Preparation of amphiphilic carbon black by postgrafting of polyethyleneimine to grafted polymer chains on the surface

Summary To prepare amphiphilic carbon black, we investigated the postgrafting reaction of polyethyleneimine (PEI) with pendant glycidyl groups of grafted polymer on carbon black surface. The grafting of polymers having pendant glycidyl groups onto carbon black surface was achieved by the copolymerization of glycidyl methacrylate (GMA) with methyl methacrylate (MMA) initiated by azo groups introduced onto the surface. Pendant glycidyl groups of poly(GMA-co-MMA)-grafted carbon black was found to react with PEI, and the corresponding polymers postgrafted to the grafted copolymer chains on carbon black surface: the percentage of PEI-postgrafting was readily controlled by the reaction conditions. PEI-postgrafted to poly(GMA-co-MMA)-grafted carbon black, whose PEI postgrafting is 3.9% showed amphiphilic nature and acted as an emulsifier. Received: 13 April 1998/Revised version: 20 May 1998/Accepted: 22 May 1998     

Utilization of N,N-diethyl-3,5-difluorobenzene sulfonamide to prepare functionalized poly(arylene ether)s

A series of poly(arylene ether)s carrying a pendant diethyl sulfonamide group was prepared by the meta activated nucleophilic aromatic substitution reaction of a new aryl difluoride monomer, N,N-diethyl-3,5-difluorobenzene sulfonamide. The synthesis of N,N-diethyl-3,5-difluorobenzene sulfonamide was achieved via the one-step reaction of diethyl amine with commercially available 3,5-difluorobenzenesulfonyl chloride. Model reactions and NMR data indicated that the fluoride atoms were sufficiently activated by the sulfonamide group, located in the meta position, to provide access to high molecular weight poly(arylene ether)s. The corresponding poly(arylene ether)s, were prepared by reaction of N,N-diethyl-3,5-difluorobenzene sulfonamide with bisphenol A, bisphenol AF, 4,4′-biphenol, hydroquinone, resorcinol, and 4,4′-dihydroxydiphenyl ether. The polymers were characterized via NMR spectroscopy, size exclusion chromatography, thermogravimetric analysis, and differential scanning calorimetry. The sulfonamide based poly(arylene ether)s displayed moderate thermal stability with 5% weight loss temperatures ranging from 366 to 385 °C, but possessed relatively low glass transition temperatures, 72–142 °C.     

Synthesis and characterization of novel sulfonated poly(arylene ether ketone)s derived from 4,4'-sulfonyldiphenol

Summary Novel sulfonated poly(arylene ether ketone)s were prepared directly by aromatic nucleophilic polycondensation of 4,4'-sulfonyldiphenol with various ratios of 4,4'-difluorobenzophenone to 5,5'-carbonylbis(2-fluorobenzenesulfonate) in dimethyl sulfoxide. The resulting polyelectrolytes were characterized by IR, NMR, TGA and DSC. The 10% weight loss temperature of the products is higher than 510°C, and their glass transition temperature is above 260°C. The introduction of 4,4'-sulfonyldiphenol with powerful electron-withdrawing group, -SO₂₋, into the main chain of sulfonated poly(arylene ether ketone)s improves the thermal stability against desulfonation. The ion-exchange capacity and swelling of the polyelectrolyte membranes were measured, which are higher than 1.23meq/g and not higher than 20.9%, respectively. The membranes show very good perspectives in polymer electrolyte fuel cell (PEMFC) application. Received: 27 March 2002 / Revised version: 7 May 2002 / Accepted: 13 May 2002     

Study of Cu2+-poly(itaconic acid-co-acrylic acid) complex and copper-polymer nanocomposites

