Peroxidase-catalyzed synthesis of lignin–phenol copolymers

Horseradish peroxidase catalyzes the copolymerization of phenols with kraft lignin in aqueous-organic solvent mixtures. Nearly all of the lignin and over one-third of the phenol (either p-cresol or p-phenylphenol) is incorporated into the copolymer which is highly insoluble in dimethylformamide (DMF), presumably because of crosslinking of lignin molecules via polyphenol bridges. The copolymer consists of 80% lignin, by weight. In the absence of a phenol, lignin is polymerized into a noncrosslinked, DMF-soluble material. Thermal analysis shows that the copolymerization of phenols with lignin results in a material with markedly lower glass transition temperatures and higher (and more uniform) curing exotherms. The materials appear to act as thermosets and may have application as replacements of conventional phenolic resins. © 1993 John Wiley & Sons, Inc.     

Anionic/nonionic mixed surfactants templates preparation of hollow polymer spheres via emulsion polymerization

We herein report a facile, convenient, and economical method to prepare hollow polymer spheres (HSs). By virtue of the phase transformation of nonionic surfactant at its cloud point, hollow spheres of polystyrene were prepared from vesicle templates formed by potassium oleate (KO) and alkyl‐phenol polyoxyethylene (n ) ether (n = 10, OP) at 70–80 °C. The morphologies of the HSs were characterized by field‐emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The diameter of the HSs varies from 200 to 800 nm, and the shell thickness is uniformly c.a. 30–50 nm. The weight ratio of monomer/surfactant was as high as 7/1. The microstructure of the HSs was very stable and remained unchanged after drying or resuspension in water. The mechanism of the formation of HSs was explained on the theory of vesicles. Furthermore, the factors affecting the formation of the hollow structure were discussed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2533–2541, 2006     

Microemulsion polymerization of styrene using a polymerizable nonionic surfactant and a cationic surfactant

High polymer/surfactant weight ratios (up to about 15:1) of polystyrene microlatexes have been successfully produced by microemulsion polymerization using a small amount of polymerizable surfactant, ω-methoxypoly(ethylene oxide)₄₀ undecyl α-methacrylate macromonomer (PEO-R-MA-40), and cetyltrimethylammonium bromide (CTAB). After generating “seeding particles” in a ternary microemulsion containing only 0.2 wt% CTAB and 0.1 wt% styrene, the additional styrene containing less than 1 wt% PEO-R-MA-40 was added dropwise to the polymerized microemulsion for a period of about 4 h at room temperature. PEO-R-MA-40 copolymerized readily with styrene. The stable microlatexes were bluish-transparent at a lower polymer content and became bluish-opaque at a higher polymer content. Nearly monodisperse latex particles with diameters ranging from 50 to 80 nm and their molar masses ranging from 0.6 to 1.6 × 10⁶ g/mol could be obtained by varying the polymerization conditions. The dependence of the number of particles per milliliter of microlatex, the latex particle size and the copolymer molar mass on the polymerization time is discussed in conjunction with the effect of the macromonomer concentration. Received: 25 October/2000 Accepted: 2 February 2001     

Peroxidase catalyzed polymerization of phenol

effect of horseradish peroxidase (HRP) and H₂O₂ concentrations on the removal efficiency of phenol, defined as the percentage of phenol removed from solution as a function of time, has been investigated. When phenol and H₂O₂ react with an approximately one-to-one stoichiometry, the phenol is almost completely precipitated within 10 min. The reaction is inhibited at higher concentrations of H₂O₂. The removal efficiency increases with an increase in the concentration of HRP, but an increase in the time of treatment cannot be used to offset the reduction in removal efficiency at low concentrations of the enzyme, because of inactivation of the enzyme. One molecule of HRP is needed to remove approximately 1100 molecules of phenol when the reaction is conducted at pH 8.0 and at ambient temperature.     

Green synthesis of soluble polyphenol: oxidative polymerization of phenol in water

Abstract

The simple stirring of phenol with an oxidant in water provided a novel green way to synthesize soluble polyphenol. The soluble polyphenol obtained had a high poly(phenylene oxide) unit ratio, poly(phenyleneoxide)/poly(phenylene)=ca. 80/20. Additionally, the insoluble fraction was identified as a poly(phenyleneoxide), which has a crosslinking point for every 5.5×10³ molecular weight. These results suggest that oxidative polymerization in water can be run in a manner to control the coupling selectivity of phenol. Both the soluble polyphenol and the insoluble fraction showed a high thermal stability. Oxidative polymerization in water provides the potential for a formaldehyde-free and regioselected soluble poly(phenyleneoxide) from phenol.     

