Antibacterial and Bacterium Adsorbing Macromolecules

Currently studies on antibacterial macromolecules, i. e., bactericidal and bacteriostatic ones, have been made to develop a new utilization field of polymeric materials. In these studies, there are immobilizations of iodine to quaternary ammonium salts, antibiotics, antibacterial groups to macromolecular substances, as well as syntheses of polymers with quaternary ammonium salts, biguanide groups, quaternary pyridinium salts, sulphonium salts, phosphonium salts, and other antibacterial groups. On the other hand, studies have been made of bacterium adsorbing macromolecules, which can remove by adsorbing bacterial cells in water. The macromolecules are the ones based on poly(4‐vinylpyridine‐co‐divinylbenzene), crosslinked poly(3‐ and 4‐chloromethylated styrene‐g‐amine), and poly(glycidyl methacrylate‐g‐amine), as well as filters and microporous membranes are covered with a macromolecule based on quaternized poly(4‐vinylpyridine‐co‐styrene). Here, a review is made of the syntheses and preparation of the respective macromolecules, as well as of their antibacterial activities and the bacterium adsorbing activities.     

Quaternized poly(2.6 dimethyl‐1.4 phenylene oxide)/polysulfone blend composite membrane doped with ZnO‐nanoparticles for alkaline fuel cells

A series of quaternized poly(2.6 dimethyl‐1.4 phenylene oxide)/polysulfone (QPPO/PSF) blend anion exchange membrane (AEM) were successfully fabricated and characterized for alkaline fuel cell application. Zinc oxide (ZnO) nanoparticles were introduced in the polymer matrix to enhance the intrinsic properties of the AEM. To confirm successful fabrication, Fourier‐transform infrared spectroscopy and nuclear magnetic resonance (¹H‐NMR) were used. The membrane properties were enhanced by the addition of ZnO nanoparticles. The addition of ZnO nanoparticles resulted to a higher ion exchange capacity (IEC) of 3.72 mmol g^?1, increase of ion conductivity (IC) up to 52.34 mS cm^?1 at 80 °C, enhancement of water uptake, and reduced methanol permeability. The QPPO/PSF/2% ZnO composite retained over 80% of its initial IC at room temperature and also retained over 50% of its initial IC at 80 °C when evaluated for alkaline stability. The maximum power output reached for the membrane electrode assembly constructed with QPPO/PSF/2%ZnO was 69 mW cm^?2 at room temperature, which is about three times more than the parent QPPO membrane. The above results indicate that QPPO/PSF/ZnO is a good candidate as an AEM for fuel cell application. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45959.     

Quaternized poly (2.6 dimethyl – 1.4 phenylene oxide)/Polysulfone anion exchange membrane reinforced with graphene oxide for methanol alkaline fuel cell application

Composite anion exchange membranes (AEM) based on quaternized poly (phenylene) oxide and polysulfone blend (QPPO/PSF) were successfully fabricated and characterized for methanol alkaline fuel cell application. To make a composite AEM, increasing graphene oxide (GO) wt.% ratios was introduced in the polymer blend. The membrane properties were enhanced by the addition of GO in comparison to the bare QPPO/PSF blend. The addition of GO resulted to a higher ion exchange capacity (IEC) of 3.21 mmol.g^?1 and an ion conductivity increase of up to 63.67 mS.cm^?1 at 80 °C. The QPPO/PSF/2%GO composite membrane reached a peak power density of 112 mW.cm^?2, which is about five (5) times more than the parent QPPO membrane at room temperature. The above results indicate that QPPO/PSF/GO is a good candidate as an anion exchange membrane for alkaline fuel cell application.     

