Polymerization Reaction Mixture Research Articles

Oxidation of VOCs on a highly stabilized furfuryl alcohol-based activated carbon supported nickel oxide catalyst

Conversion of volatile organic compounds (VOCs) such as toluene and xylene to less harmful CO2 and H2O via catalytic oxidation over the metal oxide-impregnated activated carbon beads is a viable solution for controlling emission of the pollutants. The poly(furfuryl) alcohol (PFA) precursor-based carbon beads (∼0.8 mm) were synthesized via suspension polymerization. The metal-salt was in situ dispersed in the polymerization reaction mixture, and PFA-supported Ni was carbonized (C) and steam activated (A). Decomposition of toluene (∼2000 ppm) and xylene (∼400 ppm) at 500 °C over the supported metal oxide catalysts followed the trend: NiO > CoO > CuO > FeO. Approximately 8.5% (w/w) NiO loading showed the highest VOC decomposition rate. The present results revealed that NiO-PFA/C/A was stable under the experimental VOC oxidation reaction conditions, and is an efficient oxidation catalyst for controlling VOC emissions under a continuous operation.

Simultaneous hydrogen generation and COD reduction in a photoanode-based microbial electrolysis cell

A phenolic precursor-based carbon film dispersed with cerium oxide (CeO2) and reduced graphene oxide (rGO) is prepared as the electrodes of a microbial electrolysis cell (MEC) for simultaneous hydrogen (H2) production and reduction of chemical oxygen demand (COD) in wastewater under visible light irradiation. The oxides are in situ dispersed in the polymerization reaction mixture during the synthesis stage of the phenolic film. The maximum Coulombic energy efficiency, overall H2 recovery and cathodic recovery of the CeO2-rGO/carbon film-based MEC are measured to be approximately 95, 93 and 98%, respectively at 1 V (Ag/AgCl), whereas COD reduction in the wastewater is measured to be approximately 95%. The improved hydrogen evolution and organic degradation are attributed to the electroconductive graphitic rGO and photocatalytic CeO2, respectively. The metal oxide-rGO-dispersed carbon nanocomposite film-based MEC provides an efficient means for simultaneously producing H2 and treating the organics-laden wastewater.

Laser-assisted oxidative polymerization of 3-octylthiophene (3OT) and its characterization

Regioramdom poly(3-octylthiophene) (P3OT) was successfully synthesized by laser assisted oxidative polymerization of 3-octylthiphene monomer. The polymerization reaction mixture was irradiated using a 532-nm laser source at different output power, from 0.5 W to 3 W. Results indicate that laser irradiation favors the growth of low molecular weight fractions during the polymerization reaction, promoting changes in the morphology and crystal size, with a significant reduction in process duration, from 24 h to 10 min. This polymerization route could have important industrial applications in optolectronic devices due to the widening of absorption spectrum and short synthesis time.

ATRP Catalyst Removal and Ligand Recycling Using CO2-Switchable Materials

We have designed three approaches to remove copper catalyst and recycle the ligands after atom transfer radical polymerizations, all based on using materials whose properties can be switched using only CO2 and any nonacidic gas (e.g., air, nitrogen, and argon) as triggers. The first approach involves use of a CO2-switchable solvent (Cy2NMe, N,N-dicyclohexylmethylamine) as the medium for the ATRP reaction. After addition of water to the polymerized reaction mixture and sparging with CO2, the polymer precipitates while the copper salt remains in the solvent. The second approach involves using a conventional ATRP solvent such as toluene to conduct the polymerization. Following polymerization, addition of water and CO2 sparging result in the ligand (Me6TREN) and copper salt transferring into the aqueous phase, while the polymer remains in the organic phase. Finally we demonstrate the effectiveness of the approach in ARGET ATRP using less ligand and copper salt. Residual copper in the polymer was <30 ppb using the switchable solvent and <15 ppb in toluene, while residual nitrogen was <90 ppm using the switchable solvent and <35 ppb in toluene. The feasibility of recovering and reusing the ligand for subsequent polymerizations is also established.

