Graft copolymers with poly(ethylene oxide) segments

Graft copolymers containing poly(ethylene oxide) as side chains attached to the backbone have attracted significant interest because of their unique properties. They have expanded a class of materials important for science and biomedicine. This review article describes a variety of synthetic procedures, i.e. directly by the macromonomer method or by the ‘grafting from’ technique as well as indirect routes via a polymeric precursor. The uses of these graft copolymers in numerous applications are presented to show their versatile nature and their potential. Copyright © 2007 Society of Chemical Industry     

Physicochemical properties of poly(ethylene oxide)-based composite polymer electrolytes with a silane-modified mesoporous silica SBA-15

Mesoporous silica SBA-15 was surface-modified by γ-glycidoxypropyltrimethoxy silane (GPTMS), and novel poly(ethylene oxide) (PEO)-based composite polymer electrolytes (CPE) using the silane-modified SBA-15 (SBA-15-GPTMS) as filler were prepared and characterized. The results of the low-angle X-ray diffraction (XRD) patterns and Fourier-transform infrared (FT-IR) spectroscopy indicated that GPTMS has been successfully attached to the surface of SBA-15 with a high degree of mesoscopic hexagonal pore structure. The incorporation of SBA-15-GPTMS in the PEO-LiClO₄ matrix effectively reduced the PEO crystallinity and obviously improved the conductivity and electrochemical stability of the CPEs. The CPE with 10 wt.% SBA-15-GPTMS provided the highest conductivity among all the tested CPEs, about 2-3 orders of magnitude higher than that of the PEO-LiClO₄ matrix below the melting temperature of PEO. The reasons that the CPEs using SBA-15-GPTMS as filler showed higher conductivity than that with SBA-15 were discussed.     

Synthesis and characterization of poly (ethylene oxide) containing copolyimides for hydrogen purification

Reverse selective membranes comprising poly(ethylene oxide) (PEO) containing copolyimides (PEO-PI) with variations of acid dianhydrides and diamines have been synthesized for hydrogen purification. The reverse selectivity of the membranes decimate the energy required for hydrogen recompression process. Factors including PEO content, PEO molecular weight, and fractional free volume (FFV) that would affect the gas transport performance have been investigated and elucidated in terms of degree of crystallinity, phase separation in the PEO domain as well as inter-penetration between the hard and soft segments. In mixed gas tests of CO₂ and H₂ mixtures, a highly condensable CO₂ out compete H₂ for the sorption sites in hard segment and diminishes H₂ permeability. Thus the CO₂/H₂ selectivity in the mixed gas tests is much higher than that in pure gas tests. Mixed gas permeation tests at 35 °C and 2atm show that the best reverse selective membranes have a CO₂ permeability of 179.3 Barrers and a CO₂/H₂ permselectivity of 22.7. The physical properties of PEO-PIs have also been characterized by FTIR, DSC, GPC, WAXS, AFM and tensile strain tests.     

Enhancement of electrochemical properties of hot-pressed poly(ethylene oxide)-based nanocomposite polymer electrolyte films for all-solid-state lithium polymer batteries

PEO₁₆-LiClO₄-ZnAl₂O₄ nanocomposite polymer electrolyte (NCPE) films prepared by hot-pressing method have been investigated. In order to compare with the hot-pressed NCPEs, the NCPE films have also been prepared using the conventional solution-casting method. Field emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC), conductivity (σ) and interface property studies have been carried out on above two kinds of films. The results show that the NCPE film prepared by hot-pressing method has smoother surface, higher interface stability, lower crystallization and melting temperature values than that prepared by solution-casting method. An all-solid-state lithium polymer battery using the hot-pressed NCPE film as electrolyte, lithium metal and LiFePO₄ as anode and cathode respectively, shows high discharge specific capacity, good rate capacity, high coulombic efficiency, and excellent cycling stability as revealed by galvanostatical charge/discharge cycling tests.     