Fabrication and investigation of phosphoric acid doped imidazolium siloxane crosslinked poly(2,6‐dimethyl‐1,4‐phenylene oxide) for high temperature polymer electrolyte membranes

A series of high temperature polymer electrolyte membranes were fabricated based on imidazolium poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) using methylimidazole (MeIm) and triethoxysilylpropyldihydroimidazole (SiIm) as quaternization reagents via the S_N2 nucleophilic substitution. Meanwhile SiIm was also employed as a crosslinking agent and the crosslinked Si–O–Si network was constructed through a hydrolysis procedure of SiIm in an acid medium. Compared with the PPO‐100%MeIm membrane without the crosslinking structure, the imidazolium siloxane crosslinked PPO‐x%SiIm‐y%MeIm membranes exhibited increased acid doping contents, enhanced dimensional stabilities, improved mechanical properties and higher conductivities. The PPO‐30%SiIm‐70%MeIm/(198 wt% phosphoric acid) membrane displayed a conductivity of 0.08 S cm^?1 at 180 °C without humidifying and a tensile strength of 6.4 MPa at room temperature. © 2019 Society of Chemical Industry     

Formation and analysis of a polyimide layer in composite membranes

Composite membranes containing a thin‐film layer of aromatic polyimides (PI) ensure an advantageous combination of selectivity and permeability in gas separation. A series of rigid‐chain PI with different chemical structures were studied as a thin active layer. Composite membranes were prepared by coating a solution of poly(amic acid) (PAA) and an imidization catalyst on a poly(phenylene oxide) (PPO) support with pores filled by decane. The subsequent stage of solid‐state catalytic transformation of the PAA/PPO membrane into the PI/PPO membrane determines the specific structure of the PI layer and the transport properties of the PI/PPO composite membranes. The structure of composite membranes was determined by scanning electron microscopy and analyzed in the terms of the resistance model of gas transport in composite membranes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1026–1032, 2000     

Conformal electrodeposition of poly(phenylene oxide) on TiO2 nanotube arrays with high performance for lithium ion battery

In order to improve electrochemical performances of lithium ion battery (LIB), electrochemical integration of the membrane with the electrode was accomplished by conformal electrodeposition of poly(phenylene oxide) (PPO) on three‐dimensional (3D) oriented TiO₂ nanotube arrays (TiO₂NT). The as‐synthesized PPO/TiO₂NT membrane/electrode was investigated in terms of AC impedance, XPS, SEM, EDX, galvanostatic charge/discharge, rate performance, and cycle stability. As expected, PPO was indeed combined with TiO₂NT via conformal electrodeposition; furthermore, the integrated PPO/TiO₂NT membrane/electrode delivered much better rate performance than the traditional membrane/electrode, mainly attributed to large area of membrane/electrode/electrolyte, short ionic diffusion paths and fast ionic transport. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43685.     

Effect of polystyrene stars with fullerene C60 cores on pervaporation properties of poly(phenylene oxide) membrane

Star‐shaped macromolecules with six arms of polystyrene grafted onto a fullerene C₆₀ core, or fullerene‐containing polystyrene (FPS), were used for the modification of poly(phenylene oxide) (PPO) and the preparation of a dense thin‐film membrane. The membrane structure was studied using scanning electron microscopy. The effect of FPS modifier on membrane density and mass transfer of methanol and ethylene glycol through the membrane was studied. Sorption and pervaporation tests were used to determine degree of sorption, diffusion coefficients, flux through the membrane and separation factor. In the pervaporation of a methanol–ethylene glycol mixture over the concentration range of 10–30 wt% methanol in the feed, all membranes showed high affinity to methanol. The separation factor reached a maximum at 5 wt% FPS in the membrane. The PPO/FPS membranes exhibit the best separation properties when the feed is enriched with ethylene glycol. © 2016 Society of Chemical Industry     

Studies on mechanism of phase transformation of carboxylated poly(phenylene oxide) and polystyrene blend by Fourier transform infrared spectrometry

Summary The thermally-induced phase transformation behaviors of carboxylated poly(phenylene oxide)(CPPO)/polystyrene(PS), and PPO/PS blends were studied by using a difference-spectrum method of Fourier Transform Infrared Spectrometry (FTIR). The difference intensities() and vibration frequency shifts() of the characteristic infrared absorption bands in both CPPO/PS and PPO/PS increased with raising temperature. A linear temperature dependence in the band frequency vs. temperature plots was observed for PPO/PS system, while three slopes corresponding to the three temperature ranges: below 190°C, 190°–215°C, and above 220°C, appeared in frequency-temperature curves for the CPPO/PS blend. These temperature ranges are consistent with the UCST area, the miscible area and the LCST area obtained by our previous works. The mechanism of phase transformation of CPPO/PS was discussed.     

