Electrophoretic and viscometric properties of poly (dicarboxylic acids)

The electrochemical and conformational properties of maleic acid—methyl vinyl ether copolymer, maleic acid—styrene copolymer and poly(itaconic acid) were investigated as functions of pH by means of electrophoresis and viscosity. The electrophoretic mobility and viscosity were measured in the pH range 3–10 by using different buffer solutions at 0.1 ionic strength. The curves of limiting mobility (U_c→0) and intrinsic viscosity ([η]) against pH and the relationship between [η] and U_c→0 were obtained and compared with those of poly(monocarboxylic acid). The U_c→0 and [η] curves were also compared with the potentiometric titration curve of each poly(dicarboxylic acid) obtained in 0.1N NaCl solution. These results are discussed in terms of the dissociation property of each poly(dicarboxylic acid).     

Some properties of organosoluble poly(2,5-didodecyloxy-p-phenylenevinylene) and its blends with poly(oxyethylene)

An organosoluble precursor of poly(2,5-didodecyloxy-p-phenylenevinylene) (PDDOPV) with high molecular weight was synthesized via the chlorine precursor route and characterized by IR and UV-Vis spectra, GPC, DSC, and elemental analysis. Factors effecting the thermal elimination reaction were studied. The solubility, absorption spectra and photoluminescence spectra of PDDOPV were also investigated. The conductivity of PDDOPV doped with different dopants (I₂, Br₂, FeCl₃ and H₂SO₄) and the I₂-doped conductivity of PDDOPV/PEO (polyoxyethylene) blends and PDDOPV/PEO/LiClO₄ blends were compared. The results showed that a synergistic mixed conductivity existed in the I₂-doped PDDOPV/PEO/LiClO₄ blend.     

Thermal and mechanical properties of block copolymers of poly(hexamethylene terephthalate) and poly(oxyethylene) units

Block copolyetheresters of poly(hexamethylene terephthalate) (6GT) with poly(oxyethylene) terephthalate (POET) units have been prepared by polycondensation and certain of their thermal, morphological and mechanical properties have been determined. The copolymers rich in 6GT or POET units show the crystalline characteristics of the single respective homopolymers, whereas in the middle of the composition range crystalline phases of both types coexist. Increase in the proportion of POET units causes a decrease in the melting and glass transition temperatures and in the crystallisation rates whilst concomitantly the mechanical properties change from fibrous to elastomer in type. The results are interpreted in terms of a polycrystallite model in which the compostion-dependent nature of the crystallites and tie bars determines the overall mechanical properties of the copolymers.     

Cellulose nanocrystals reinforced poly(oxyethylene)

Nanocomposite materials were prepared from poly(oxyethylene) (POE) as the matrix and a stable aqueous suspension of cellulose nanocrystals extracted from tunicate as the reinforcing phase. After dissolving POE in water and mixing with the cellulose nanocrystals suspension, solid films were obtained by casting and evaporating the preparations. Resulting films were characterized using scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis and dynamic mechanical analysis. Favorable interactions between cellulose and POE were evidenced and assumed to be partially responsible for a decrease of the crystallinity of the matrix. A thermal stabilization of the nanocomposites for temperatures higher than the melting temperature of POE was reported and ascribed to the formation of a rigid cellulosic network within the matrix assumed to be governed by a percolation effect. The formation of this percolating network was not altered by the matrix crystallization process and filler/POE interactions.     

Improved synthesis of oxymethylene-linked poly(oxyethylene)

Polyethylene glycol 400 was reacted with CH₂Cl₂ in the presence of KOH to form oxymethylene-linked chains. The method gave a high yield of colourless high-molecular-weight elastomer. The ionic conductivity of a mixture of the polymer with LiCF₃SO₃ ([O]/[Li] = 25) was about 5 × 10^?5S cm^?1 at 25°C.     

Hydrophilicity,crystallinity and electrostatic dissipating properties of poly(oxyethylene)-segmented polyurethanes

