A variety of disubstituted (double-comb) polysiloxane polymers have been prepared containing linear, branched, and cyclic oligoethyleneoxide units, –(OCH2CH2)n–, in the side chains and as part of the siloxane backbone. Copolymers, using mixtures of linear ethylene oxide side chains, were also synthesized. These polymers were doped with LiN(SO2CF3)2 (LiTFSI, 1) and conductivities of the polymer-salt complexes were determined as a function of temperature and doping level. The maximum conductivity of these polymers at 25 ° C was 2.99 ×10–4, for a copolymer containing equimolar amounts of side chains with n = 5 and 6. 相似文献
Abstract New poly(azomethine sulfones) with linear structures containing methylene bis(2-oxobenzylidene aniline), methylene bis(4-oxobenzylidene aniline), 1,4-bis(4-oxobenzylidene amino)phenylene and 1,4-bis(2-oxobenzylidene amino)phenylene units were prepared in the conventional literature manner by the reaction of azomethine bisphenols (M 1–4) with 4,4′-sulfonyl bischlorobenzene. The resulting polymers were confirmed by IR, 1H-NMR and elemental analysis, and were characterized by UV measurements, viscosities, solubilities, DSC and thermo-gravimetric analysis (TGA) in air. A difference in the solubility and thermal behavior between the polymers with ortho- and para- chains was observed. The hydrolitic stability of the polymers in 10% wt aqueous sulfuric acid was reasonable 相似文献
Summary: Thermally curable benzoxazine ring‐containing polystyrene macromonomers were synthesized and characterized. 1,4‐Dibromo‐2,5‐bis(bromomethyl)benzene and 1,4‐dibromo‐2‐(bromomethyl)benzene were used as initiators in the atom transfer radical polymerization of styrene. The resulting polymers were used in combination with 3‐aminophenylboronic acid hemisulfate, for a Suzuki coupling. The obtained polymers, with amino groups in the middle or end of the chains, were reacted with formaldehyde and phenol to yield benzoxazine ring‐containing macromonomers. In addition to the glass transition temperature of the polystyrene segment observed at ca. 105 °C, differential scanning calorimetry thermograms exhibit an exotherm at ca. 276 °C corresponding to the oxazine thermal polymerization. Both macromonomers undergo thermal curing with the formation of thermosets having polystyrene segments.
Structure of the benzoxazine‐functionalized polystyrene. 相似文献
Biotinylated polymers with side‐chain aldehydes were prepared for use as multifunctional scaffolds. Two different biotin‐containing chain transfer agents (CTAs) and an aldehyde‐containing monomer, 6‐oxohexyl acrylate (6OHA), are synthesized. Poly(ethylene glycol) methyl ether acrylate (PEGA) and 6OHA are copolymerized by reversible addition‐fragmentation chain transfer (RAFT) polymerization in the presence of the biotinylated CTAs. The resulting polymers are analyzed by GPC and1H NMR spectroscopy. The polymer end groups contained a disulfide bond, which could be readily reduced in solution to remove the biotin. Reactivity of the aldehyde side chains is demonstrated by oxime and hydrazone formation at the polymer side chains, and conjugate formation of fluorescently labeled polymers with streptavidin is investigated by gel electrophoresis.
The incorporation of metallic units into polymer chains has emerged as a promising route towards functional metal‐containing (nano)materials. The resulting polymers possess rich functions derived from their metallic elements, such as redox, optical, catalytic and magnetic properties. In addition, the directional and dynamic nature of metal coordination interactions provides further variables for the exploration of novel materials with designed nanostructures. These types of polymers can be synthesized through direct metal‐ligand coordination or chain polymerization of metal containing monomers. Depending on the polymerization techniques and starting components, the resulting polymers, akin to their organic counterparts, can be produced in the form of insoluble networks, processible chain structures, gels or colloids. Research into this rising multidisciplinary subject has benefited from recent progress in several related areas such as supramolecular chemistry, colloidal chemistry etc., with the combination of the relative merits of each ensuring further developments in each individual discipline. For example, as a result of studies into organometallic block copolymers self‐assembly behavior, living supramolecular polymerization has been unprecedentedly realized for the architectural design of micelles (see image on the right). Nevertheless, the field is still in a developmental stage and offers ample opportunities for fundamental research, as well as material exploration. In this Feature Article, we intend to overview the field with a brief survey of recent literature.