Enzymatic oxidative polymerization of para‐imine functionalized phenol catalyzed by horseradish peroxidase

Enzymatic oxidative polymerization of a new para‐imine functionalized phenol derivative, 4‐(4‐hydroxybenzylideneamino)benzoic acid (HBBA), using horseradish peroxidase enzyme and hydrogen peroxide oxidizer has been investigated in an equivolume mixture of an organic solvent (acetone, methanol, ethanol, dimethylformamide, 1,4‐dioxane, and tetrahydrofuran) and phosphate buffer (pH = 5.0, 6.0, 6.8, 7.0, 7.2, 8.0, and 9.0) at different temperatures under air for 24 h. The resulting oligomer, oligo(4‐(4‐hydroxybenzylideneamino)benzoic acid) [oligo(HBBA)], was characterized using ultraviolet–visible, Fourier transform infrared (FT‐IR), ¹H nuclear magnetic resonance (NMR), cyclic voltammetry, size exclusion chromatography, differential scanning calorimetry, and thermogravimetric analyses. Polymerization involved carbon dioxide and hydrogen elimination from the monomer, and terminal units of the oligomer structure consisted of phenolic hydroxyl (–OH) groups at the ends. The polymer is mainly composed of a mixture of phenylene and oxyphenylene units according to ¹H NMR and FT‐IR analyses. Effects of solvent system, temperature and buffer pH on the polymerization have been investigated in respect to the yield and molecular weight (M_n) of the product. The best condition in terms of the highest molecular weight (M_n = 3000 g/mol, DP ~ 15) was achieved in an equivolume mixture of 1,4‐dioxane/pH 5.0 phosphate buffer condition at 35°C. Electrochemical characterization of oligo(HBBA) was investigated at different scan rates. The resulting oligomer has also shown relatively high thermal stability according to thermogravimetric analysis. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis of a nonionic water soluble semiconductive polymer

A new nonionic water-soluble fluorescent conjugated polymer is reported with hydroxyl and amide side chains surrounding an aromatic polymer backbone.     

Solvent‐tunable colors in imprinted helical structures on polymer template via multiple UV‐induced polymerization

A solvent tunable single‐layer polymer film with a multipitched photonic structure as a new photonic band gap material has been developed by imprinting the helical structures on polymer matrices through multiple photocrosslinking in an induced chiral nematic mesophase. Here, the polymer matrices themselves served as a chiral template, which exhibited Bragg reflections in the absence of both a chiral dopant and anisotropic materials because of the memory effects of the polymer network. Tuning of colors was achieved by making a refractive index contrast in the two periodic media of imprinted solid helical structure and the isotropic liquids that fill it. On incorporation of various isotropic liquids in the imprinted matrices, a sharp peak in the reflection spectrum shifted drastically, which indicated that the wavelength shifts strongly depended on the sort of liquids that filled the matrices. The effects of temperature on the imprinted polymer template feeding the various liquids were studied through the reflectance spectra. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

红外光谱研究以非离子型表面活性剂所组成微乳液的水结构

由烷基聚氧乙烯醚(AEO9)/正己醇/正十六烷/水所组成的微乳液,采用红外光谱对水内核的微观结构进行研究。以水分子的OH伸缩振动谱带, 由高斯分布曲线面积得出不同结构水的含量。只有少量水与表面活性剂结合, 另有部分水束缚于聚氧乙烯链段之间, 这些水与水相中的自由水呈动态平衡。当体系在剧烈振动后, 少量结合水转为束缚水, 静止后又恢复原状。     

Hexagonal close packing of nonionic surfactant micelles in water

The knowledge of the exact shapes of micelles in various micellar phases found in both lyotropic and thermotropic liquid crystals is very important to our understanding of the underlying principles of molecular self-assembly. In the current paper we present a detailed structural study of the hexagonal close packed (hcp, space group P63/mmc) micellar phase, observed in the binary mixtures of nonionic surfactant C12EO8 and water. The reconstructed electron density map of the phase shows perfectly spherical micelles. A spherical core/shell model of micelles, which fits the observed X-ray diffraction pattern satisfactorily, is subsequently constructed. The results confirm the previous assumption that the hcp phase consists of spherical close contacting micelles, each of which contains a low-density core of aliphatic parts and a high-density shell of hydrated ethylene oxide segments, with the gaps between the micelles filled by pure water.     

Incorporation of nonionic emulsifier inside methacrylic polymer particles in emulsion polymerization

The incorporations of polyoxyethylene lauryl ether (Emulgen 109P) and polyoxyethylene nonylphenyl ether (Emulgen 911) nonionic emulsifiers inside poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), and poly(iso-butyl methacrylate) (Pi-BMA) particles prepared by emulsifier-present emulsion polymerizations were examined. To measure the amounts of the incorporated nonionic emulsifiers, optimum compositions of 2-propanol aqueous solutions to remove the nonionic emulsifier from the particle surfaces without removal from the insides were determined. The amount of the incorporation measured by gel permeation chromatography was increased in the order of PMMA > PEMA > Pi-BMA, which accorded with the order of miscibility between each polymer and the emulsifier.     