Highly effective Cu/Zn-carbon micro/nanofiber-polymer nanocomposite-based wound dressing biomaterial against the P. aeruginosa multi- and extensively drug-resistant strains

Pseudomonas aeruginosa (P. aeruginosa) is the most prevalent bacteria in the infections caused by burn, surgery, and traumatic injuries. Emergence of the P. aeruginosa bacterial resistance against various clinical drugs for wound treatment is the major concern nowadays. The present study describes the synthesis of the polyvinyl alcohol (PVA) and cellulose acetate phthalate (CAP) polymeric composite film (~0.2mm thickness) reinforced with the Cu/Zn bimetal-dispersed activated carbon micro/nanofiber (ACF/CNF), as a wound dressing material. The focus is on determining the efficacy of the prepared biomaterial against the multi and extensively drug-resistant P. aeruginosa strains isolated from the burning, surgical, and traumatic injury-wounds. The primary synthesis steps for the biomaterial include the mixing of a blend of CAP powder and the asymmetrically distributed Cu/Zn bimetals in ACF/CNF, into the polymerization reaction mixture of PVA. Biochemical tests showed that the prepared composite material significantly enhanced the in-vitro blood clotting rate, platelet aggregation, and macrophage cell proliferation, indicating the suitability of the material as a fast wound healer. The antibacterial tests performed against the P. aeruginosa strains showed that the material effectively suppressed the bacterial growth, with the bimetal nanoparticles dispersed in the material serving as an antibacterial agent. The PVA/CAP polymer composite served as an encapsulating agent providing a slow release of the nanoparticles, besides increasing the hemostatic properties of the biomaterial. The ACF/CNF served as a support to the dispersed bimetal nanoparticles, which also provided a mechanical and thermal stability to the material. Experimentally demonstrated to be biocompatible, the prepared metal-carbon-polymer nanocomposite in this study is an effective dressing material for the P. aeruginosa-infected wounds.

Novel acrylic/nanocellulose microsphere with improved adhesive properties

A synthesis of acrylic microsphere pressure sensitive adhesives with addition of nanocellulose filler is presented. In the first stage α cellulose was modified by acid hydrolysis and the produced nanocellulose suspension was added into the continuous phase of a suspension polymerization reaction mixture. The amount of nanocellulose varied in range from 0wt% (reference synthesis) to 5wt% calculated on monomer amount. The first part of the study was assigned to the characterization of the synthesized adhesive suspension. Particle sizes and particle size distributions were measured. Then, adhesives were coated via a transfer coating process and adhesive properties were evaluated. Additionally, polymer glass transition temperatures were determined and due to significant differences in measured adhesive properties, adhesive viscoelastic properties were examined using dynamic mechanical analysis (DMA). Results showed that it's possible to use nanocellulose as a nanofiller in microsphere adhesives. Suspensions were stable, mean particle sizes decreased with increasing nanocellulose content mainly due to a higher continuous phase viscosity. Adhesive properties testing revealed non typical behavior for the nanocomposite microsphere PSA material. All three measured adhesive properties increased with increasing nanocellulose content. A synergistic effect of lower particle sizes along with hydrogen bonding exhibited an increase in adhesive properties. DMA analysis showed that the storage modulus (G') increased with increasing amount of added nanocellulose. At the same time a decrease in maximal tan δ values was observed which concurred with improved cohesivity, hence higher shear strength.

Synthesis and characterization of copolymers composed of 3-hexylthiophene and fluorene via chemical oxidation with FeCl3

A series of conducting copolymers including fluorene (F) and 3-hexylthiophene (3HT) were synthesized in chloroform via chemical oxidative polymerization with FeCl3. The incorporation of 3HT and fluorene units into the resultant polymer main chain was verified via proton nuclear magnetic resonance (1H NMR) and matrix-assisted laser desorption/ionization mass spectrometry. During copolymerization, the molar ratios of fluorene and thiophene changed (0 to 100%). Thus, the fluorene content in the copolymers was proportional to that of the fluorene fed into the polymerization reaction mixture. Ultraviolet–visible (UV–Vis) and fluorescence spectra indicated that the absorption and emission peak wavelengths of the resulting copolymer were significantly affected by the fluorene content. The quantum yield determined using the relative method increased from 0.26 to 0.73 with an increase in the fluorene content. The thermal stability of the copolymers also improved with the presence of fluorene. A series of conducting copolymers including fluorene (F) and 3-hexylthiophene (3HT) were synthesized in chloroform by chemical oxidative polymerization with FeCl3, and the incorporation of fluorene and 3HT units into the resultant copolymer main chain was clarified. The quantum yield value of obtained copolymers determined by relative method increased by the amount of incorporated fluorene molecules in the resulting copolymer backbone. In addition, fluorene was demonstrated to play an important role in enhancing the thermal stability of the copolymers.

