Phenolic materials via ring-opening polymerization: Synthesis and characterization of bisphenol-A based benzoxazines and their polymers

Compounds with bifunctional benzoxazine groups in their molecular structures form crosslinked structures characteristic of phenolic materials through a ring-opening reaction mechanism. This family of compounds offers greater flexibility than conventional novolac or resole resins in terms of molecular design. It is also superior to conventional phenolic resin in process control since it releases no by-product during curing reactions. The materials thus obtained exhibit excellent mechanical integrity with glass transition temperatures over 200°C. The synthesis, composition, and structural analysis of precursors based on bisphenol-A are discussed herein. © 1994 John Wiley & Sons, Inc.     

Radical polymerization of new functional monomer: Methacryloyl isocyanate containing 4‐chloro‐1‐phenol

New functional monomer methacryloyl isocyanate containing 4‐chloro‐1‐phenol (CPHMAI) was prepared on reaction of methacryloyl isocyanate (MAI) with 4‐chloro‐1‐phenol (CPH) at low temperature and was characterized with IR, ¹H, and ¹³C‐NMR spectra. Radical polymerization of CPHMAI was studied in terms of the rate of polymerization, solvent effect, copolymerization, and thermal properties. The rate of polymerization of CPHMAI has been found to be smaller than that of styrene under the same conditions. Polar solvents such as dimethylsulfoxide (DMSO) and N,N‐dimethyl formamide (DMF) were found to slow the polymerization. Copolymerization of CPHMAI (M₁) with styrene (M₂) in tetrahydrofuran (THF) was studied at 60°C. The monomer reactivity ratio was calculated to be r₁ = 0.49 and r₂ = 0.66 according to the method of Fineman—Ross. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 469–473, 2000     

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.     

“Radical‐controlled” oxidative polymerization of phenol: Comparison with that of 4‐phenoxyphenol

“Radical‐controlled” oxidative polymerization of phenol (p‐1) by (1,4,7‐triisopropyl‐1,4,7‐triazacyclononane)copper(II) catalyst was performed and compared with that of 4‐phenoxyphenol (p‐2) in detail. Although the coupling selectivity for p‐1 seemed to be controlled by the catalyst, the C? C coupling, which was excluded completely for p‐2, occurred to some extent. The initial reaction rate of p‐1 was much smaller than that of p‐2, leading to the difference of polymerization behavior between p‐1 and p‐2. The rate‐determining step would be the coupling of controlled radicals species from the ESR measurement of the reaction mixture. The polymer resulting from p‐1 consisted mainly of phenylene oxide units, but had no crystallinity in contrast to the crystalline polymer from p‐2. However, the present polymer showed the highest thermal stability in the polymers obtained by oxidative polymerization of p‐1. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1955–1962, 2005     

The initial oxidative polymerization kinetics of 2,6-dimethylphenol with a Cu-EDTA complex in water

The initial oxidative polymerization kinetics of 2,6-dimethylphenol (DMP) catalyzed by a Cu(II)-EDTA complex in water was studied. The initial polymerization rate of DMP (R₀) increases with an increase in concentrations of DMP and catalyst. R₀ firstly increases with the molar ratio of N/Cu and then decreases. The reaction order with respect to oxygen is 0.1. R₀ increases with NaOH concentration and reaches its maximum value at a concentration of 0.50 mol/L. 1/R₀ is in direct proportion to 1/[DMP]₀, which indicates that the initial polymerization kinetics of DMP in water obeys Michaelis-Menten model. The dissociation rate constant of the intermediate complex (k₂) and Michaelis-Menten constant (K_m) at various temperatures are calculated. It is found that both k₂ and K_m increase with an increase in temperature.     

