利用造纸污泥制备木素基阳离子絮凝剂及其性能的研究

以造纸污泥中提取的木质素为原料,合成了木素基阳离子絮凝剂。研究了催化剂种类、反应物配料比、反应温度、反应时间等对合成产物脱色性能的影响,确定了较佳合成工艺条件为:引发剂K2S2O8用量为木质素磺酸钠质量的0.7%,活化时间1.5 min,木质素磺酸钠与单体质量比为1∶1.5,反应温度为70℃,反应时间1.5 h,采用红外光谱对产物结构进行了表征。产物对几种模拟染料废水具有良好的脱色性能,在酸性(pH1～2)条件下,脱色率均达84.4%以上。通过比较木质素与接枝产物的絮凝效果以及絮体的微观形貌,对其絮凝机理进行了初步探讨。     

Effect of hydrodynamic conditions of the kinetics of Bentonite Suspension Flocculation by Cationic Polyelectrolytes and the strength of formed flocs

The influence of Zetag and SNF FO cationic polyelectrolytes on the aggregation kinetics of bentonite particles in a flow system is studied in detail as a function of the dose of added polymer, charge density of its macromolecules, the regime and intensity of system stirring, and the type of stirrer (magnetic and mechanical stirrers). It is shown that there is an optimal regime, namely, the alternation of slow and rather rapid stirring, that provides the formation of the largest and strongest flocs. The rate of aggregation and the size of formed flocs increase with the amount of added reagent irrespective of the intensity of system stirring, as well as with an increase in the charge density of polyelectrolyte, which is responsible for the affinity of macromolecules for the surface. The effect of polymer charge on the flocculation kinetics is exhibited first of all upon the slow stirring of suspension. The difference in the sizes of aggregates resulted from the flocculation of macromolecules with different charges is leveled with an increase in stirring intensity. An empirical method for comparing the efficiency of the flocculating action of polymers in suspensions prepared using different types of stirrers is proposed.     

Semi‐interpenetrating polymer networks composed of poly(N‐isopropyl acrylamide) and polyacrylamide hydrogels

Three series of semi‐interpenetrating polymer networks, based on crosslinked poly(N‐isopropyl acrylamide) (PNIPA) and 1 wt % nonionic or ionic (cationic and anionic) linear polyacrylamide (PAAm), were synthesized to improve the mechanical properties of PNIPA gels. The effect of the incorporation of linear polymers into responsive networks on the temperature‐induced transition, swelling behavior, and mechanical properties was studied. Polymer networks with four different crosslinking densities were prepared with various molar ratios (25:1 to 100:1) of the monomer (N‐isopropyl acrylamide) to the crosslinker (methylenebisacrylamide). The hydrogels were characterized by the determination of the equilibrium degree of swelling at 25 °C, the compression modulus, and the effective crosslinking density, as well as the ultimate hydrogel properties, such as the tensile strength and elongation at break. The introduction of cationic and anionic linear hydrophilic PAAm into PNIPA networks increased the rate of swelling, whereas the presence of nonionic PAAm diminished it. Transition temperatures were significantly affected by both the crosslinking density and the presence of linear PAAm in the hydrogel networks. Although anionic PAAm had the greatest influence on increasing the transition temperature, the presence of nonionic PAAm caused the highest dimensional change. Semi‐interpenetrating polymer networks reinforced with cationic and nonionic PAAm exhibited higher tensile strengths and elongations at break than PNIPA hydrogels, whereas the presence of anionic PAAm caused a reduction in the mechanical properties. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3987–3999, 2004     

Synthesis and cationic photopolymerization of new fluorinated,polyfunctional propenyl ether oligomers

New fluorinated, polyfunctional propenyl ether functionalized resins were synthesized, and their behavior in cationic photopolymerization was investigated. The photopolymerization proceeded efficiently with a high double‐bond conversion (>90%), giving rise to UV‐cured coatings characterized by low glass‐transition temperatures (?33 °C ≤ glass‐transition temperature ≤ ?15 °C) and hydrophobic surface properties. A fluorinated additive was also employed as a reactive additive in the cationic photopolymerization of trimethylolpropane tripropenyl ether, increasing the double‐bond conversion, polymer network flexibility, thermal stability, and surface hydrophobicity. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6943–6951, 2006     

Preparation and characterization of Type II anion exchange membranes from poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)