Plaques of poly(oxyethylene)-segmented polyurethanes prepared from isophorone diisocyanate (IPDI) and polyethylene glycol (PEG) were used to probe the structure/property relationships with regard to hydrophilicity, crystallinity and electrostatic dissipating (ESD) ability. The prepared urethane polymers or oligomers consistently exhibited lower surface resistivities than their corresponding PEG-1000, 2000 and 8000 starting materials. The magnitude of the decrease in surface resistivity (ohm/sq) was correlated with heat of crystallinity, measured by differential scanning calorimetry. Surface resistivity as low as 10^7.5 ohm/sq for PEG-1000/IPDI polyurethane, a decrease by 2.5 orders of magnitude from pure PEG-1000, was observed and attributed to the differences in crystallinity. Polyurethanes containing PEG, polypropylene glycol (PPG) and mixed PEG/PPG were also prepared for comparison. The mixed PEG/MDEA (N -methyl diethanolamine) polyurethanes further demonstrated the importance of the nature and mobility of the hydrophilic groups for lowering the polymer surface resistivity. To account for these observations, an electron conducting mechanism via association and mobility of the hydrogen-bonded water molecules with hydrophilic poly(oxyethylene) groups is suggested. © 1999 Society of Chemical Industry     

Molecular characterisation of oxymethylene-linked poly(oxyethylene)

Tetraethylene glycol (TEG) or polyethylene glycol 200 (PEG200) was reacted with CH₂Br₂ in a modified Williamson synthesis to form oxymethylene-linked chains. Analytical and preparative gel permeation chromatography plus nuclear magnetic resonance spectroscopy were used to show that the product of reaction consisted of rings with degree of condensation n = 1?15 or more (i.e. 14 to 210 or more atoms in the rings formed from TEG) and chains with molecular weights up to 10⁶ and a wide molecular weight distribution.     

Oligomeric plasticizers from crambe oil-derived dicarboxylic acids for poly(vinyl chloride)

Seventeen oligomeric plasticizers were prepared by polyesterification of long chain dicarboxylic acids with propylene glycol and terminator acid or alcohol. All, except one terminated by dodecyl alcohol, were compatible with poly(vinyl chloride). Films plasticizied with these polyesters were similar in transparency and flexibility to films plasticized with bis(2-ethylhexyl) phthalate. Poly(vinyl chloride) sheets containing brassylic acid polyesters with of 2200–2300 or a crambe mixed dicarboxylic acids polyester with of 2100 exhibited superior permanence with overall performance comparable to sheets plasticized with bis(2-ethylhexyl) phthalate commercial polymeric plasticizer. Presented at the American Chemical Society Meeting, Atlantic City, September, 1974. ARS, USDA.     

Poly[poly(oxypropylene) phosphate] macroionophores for transport and separation of cations in a hybrid: Cation‐exchange polymer and liquid membrane system

Poly[poly(oxypropylene) phosphate]s (PPOPP, M_n = 5800, 8100, 10,400), with different POP units (400, 1200, 2000), were synthesized and applied as cation‐selective macroionophores in a multimembrane hybrid system (MHS). The solution of PPOPP in dichloroethane formed the flowing liquid membrane (FLM) circulating between two polymer cation‐exchange membranes, and subsequently, between two polymer‐made pervaporation (PV) membranes. It was found that the PPOPP macroionophores activate the preferential transport of Zn²⁺ cations from aqueous solutions containing competing Cu²⁺, Ca²⁺, Mg²⁺, K⁺, and Na⁺ cations. The following separation orders were observed for PPOPPs with POP‐400 and POP‐1200: Zn²⁺ > Cu²⁺ ? Ca²⁺, Mg²⁺, K⁺, Na⁺, and for PPOPP with POP‐2000: Zn²⁺ > Cu²⁺,Ca²⁺ ? Mg²⁺, K⁺, Na⁺. Always, the particular cations are separated as: Zn²⁺ > Cu²⁺, Ca²⁺ > Mg²⁺, and K⁺ > Na⁺. The properties of PPOPPs were compared to respective transport and separation characteristics corresponding to those of respective poly(propylene glycol)s and poly(oxypropylene) bisphosphates. The results of investigation indicate that the bifunctional character of PPOPPs is caused by the presence of ionizable groups and probably pseudocyclic POP structures. By comparing the separation of cations in the simple MHS[FLM] system and the system supported by pervaporation unit [MHS[FLM‐PV] it was found that continuous dehydration of an organic FLM improves the system overall performance. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1436–1445, 2004     

Thermal analysis of poly(acrylic acid)/poly(oxyethylene) blends

Blends between poly(acrylic acid) and two different poly(oxyethylenes), (1) polyethylene glycol (PEG-1000) and (2) poly(oxyethylene) (20) sorbitan monooleate (Tween-80), were studied by differential scanning calorimetry. The glass transition temperatures, T_g, of the various compositions of these blends were found to follow Fox's equation. At room temperature, blends containing no more than 60% PEG-1000 were amorphous and exhibited only a single glass transition. For these blends with PEG-1000, the glass transition temperatures for the annealed samples were higher than for the quenched samples due to the formation of a PEG crystalline phase. It was also found that addition of an amorphous polymer such as poly(acrylic acid) significantly reduced the degree of crystallinity of a semicrystalline polymer such as poly(oxyethylene). The Tween-80 systems did not show phase separation at room temperature. The compatibility between this poly(acrylic acid) and this poly(oxyethylene) was attributed to hydrogen bonding and to the lower crystalline lattice energy of this poly(oxyethylene) through its effect on its ideal solution solubility. © 1993 John Wiley & Sons, Inc.     