气相色谱法同时测定树脂中氯化苄、苄醇和苯酚

对于通用型酚醛树脂和专用型酚醛树脂,其游离酚的分析方法通常采用容量法。但对碳素材料专用酚醛树脂,由于在生产时添加氯化苄对酚醛树脂进行改性,使树脂能浸润碳素材料的中心。这种树脂的生产过程控制和产品质量检验时,涉及游离酚、氯化苄和苄醇的分析测定,如果采用分别测定,其操作相当繁琐,准确性也不高。在常规方法蒸馏苯酚的过程中,氯化苄和苄醇也会被蒸馏出来,蒸馏出来的氯化苄和苄醇对苯酚的容量分析有干扰。在此基础之上,对氯化苄、苄醇和苯酚的蒸馏进行回收率测定,结果表明回收率满足要求。因此,本文建立了气相色谱法同时测定碳素材料专用树脂中的氯化苄、苄醇和苯酚的分析方法。即采用与容量分析方法一样的样品前期处理（酒精溶解样品、水浴蒸馏）,使游离酚、氯化苄和苄醇同时与树脂分离后,采用气相色谱法测定。本方法使测定步骤简化,可用于氯化苄改性的专用酚醛树脂的科研和生产控制。     

Horseradish peroxidase‐based hybrid nanoflowers with enhanced catalytical activities for polymerization reactions of phenol derivatives

Catalytic activity and stability of HRP‐Cu²⁺ hybrid nanoflowers (hCu‐NFs) in the polymerization reactions of phenol derivatives was investigated. It was observed that the catalytic activity and stability of hybrid nanoflowers on the polymerization of the phenol derivatives was considerably higher compared to free Horseradish peroxidase (HRP) enzyme. The hCu‐NFs effectively polymerized phenolic compounds as a novel nanobiocatalyst and led to polymers having quite high yields, molecular weights, and thermal stabilities compared to free HRP enzyme. The hCu‐NFs provide substantial repeated use and showed some degree of catalytic activity even after fourth cycle experiment in the polymerization reactions.     

Electroactive polyimide with oligoaniline in the main chain via oxidative coupling polymerization

By oxidative coupling polymerization of the imidic macromonomer of oligoaniline and p-phenylenediamine we have prepared an electroactive polyimide, exhibiting exciting molecular structure, electrochemical properties and excellent thermal stability. The polymerization characteristics and structure of the electroactive polyimide were systematically studied by Fourier-transform infrared (FTIR) spectra and X-ray powder diffraction (XRD). Electrochemical activity of the polyimide was tested in 1.0 M H₂SO₄ aqueous solution and it shows two redox peaks, which is the same as that of polyaniline. Moreover, the thermal properties of the polyimide were evaluated by thermogravimetric analysis (TGA). Its electrical conductivity is about 8.87 × 10⁻⁶ S cm⁻¹ at room temperature upon preliminarily protonic-doped experiment.     

Effect of phenol and derivatives on atom transfer radical polymerization in the presence of air

The various phenolic compounds in conjunction with Cu(II) or Cu(I)‐N,N,N′,N″,N″‐pentamethyl diethylenetriamine (PMDETA) complexes are used to initiate atom transfer radical polymerization (ATRP) of methyl methacrylate, styrene, and methyl acrylate in the presence of a limited amount of air at temperatures in the range of 80–110 °C. Meanwhile, an effort is directed toward the elucidation of the role of phenol and derivatives in ATRP catalyzed by Cu(II)/PMDETA. The catalytic sequence involves the formation of Cu(I) by electron transfer from phenol to Cu(II); Cu(I) so formed can then react in two distinctly different ways: with organic halide to form a propagating radical or with oxygen to form copper salt in its higher oxidation state; and regeneration of Cu(I) by excess phenol. Such regeneration of Cu(I) would be expected to lead to polymerization as a result of the consumption of oxygen and phenol as well. The phenols with electron releasing groups tended to increase the conversion of the polymerization. In this respect, sodium phenoxide, a more effective additive was found, whereas p‐nitro phenol was the least effective. The obtained polymers displayed the common features of a controlled polymerization such as molecular weight control and low polydispersity index value (M_w/M_n < 1.5). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 351–359, 2004     

Peroxidase-catalyzed oxidative polymerization of phenol with a nonionic polymer surfactant template in water

Peroxidase-catalyzed oxidative polymerization of phenol has been examined using the template, poly(ethylene glycol) monododecyl ether (PEGMDE), in water. The role of this template, which forms a complex with phenol in the polymerization, was verified by UV measurements. During the reaction, a complex of the resulting polymer and PEGMDE was precipitated in high yields. The amount and the PEG chain length of PEGMDE strongly affected the polyphenol yield. The unit molar ratio of polyphenol and PEG of the template was about 1:0.9. The presence of the PEGMDE template in the aqueous medium greatly improved the regioselectivity of the polymerization, yielding polyphenol with a phenylene unit content close to 90%. FT-IR, DSC, and XRD analyses confirmed the formation of the miscible complex of polyphenol and PEGMDE by hydrogen-bonding interactions.     