To separate hydrophilic anions from hydrophobic ones, Type II PPO-based anion exchange membranes were developed. Different from Type I (with both trimethylbenzylammonium and triethylbenzylammonium groups), Type II has an excellent hydrophobicity modifier as fixed groups: dimethyethanolammonium groups, which were introduced into PPO (poly(2,6-dimethyl-1,4-phenylene oxide)) by following benzyl bromination of PPO and subsequent quaternary amination with a dimethylethanolamine (DMEA) aqueous solution. The membrane's intrinsic properties are dependent on DMEA concentration and amination temperature. The optimum conditions for membrane preparation are as follows: amination temperature 70 °C, time 30–48 h, and DMEA concentration 1:3–1:5 (v/v, DMEA to water). The obtained Type II anion exchange membranes had an IEC of 1.5 mmol/g dry membrane, water content of 30%, and membrane area resistance of 30 Ω cm². The introduced dimethyethanolammonium groups can block hydrated anions from the access to membranes but let hydrophobic anions transport; hence, an effective separation between hydrophilic and hydrophobic anions can be achieved during electro-membrane operation.     

Novel high performance RTM bismaleimide resin with low cure temperature for advanced composites

A novel performance matrix, coded as LCRTM, with low cure and post‐cure temperature (≤ 200°C) for fabricating advanced polymer composites via resin transfer molding (RTM), was successfully developed, made up of 4,4′‐bismaleimidodiphenylmethane (BDM) and N‐allyl diaminodiphenylether (ADDE). Investigations show that the stoichiometry of BDM and ADDE has great effect on the processing and performance parameters of the resultant resins. In the case of the optimum formulation (the mole ratio of BDM and ADDE is 1:0.55), the injection temperature range is between 70–82°C, and the pot life at 80°C is 300 min, moreover, the cured resin has desirable thermal and mechanical properties after being cured at 200°C for 6 hr, reflecting a great potential as high performance matrices for fabricating advanced composites via the RTM technique. Copyright © 2005 John Wiley & Sons, Ltd.     

Factorial design of nanosized polyisoprene synthesis via differential microemulsion polymerization

The synthesis of nanosized polyisoprene latex was carried out by differential microemulsion polymerization using 2, 2′‐Azoisobutyronitrile (AIBN) initiator system under various reaction conditions. A fractional factorial experimental design was applied to study the effects of reaction variables: amount of initiator and surfactant, monomer‐to‐water ratio, reaction temperature, and stirring speed on rubber particle size and monomer conversion. The analysis of the results from the design showed the main effects on the observed response and the amount of initiator, reaction temperature and stirring speed in the range of the test had significant effects on polyisoprene particle size. The significant effects on monomer conversion were reaction temperature, stirring speed, and interaction between reaction temperature and stirring speed in the range of the test. The optimum conditions gave highest monomer conversion of 90% and average particle size of polyisoprene of 27 nm. The nanosized polyisoprene was also characterized by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis and application as polymer electrolyte of hyperbranched polyether made by cationic ring‐opening polymerization of 3‐{2‐[2‐(2‐hydroxyethoxy)ethoxy]ethoxymethyl}‐3′‐methyl‐oxetane

A novel cyclic ether monomer 3‐{2‐[2‐(2‐hydroxyethoxy)ethoxy]ethoxy‐methyl}‐3′‐methyloxetane (HEMO) was prepared from the reaction of 3‐hydroxymethyl‐3′‐methyloxetane tosylate with triethylene glycol. The corresponding hyperbranched polyether (PHEMO) was synthesized using BF₃·Et₂O as initiator through cationic ring‐opening polymerization. The evidence from ¹H and ¹³C NMR analyses revealed that the hyperbranched structure is constructed by the competition between two chain propagation mechanisms, i.e. active chain end and activated monomer mechanism. The terminal structure of PHEMO with a cyclic fragment was definitely detected by MALDI‐TOF measurement. A DSC test implied that the resulting polyether has excellent segment motion performance potentially beneficial for the ion transport of polymer electrolytes. Moreover, a TGA assay showed that this hyperbranched polymer possesses high thermostability as compared to its liquid counterpart. The ion conductivity was measured to reach 5.6 × 10^?5 S/cm at room temperature and 6.3 × 10^?4 S/cm at 80 °C after doped with LiTFSI at a ratio of Li:O = 0.05, presenting the promise to meet the practical requirement of lithium ion batteries for polymer electrolytes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3650–3665, 2006     

Precise synthesis of end‐functionalized thermosensitive poly(vinyl ether)s by living cationic polymerization

