observed to be the functions of excipient composition, iodine loading, and coating materials. Iodine release was determined by UV–VIS spectroscopy and volumetric titrations. The tablets were also assessed for antimicrobial activity against Escherichia coli, Staphylococcus aureus, Listeria monocytogenes Scott A, and Salmonella typhimurium. The disinfection efficiency of the developed tablets was compared with a commercial formulation (Potable Aqua®) as both contain iodine‐releasing active compounds and work on the antimicrobial property of released iodine. The difference between the two formulations is that water‐dispersible Potable Aqua® has a higher amount of free iodine quickly available in water thereby making it a fast‐action emergency water purifier, whereas the developed water‐insoluble polymer–iodine tablets act slowly and require 24 h to show the same disinfection efficacy with lower content of iodine in water. Overnight release of iodine in water from polymer–iodine tablets was effective in 99.9% reduction of an initial cell count of ～ 10⁷ colony forming units (cfu)/mL. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermal and catalytic aspects of Ln(III) polymer–metal complexes

BACKGROUND: In this era, polymer‐supported catalysts are gaining more attention, as they are effective in reduction of pollution, production cost and give good yield. Due to the versatility of lanthanide catalysts in organic synthesis, we envisioned that lanthanides(III) supported polymers would afford a novel type of solid phase Lewis acids. RESULTS: The polymer–metal complexes are found to be efficient and effective catalysts in the Biginelli three‐component, one‐pot synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones. The synthesized polymer is thermally more stable and porous in nature than polychelates. CONCLUSION: The polymer–metal complexes can be used as economical and eco‐friendly catalysts for synthesis of substituted 3,4‐dihydropyrimidin‐2(1H)‐ones with different aromatic aldehydes and β‐ketoesters. Thermal stability of the polymer is higher than that of polychelates due to the presence of intramolecular hydrogen bonding. Copyright © 2009 Society of Chemical Industry     

Synthesis of a novel amphoteric chelating polymer flocculant and its performance in Cu2+ removal

A novel amphoteric chelating polymer flocculant (ACPF) was synthesized. The synthesis involved the copolymerization of dimethyldiallylammonium chloride and acrylamide to prepare poly(dimethyldiallylammonium chloride‐co‐acrylamide) [P(DMDAAC‐co‐AM)], Mannich reaction of P(DMDAAC‐co‐AM) with triethylenetetramine and formaldehyde to prepare P(DMDAAC‐co‐AM)‐graft‐TETA, and xanthogenation of P(DMDAAC‐co‐AM)‐graft‐TETA with CS₂ and NaOH. The removal performance of ACPF toward Cu²⁺ was investigated, and the ACPF structure was characterized. ACPF performance considerably improved at 121–187 mL/g intrinsic viscosity, 20.78–28.32 mol % cationic degree of P(DMDAAC‐co‐AM), and 22.11–28.44% sulphur content of ACPF. The Cu²⁺ removal rate was above 99% at a 1.98 : 1 molar ratio of ‐CSS^? to Cu²⁺. This rate was 5.86% higher than that using polyacrylamide‐graft‐triethylenetetramine‐dithiocarbamate (PAM‐graft‐TETA‐DTC). The zeta potential and sedimentation rate of flocs obtained from ACPF were higher and their volume was smaller than those from sodium triethylenetetramine‐multidithiocarbamate and PAM‐graft‐TETA‐DTC at the same sulphur dosage. This result indicates that the positive charges of ACPF polymeric chains effectively neutralize excess negative charges in flocs, which benefits the bridging of flocs with negative charges to promote their formation and growth. These positive charges can also cause the flocs to become larger and tighter, thereby improving flocculation and settling performance. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Heterogeneous polymer–polymer composites. II. Preparation and properties of model systems

A two-stage emulsion polymerization procedure has been developed and used to prepare relatively uniform populations of heterogeneous acrylic latex particles (HLP). One class of particles (HLP1) can be described as composite materials comprising a glassy continuous phase and a rubbery discrete phase. Another class (HLP2) can be described (at high rubber content) as composite materials comprising a rubbery continuous phase and a glassy discrete phase. The phase structure of the HLP1 is sufficiently stable to allow fabrication of composites having a uniform spatial distribution of inclusions by direct compression molding. Although the observed particle structure of the HLP2 does not depend markedly on crosslinking, the phase structure and mechanical properties of compression moldings do. Crosslinking of the glassy stage appears to stabilize HLP2 phase structure during molding, while crosslinking of the rubbery stage favors phase inversion. The observed HLP2 particle structures and the morphology of molded HLP1 specimens are consistent with a shell-core model. It is found that the modulus and thermal expansion coefficient of many of these materials can be adequately described in terms of a simple theoretical model for the elastic and thermoelastic properties of particulate composites, provided that an interaction parameter interpreted as a maximum packing fraction is introduced.     