A novel acrylate carrying a hindered phenol moiety as monomer and terminator in radical polymerization

Radical polymerizations of methyl methacrylate (MMA), styrene (St), and vinyl acetate (VAc) were carried out in the presence of a novel phenyl acrylate derivative bearing a hindered phenol moiety (HPA). It has been clarified that HPA acts as a retarder and inhibitor for the polymerizations of MMA and VAc, respectively, and that in the polymerization of St it behaves as a monomer to give a copolymer. These additive effects were interpreted in terms of intramolecular transfer of the phenolic hydrogen in competition with propagation of the HPA radical to monomers. © 1994 John Wiley & Sons, Inc.     

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 and characterization of electroactive copolymer with phenyl-capped aniline tetramer in the main chain by oxidative coupling polymerization

A novel electroactive alternating copolymer, with fixed conjugated length of oligoaniline (phenyl-capped aniline tetramer) in the main chain, was successfully synthesized via oxidative coupling polymerization. The structure of the copolymer was systematically studied by Fourier-transform infrared (FTIR) spectra, NMR, elemental analysis (EA), UV-vis spectra and X-ray powder diffraction (XRD). And its electrochemical behavior was studied by cyclic voltammetry (CV) measurement. It was found that the obtained copolymer bearing phenyl-capped aniline tetramer segments had a reversible electrochemical property in the cyclic voltammetry, and the copolymer was oxidized to its emeraldine oxidation state and then to the pernigraniline oxidation state, which was same as that of polyaniline. Moreover, the thermal properties of the copolymer were evaluated by thermogravimetric analysis (TGA). The electrical conductivity of the obtained copolymer was about 1.43 × 10⁻⁷ S cm⁻¹ at room temperature.     

In-situ oxidative polymerization of aniline on hydrothermally synthesized MoSe2 for enhanced photocatalytic degradation of organic dyes

In this paper, we report synthesis of MoSe₂-polyaniline by in-situ polymerization method. Simple and eco-friendly hydrothermal technique is used for the synthesis of MoSe₂. Sample characterizations were done using Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD), UV–vis Spectroscopy, Fourier Transform Infra-Red Spectroscopy (FTIR) and Raman Spectroscopy. Photocatalytic dye degradation was performed using nanocomposite on Methylene blue (MB) and Methyl orange (MO). Photocatalytic degradation efficiency (?) was found to be ～65% and ～94% for MB and MO, respectively. Reaction kinetics were studied and fitted well with pseudo first order model because of the mesoporous structure of polyaniline (PANI). Material reusability and regenerability was also checked for number of cycles.     

The catalytic role of transition metal salts on supercritical water oxidation of phenol and chlorophenols in a titanium reactor

The oxidation of phenol and some chlorophenols by molecular oxygen at a concentration of 1.5x10^-4 mol dm^-3 has been studied in a small static titanium tubular reactor at temperatures of 648, 657, 673 K and a pressures of 22 MPa. The effect of transition metal salts (CuSO₄, VSO₄, FeSO₄, MnSO₄, NiSO₄, CoSO₄), added in small environmentally acceptable amounts as homogeneous catalysts, was also studied, with copper showing a good catalytic effect. This revised version was published online in June 2006 with corrections to the Cover Date.     