Star-shaped cyclopolymers: A new category of star polymer with rigid cyclized arms prepared by controlled cationic cyclopolymerization and subsequent microgel formation of divinyl ethers

The combination of living/controlled cationic cyclopolymerization and crosslinking polymerization of bifunctional vinyl ethers (divinyl ethers) was applied to the synthesis of core-crosslinked star-shaped polymers with rigid cyclized arms. Cyclopolymerization of 4,4-bis(vinyloxymethyl)cyclohexene (1), a divinyl ether with a cyclohexene group, was investigated with the hydrogen chloride/zinc chloride (HCl/ZnCl2) initiating system in toluene at 0 °C. The reaction proceeded quantitatively to give soluble poly(1)s in organic solvents. The content of the unreacted vinyl groups in the produced polymers was less than ∼3 mol%, and therefore, the degree of cyclization of the polymers was determined to be ∼97%. The number-average molecular weight (Mn) of the polymers increased in direct proportion to monomer conversion and further increased on addition of a fresh monomer feed to the almost completely polymerized reaction mixture, indicating that living cyclopolymerization of 1 occurred. The chain linking reactions among the formed living cyclopolymers with 1,4-bis(vinyloxy)cyclohexane (3) as a crosslinker in toluene at 0 °C produced core-crosslinked star-shaped cyclopoly(1)s [star-poly(1)s] in high yield (100%). Dihydroxylation of the cyclohexene double bonds of star-poly(1) gave hydrophilic water-soluble star-shaped polymers with rigid arm structure [star-poly(1)-OH] with thermo-responsive function in water. Tgs of star-poly(1) and star-poly(1)-OH were 135 °C and 216 °C, respectively; these values are very high as vinyl ether-based star-shaped polymers. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1094–1102

Facile Synthesis of Hydroxyl‐Terminated Oligoethylenes

The synthesis of terminal hydroxyl‐functionalized oligoethylene is achieved in a two‐step one‐pot method. Aluminum long chain alkyls (Al‐PE) were generated by a catalytic chain transfer reaction involving iron 2,6‐bis(imino)pyridyl ligation catalysts and methyl aluminoxane (MAO) aluminum alkyl precursors. At a high catalyst/cocatalyst ratio (&gt;5 000) and a low ethylene pressure (1 bar) the chain transfer to aluminum is the dominant termination step. Discharging oxygen or dry air into the post polymerization reaction mixture leads to aluminum alkoxides (Al‐O‐PE) and after hydrolysis to hydroxyl‐functionalized polyethylene (PE‐OH). The degree of oxy‐functionalization (up to 88 ± 3%) increased with increasing oxygen pressure and temperature and was more efficient with aluminum alkyls with a lower molecular weight.

Effect of fabrication technique on microstructure and electrical conductivity of polyaniline-TiO2-PVA composite material

The aim of this workis to study the microstructure and D.C electrical conductivity of polyaniline-TiO2-poly-vinyl alcohol polymeric composite material synthesized by two methods. The first method of synthesis involved mixing of 40 wt% blendedpowders of polyaniline and TiO2 micro particles in aqueous solution of PVA and the second method used ‘in situ’ deposition technique in which nano particle sized fine grade anatase TiO2 powder (approximately 50nm average particle size) was placed in the polymerization reaction mixture of aniline, which resulted in polyaniline being deposited on the surface of nano-TiO2 particles forming a core-shell structure. 40 wt% of this composite polymer was then directly blendedwith aqueous solution of poly vinyl-alcohol, resulting in composite polymer of polyaniline-TiO2-poly-vinyl alcohol. The microstructural studies and electrical conductivity results shows that the second method of fabrication not only gives continuous fibrous structure to the conducting polymer without any agglomeration of TiO2, whereas in first method agglomeration of TiO2 results in conducting and non-conducting zone. It gives films with higher D.C electrical conductivity, in comparison to first method, which increases with increasing voltage.