Preparation of bipolar membranes. II

The bipolar multilayer membrane was prepared by a new technique. The interfacial layer and cation layer were formed by only one step. The anion and cation layers were made from the same material from which chloromethylated polysulfone was used as a basic material. The bipolar membranes were composed of a solvent‐resistant anion layer with crosslinking matrix by the reaction of chloromethylated polysulfone in DMF with diamine; an ultrathin interfacial layer from chloromethylated polysulfone solution in DMF, containing cation‐exchange resin and both quaternary and nonquaternary amine groups; and a cation layer from chloromethylated polysulfone dispersing cation resin powder. The prepared bipolar membrane exhibits a lower voltage drop over 100 mA/cm² and stable performances at a long‐term operation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1733–1738, 2001     

Robust poly(p-phenylene oxide) anion exchange membranes reinforced with pore-filling technique for water electrolysis

Mechanical robustness and durability are crucial for anion exchange membranes to guarantee the longevity and consistent performance of AEM water electrolysis (AEMWE) systems. In this study, a composite membrane based on the quaternized poly(p-phenylene oxide) (QPPO)/polytetrafluoroethylene (PTFE) was developed. This membrane was fabricated by enhancing the QPPO-based AEM through a pore-filling technique within a porous PTFE structure. The tensile strength of the composite membrane was increased significantly from 16.5 to 31 MPa. The conductivity of the composite membrane was 6.25 mScm⁻¹ lower than 30 mScm⁻¹ of the QPPO-based membrane at 20°C, resulting from the low volume fraction of QPPO in the composite membrane. At 40% RH, the net change mass of the composite membrane is 1.59%, much lower than that of QPPO-based membrane (10.98%) at 40°C. The composite membrane demonstrated a significantly increased lifetime in the working electrolyzer (>200 h) compared with an otherwise identical electrolyzer assembled with a QPPO-based membrane (50 h).     

Carbon molecular sieve membranes derived from trimethylsilyl substituted poly(phenylene oxide) for gas separation

Carbon molecular sieve membranes for gas separation prepared using poly(phenylene oxide) (PPO) as precursor have been examined. The PPO precursor was modified by introducing a trimethylsilyl (TMS) substituent and its effect on the gas transport property of the resulting carbon membrane was examined. TMS-substituted PPO (TMSPPO) was prepared in a high yield by a simple one-step reaction, and its carbon membrane was successfully fabricated. The modification improved the gas permeability of the resulting membrane which also exhibited excellent O₂/N₂ and CO₂/CH₄ separation performance comparable to those of polyimide-derived carbon membranes. From the analysis of the microstructure of the TMSPPO carbon membranes, it is believed that the TMS groups improve gas diffusivity by increasing the micropore volume.     

Compatibilization and toughening of poly(2,6‐dimethyl‐1,4‐phenylene oxide)/polyamide 6 alloy with poly(ethylene 1‐octene): Mechanical properties,morphology, and rheology

Blends of a poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO)/polyamide 6 (PA 6) alloy toughened with a novel polyolefin elastomer poly(ethylene‐1‐octene) (POE) were prepared via melt extrusion. In order to improve the compatibilization between POE and the PPO/PA 6 alloy, POE was grafted with maleic anhydride (MA), which could react with the amine group of PA 6. The Izod impact strength of the blends exhibited an optimum when the extent of MA grafting of POE was changed, which is an order of magnitude higher than that of the untoughened blends. The morphology revealed that the size of the POE particles decreased with an increasing MA grafting ratio of POE. Studies on the tensile properties and rheology of the blends were also carried out. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3110–3116, 2003     