水对镍系催化丁二烯聚合的影响

比较了正辛醇-三氟化硼乙醚络合物（n－C8H17OH─B）预混和稀三氟、化硼乙醚络合物（B）单加两种体系的丁二烯聚合中微量水的作用规律，测定了这些体系的动力学参数。研究发理,水加在丁二烯中比直接加在溶剂油中好；二种聚合体系都存在含水量的临界值范围，H2O与三异丁基铝的摩尔比约在0.3～2．3之间，在此范围内调节含水量．体系较稳定：丁二烯中有水时，稀B单加比陈化液和B组分同时加入体系中，前者聚合速度较快。     

Synthesis of poly(2,5-dimethylphenylene sulfide) through oxidative polymerization of sulfur chloride with p-xylene

Poly(2,5-dimethylphenylene sulfide) was prepared by oxidative polymerization of sulfur chloride with p-xylene using 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) as an oxidizing agent. The reaction proceeded efficiently under atmospheric pressure and at room temperature. The polymer formed had a high melting temperature and linear structure which was confirmed by spectroscopies. The effects of reaction time, solvent, temperature and oxidizing agent on polymerization are also discussed.     

Preparation and characterization of polyaniline/manganese dioxide composites via oxidative polymerization: Effect of acids

Polyaniline/manganese dioxide (PANI/MnO₂) composites have been chemically prepared by oxidative polymerization of aniline in acidic medium containing MnO₂ as an oxidant. The acids used were; H₂SO₄, HNO₃, HCl, and H₃PO₄ The prepared composites were characterized by SEM, elemental analysis, FT-IR, XRD, TGA, and magnetic susceptibility. XRD measurements of the composites revealed that the crystal structure of incorporated MnO₂ undergone a distortion and converted into amorphous. Thus, the XRD pattern of PANI was predominate. The degree of crystallinity of the prepared composites is depended on the type of compensated acid anions and has the order; . This order is agrees with the order of crystallographic radii and the shape of the corresponding acid anions. From the value of point zero charge of MnO₂ (pzc at pH ≈7.5) and FT-IR spectra, it was concluded that adsorbed acids anions on the oxide surface works as the charge compensator for positively charge PANI in the formation of PANI/MnO₂. The content of PANI in the composite was depended on the type of acid used. Thermogravimetric study exhibited that the composite with low content of PANI has a higher thermal stability. Magnetic susceptibility measurements revealed that the composites has a diamagnetic properties. A schematic composition of the composites has been suggested.     

Microwave‐assisted nitroxide‐mediated polymerization for water‐soluble homopolymers and block copolymers synthesis in homogeneous aqueous solution

We performed a critical reinvestigation of microwave enhancement of nitroxide‐mediated polymerization (NMP) of acrylamide (AM) in aqueous media in the dynamic (DYN) mode with a combination of a conventional hydrosoluble radical initiator and a β‐phosphonylated nitroxide (SG1). Based on the results of our previous work, a complementary series of polymerization reactions was carried out between 130 and 160 °C using only the DYN mode to ascertain the existence of a microwave effect. The polymer conversion (p), molar masses, polydispersity index, and viscosity of each sample were measured. The temperature was monitored inside and outside of the vessel using an optical fiber sensor and an IR sensor, respectively. Microwave enhancement of polymerization, temperature control and viscosity of the reaction media were closely related. We also furthered the field of hydrophilic AB diblock copolymer synthesis using a tertiary SG1‐based macroalkoxyamine and directly synthesized both poly(acrylamide‐b‐sodium 2‐acrylamido‐2‐methylpropanesulfonate), a neutral‐b‐anionic diblock copolymer, and poly(acrylamide‐b‐3‐dimethyl(methacrylamidopropyl)ammonium propanesulfonate), a neutral‐b‐zwitterionic diblock copolymer, in homogeneous aqueous media. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

AlFe-pillared clay catalyst for phenol oxidation in water solution

Catalytic wet peroxide oxidation of phenol over AlFe-pillared montmorillonites, with different iron contents, was carried out at room temperature, in a glass batch reactor, under constant airflow and halogen lamp light. At lower concentration (0.5 mg phenol/100 cm³ water) a phenol conversion of 100% was achieved independently of the iron content in pillared clay catalyst. However, at higher phenol concentration (5.0 mg phenol/100 cm³ water) retardation of the catalyst activity was observed. This revised version was published online in June 2006 with corrections to the Cover Date.