A series of poly(2‐methoxyethyl vinyl ether)s with narrow molecular weight distributions and with perfectly defined end groups of varying hydrophobicities was successfully synthesized by base‐assisting living cationic polymerization. The end group was shown to greatly affect the temperature‐induced phase separation behavior of aqueous solutions (lower critical solution temperature‐type phase separation) or organic solutions (upper critical solution temperature‐type phase separation) of the polymers. The cloud points were also influenced largely by the molecular weight and concentration of the polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Tunable phase‐separation behavior of thermoresponsive polyampholytes through molecular design

Here, we report that carboxylated poly‐l ‐lysine, a polyampholyte, shows lower critical solution temperature (LCST)‐type temperature‐responsive liquid–liquid phase separation and coacervate formation in aqueous solutions. The phase‐separation temperature of polyampholytes is strongly affected by the polymer concentration, balance between the carboxyl and amino groups, hydrophobicity of the side chain, and NaCl concentration in the solution. We concluded that the phase separation was caused by both electrostatic interactions between the carboxyl and amino groups and intermolecular hydrophobic interactions. The addition of NaCl weakened the electrostatic interactions, causing the two phases to remix. The introduction of the hydrophobic moiety decreased the phase‐separation temperature by making the molecular interactions stronger. Finally, temperature‐responsive hydrogels were prepared from the polyampholytes to explore their applicability as biomaterials and in drug delivery systems. The fine‐tuning of the phase‐separation temperature of poly‐l ‐lysine‐based polyampholytes through molecular design should open new avenues for their use in precisely controlled biomedical applications. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 876–884     

Solid‐Phase Microextraction Followed by High‐Performance Liquid Chromatography with Fluorimetric and UV Detection for the Determination of Polycyclic Aromatic Hydrocarbons in Water

Abstract

We have developed a solid‐phase microextraction procedure for polycyclic aromatic hydrocarbons. A simplex experimental design was employed to optimize the process. A polydimethylsiloxane/divinylbenzene fiber was selected. The optimum conditions were: an extraction step in the immersion mode, over a period of 60 min at 70°C using high‐speed stirring, and an 8 min desorption step using acetonitrile (90 µl). Linear relationships were obtained for all compounds, except for naphthalene. Our method showed a good precision and accuracy with a detection limit between 0.005 and 0.306 µg l^?1. Our method was used to detect PAHs in real water samples.     

Synthesis and Performance Evaluation of Temperature-controlled Viscous Acid

A temperature-controlled viscous acid thickener was obtained by copolymerizing acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, diallyl dimethyl ammonium chloride, and N-vinyl-2-pyrrolidinone, four monomers by aqueous solution polymerization, the mass ratio of the four monomers was 6: 2: 1: 1, the reaction temperature was 45°C and the reaction time was 6 h. The total mass concentration of the monomer was 25% and the oxidation-reduction system of ammonium persulphate and sodium hydrogen sulfite (mass ratio 1: 1) was used as the initiator, the amount was 0.9% of the total mass of the monomer, and the pH of the reaction solution was 6–8. Selecting glutaric dialdehyde and zirconium(IV) acetylacetonate as cross-linking agents, and compounding the synthesized quaternary copolymer after the mass ratio of the two reagents was 1: 1 to achieve acid temperature control viscous properties, were carried out. At 90°C, the quadripolymer and the cross-linking agent were mixed at a mass ratio of 5: 3, and then cross-linked at 60, 80, and 90°C, respectively, as time increased. The apparent viscosity increased sharply, and the apparent viscosity reached a maximum after 20, 15, and 10 min, and the maximum values were 680, 690, and 750 mPa s, respectively. The reaction of marble with thickening acid (20% hydrochloric acid + 1% thickener) and temperature-controlled viscous acid (20% hydrochloric acid + 1% thickener + 0.6 cross-linking agent) was performed at 90°C. The mass loss of marble was 58 and 42% of that of 20% pure hydrochloric acid, respectively. The performance evaluation results show that the temperature-controlled viscous acid has a good compatibility, and the retarding performance is greatly improved compared with the conventional thickened acid. It has good cross-linking and gel breaking performance under high temperature conditions and is suitable for high temperature formations with temperatures above 90°C. Between its excellent compatibility, it can be selected according to the corresponding formation conditions and construction purposes, and other types of acid working fluid or oilfield additives can be used together to achieve better construction results.

     

Synthesis and Characterization of Nano‐Ziconium Dioxide in Recombination Surfactant Association System

This article investigates the influence factors of reagent ratio, pH, stirring intensity, sintering temperature along with ultrasonic wave to particle size, distribution of nanoziconium dioxide in recombination surfactant system. The optimized reagent ratio (wt) of cyclohexan, OP‐10, n‐Amyl alcohol, zircon salt solution are 55%, 17.5%, 17.5%, 10%, respectively. At pH=8.7, the size of nanozirconium oxide has the priority of smaller (<10 nm), narrower particle size distribution and better performance in W/O form.     