Synthesis and characterization of emulsion polymerized mixed matrix aluminum silicate/poly(2,6‐dimethyl 1,4‐phenylene oxide) films

A series of poly (2,6‐dimethyl‐1,4‐phenylene oxide) (PPO)‐based organic/inorganic films for the potential application in membrane gas separation were prepared by employing a method in which aluminum hydroxonitrate contained in a stable water‐in‐oil (W/O) emulsion, the oil phase being a solution of PPO in trichloroethylene, was mixed with a homogeneous solution of PPO in trichloroethylene containing tetraethyl orthosilicate (TEOS). Inorganic polymerization occurred in or at the surface of the aqueous droplets of the W/O emulsion. Subsequently, thin films were prepared by a spin coating technique, and they were referred to as emulsion polymerized mixed matrix (EPMM) films. Scanning electron micrographs taken from a film cross section indicated the presence of particles in the PPO matrix, and energy dispersive X‐ray measurements showed that the embedded particles contained Al and Si elements. Differential scanning calorimetry analysis showed a decrease in the glass transition of the EPMM films with increase of TEOS loading. The compatibility between aluminum silicate nanoparticles and PPO in the EPMM films was confirmed by air separation tests. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation,curing properties,and phase morphology of epoxy‐novolac resin/multiepoxy‐terminated low‐molecular‐weight poly(phenylene oxide) blend

The multiepoxy‐terminated low‐molecular‐weight poly (phenylene oxide) (PPOE) was synthesized by modifying the terminal hydroxyl group of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) with epoxy‐novolac resin (EPN). The curing kinetics, phase morphology, and thermal stability of the cured EPN/PPOE blends were investigated and compared to the unmodified EPN/PPO and EPN/EPPO (epichlorohydrin‐modified PPO) blends. As revealed by the Fourier transform infrared and differential scanning calorimetry analyses, PPOE took part in the curing reaction and formed a crosslinked structure with EPN. The curing rate of EPN/PPOE blends first increased and then decreased with the increase of PPOE fraction. PPOE had both catalytic and steric hindrance effects on the curing reaction. EPN/PPOE blends showed faster curing rate and higher degree of curing than the corresponding EPN/PPO and EPN/EPPO blends. The reactive blending improved the dispersion of PPOE in EPN matrix and the thermal stability of the blend. POLYM. ENG. SCI., 54:2595–2604, 2014. © 2013 Society of Plastics Engineers     

Synthesis and characterization of a poly(ether–ester) copolymer from poly(2,6 dimethyl‐1,4‐phenylene oxide) and poly(ethylene terephthalate)

A series of poly(ether–ester) copolymers were synthesized from poly(2,6 dimethyl‐1,4‐phenylene oxide) (PPO) and poly(ethylene terephthalate) (PET). The synthesis was carried out by two‐step solution polymerization process. PET oligomers were synthesized via glycolysis and subsequently used in the copolymerization reaction. FTIR spectroscopy analysis shows the coexistence of spectral contributions of PPO and PET on the spectra of their ether–ester copolymers. The composition of the poly(ether–ester)s was calculated via ¹H NMR spectroscopy. A single glass transition temperature was detected for all synthesized poly(ether–ester)s. T_g behavior as a function of poly(ether–ester) composition is well represented by the Gordon‐Taylor equation. The molar masses of the copolymers synthesized were calculated by viscosimetry. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