Study of a new polymer electrolyte poly(ethylene oxide): NaClO3 with several plasticizers for battery application

Sodium ion conducting thin film polymer electrolytes based on poly(ethylene oxide) (PEO) complexed with NaClO₃ were prepared by a solution‐casting method. Characterization by XRD, IR spectroscopy and AC conductivity has been carried out on these thin film electrolytes to analyse their properties. The conductivity studies show that the conductivity value of PEO:NaClO₃ complex increases with the increase in salt concentrations. Increase in conductivity was found in the electrolyte system by the addition of low molecular weight polymer poly(ethylene glycol) (PEG) and the organic solvents dimethylformamide (DMF) and propylene carbonate (PC). Using these electrolyte systems, cell parameters were measured from the discharge study with the application of load 100 kΩ at room temperature with common cell configuration Na|electrolyte|C:I₂:electrolyte. The open circuit voltage (OCV) ranges from 2.81 to 3.23 V and the short circuit current (SCC) ranges from 340 to 1180 µA. © 2001 Society of Chemical Industry     

Novel polymer electrolyte composed of poly(ethylene oxide), lithium triflate,and benzimidazole

This work has demonstrated that the incorporation of benzimidazole derivatives, 2,2′‐p‐phenylene‐bisindole (PPBI), enhances the ionic conductivity of a poly(ethylene oxide) (PEO)–based electrolyte by 20 times more than the plain system. Specific interactions among amino group, ethyl oxide, and lithium cation were investigated using differential scanning calorimetry (DSC), FTIR, and alternating current impedance. The DSC characterization confirms that the initial addition of PPBI is able to enhance the PEO crystallinity attributed to the interaction between the negative charge from the amino group and the lithium cation. Three types of complexes are present: complex I is present in the PEO phase, complex II resides at interphase, and complex III is located within the PPBI domain. Complex II plays the key role in stabilizing these two microstructure phases. FTIR spectra confirm that because of the presence of PPBI one is able to dissolve lithium salts more easily than in the plain electrolyte system and thus increase the fraction of free ions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 719–725, 2004     

Preparation and characterization of poly(lactic acid)/poly(ethylene oxide) blend film: effects of poly(ethylene oxide) and poly(ethylene glycol) on the properties

Poly(lactic acid) (PLA) film plasticized with poly(ethylene oxide) (PEO) at various weight percentages (1–5 wt%) was prepared to improve the elongation, thus overcoming the inherent brittleness of the material. After optimization of the amount of PEO (4 wt%) through mechanical analysis, poly(ethylene glycol) (PEG), a well‐established plasticizer of PLA, was added (0.5–1.5 wt%) without hampering the transparency and tensile strength much, and again its amount was optimized (1 wt%). Neat PLA and PLA with the other components were solvent‐cast in the form of films using chloroform as a solvent. Improvement in elongation at break and reduction in tensile strength suggested a plasticizing effect of both PEO and PEG on PLA. Thermal and infrared data revealed that the addition of PEO induced β crystals in PLA. Scanning electron micrographs indicated a porous surface morphology of the blends. PEO alone in PLA exhibited the best optical clarity with higher percentage crystallinity, while PEG incorporation in PLA/PEO resulted in superior barrier properties. Also, the stability of the blends under a wide range of pH means prospective implementation of the films in packaging of food and non‐food‐grade products. © 2018 Society of Chemical Industry     

Rheological properties of poly(ethylene oxide) aqueous solutions

This article describes the rheological properties of certain poly(ethylene oxide)s dissolved in water-based solvents. The experimental results show that the rheological properties in aqueous solutions are significantly affected by the solvent properties, which have been changed by the use of ethanol–water mixtures and electrolyte solutions and by the variation of the ambient pressure and temperature. The variation of the temperature and pressure is seen to change the polymer chain configuration and also the interactions of polymer segments with the solvent molecules. This gives rise to distinctive and apparently unusual rheological properties for these systems with the variation of the ambient temperature and pressure. The study generally illustrates that the rheology of these systems are, to a large degree, influenced by the hydrogen bonding in the solvent and between the solvent as well as the polymer. At a first-order level, the increase of the pressure and the temperature and also the addition of electrolytes, and the inclusion of an aqueous diluent, produce comparable effects. In essence, these changes seem to disrupt the hydrogen bonding structure in the solutions and, hence, the solvent quality in a comparable fashion. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 419–429, 1998     

Synthesis and applications of heterobifunctional poly(ethylene oxide) oligomers

Poly(ethylene oxide) (PEO) oligomers are employed extensively in pharmaceutical and biomedical arenas mainly due to their excellent physical and biological properties, including solubility in water and organic solvents, lack of toxicity, and absence of immunogenicity. PEO can be chemically modified and reacted with, or adsorbed onto, other molecules and surfaces. Sophisticated applications for PEO have increased the demand for PEO oligomers with tailored functionalities, and heterobifunctional PEOs are often needed. This review discusses the synthesis and applications of heterobifunctional PEO oligomers possessing amine, carboxylate, thiol, and maleimide functional groups.     