An approximate method for the determination of polymer–polymer interaction parameters of incompatible polymers in solution

A method is developed, based on Scott's equations for ternary systems of two polymers and a mutual solvent, for the calculation of values of the polymer–polymer interaction parameter, χ₂₃, for systems in which both polymer–solvent interaction parameters χ₁₂ and χ₁₃ are not known a priori. Equilibrium phase studies were carried out on ternary systems of polystyrene, polybutadiene, and tetrahydrofuran or toluene at 23°C and 1 atm. Typical interaction parameter values (χ₂₃) calculated by this new method were compared with the values of χ₂₃ determined earlier using standard equations and known χ₁₂ values for these systems, and were found to agree very well. It is concluded that the technique presented in this article can be used for mixed polymer systems in good mutual solvents where neither polymer–solvent interaction parameter is known, for determining an approximate value of the χ₂₃ parameter alone.     

Development of polymer films and its application on leather surfaces

Ten different formulations are prepared with a urethane acrylate oligomer in combination with two monofunctional monomers (EHA with low T_g and NVP with a carboamide group) and a difunctional acrylate monomer (TPGDA) in the presence of a plasticizer. Polymer films are prepared with these formulated solutions under UV radiation. Their properties (gel, hardness, tensile characters, etc.) are determined. These solutions are coated on leather substrates and cured under UV radiation. The improvement of quality of leather is manifested through the enhancement of tensile strength and elongation of the coated leather. The coating also imparts high gloss on the leather surface as well as high wear resistance. It also protects the leather from the damage of weathering effect. The best formulation is determined to be the one containing NVP with a carboamide group and a plasticizer. © 1996 John Wiley & Sons, Inc.     

Generalized Flory–Huggins model for heat‐of‐mixing and phase‐behavior calculations of polymer–polymer mixtures

An extended and generalized Flory–Huggins model for calculating the heats of mixing and predicting the phase stability and spinodal diagrams of binary polymer–polymer mixtures is presented. In this model, the interaction parameter is considered to be a function of both temperature and composition. It is qualitatively shown that the proposed model can calculate the heats‐of‐mixing curves containing exothermic, endothermic, and S‐shaped or sigmoidal types and predict the spinodals, including the upper and lower critical solution temperatures, and closed‐loop miscibility regions. Using experimental results of analog calorimetry for four polymer mixtures of polystyrene/poly(vinyl chloride) (PS/PVC), polycarbonate (PC)/poly(ethylene adipate) (PEA), polystyrene/poly(vinyl acetate) (PS/PVAc), and ethylene vinyl acetate copolymer (EVA Co)/chlorinated polyethylene (CPE), the capabilities of the proposed functionality for the interaction parameter was studied. It is shown that this function can be used satisfactorily for the heat‐of‐mixing calculations and phase‐behavior predictions. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1328–1340, 2000     

Synthesis and application of polymer–clay nanocomposite‐supported dichromate oxidizing agent

A hybride polymer–clay nanocomposite supported dichromate reagents was prepared. Direct interaction of poly(styrene‐co‐N‐methyl‐4‐vinylpyridinium) iodide with sodium montmorillonite (MMT) through ion exchange between sodium cations in MMT and pyridinium ions in the copolymer afforded a polymer–clay nanocomposite (3). The resulting nanocomposite was reacted with potassium dichromate to form the nanocomposite‐supported reagents (4). The structure of the resulting nanocomposite was characterized by elemental analysis, infrared spectroscopy, X‐ray diffraction and transmission electron microscopy. The dispersion of the MMT particles in the polymer matrix was confirmed using scanning electron microscopy. X‐ray mapping for silicon in the nanocomposite revealed uniform distribution of Si in the polymer matrix. The effectiveness of these materials has been tested for oxidation of saturated primary, secondary and benzylic alcohols to their corresponding aldehydic and ketonic compounds in addition to oxidation of quinol to the corresponding quinone. Importantly, there is almost no formation of side‐product of this process. POLYM. COMPOS., 36:2066–2075, 2015. © 2014 Society of Plastics Engineer     

Probe dependency of polymer‐plasticizer and polymer‐polymer interaction parameters in inverse gas chromatography

Inverse gas chromatography has been widely used to determine the Flory–Huggins parameter, χ, between a plasticizer and a polymer, or between two polymers. Many studies showed that interaction parameters may be probe dependent. In a recent study it was proposed that, when a specific interaction occurred between two polymers, the probes had less interaction with the polymers, leading to a lower solubility parameter for polymer blends than the volume average of the components. An equation was derived to relate the probe dependency to the deviation of solubility parameter of polymer mixtures. Here this approach is applied to plasticized poly(vinyl chloride) (PVC) and a copolymer, and to poly(vinylidene fluoride)–poly(ethyl methacrylate) blends. For a PVC and epoxidized oil system the relative deviation of specific retention volume showed two trends, with saturated hydrocarbons as one group, and polar and aromatic probes as another group. For the poly(vinylidene fluoride)/poly(ethyl methacrylate) system the plot of retention volume deviation versus solubility parameter of probes also showed separate trends for n‐alkanes, esters, and alcohols. But the plot of ?₂?₃RT(χ₂₃/V₂) versus solubility parameter had better linearity for the systems studied. The slope of this plot was used as an indicator for miscibility. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Quantitative measurement of interdiffusion at polymer–polymer interfaces with TEM/EDS and EELS