Cationic cyclopolymerization of divinyl ethers with norbornane‐, norbornene‐, or adamantane‐containing substituents: Synthesis of cyclopoly(divinyl ether)s with bulky rigid side chains leading to high glass transition temperature

ABSTRACTCationic cyclopolymerizations of 2,2‐bis(vinyloxymethyl)bicyclo[2.2.1]heptane (1), 5,5‐bis(vinyloxymethyl)‐2‐bicyclo[2.2.1]heptene (2), and 2,2‐bis(vinyloxymethyl)tricyclo[3.3.1.1]3, 7decane (3), divinyl ethers with a norbornane, norbornene, or adamantane unit, respectively, were investigated with the HCl/ZnCl2 initiating system in toluene and methylene chloride at −30 °C. All the reactions proceeded quantitatively to give gel‐free, soluble polymers in organic solvents. The number‐average molecular weight (Mn) of the polymers increased in direct proportion to monomer conversion and further increased on addition of a fresh monomer feed to the almost completely polymerized reaction mixture. The contents of the unreacted vinyl groups in the produced soluble polymers were less than ∼10 mol %, and therefore, the degree of cyclization of the polymers was determined to be over ∼90%. These facts show that cyclopolymerization of 1, 2, and 3 exclusively occurred and the poly(vinyl ether)s with the cyclized repeating units and polycyclic pendants were obtained with their molecular weights being regulated. BF3OEt2 initiator also caused cyclopolymerization of 1, 2, and 3 to give the corresponding high‐molecular‐weight cyclopolymers quantitatively. Glass transition temperatures (Tg's) of poly(1) and poly(2) were 165–180 °C, and Tg's of poly(3) were 211–231 °C; these values are very high as vinyl ether polymers. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2445–2454

Thermal stability of several polyaniline/rare earth oxide composites (I): polyaniline/CeO2 composites

Polyaniline (PANI)/CeO2 composites were prepared by adding CeO2 powder into the polymerization reaction mixture of aniline. Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD) were used to characterize the composites. Thermogravimetry (TG) and derivative thermogravimetry (DTG) were used to study the thermal stability of the composites. IR and XRD results show that interaction exists between PANI and CeO2. This interaction maybe is hydrogen bonding action between the hydroxyl groups on the surface of the CeO2 and the imine groups in the PANI molecular chains. TG–DTG analysis indicates that the thermal stability of the composites is higher than that of the pure PANI. The improvement in the thermal stability of the composites is attributed to the interaction between PANI and CeO2, which restricts the thermal motion of PANI chains and shields the degradation of PANI in the composites.

Living/controlled cationic cyclopolymerization of divinyl ether with a cyclic acetal moiety: Synthesis of poly(vinyl ether)s with high glass transition temperature based on incorporation of cyclized main chain and cyclic side chains

AbstractCationic cyclopolymerization of 2‐methyl‐5,5‐bis(vinyloxymethyl)‐1,3‐dioxane (1), a divinyl ether with a cyclic acetal group, was investigated with the HCl/ZnCl2 initiating system in toluene and methylene chloride at −30 °C. The reaction proceeded quantitatively to give gel‐free, soluble polymers in organic solvents. The number‐average molecular weight (Mn) of the polymers increased in direct proportion to monomer conversion, and further increased on addition of a fresh monomer feed to the almost completely polymerized reaction mixture, indicating that the polymerization proceeded in living/controlled manner. The contents of the unreacted vinyl groups in the produced soluble polymers were less than ∼3 mol %, and therefore, the degree of cyclization was determined to be ∼97%. In contrast, the pendant cyclic acetal groups remained intact in the polymers under the present cationic polymerization conditions. These facts show that cyclopolymerization of 1 almost exclusively occurred and the poly(vinyl ether)s with the cyclized repeating units and cyclic pendant acetal rings were obtained. Glass transition temperature (Tg) and thermal decomposition temperature (Td) of poly(1) (Mn = 7870, Mw/Mn = 1.57) were found to be 166 and 338 °C, respectively, indicating that poly(1) had high Tg and high thermal stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 952–958, 2010