Synthesis and characterization of poly(oxyethylene)–poly(caprolactone) multiblock copolymers

Novel poly(oxyethylene)/poly(caprolactone) POE/PCL copolymers were synthesized by step growth polymerization of poly(ε-caprolactone) diols and poly(ethylene glycol) diacids using dicyclohexylcarbodiimide as coupling agent. The reaction was performed at room temperature and yielded multiblock copolymers with predetermined POE and PCL block lengths. The resulting copolymers were characterized by various analytical techniques including SEC, IR, ¹H NMR, DSC and X-ray diffractometry. Data showed that the properties of these polymers can be modulated by adjusting the chain lengths of the macromonomers. In particular, one or two crystalline structures can exist within the copolymers of various crystallinities. © 1998 SCI.     

Mesogen-jacketed liquid crystalline polymers substituted with oligo(oxyethylene) as peripheral chain

Mesogen-jacketed liquid crystalline polymer (MJLCP) is a typical rod-shaped macromolecule. Its unique molecular architecture allows one to tune the geometric parameters of the macromolecular rod. Moreover, the rod surface chemistry can be controlled by designing the peripheral groups of the lateral mesogens. In previous work in this system, short alkyl chains have been used and the resultant macromolecular rods therefore have a hydrophobic surface. In this paper, we report using oligo(oxyethylene) groups as the peripheral groups of the lateral mesogens. Poly{{2,5-bis[4-methoxyoligo(oxyethylene)phenyl]oxycarbonyl}styene} (PnEOPCS) with different oligo(oxyethylene) chain length has been synthesized. These oligo(oxyethylene) groups led to macromolecular rods with hydrophilic surface. Differential scanning calorimetry, polarized light microscopy, and one-/two-dimensional wide-angle X-ray diffraction experiments were carried out to study the phase structures and phase behaviors of this series of polymer. The existence of flexible polar groups lowered the glass transition temperatures of PnEOPCS. All polymers studied showed supramolecular columnar nematic or hexatic columnar nematic phase, which arose from the parallel alignment of the polymer supramolecular rods. The diameter of the cylindrical building block increased with increasing the length of the oligo(oxyethylene) groups. The macromolecular rod surface can be further tuned by complexation the oligo(oxyethylene) with lithium salts. Detailed study showed that this complexation also tremendously affected the liquid crystalline phase of the polymer.     

离子液体修饰磺化聚醚醚酮作为离子交换膜

通过NaBH₄还原磺化聚醚醚酮(SPEEK)得到羟基功能化的SPEEK后,采用酯化反应将离子液体1-羧甲基-3-甲基咪唑氯盐接枝到磺化聚醚醚酮上得到接枝聚合物。实验结果表明：离子液体修饰后的磺化聚醚醚酮离子交换膜吸水率和溶胀度降低,而导电率得到了显著提高。     

Dynamics of unentangled cyclic and linear poly(oxyethylene) melts

Monodisperse low-molecular-weight (400-1500 g/mol) cyclic poly(oxyethylene)s (CPOE)s were synthesized from linear dihydroxy-terminated poly(oxyethylene)s (LPOE)s. The self-diffusion, NMR spin-spin relaxation, and zero-shear viscosity of CPOE and LPOE, as well as linear dimethoxy-terminated poly(oxyethylene) (LPOEDE), were measured in the melt state. The self-diffusion coefficients measured at 56 °C were ordered in the following sequence: LPOEDE > CPOE > LPOE, which is in excellent agreement with NMR spin-spin relaxation and viscosity data. The slower motion of LPOE compared to LPOEDE was attributed to chain-end hydrogen bonding. Scaling relations with molecular weight and activation energies were reconciled with chain-end and topological effects.     