Summary Ultrafine copper particles with diameters in the range of nanometer scale have been prepared in a polymer matrix, using ionic aggregates in Cu²⁺-random poly(itaconic acid-co-acrylic acid) complex precursor films as “microreactors” of controllable size.The morphology and formation of metallic copper particles were studied by transmission electron microscopy and X-ray diffraction techniques. Results from the measurements indicate the copper ions were transformed into nanocrystalline by in situ chemical reduction. It was also found that the polymer chains prohibited the excessive aggregation of the metal atoms and have protective effect on the ultrafine copper particles. Received: 20 May 1998/Revised version: 4 September 1998/Accepted: 16 September 1998     

Grafting reaction of living polymer cations with amino groups on chitosan powder

The grafting of polymers having controlled molecular weight and narrow molecular weight distribution onto chitosan powder by the termination of living polymer cation with amino groups on chitosan powder was investigated in heterogeneous system. The amino groups of chitosan powder successfully reacted with living poly(isobutyl vinyl ether) [poly(IBVE)] and poly(2-methyl-2-oxazoline) [poly(MeOZO)] cation with controlled molecular weight and narrow molecular weight distribution to give the corresponding polymer-grafted chitosan powders. The percentage of poly(MeOZO) grafting gradually increased and reached 24.5% after 4 days. The solubility of poly(MeOZO)-grafted chitosan in water increased with an increase in the amount of grafted polymer. It was suggested that grafting reaction of living polymer cation with chitosan powder proceeds from surface amino groups to inner amino groups of the powder with progress of the reaction. The mole number of grafted polymer chain on chitosan powder decreased with an increase in the molecular weight of the living polymer cation because the steric hindrance of functional groups of chitosan powder increased with the increasing molecular weight of living polymer. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1883–1889, 1998     

Characterization of chloro-fluorinated poly(arylene ether)s for optical waveguide application

Summary Optical polymers which exhibit good thermal stability, controllable refractive index, and low optical loss in the optical communication wavelengths of 1.3 and 1.55 μm were synthesized from 4,4'-(hexafluoroisopropylidene)diphenol (bisphenol AF) and decafluorobiphenyl. The copolymers were prepared by the appropriate molar ratio of 4,6-dichlororesorcinol and bisphenol AF with decafluorobiphenyl. Optical properties such as refractive index and absorption behavior in the near IR region of the resulting polymers were characterized. As the content of chlorine was increased, the refractive indices of polymer were increased without causing further optical loss. Embedded optical waveguides were fabricated by using fluorinated and chloro-fluorinated poly(arylene ether)s. Received: 2 June 1998/Revised version: 27 July 1998/Accepted: 4 August 1998     

Synthesis and characterization of aromatic poly(ether sulfone)s with pendent benzoyl groups

Summary The new sulfone-activated difluoro monomers with benzoyl substituents, bis(2-benzoyl-4-fluorophenyl) sulfone and 2-benzoyl-4,4'-difluorophenyl sulfone, were synthesized and converted to the corresponding poly(aryl ether sulfone)s with bisphenol A. While homopolymerization of the two monomers gave low molecular weight polymers because of cleavage of sulfone induced by the pendent benzoyl group at ortho position, copolymerization with his(4-fluorophenyl) sulfone comonomer produced moderately high molecular weight polymers. The inherent viscosities of the synthesized polymers were 0.20–0.38 dL/g and the glass transition temperatures of the polymers were 173–195°C. Thermogravimetric analysis showed that thermal stability of the polymers decreased as the polymers contain more benzoyl substituents. Received: 15 May 1998/Revised version: 13 October 1998/Accepted: 4 November 1998     

Swelling behavior of emulsion polymer particles: comparison between fully cross-linked and partially cross-linked poly(acrylate) latexes

Summary Measurement of swelling is used to estimate the extent of cross-linking of latex particles prepared by emulsion polymerization. In this paper we report swelling data as a function of solvent activity for two latexes: (1) a poly(butylacrylate) (PBA) latex, and (2) a poly(isodecylacrylate) latex. In the latter case comparison is made between the swelling behavior of fully cross-linked, i.e., networks without free polymer chains, and partially cross-linked latexes. It is demonstrated that the equilibrium swelling properties are only slightly affected by the presence of uncross-linked chains. Swelling gives reliable results for the cross-link density only if the latex does not contain free chains. Received: 3 March 1998/Revised version: 13 May 1998/Accepted: 10 June 1998     