Circular dichroism study of enzymatic manipulation on magnetic and metallic DNA template nanowires

Circular dichroism spectroscopy (CD) was used to examine the mechanism of endonuclease clipping and ligation of the DNA template nanowires. The biomolecular manipulation of the DNA template is compared for both metallic (Au) and magnetic (Fe₂O₃ and CoFe₂O₄) nanowires. The dependence of nanoparticle (NP) concentration on enzymatic clipping and DNA ligation was studied, in addition to performing absorbance and thermal melting experiments. Low-NP concentration preserved and digested the DNA template structure. Yet, at higher NP concentrations, the DNA template began to denature before enzyme addition. It was also observed that ligation of the digested DNA occurred more efficiently at low-NP concentrations. These results provide significant information on structural alteration and biorecognition effectiveness of the DNA template after enzymatic manipulation.     

Overlapping of three-phase regions in a water/nonionic surfactant/triglyceride system

It was found that two types of three-phase regions containing surfactant phases (microemulsions) are overlapped and the four coexisting phases including excess water and oil phases appear in a three-component system of water/hexaethyleneglycol tetradecyl ether (R₁₄EO₆)/triglyceride (1,2,3-[tris(2-ethylhexanoyloxy)] propane, TEH). A schematic diagram of three- and four-phase behavior was constructed based on the real phase diagrams. One type of three-phase behavior is the same as that typically appearing over a wide range of water/oil ratios in a water/nonionic surfactant/hydrocarbon system. The other type of three-phase behavior is similar to that observed over a wide range of water/oil ratios in a system of water/nonionic surfactant/amphiphilic oil such as long-chain alcohols, fatty acids, and triglycerides. The result clearly shows how two three-phase regions interact with each other and are transferred from one to another.     

Temperature effect on template polymerization of methacrylic acid using stereocomplex formation on quartz crystal microbalance substrates

The radical polymerization of methacrylic acid (MAA) at 0, 20, 40, and 70 °C was achieved in porous isotactic (it‐) poly(methyl methacrylate) (PMMA) films on quartz crystal microbalance (QCM) substrates, which were prepared by layer‐by‐layer assembled stereocomplex films of it‐PMMA and syndiotactic (st‐) poly(methacrylic acid) (PMAA), followed by the subsequent extraction of st‐PMAA. The MAA polymerization yields increased from 35 to 75%, as the polymerization temperature increased from 0 to 70 °C. Furthermore, infrared spectroscopy revealed that a higher polymerization temperature is necessary to form it‐PMMA/st‐PMAA stereocomplexes via stereoregular polymerization manner that resemble native it‐PMMA/st‐PMAA stereocomplexes. X‐ray diffraction pattern of porous it‐PMMA were also investigated for reaction fields. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3032–3036     

Oxidative polymerization of p-alkylphenols catalyzed by horseradish peroxidase

Enzymatic oxidative polymerization of p-alkylphenols using horseradish peroxidase as catalyst has been carried out in two polymerization solvent systems: a mixture of phosphate buffer (pH 7) and 1,4-dioxane, and a reverse micellar solution, yielding powdery polymeric materials. The polymer yield was much dependent upon the type of alkyl group in the monomer as well as the solvent type. In case of the polymerization of umbranched alkylphenols in the aqueous 1,4-dioxane, the polymer yield increased with increasing chain length of the alkyl group from 1 to 5, and the yield of the polymer from hexyl or heptylphenol was almost the same as that of the pentyl derivative. The relationship between the type of substituent and the polymer yield in the reverse micellar system was different from that in the aqueous 1,4-dioxane; the highest yield was achieved from ethylphenol. The resulting polymers had molecular weight of several thousands. The polymer was estimated to be composed from a mixture of phenylene and oxyphenylene units from IR analyses. TG measurement exhibited that the polymer had relatively high thermal stability. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1453–1459, 1997     