Preparation and application of a novel core–shell‐particle‐supported zirconocene catalyst

The use of functional groups bearing silica/poly(styrene‐co‐4‐vinylpyridine) core–shell particles as a support for a zirconocene catalyst in ethylene polymerization was studied. Several factors affecting the behavior of the supported catalyst and the properties of the resulting polymer, such as time, temperature, Al/N (molar ratio), and Al/Zr (molar ratio), were examined. The conditions of the supported catalyst preparation were more important than those of the ethylene polymerization. The state of the supported catalyst itself played a decisive role in both the catalytic behavior of the supported catalyst and the properties of polyethylene (PE). IR and X‐ray photoelectron spectroscopy were used to follow the formation of the supports. The formation of cationic active species is hypothesized, and the performance of the core–shell‐particle‐supported zirconocene catalyst is discussed as well. The bulk density of the PE formed was higher than that of the polymer obtained from homogeneous and polymer‐supported Cp₂ZrCl₂/methylaluminoxane catalyst systems. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2085–2092, 2001     

Free volume and oxygen transport in cold‐drawn polyesters

Poly(ethylene terephthalate) (PET), poly(ethylene terephthalate‐co‐4,4′‐bibenzoate) (PETBB55), and poly(ethylene 2,6‐naphthalate) (PEN) were cold‐drawn to achieve uniform extension without crystallization or stress whitening, and oxygen transport properties were studied at temperatures from 10 to 40 °C. Correlation of oxygen solubility and polymer specific volume made it possible to consider the oriented polyester as a one‐phase densified glass. Orientation was viewed as decreasing the amount of excess‐hole free volume and bringing the nonequilibrium polymer glass closer to the equilibrium condition. Between 10 and 40 °C, the amount of excess‐hole free volume in PET decreased as the polymer approached the glass transition temperature. In contrast, temperature changes in this range had little effect on the excess‐hole free volume in PETBB55 and PEN, which were well below their glass transition temperature. Gas diffusion was viewed as discrete jumps of the oxygen molecule between holes of excess‐free volume. The jump length was extracted from the activation energy for diffusion according to a channel‐formation model. The result agreed well with the hole spacing estimated from a simple lattice model using the hole density reported in the literature. Extending the lattice model to estimate the mean excess‐free volume hole radius from the fractional free volume resulted in good correlation with the hole radius obtained from positron annihilation lifetime spectroscopy. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 493–504, 2004     

Aggregation of poly(1,3‐cyclohexadiene): Effects of molecular weight and polymer chain structure

The aggregation of poly(1,3‐cyclohexadiene) (PCHD), obtained by anionic polymerization with alkyllithium/amine systems, was examined using size exclusion chromatography (SEC) and size exclusion chromatography coupled with a multiangle laser light scattering photometer (SEC‐MALS). The PCHD polymer chain has a structure consisting of a main chain formed by 1,2‐addition (the 1,2‐CHD unit) and 1,4‐addition (the 1,4‐CHD unit). Mild stirring with relatively low temperature in the polymerization reaction forms an aggregation of PCHD. The molecular weight and molar ratio of 1,2‐CHD/1,4‐CHD units in the polymer chain strongly influence the aggregation of PCHD. In a high molecular weight PCHD, containing ～50% 1,2‐CHD units, an aggregation of the polymer was observed in tetrahydrofuran (THF) solution at room temperature. This aggregation of PCHD was soluble in 1,2,4‐trichlorobenzene (TCBz) and could be separated into each polymer molecule. In contrast, a polymer chain with a high content of 1,4‐CHD units having a relatively low cis‐stereospecificity was easily soluble in THF and TCBz without aggregating. A long polymer chain structure with a high content of 1,2‐CHD units is considered to be the reason for the generation of strong intermolecular forces contributing to the aggregation of PCHD with the solvophobic interactions. The degree of aggregation could be controlled by the conditions of the PCHD polymer solution. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1442–1452, 2006     

A bicyclic conjugated diene monomer,tetrahydroindene, for cationic polymerization and a novel alicyclic hydrocarbon polymer with heat resistance