PPO–PC block‐copolymers used as compatibilizers in PS/PC blends

Block‐copolymers containing poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) and polycarbonate of bisphenol A (PC) segments were employed as compatibilizers in polystyrene (PS)/PC blends. Block‐copolymers were prepared starting from oligomeric diols‐terminated PPO and PC. The poly(phenylene ethers) was obtained by oxidative coupling of 2,6‐dimethyl‐phenol in presence of tetramethyl bisphenol A. The copolymers were obtained with a chain extension reaction between the starting oligomers using bischloroformate of bisphenol A or phosgene as coupling agent. PS/PC blends, cast from chloroform solutions or mixed by melt, were studied by differential scanning calorimeter (DSC), dynamic‐mechanical thermal analysis (DMTA), and optical microscopy (OP). The thermal and morphological analyses showed a clear compatibilization effect between PS and PC, if PPO–PC copolymer is added when blending is performed in the melt; in addition, also mechanical properties are increased when compared with blends without PPO–PC. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4654–4660, 2006     

Miscibility and specific interactions in blends of poly(vinyl phenyl ketone hydrogenated) with poly(2,6‐dimethyl‐1,4‐phenylene oxide)

The miscibility behavior of poly(vinyl phenyl ketone hydrogenated) (PVPhKH) and poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) are studied by differential scanning calorimetry, thermomechanical analysis, and FTIR spectroscopy. Two miscibility windows between 10 to 40 and 60 to 90 wt % PPO are detected. Only the blend with 50 wt % PPO is immiscible. The best fit of the Gordon–Taylor equation of the experimental glass‐transition temperatures for miscible PVPhKH/PPO blends is shown. A study by FTIR spectroscopy suggests that hydrogen bonding interactions are formed between the hydroxyl groups of PVPhKH and the ether groups of PPO. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1887–1892, 2004     

Compatibilization of PPO/LCP blends by semi‐interpenetrating liquid crystalline polymer networks LCP/PS

A new approach for enhancing the compatibility of liquid crystalline polymers (LCPs) with engineering thermoplastics is developed in this paper. By adding a new type of compatibilizer to poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO)/LCP blends (semi‐interpenetrating LCP network (ILCPN) comprising the liquid crystalline polymer poly‐(ethylene terephthalate)/p‐hydroxybenzoic acid (PET/60PHB) and crosslinked polystyrene), a well‐compatibilized PPO/LCP composite with considerably improved mechanical properties was obtained. Compared with the uncompatibilized PPO/LCP blend, the bending strength and the Izod impact strength of the compatibilized sample with 5% semi‐ILCPN increase more than 2 and 4 times, respectively.     

Electrodeposition of insulating poly(phenylene oxide) films with variable thickness

Ability to control key characteristics of electrodeposited polymers plays a vital role for their applications. In this work the results on tailoring the thickness of electronically insulating poly(phenylene oxide) (PPO) type polymer films have been showed. Pinhole‐free PPO films with variable thickness in the range of 10–50 nm were grown by controlling the potential applied during the electrochemical polymerization on the surface of titanium nitride (TiN) substrates. The insulating properties of the PPO film were confirmed by testing its permeability to redox species by cyclic voltammetry. Thermal stability of the PPO films with different thicknesses was investigated by in‐situ spectroscopic ellipsometry up to 400 °C in various environments. This insight is important for the optimization of the PPO anneal conditions in order to remove the residual solvent and potentially improve the polymer chains stacking. Our results provide the basis for electrodeposition of PPO films with variable thickness for diverse applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44533.     

Properties and radiation resistance of aromatic polymer-based polyblends

Blends of either of two different poly(phenylene oxide) (PPO) derivatives with poly(2-vinylnaphthalene) (P2VN) were prepared by casting from chloroform. The content of P2VN in the blends ranged from 0 to 25 wt % for each PPO derivative. Two kinds of PPO derivatives, p–t-butylbenzoyl poly(phenylene oxide) (p–t-BB-PPO) and benzoyl poly(phenylene oxide) (B-PPO), were used. The effects of the addition of P2VN to PPO derivatives were investigated by their thermal stability, light-resistance, and tensile properties. Even though the addition of P2VN to the PPO derivatives decrease the mechanical properties, the radiation resistance was improved. The radiation resistance and tensile properties of B-PPO and its blends with P2VN were higher than those of the p–t-BB-PPO and its blends with P2VN. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1697–1705, 1999