Effect of the ionic conductivity of a polymer matrix on the electrooptical properties of polymer-dispersed liquid crystal films

Summary The influence of ionic conductivity on the electrooptical response was investigated. A new monomer of 2-(poly(ethylene glycol)oxycarbonyl)-bicyclo[2.2.1] hepta-2,5-diene (PEGOC-BCHD) was synthesized and polymerized. Polymer/liquid crystal composite films are composed of poly(PEGOC-BCHD), E8, and alkali metal salts. The ionic conductivities were measured as a function of the ratio of LiClO₄/ethylene oxide for various molecular weights of poly(ethylene glycol). The results indicate that the threshold field and response rise time can be reduced by increasing ionic conductivity of the matrix polymer. Liquid crystal droplets were observed in a continuous matrix phase in the form of ‘Swiss cheese’ morphology. Received: 13 March 1998/Accepted: 19 May 1998     

Solid state NMR study of poly(methyl methacrylate)/polyvinylpyrrolidone blends

The behaviour of poly(methyl methacrylate)/polyvinylpyrrolidone (PNMA/PVP) blends was investigated by solid state nuclear magnetic resonance (NMR) using proton spin-lattice relaxation time in the rotating frame (T1^Hρ), which was measured from the variable contact time experiment. From T1^Hρ relaxation measurements scale, it was possible to obtain a response of the degree of intimacy mixture of polymer blend components. Good compatibility was observed for all proportions studied, as a consequence of the interaction process of blends components. Received: 18 February 1998/Revised version: 25 May 1998/Accepted: 10 June 1998     

Preparation and properties of poly(methyl methacrylate) crosslinked with multimonomers

Summary Multimonomers, such as poly(2-acryloyloxyethyl methacrylate) and poly(2-methacryloyloxyethyl methacrylate) were used as new macrocrosslinkers to crosslink poly(methyl methacrylate). The influence of the kind of macrocrosslinker, its molecular weight and amount on the crosslink density and some properties of the crosslinked polymers networks, such as swelling and mechanical properties (tensile strength and elongation at break) have been examined. The results obtained were compared with those for poly(methyl methacrylate) crosslinked with conventional crosslinker 1,4-butanediol dimethacrylate. Received: 10 March 1998/Revised version: 26 May 1998/Accepted: 10 June 1998     

Synthesis and properties of poly(aryl ether sulfone)s containing the phthalazinone moiety

Three series of poly(aryl ether sulfone)s (PAESs) containing the phthalazinone moiety in the polymer backbone were synthesized by solution polycondensation of bis(4-chlorophenyl) sulfone with three commercial bisphenols and 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one. Bisphenol-A, hydroquinone, and bis(4-hydroxyphenyl) sulfone, or bisphenol-S, were selected as the commercial bisphenols for copolymerization. The synthesized polymers exhibited very high glass transition temperatures and excellent thermooxidative properties. They also showed superior mechanical properties and fair rheological properties. The introduction of relatively flexible moieties, such as benzene rings, onto the poly(phthalazinone ether sulfone) (PPES) chain led to a decrease in glass transition temperature with respect to the phthalazinone homopolymer. However, the processability of PPES was improved dramatically by the addition of these commercial bisphenols. The properties of synthesized PAESs can be tailored by changing the molar ratios of bisphenols to phthalazinone monomer. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:137–143, 1998     

Properties of the polyethylene/poly (2,6-dimethyl-1,4-phenylene ether)/polystyrene system in the presence of SEPS block copolymers