This study was directed toward the cationic polymerization of tetrahydroindene (i.e., bicyclo[4.3.0]‐2,9‐nonadiene), a bicyclic conjugated diene monomer, with a series of Lewis acids, especially focusing on the synthesis of high‐molecular‐weight polymers and subsequent hydrogenation for novel cycloolefin polymers with high service temperatures. EtAlCl₂ or SnCl₄ induced an efficient and quantitative cationic polymerization of tetrahydroindene to afford polymers with relatively high molecular weights (number‐average molecular weight > 20,000) and 1,4‐enchainment bicyclic main‐chain structures. The subsequent hydrogenation of the obtained poly(tetrahydroindene) with p‐toluenesulfonyl hydrazide resulted in a saturated alicyclic hydrocarbon polymer with a relatively high glass transition (glass‐transition temperature = 220 °C) and improved pyrolysis temperature (10% weight loss at 480 °C). The new diene monomer was randomly copolymerized with cyclopentadiene at various feed ratios in the presence of EtAlCl₂ to give novel cycloolefin copolymers, which were subsequently hydrogenated into alicyclic copolymers with variable glass‐transition temperatures (70–220 °C). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6214–6225, 2006     

Silyl glyoxylates as high‐performance photoinitiators for cationic and hybrid polymerizations: Towards better polymer mechanical properties

Silyl glyoxylates are proposed here as high‐performance photoinitiators (PIs) for the hybrid polymerization of cationic and radical monomers. Recently, silyl glyoxylates were reported as a new class of high‐performance Type I photoinitiators for free radical polymerization under air upon exposure to different near‐UV and blue LEDs. In this article, we report this new class of photoinitiators to initiate cationic polymerization in combination with an iodonium salt. This system can also be used to initiate simultaneously free radical and cationic polymerizations, for example, for the free radical/cationic hybrid polymerization and for the synthesis of interpenetrating polymer networks. The system silyl glyoxylate/iodonium exhibits excellent polymerization performances and exceptional bleaching properties compared to other well established photoinitiators (e.g., camphorquinone). Furthermore, a hybrid monomer is also introduced in this article (2‐vinyloxyethoxyethyl methacrylate [VEEM]) leading to a huge improvement of the mechanical properties of the final polymer through hybrid polymerization. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1420–1429     

A new sequence isomer of AB‐polybenzimidazole for high‐temperature PEM fuel cells

A new sequence isomer of AB‐polybenzimidazole (AB‐PBI) was developed as a candidate for high‐temperature polymer electrolyte membrane fuel cells. A diacid monomer, 2,2′‐bisbenzimidazole‐5,5′‐dicarboxylic acid, was synthesized and polymerized with 3,3′,4,4′‐tetraaminobiphenyl to prepare a polymer that was composed of repeating 2,5‐benzimidazole units. In contrast to previously prepared AB‐PBI, which contains only head‐to‐tail benzimidazole sequences, the new polymer also contains head‐to‐head and tail‐to‐tail benzimidazole sequences. The polymer was prepared in polyphosphoric acid (PPA) and cast into membranes using the sol–gel PPA process. Membranes formed from the new AB‐PBI were found to be mechanically stronger, possessed higher acid doping levels, and showed improved fuel cell performance, when compared to the previously known AB‐PBI. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Evaluation of poly([2‐(acryloyloxy)ethyl]trimethylammonium chloride) cationic polymer capillary coating for capillary electrophoresis and electrokinetic chromatography separations

Capillary electrophoresis and electrokinetic chromatography are typically carried out in unmodified fused‐silica capillaries under conditions that result in a strong negative zeta potential at the capillary wall and a robust cathodic electroosmotic flow. Modification of the capillary wall to reverse the zeta potential and mask silanol sites can improve separation performance by reducing or eliminating analyte adsorption, and is essential when conducting electrokinetic chromatography separations with cationic latex nanoparticle pseudo‐stationary phases. Semipermanent modification of the capillary walls by coating with cationic polymers has proven to be facile and effective. In this study, poly([2‐(acryloyloxy)ethyl]trimethylammonium chloride) polymers were synthesized by reversible addition‐fragmentation chain transfer polymerization and used as physically adsorbed semipermanent coatings for capillary electrophoresis and electrokinetic chromatography separations. An initial synthesis of poly([2‐(acryloyloxy)ethyl]trimethylammonium chloride) polymer coating produced strong and stable anodic electroosmotic flow of –5.7 to –5.4 × 10⁻⁴ cm²/V⋅s over the pH range of 4–7. Significant differences in the magnitude of the electroosmotic flow and effectiveness were observed between synthetic batches, however. For electrokinetic chromatography separations, the best performing batches of poly([2‐(acryloyloxy)ethyl]trimethylammonium chloride) polymer performed as well as the commercially available cationic polymer polyethyleneimine, whereas polydiallylammonium chloride and hexadimethrine bromide did not perform well.