Transmission electron microscopy and energy dispersive spectroscopy (TEM/EDS) were used to map the concentration profile at the interface of a poly(vinyl chloride) and poly(methyl methacrylate) bilayer. Thin sections in the order of 800 Å were cut using an ultramicrotome, examined with TEM, and the concentration profile was mapped with EDS. The intensity of fluorescene X-rays was adjusted for sample thickness variation by measuring the relative thickness across the interface with electron energy-loss spectroscopy (EELS). The interfacial thickness of the bilayer after 6 h at 120°C was 1.5 μm, whereas the interdiffusion coefficient was determined as 8.0 × 10^?14 cm²/s. © 1995 John Wiley & Sons, Inc.     

Multiparameter solution model and evaluation of polymer–polymer miscibility using inverse gas chromatography data

Inverse gas chromatography (IGC) has been widely used to determine the Flory–Huggins parameters, χ, between solutes (probes) and polymers. This study correlated the Flory–Huggins parameter data using a multiparameter model, which included dispersion, polarity, acidity, and basicity components. The parameters of poly(ε‐caprolactone) (PCL) and polyepichlorohydrin (PECH) were calculated from IGC data using a series of probes. The parameters of the polymers were used to evaluate mutual miscibility between PCL and PECH. The results predicted miscibility in agreement with the conclusion of an IGC study using blends of PCL and PECH. A method to estimate the confidence interval of polymer parameters was proposed. The anomalous solubility parameter of polymer mixtures previously reported was also explained using this model. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Investigation of binary polymer/surfactant or ternary polymer/surfactant/Cu2+ complexes in aqueous solution through Nile red probing

The optical properties (absorption and emission) of Nile red have been widely used for staining or probing purposes in diverse aqueous systems. However, the applications of Nile red for the determination of the critical aggregation concentration of polymer/surfactant complexes or for the investigation of ternary polymer/surfactant/Cu²⁺ systems are very limited. The interactions between anionic polyelectrolytes and the oppositely charged surfactant N,N,N,N‐dodecyltrimethylammonium chloride were investigated in dilute aqueous solution, exploiting the optical properties of Nile red. It is shown that the emission properties of Nile red present better sensitivity than its absorption properties, concerning the detection of the hydrophobic polymer/surfactant complexes formed in aqueous solution. Moreover, it is found that the formation of ternary polymer/surfactant/Cu²⁺ complexes leads to a pronounced quenching of the luminescence of Nile red. The corresponding Stern–Volmer plots indicate that quenching is more favourable when coordination of Cu²⁺ ions with poly(sodium acrylate) takes place, as compared to simple electrostatic binding of these ions with poly(sodium styrene sulfonate). Nile red is a sensitive and accurate tool, as an alternative to pyrene, for the characterization of binary polymer/surfactant complexes or for obtaining information on the local arrangement of ternary polymer/surfactant/Cu²⁺ systems in aqueous solution. Copyright © 2010 Society of Chemical Industry     

Conductive polymer‐coated mesh films with tunable surface wettability for separation of oils and organics from water

Here, we reported the preparation of hydrophobic mesh films by coating conductive polymers including polyaniline and polypyrrole (PPy) onto stainless steel grid through a simple electrodepositing process by combination with modification of hydrophobic materials. The hydrophobic mesh films can be used for continual separation of oils and organics from water with high selectivity. Furthermore, mesh film with reversible switching wettability from hydrophobicity to hydrophilicity can be obtained by electrodepositing of PPy in the presence of perfluorooctanesulfonate dopants at different electric potential, which makes it possible to prepare functional mesh materials with remotely controllable surface wettability for selective absorption and purification. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40759.     

Heterogeneous polymer–polymer composites. I. Theory of viscoelastic properties and equivalent mechanical models

The representation and interpretation of dynamic mechanical properties of heterogeneous polymer–polymer composites are discussed in terms of equivalent mechanical models and the viscoelastic form of the well-known Kerner equation. Model parameters calculated from dispersed phase volume fraction and matrix Poisson's ratio (using the Kerner equation) are in fairly good agreement with experimental values for systems comprising soft inclusions in a hard matrix. The effects of partial phase inversion on dynamic properties are discussed in terms of an extension of the Kerner equation. Model calculations indicate that the in-phase component of the complex modulus depends primarily on dispersed phase volume concentration, while the out-of-phase component depends on both the concentration and the morphology of the dispersed phase. Although substantial information about the microstructure of polymer–polymer composites can in principle be deduced from dynamic measurements, quantitative correlation between dynamic properties and use properties such as impact strength (which may have a quite different dependence on structural parameters) is probably fortuitous.