Poly(1,2‐diaminobenzene) and poly(1,3‐diaminobenzene): Synthesis,characterization, and properties

Poly(1,2‐diaminobenzene) (1,2‐DAB) and poly(1,3‐diaminobenzene) (1,3‐DAB) have been synthesized by using ammonium persulfate as oxidizing agent in the presence and in the absence of the following metal ion salts: CuCl₂, NiCl₂, and CoCl₂ with different HCl concentrations. The products showed a different content of the metal ion depending on the HCl concentration. The polymers were characterized by Fourier transform infrared (FTIR), ultraviolet‐visible (UV‐Vis) spectroscopy, thermal analysis, and electrical conductivity. The polymerization yield depended on the presence of metal ions that can react as oxidizing reagents and/or catalysts. The polymerization mechanism depended on the position of the substituent. For poly(1,2‐DAB) a ladder‐type structure was obtained, and for poly(1,3‐DAB) one similar to that of polyaniline. The thermal stability increased as the metal ion content in the polymer matrix increased. The electrical conductivity of the polymer did not depend on the metal ion content in the polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2564–2572, 2002     

Dual functionality of PTSA as electrolyte and dopant in the electrochemical synthesis of polyaniline,and its effect on electrical properties

The electrochemical synthesis of polyaniline (PAni) powder was carried out from an aqueous solution of 0.15 mol L^?1 aniline with varying concentrations of p‐toluenesulphonic acid (PTSA) at room temperature. The PAni samples thus obtained were characterized using DC and AC conductivity, dielectric properties, infrared spectroscopy, thermogravimetric analysis, X‐ray analysis, scanning electron microscopy and ultraviolet spectroscopy. Results showed that PTSA is acting both as electrolyte and doping agent. With an increase in the PTSA concentration, there is more polaron formation, and this means an increase in charge carrier concentration and mobility. This accounts for the increase in conductivity and improved dielectric properties of the resultant PAni. The polymer was subjected to a heating and cooling cycle. The change in conductivity during the heating cycle is quite different from that during the cooling cycle, indicating some kind of hysteresis phenomenon occurring in the system. Moreover there is a net decrease in room temperature conductivity of PAni when subjected to the heating–cooling cycle. This may be due to the oxidation of PAni and generation of some kind of disorder in the structure of PAni during the heating–cooling process. Copyright © 2007 Society of Chemical Industry     

A study on the synthesis,characterization and properties of polyaniline/magnesium boride nanocomposites

The present paper reports the novel synthesis of polyaniline/magnesium boride (PAni/MgB₂) nanocomposites. Nanowires 50–100 nm in diameter grown by the sol–gel technique were incorporated in the PAni to prepare PAni/MgB₂ nanocomposites, which yielded an enhancement of conductivity by 5 orders of magnitude. PAni was synthesized through the chemical oxidative polymerization method. The composition of the prepared nanocomposites was tunable, i.e. the amount of dopant was varied and the effects on various parameters were observed by different techniques. The morphology of PAni/MgB₂ nanocomposites was determined using SEM. The temperature dependence of the conductivity of all composites was measured in the temperature range 300–450 K and it was observed that samples having a high concentration of MgB₂ show the highest conductivity. The molecular structure of the nanocomposites was further characterized by Fourier Transform IR spectroscopy which showed small structural changes in the backbone of PAni. I?V measurements showed that the current increases on increasing MgB₂ content. UV?visible spectra exposed the occurrence of an indirect optical transition in the composite. © 2013 Society of Chemical Industry     

Synthesis,characterization, and electrical conductivity of polyaniline derivatives: Study with the metal ions Cu(II), Ni(II), and Co(II)