Mesh phases in a ternary nonionic surfactant, oil, and water system

The binary system of hexaethylene glycol n-hexadecyl ether (C16EO6) and water (2H2O) has a complex, temperature-dependent lyotropic phase sequence, in the concentration region of 48-62 wt %. On cooling it shows the sequence lamellar phase, L(alpha), random mesh phase Mh1(0), rhombohedral mesh phase, Mh1(R(-)3m), bicontinuous cubic phase, V1(Ia(-)3d), and a two-phase hexagonal region, H1+Lbeta. On heating from the latter two-phase region the phase sequence is V1(Ia(-)3d), ,Mh1(0), and Lalpha. Polarizing optical microscopy, 2H nuclear magnetic resonance, and small-angle X-ray scattering have been used to study the stability of these phases, their sequence, and their physical parameters with the addition of the oils, 1-hexene, decane, and octadecane. The oils are located within the alkyl chain regions of the mesophase structures. Depending on whether the added oil is "penetrating" or "swelling", it may reside in the region between the C16 alkyl chains of the surfactant or at the center of the bilayer and affect phase stability. Oils affect both the volume of the alkyl chain region (at fixed surfactant water mole ratio) and the rigidity of the interfacial region. Both effects can influence the phase structures and their ranges of stability. Adding different types of oil to the mesh phases gives an opportunity to understand the factors that are important in their formation. The transition from the Mh1(R(-)3m) phase to Mh1(0) phase is triggered by the hydrocarbon region swelling to a critical volume fraction of 0.32, a surfactant rod radius of approximately 1.75 nm, and a critical water layer thickness of approximately 2.5 nm. The latter is most likely responsible for a weakening of the interlayer headgroup overlap interaction and the loss of correlation between the layers. The lamellar phase becomes the only stable phase at high oil content.     

Enzymatic polymerization of aniline and phenol derivatives catalyzed by horseradish peroxidase in dioxane

Phenylenediamines, 4‐aminophenol and 1,4‐hydroquinone were polymerized via the catalysis of horseradish peroxidase in dioxane at ambient conditions by using hydrogen peroxide as the oxidant. Polymers formed in good yields are black powders soluble in dimethylformamide and dimethylsulfoxide. Several factors influencing the polymer yield were examined using 2‐phenylenediamine as substrate. It was found that pH value gave almost no influence in the range between 6.0 and 7.0, while the polymer yield increased as the concentration of the substrate in dioxane increased. The influence of the oxidant amount was still more obvious; larger excess of the oxidant being necessary in getting higher polymer yield. Using the optimized polymerization conditions, the yield of poly(2‐phenylenediamine) was achieved up to 77.8%. Weight average molecular weight of the polymers are higher than 1 × 10⁴ as determined by gel permeation chromatography. The structure of the polymers was characterized by using nuclear magnetic resonance and infrared techniques. Copyright © 2000 John Wiley & Sons, Ltd.     

Structure of BRIJ-35 nonionic surfactant in water: a reverse Monte Carlo study

There are some contradictions in the literature on the structure of micelles formed by the BRIJ-35 surfactant in water. One can find reasonable differences in the aggregation numbers and micellar sizes, but there is a lack of data on the intermicellar structure. In this study, we reevaluated the small-angle neutron scattering experiments performed previously on the BRIJ-35 surfactant in the concentration range of 5-200 g/dm3 at 20, 40, and 60 degrees C. The data were analyzed with a reverse Monte Carlo-type method developed recently for colloids. The micelles were modeled as spherical cores representing the hydrophobic parts and number of balls put on the cores to mimic the hydrated hydrophilic chains. The simulations provided data on the mean aggregation number and on the extent of hydration of the hydrophilic shell of the micelles. We obtained intermicellar pair-correlation functions indicating different micelle-micelle interactions from the usually assumed hard-sphere ones.     

Palladium-catalyzed transfer hydrogenation of organic substrates by hypophosphite in water containing a nonionic surfactant

Palladium-catalyzed transfer hydrogenation of some organic substrates in water containing a nonionic surfactant was examined using sodium hypophosphite as a hydrogen source. Hydrogenation of organohalides such as polychloroarenes, alkenes, alkynes, nitro compounds, aromatic aldehydes, and O-benzyl and N-benzyl derivatives efficiently proceeded to give the corresponding reduction products. The addition of a nonionic surfactant, such as Tween 20, proved to be effective in obtaining satisfactory results in most cases.     

Chemical potential of a nonionic surfactant in solution

The chemical potential of a surfactant in solution can be calculated from the Gibbs adsorption equation when the surface excess of the surfactant and the surface tension of the solution as a function of surfactant concentration are known. We have investigated a solution of the nonionic surfactant 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) in the polar solvent 3-hydroxypropionitrile at concentrations below and above the critical micelle concentration (cmc). Neutral impact collision ion scattering spectroscopy was applied for the direct measurement of the surface excess of POPC as a function of concentration. The Gibbs adsorption equation was applied in conjunction with surface tension measurements to evaluate the chemical potential and the activity coefficients of POPC, respectively. We find that the solution shows ideal behavior up to the cmc and that the chemical potential remains constant at concentrations larger than the cmc.