The coordination polymers [CuBr(1, 7‐phen‐κN7)] ( 1a ), [CuI(1, 7‐phen)] ( 2a ) and [(CuI)2(1, 7‐phen‐κN7)] ( 2b ) may be prepared by treatment of the appropriate copper(I) halide with 1, 7‐phenanthroline (1, 7‐phen) in acetonitrile. 1a exhibits staircase CuBr double chains, 2a novel quadruple CuI chains. Their thermal properties were investigated by DTA‐TG and temperature resolved powder X‐ray diffraction. On heating, both 1:1 compounds decompose to 2:1 polymers and then finally to CuBr or CuI. With 4, 7‐phenanthroline (4, 7‐phen), CuBr affords both 1:1 and 2:1 complexes ( 5a , 5b ), CuI 1:1 , 2:1 and 3:1 complexes( 6a , 6b , 6c ) in acetonitrile at 20 °C. 5a and 6a display lamellar coordination networks, with the former containing zigzag CuBr single chains, the latter 4‐membered (CuI)2 rings. A second 2:1 complex [(CuI)2(4, 7‐phen‐μ‐N4, N7)] ( 6b ′) with staircase CuI double chains can be obtained by reacting CuI with 4, 7‐phen in a sealed glass tube at 110 °C. Both 5a and 6a exhibit thermal decomposition pathways of the general type 1:1 → 2:1 → 3:1 → CuX, and novel CuX triple chains are proposed for the isostructural 3:1 polymers 5c and 6c . X‐ray structures are reported for complexes 1a , 2b , [(CuCN)3(CH3CN)(1, 7‐phen‐μ‐N1, N7)] ( 3c· CH3CN), [CuSCN(1, 7‐phen‐κN7)] ( 4a ), 5a , 6a and [CuCN(4, 7‐phen‐μ‐N4, N7)] ( 7a ). 相似文献
The synthesis and characterization of the first supramolecular aggregates incorporating the organometallic cyclo‐P3 ligand complexes [CpRMo(CO)2(η3‐P3)] (CpR=Cp (C5H5; 1a ), Cp* (C5(CH3)5; 1b )) as linking units is described. The reaction of the Cp derivative 1a with AgX (X=CF3SO3, Al{OC(CF3)3}4) yields the one‐dimensional (1D) coordination polymers [Ag{CpMo(CO)2(μ,η3:η1:η1‐P3)}2]n[Al{OC(CF3)3}4]n ( 2 ) and [Ag{CpMo(CO)2(μ,η3:η1:η1‐P3)}3]n[X]n (X=CF3SO3 ( 3a ), Al{OC(CF3)3}4 ( 3b )). The solid‐state structures of these polymers were revealed by X‐ray crystallography and shown to comprise polycationic chains well‐separated from the weakly coordinating anions. If AgCF3SO3 is used, polymer 3a is obtained regardless of reactant stoichiometry whereas in the case of Ag[Al{OC(CF3)3}4], reactant stoichiometry plays a decisive role in determining the structure and composition of the resulting product. Moreover, polymers 3a, b are the first examples of homoleptic silver complexes in which AgI centers are found octahedrally coordinated to six phosphorus atoms. The Cp* derivative 1b reacts with Ag[Al{OC(CF3)3}4] to yield the 1D polymer [Ag{Cp*Mo(CO)2(μ,η3:η2:η1‐P3)}2]n[Al{OC(CF3)3}4]n ( 4 ), the crystal structure of which differs from that of polymer 2 in the coordination mode of the cyclo‐P3 ligands: in 2 , the Ag+ cations are bridged by the cyclo‐P3 ligands in a η1:η1 (edge bridging) fashion whereas in 4 , they are bridged exclusively in a η2:η1 mode (face bridging). Thus, one third of the phosphorus atoms in 2 are not coordinated to silver while in 4 , all phosphorus atoms are engaged in coordination with silver. Comprehensive spectroscopic and analytical measurements revealed that the polymers 2 , 3a , b , and 4 depolymerize extensively upon dissolution and display dynamic behavior in solution, as evidenced in particular by variable temperature 31P NMR spectroscopy. Solid‐state 31P magic angle spinning (MAS) NMR measurements, performed on the polymers 2 , 3b , and 4 , demonstrated that the polymers 2 and 3b also display dynamic behavior in the solid state at room temperature. The X‐ray crystallographic characterisation of 1b is also reported. 相似文献