Synthetic Polymer Nanoparticles with Antibody-like Affinity for a Hydrophilic Peptide

Synthetic polymer nanoparticles with antibody-like affinity for a hydrophilic peptide have been prepared by inverse microemulsion polymerization. Peptide affinity was achieved in part by incorporating the target (imprint) peptide in the polymerization reaction mixture. Incorporation of the imprint peptide assists in the creation of complementary binding sites in the resulting polymer nanoparticle (NP). To orient the imprint peptide at the interface of the water and oil domains during polymerization, the peptide target was coupled with fatty acid chains of varying length. The peptide--NP binding affinities (ca. 90-900 nM) were quantitatively evaluated by a quartz crystal microbalance (QCM). The optimal chain length was established that created high affinity peptide binding sites on the surface of the nanoparticles. This method can be used for the preparation of nanosized synthetic polymers with antibody-like affinity for hydrophilic peptides and proteins ("plastic antibodies").

Thermosensitive diblock copolymers with designed molecular weight distribution: Synthesis by continuous living cationic polymerization and micellization behavior

AbstractThe synthesis of diblock copolymers with designed molecular weight distributions (MWDs) was successfully demonstrated in a continuous living cationic polymerization system using simple equipment. The control of MWDs was achieved by gradually feeding a polymerization reaction mixture into a terminating agent. As thermosensitive diblock copolymers, poly(vinyl ethers) containing a thermosensitive segment with oxyethylene side chains and a hydrophilic segment were prepared. The polymerization was carried out in a gas‐tight microsyringe, and the polymerization mixture was added continuously into methanol during the second‐stage polymerization. The self‐association behavior of the resulting diblock copolymers was evaluated by dynamic light scattering in water. MWD‐designed polymers with thermosensitive segments that varied continuously in length and hydrophilic segments of nearly uniform lengths formed micelles with a broad size distribution. Conversely, polymers with nearly uniform thermosensitive segments and hydrophilic segments of different lengths formed micelles with a narrow size distribution, as observed with conventional narrow MWD diblock copolymers. Thus, the MWD of the thermosensitive segment proved a decisive factor in achieving fine control of self‐association. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2212–2221, 2008

Living cationic polymerization of 2-adamantyl vinyl ether

Living cationic polymerization of 2-adamantyl vinyl ether (2-vinyloxytricyclo[3.3.1.1]3,7decane; 2-AdVE) was achieved with the CH3CH(OiBu)OCOCH3/ethylaluminum sesquichloride/ethyl acetate [CH3CH(OiBu)OCOCH3/Et1.5AlCl1.5/CH3COOEt] initiating system in toluene at 0 °C. The number-average molecular weights (Mn's) of the obtained poly(2-AdVE)s increased in direct proportion to monomer conversion and produced the polymers with narrow molecular weight distributions (MWDs) (Mw/Mn = ∼1.1). When a second monomer feed was added to the almost polymerized reaction mixture, the added monomer was completely consumed and the Mn's of the polymers showed a direct increase against conversion of the added monomer. Block and statistical copolymerization of 2-AdVE with n-butyl vinyl ether (CH2CHOCH2 CH2CH2CH3; NBVE) were possible via living process based on the same initiating system to give the corresponding copolymers with narrow MWDs. Grass transition temperature (Tg) and thermal decomposition temperature (Td) of the poly(2-AdVE) (e.g., Mn = 22,000, Mw/Mn = 1.17) were 178 and 323 °C, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1629–1637, 2008