Synthesis of poly (p-methylstyrene) - graft-poly (oxyethylene) and application as a polymeric surfactant in emulsion polymerization

Poly(p-methylstyrene)-graft-poly(oxyethylene) copolymers were prepared from p-methylstyrene and æ-hydroxy-ω-methyl-poly(oxyethylene) using a ‘grafting on to’ technique. A total of 10 copolymers were synthesized varying in the hydrophobic back bone chain lengths, hydrophilic branch lengths and frequency of branches. The stabilizing efficiency of these amphipathic copolymers was studied in the emulsion polymerization of styrene. Using the number, size and size distribution of the particles as the criterion of stability, it was found that the polyoxyethylene (PEO) chain length is not as crucial for stability as the availability of the backbone for anchoring. A change in the backbone chain length (from M?_n = 1000 to 24000) with the same percent PEO had no effect on the outcome of the reaction: the latices stabilized to the same number of particles of the same size.     

Phase behaviors of poly(oxyethylene)-grafted polypropylene copolymers

A family of amphiphilic graft copolymers were prepared from a maleated polypropylene (PP-g-MA) and various crystalline poly(oxyethylene)-segmented amines of 1000 to 3000 molecular weight. Structurally, these copolymers consist of polypropylene (PP) backbone and several crystalline poly(oxyethylene) (POE) pendants in the structure. In the observation of their phase behaviors by using a differential scanning calorimeter (DSC), the interference between the POE segments and PP backbone was found. In a particular case (PP-g-MA/ED-2001), the heat of POE crystallization did not show off in the cooling curve of the DSC, but appeared during the consecutive heating process. Generally, heating and cooling patterns of the DSC analyses showed the shifts of melting and crystallizing temperatures, depending on the length and the termini of POE, from those of the starting materials— PP-g-MA and POE amines. The TGA and optical microscopy observation further supported the DSC analyses.     

Cross-linking poly(ethylene oxide) and poly[oxymethylene-oligo(oxyethylene)] with ultraviolet radiation

Poly(ethylene oxide) (PEO) and poly[oxymethylene-oligo(oxyethylene)] (PEM) disks are cross-linked by exposure to 254 nm radiation. The rate of formation of cross-links is greatly enhanced by the presence of benzophenone, and an average cross-link density of up to 6 mol % of ethoxy units can be obtained after several hours of irradiation. The highly cross-linked polymers are insoluble in water or organic solvents and show improved physical properties for handling and the formation of free-standing films. Scanning calorimetry and polymer swelling are employed to characterize the polymers, and impedance measurements are reported for sodium salt complexes prepared from the cross-linked polymers. Dynamic modulus measurements show that, upon irradiation, PEO and PEM become cross-linked, elastomeric solids. © 1994 John Wiley & Sons, Inc.     

Novel block copolymers containing poly(phenylmaleimide) segments: Block copolymerization ofN-phenylmaleimide onto poly(oxyethylene) and poly(butadiene)

Summary Novel block copolymers having poly(N-phenylmaleimide) segments onto poly(oxyethylene) or poly(butadiene) were synthesized. The block copolymerization of N-phenylmaleimide was carried out anionically with lithium alkoxides of poly(ethylene glycol) or α,ω-dihydroxypoly(butadiene). The block copolymers obtained were characterized by¹H NMR, GPC and TLC.     

Polyarylates (polyesters from aromatic dicarboxylic acids and bisphenols)

After a short review on the literature of aromatic polyarylates synthesis the following aspects are described: preparation of some monomers; preparation of the polymers by different chemical processing routes; physical properties; moulding behaviour. Amorphous polymers are especially considered. Figures on continuous melt condensation via the diphenylester route are given. Some polyarylates have attractive mechanical and electrical properties. Injection moulding is only possible if the glass temperature is not too high (≤200°C), and even with these polymers thermal decomposition during injection moulding is a limiting factor for their technical use. The weak point is the ester group. Extrusion, pressing, and solution casting are technically feasable.     

Single step room temperature oxidation of poly(ethylene glycol) to poly(oxyethylene)-dicarboxylic acid

Poly(oxyethylene)-dicarboxylic acids were obtained in high yields by room temperature oxidation of poly(ethylene glycol)s of molecular weights in the 4000–100,000 range using Jone's reagent (CrO₃ and H₂SO₄) as the oxidizing agent. Oxidation by-products from the reaction mixture were eliminated by adsorbing chromium salts onto activated charcoal. The acid values of poly(oxyethylene)-dicarboxylic acids so synthesized were in agreement with the theoretical values. Poly(oxyethylene)-dicarboxylic acids were characterized by ¹H-NMR, IR spectroscopy. Spectral data were in agreement with the proposed structures of products. In summary, a convenient, one pot method for the synthesis of a wide range of poly(oxyethylene)-dicarboxylic acids was developed. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 883–890, 1998