An immiscible polymer system of polyethylene (HDPE)/poly(2,6-dimethyl-1,4-phenylene ether)/polystyrene was compatibilized in the presence of a specific formulated compatibilizer and the properties of this system were studied, in particular, as a function of the poly(phenylene ether) and polystyrene content in the blend with polyethylene and as a function of compatibilizer concentration. The compatibilizer used was a hydrogenated styrene/isoprene/styrene triblock copolymer (SEPS) which also contained quantities of polypropylene and paraffin oil. Selected thermal, mechanical, and processing properties were investigated and their special features are discussed. In relation to specific properties like the modulus of elasticity and notched Izod impact strength, the polymer system with a hydrogenated SEPS triblock copolymer investigated seems to be a better compatibilized system than other blends described. The phase behavior of the polymer system was characterized using DSC and showed three general polymer phases: a partially crystalline polyethylene phase, an amorphous mixed phase of miscible poly(phenylene ether) and polystyrene, as well as a preferred isotactic crystalline polypropylene phase. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1835–1842, 1997     

高性能/高温聚合物的设计、性能和应用进展(Ⅵ)其他反应性端基及链内乙炔基齐聚物及其固化

综述了诸如星形支化苯乙炔封端苯并喹喔啉齐聚物、苯乙炔端基芳醚聚合物、烯丙基聚苯醚、含庞大芴基的聚芳醚等反应性端基芳醚齐聚物,主链含乙炔单元的聚(酰胺-酰亚胺)、马来酰亚胺端基聚合物,热塑性塑料增韧双马来酰亚胺和超支化聚醚酰亚胺的合成、性能和固化技术。     

Polymer-dispersed liquid crystal films using poly(2-methyloxycarbonyl-bicyclo[2.2.1] hepta-2,5-diene-co-poly(ethylene glycol) methacrylate) as a matrix resin

Summary Dependence of the electrooptical response time of a polymer/liquid crystal (LC) composite film on the ionic conductivity and dielectric property of the matrix polymer has been investigated. Poly(2-methyloxycarbonyl-bicyclo[2.2.1]hepta-2,5-diene-co poly(ethylene glycol) methacrylate) was synthesized by photo-polymerization. Ionic conductivity and relative dielectric constant were found to be greatly dependent on the content of poly(ethylene glycol) methacrylate in the copolymer. The results indicate that the matrix polymer with high conductivity and dielectric constant has led to the short response time. Received: 9 June 1998/Revised version: 4 November 1998/Accepted: 6 November 1998     

Hollow fiber microfiltration membranes from poly(ether ether ketone) (PEEK)

A procedure for obtaining high performance large internal diameter (ID; >1 mm) hollow fiber microfiltration membranes from poly(ether ether ketone) (PEEK) is presented. A simple mixture of isomers of diphenylphthalate is a good solvent for employing the thermal‐phase inversion process to obtain PEEK membranes. Obtaining large ID hollow fibers with substantial transmembrane flux requires sufficient melt strength during spinning to prevent excessive draw of the extruding fiber. The use of a second leachable polymer to the blend satisfies the conditions, and polysulphone (PS) is found to provide superior membranes relative to either poly(etherimide) (PEI) or poly(ether sulphone) (PES) as a second polymer. PEEK membranes obtained by this process yield better chemical resistance to a concentrated warm surfactant/oil solution. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 175–181, 1999     

Determination of solvent/polymer interaction parameters of moderately concentrated polymer solutions by vapor pressure osmometry

The paper describes the application of vapor pressure osmometry (VPO) to determine solvent/polymer interaction parameters for various polymer solutions containing high-molecular weight polymers in the semi-diluted concentration range. The theoretical basis for the data evaluation is the Flory–Huggins (FH) model and a virial expansion up to the third virial term. For validation already well characterized polymer/solvent systems poly(vinylpyrrolidone)/water, polysulfone/N,N-dimethylformamide (DMF), and poly(ether sulfone)/DMF were investigated. In the second part interaction parameters of poly(ether imide) (PEI) in solvents with technical relevance for membrane formation (DMF, N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc)) were examined at different concentrations and temperatures. The results document that VPO is a fast and promising method for characterization of semi-diluted polymer solutions containing polymers with higher molecular weight. Results confirm the decrease of solvent power for PEI in the series: NMP > DMAc > DMF.     