Living cationic polymerization of vinyl ether with a cyclic acetal group

AbstractThe living cationic polymerization of 5‐ethyl‐2‐methyl‐5‐(vinyloxymethyl)‐1,3‐dioxane (1), a vinyl ether with a cyclic acetal unit, was investigated with various initiating systems in toluene or methylene chloride at 0 to −30 °C. With initiating systems such as hydrogen chloride (HCl)/zinc chloride (ZnCl2), isobutyl vinyl ether–acetic acid adduct [CH3CH(OiBu)OCOCH3]/tin tetrabromide (SnBr4)/di‐tert‐butylpyridine (DTBP), and CH3CH(OiBu)OCOCH3/ethylaluminum sesquichloride (Et1.5AlCl1.5)/ethyl acetate (CH3COOEt), the number‐average molecular weights (Mn's) of the obtained poly(1)s increased in direct proportion to the monomer conversion and produced polymers with relatively narrow molecular weight distributions [MWDs; weight‐average molecular weight/number‐average molecular weight (Mw/Mn) = 1.2–1.3]. To investigate the living nature of the polymerization with CH3CH(OiBu)OCOCH3/SnBr4/DTBP, a second monomer feed was added to the almost polymerized reaction mixture. The added monomer was completely consumed, and the Mn values of the polymers showed a direct increase against the conversion of the added monomer, indicating the formation of a long‐lived propagating species. The glass transition temperature and thermal decomposition temperature of poly(1) (e.g., Mn = 13,600, Mw/Mn = 1.30) were 29 and 308 °C, respectively. The cyclic acetal group in the pendants of the polymer of 1 could be converted to the corresponding two hydroxy groups in a 65% yield by an acid‐catalyzed hydrolysis reaction. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4855–4866, 2007

Synthesis, characterization and thermal analysis of polyaniline (PANI)/Co3O4 composites

Conducting polyaniline/Cobaltosic oxide (PANI/Co3O4) composites were synthesized for the first time, by in situ deposition technique in the presence of hydrochloric acid (HCl) as a dopant by adding the fine grade powder (an average particle size of approximately 80 nm) of Co3O4 into the polymerization reaction mixture of aniline. The composites obtained were characterized by infrared spectra (IR) and X-ray diffraction (XRD). The composition and the thermal stability of the composites were investigated by TG-DTG. The results suggest that the thermal stability of the composites is higher than that of the pure PANI. The improvement in the thermal stability for the composites is attributed to the interaction between PANI and nano-Co3O4.

Study on the Synthesis and Characterization of PANi/Nano-CeO&lt;sub&gt;2&lt;/sub&gt; Composites

The nano-CeO2 was synthesized by two-step solid-phase reaction. The image of TEM showed that nano-CeO2 with an average size of about 70 nm. The series of polyaniline/nano-CeO2 composites with different PANi: CeO2 ratios were prepared by in-situ polymerization in the presence of hydrochloric acid (HCl) as dopant by adding nano-CeO2 into the polymerization reaction mixture of aniline. The composites obtained were characterized by FT-IR and UV-vis spectroscopy analysis. The FT-IR spectra of nanocomposites indicate different blue-shifts, attributed to C–N stretching mode for benzenoid unit. The UV-vis spectra of nanocomposites display einstein-shifts compared with PANi at 620nm. The conductivity properties of the composites are also changed compare to the pure PANi. These results suggest that the interactions between the polymer matrix and nanoparticles take place in polyaniline/nano- CeO2 composites.

Acacia stabilized polyaniline dispersions: preparation, properties and blending with poly(vinyl alcohol)

Polyaniline (PANI) dispersion in water has been prepared by using industrially produced and cheaper stabilizer, namely gum acacia — dried exudates from a species of acacia tree. Gum acacia stabilized PANI particles can be easily isolated from the aniline polymerization reaction mixture and then re-dispersed in water. By increasing the content of gum acacia — in the polyaniline-gum acacia (PANI-ACACIA) redispersable composite from 42 to 70 wt.% it is possible to diminish the average particle diameter from 450 nm to 200 nm and lower its size distribution. The suitability of the dispersion for blending with water-soluble polymers, such as for example poly(vinyl alcohol) (PVA) has also been tested. The composite PANI-ACACIA containing 60 wt.% of gum acacia has yielded the best blends with PVA with the conductivity in the range of 10 − 4 to 10 − 5 S/cm.