Poly(2-aminophenol), poly(3-aminophenol), poly(2-aminobenzyl alcohol), and poly(3-aminobenzyl alcohol) were synthesized by using ammonium persulphate as oxidizing reagent in HCl and HCl/CH₃CN mediums in the presence and absence of Cu(II), Ni(II), and Co(II) ions. The polymers were characterized by Fourier transform infrared spectroscopy, ultraviolet-vis spectroscopy, thermal analysis, and electrical conductivity measurements. The substituent in 2- and 3-positions decreases the yield regarding aniline. Poly(2-,3-aminobenzyl alcohol) are obtained in an intermediate redox state and polymerized as aniline. On the contrary, poly(aminophenols) are obtained as overoxidated structures. The presence of metal ion produces an important increase of the polymerization yield. The metal cations would act as oxidizing agents. The incorporation of these metal ions depends on the reaction medium. The metal ion increases the thermal stability. Poly(2-aminobenzyl alcohol)-copper ions also increases the electrical conductivity. The electrical conductivity is higher by acid doping than by the incorporation of metal ions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 330–337, 2001     

Characterization and properties of amphiphilic block polymer based on poly(ethylene oxide) and poly(butyl acrylate)

PEO‐b‐PBA [PEO: poly(ethylene oxide); PBA: poly(butyl acrylate)], an amphiphilic block copolymer, prepared by redox radical polymerization, was characterized by infrared and ¹H nuclear magnetic resonance spectroscopy. The result revealed the existence of PEO and PBA segment in purified block copolymer. The thermal behavior of the block copolymer was determined by differential scanning calorimetry. With the introduction of PBA noncrystalline segment, the crystallinity of PEO was decreased. The emulsifying and water absorptive properties of PEO‐b‐PBA were also examined. It was found that the emulsifying volume and type were dependent on the amount of block copolymer and the PEO content in block copolymer. Under a certain range, the emulsifying volume increases with an increase of PEO content. The more the PEO content in block copolymer, the stronger the water absorptivity was. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3432–3436, 2003     

含聚环氧乙烷链段梳形结构聚(异戊二烯-g-苯乙烯)的合成与表征

以聚苯乙烯(PS)大分子单体和异戊二烯为共聚单体,四氢呋喃为调节剂,正丁基锂为引发剂,三异丁基铝为助引发剂,脂肪族缩水甘油醚为官能化改性剂,采用一锅法经活性负离子共聚合制得以聚异戊二烯为主链、PS为规整侧链,且末端含星形聚环氧乙烷链段的极性化梳形聚(异戊二烯-g-苯乙烯-s-环氧乙烷)(PI-g-PS-s-PEO),利用凝胶渗透色谱仪、傅里叶变换红外光谱仪、差示扫描量热仪等对所制备的PI-g-PS-s-PEO进行了表征,并考察了PI-g-PS-s-PEO中聚环氧乙烷链段(PEO)质量分数(w_PEO)的影响因素。结果表明,产物具有分子结构可设计、分子量分布窄等优点。此外,PS大分子单体分子量对w_PEO无影响,减小缩水甘油醚分子量、增加其用量及延长封端反应时间均可提高w_PEO,且w_PEO在0.1%～1.8%可调。     

Ionic transport behavior in poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) and LiClO4 complex

The effect of LiClO₄ on the ionic transport behavior in poly(ethylene oxide)₂₀-poly(propylene oxide)₇₀-poly(ethylene oxide)₂₀ (P123) polymer electrolyte was studied. Its conductivity reaches maximum as molar ratio between ether O atoms and lithium ions [n(O)/n(Li)] equals 8. The results show that LiClO₄ could interact with P123 well and has impacts on polymer organization and chain dynamics. As LiClO₄ concentration decreases, the glass transition temperature (T_g) decreases and the free ion percentage increases. The tendency of conductivity with LiClO₄ concentration is the result of competing effects between polymer chain mobility and free charge carrier concentration.     

Structure and properties of fluorinated polymer/poly(ethylene oxide) blends

BACKGROUND: In order to explore ways for improving the toughness of copolymers of vinylidene difluoride and chlorotrifluoroethylene (P(VDF‐CTFE)), polyethylene oxide (PEO) with ultrahigh molecular weight and good mechanical properties was applied for the first time to prepare P(VDF‐CTFE)/PEO blends for adhesives applications. RESULTS: The results show that with an increase of PEO content, the mechanical properties of the blends are improved markedly, and blends with high strength, modulus and toughness are obtained. The difference in the solubility parameters of P(VDF‐CTFE) and PEO is small, and only a single α‐relaxation peak is observed in the high‐temperature zone for the blends, indicating that the blend system is partially miscible. The experimental values for the glass transition temperature of the blend varying with PEO content are always higher than those predicted by the Fox equation, and a strong interaction is supposed to occur between the molecules of P(VDF‐CTFE) and PEO. The relative crystallinity of the blends increases with PEO content, and the PEO particles disperse homogeneously in the P(VDF‐CTFE) matrix, whose average size decreases with increasing PEO content. Phase‐inverted morphologies of the blends are observed above 60 wt% of PEO. CONCLUSION: The partial miscibility of P(VDF‐CTFE)/PEO blends leads to an improvement of the mechanical properties of the blends, which is an effective way to improve the toughness of fluorinated polymers. Copyright © 2009 Society of Chemical Industry     