Blends of a thermotropic liquid crystalline polymer and some flexible chain polymers and the determination of the polymer-polymer interaction parameter of the two polymers

Summary Blends of a thermotropic liquid crystalline polymer (LCP) with poly(ether imide) (PEI), poly(ether ether ketone) (PEEK), polysulfone (PSF) and polyarylsulfone (PAS) prepared by screw extrusion have been investigated by differential scanning calorimeter and dynamic mechanical thermal analysis. From the measured glass transition temperature (T_g) and specific heat increment (ΔC_p) at the T_g, it appears that the LCP dissolves more in the PEI- and PEEK-rich phases than does the PEI and PEEK in the LCP-rich phase. From the DSC study of PSF-LCP and PAS-LCP blends, the T_g(PSF) and T_g(PAS) of each blends are almost constant with blend composition. Therefore, it is concluded that PSF and PAS are immiscible with LCP. The polymer-polymer interaction parameter (χ₁₂) and the degree of disorder (y/x₁) of LCP have been investigated using the Flory lattice theory in which the anisotropy of LCP is considered. The χ₁₂ values have been calculated from the T_g data and found to be 0.181 ± 0.004 at 593 K for the PEI-LCP blends and 0.069 ± 0.006 at 623 K for the PEEK-LCP blends. Using the previously presented method, the χ₁₂ and y/x₁ in partially miscible systems have been determined. Received: 6 April 1998/Revised version: 8 June 1998/Accepted: 17 June 1998     

车用燃料电池质子交换膜的制备及性能

合成了一系列具有不同支化度的磺化聚芳醚砜材料,并对其结构和性能进行了表征。所制备的磺化的支化聚芳醚砜材料的分子量可达7.00×105以上,并且分子量分布在1.17左右,拉伸强度可达20.55~28.81 MPa。随着聚合物支化度的增加,聚合物的热稳定性得到改善,在550℃下的热失重可降低至39%~45%。高支化的磺化聚芳醚砜薄膜的氧化稳定性也得到改善,80℃下的使用寿命可提高至7.25 h。支化的磺化聚芳醚砜薄膜的吸水率和质子传导率都较高。80℃下高支化度的聚芳醚砜薄膜的质子传导率可达0.33 S/cm。对其微观形貌进行观测发现,支化聚芳醚砜中的支化结构可对周围的亲水磺酸基团起支撑作用,促使其发生团聚而形成连续的质子通道。     

A mucoadhesive polymer prepared by template polymerization of acrylic acid in the presence of poly(ethylene glycol) macromer

A new mucoadhesive polymer complex was prepared by the template polymerization of acrylic acid with poly(ethylene glycol) macromer (PEGM) as a template polymer. Fourier transform infrared results showed that the poly(acrylic acid) (PAA)/PEGM mucoadhesive polymer complex was formed by hydrogen bonding between the carboxyl groups of PAA and the ether groups of PEGM. The glass‐transition temperature of the PAA/PEGM mucoadhesive polymer complexes was shifted to a lower temperature as the repeating unit ratio of PAA/PEGM in the complex decreased. The dissolution rate of the PAA/PEGM mucoadhesive polymer complex was much slower than that of the PAA/poly(ethylene glycol) (PEG) mucoadhesive polymer complex and was dependent on the pH and molecular weight of PEGM. The mucoadhesive force of the PAA/PEGM mucoadhesive polymer complexes was stronger than that of commercial Carbopol 971P NF and almost the same as that of the PAA/PEG mucoadhesive polymer complex. The PAA/PEGM interpolymer complex seemed to be a better mucoadhesive polymer matrix than the PAA/PEG interpolymer complex. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1904–1910, 2002