Isothermal crystallization kinetics of poly(ethylene terephthalate)-poly(ethylene oxide) segmented copolymer with two crystallizing blocks

The isothermal crystallization kinetics and morphology of poly(ethylene terephthalate)-poly(ethylene oxide) (PET30-PEO6) segmented copolymer, and poly(ethylene terephthalate) (PET) and poly(ethylene oxide) (PEO) homopolymers have been studied by means of differential scanning calorimetry (DSC) and a transmission electron microscope (TEM). It is found that the nucleation mechanism and growth dimension of PEO in the copolymer are different from that in the homopolymer, which is attributed to the effect of the crystallizability of PET-blocks. Furthermore, the crystallization rate of PEO-blocks in the copolymer is slower than that in the homopolymer because the PET-blocks phase is always partially solidified at the temperatures when PEO-blocks begin to crystallize. In contrast, the isothermal crystallization rate of PET-blocks in the copolymer is faster than that in the homopolymer because the lower glass transition temperature of the PEO-blocks (soft blocks) increases the mobility of the PET-blocks in the copolymer.     

Hydrogen bonding effect on the poly(ethylene oxide), phenolic resin,and lithium perchlorate–based solid‐state electrolyte

The interaction behavior of solid‐state polymer electrolytes composed of poly(ethylene oxide) (PEO)/novolac‐type phenolic resin and lithium perchlorate (LiClO₄) was investigated in detail by DSC, FTIR, ac impedance, DEA, solid‐state NMR, and TGA. The hydrogen bonding between the hydroxyl group of phenolic and ether oxygen of the PEO results in higher basicity of the PEO. The higher basicity of the ether group can dissolve the lithium salts more easily and results in a greater fraction of “free” anions and thus higher ionic conductivity. DEA results demonstrated that addition of the phenolic increases the dielectric constant because of the partially negative charge on the ether group induced by the hydrogen bonding interaction between ether oxygen and the hydroxyl group. The study showed that the blend of PEO(100)/LiClO₄(25)/phenolic(15) possesses the highest ionic conductivity (1.5 × 10^?5 S cm^?1) with dimensional stability. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1207–1216, 2004     

Synthesis and characterization of polyaniline derivative and silver nanoparticle composites

BACKGROUND: There has been a recent surge of interest in the synthesis and applications of electroactive polymers with incorporated metal nanoparticles. These hybrid systems are expected to display synergistic properties between the conjugated polymers and the metal nanoparticles, making them potential candidates for applications in sensors and electronic devices. RESULTS: Composites of polyaniline derivatives—polyaniline, poly(2,5‐dimethoxyaniline) and poly(aniline‐2,5‐dimethoxyaniline)—and silver nanoparticles were prepared through simultaneous polymerization of aniline derivative and reduction of AgNO₃ in the presence of poly(styrene sulfonic acid) (PSS). We used AgNO₃ as one of the initial components (1) to form the silver nanoparticles and (2) as an oxidizing agent for initiation of the polymerization reaction. UV‐visible spectra of the synthesized nanocomposites reveal the synchronized formation of silver nanoparticles and polymer matrix. The morphology of the silver nanoparticles and degree of their dispersion in the nanocomposites were characterized by transmission electron microscopy. Thermogravimetric analysis and differential scanning calorimetry results indicate an enhancement of the thermal stability of the nanocomposites compared to the pure polymers. The electrical conductivity of the nanocomposites is in the range 10^?4 to 10^?2 S cm^?1. CONCLUSION: A single‐step process for the synthesis of silver nanoparticle–polyaniline derivative nanocomposites doped with PSS has been demonstrated. The approach in which silver nanoparticles are formed simultaneously during the polymerization process results in a good dispersion of the nanoparticles in the conductive polymer matrix. Copyright © 2008 Society of Chemical Industry