Molecular simulation techniques have been applied to previously synthesised liquid crystalline polymers containing azobenzene and diphenyl mesogenic groups within the chain. Single chains and amorphous unit cells of aromatic polymers with a degree of polymerisation of 4–16 and containing propylene and diethyletheric (oxydiethylene) spacers were used. The energy was minimised and then molecular dynamics were performed for 1000 ps at seven temperatures between 10 and 600 K. The axial ratio or coefficient of asymmetry was calculated from computer-generated structures. The predictive capability of the orientational order parameter was used to estimate the degree of orientation and the liquid crystalline–isotropic transition temperature of the polymers. The simulated results for the monotropic polymers agreed very well with Maier–Saupe mean field theory and experimental data, though the enantiotropic polymer did not show a good agreement. The predicted glass transition and decomposition temperatures of the simulated polymers are also reported. 相似文献
A series of novel, linear, soluble, high‐molecular‐weight, fluorinated aromatic polymers has been obtained for the first time using a superacid‐catalyzed polyhydroxyalkylation reaction of fluorinated carbonyl‐containing compounds: 1,1,1,‐trifluoroacetone ( 1 ), 2,2,2‐trifluoroacetophenone ( 2 ), 2,3,4,5,6,‐pentafluorobenzaldehyde ( 3 ), and octafluoroacetophenone ( 4 ) with aromatic hydrocarbons such as biphenyl ( a ), phenyl ether ( b ), terphenyl ( c ), and 4,4′‐diphenoxybenzophenone ( d ). These Friedel‐Crafts‐type aromatic electrophilic substitution reactions are performed at room temperature in trifluoromethane sulfonic acid or in its mixtures with dichloromethane. The polymers obtained are soluble in common organic solvents, and colorless transparent films could be cast from the solutions. 1H and 13C NMR analyses of the polymers synthesized reveal their linear, highly regular structure. The polymers also possess high thermostability.
A series of side-chain liquid-crystalline polymers, poly[N-(4-methoxyazobenzene- 4′-oxyalkyl)ethyleneimine](PEnZO), has been synthesised in which the number of methylene units in spacers varies from two to six. The structures of the synthesised monomers and polymers were confirmed by infrared (IR) and 1H nuclear magnetic resonance (1H NMR) spectroscopy. The thermal properties of these polymers have been investigated using differential scanning calorimetry (DSC), polarising optical macroscopic (POM) X-ray diffraction and thermogravimetric analysis (TGA). The test results indicated that the obtained polymers exhibited thermotropic liquid-crystalline mesomorphism of nematic type with schlieren textures. It was observed that the thermal behaviours of the polymers were strongly dependent on the degree of substitution and the length of spacers. Polymers containing less than 57% of mesogenic groups did not exhibit mesogenic phase and resembled amorphous polymer. A more pronounced odd–even effect in the melting points and their enthalpy changes was observed on increasing the spacer length in which the odd members displayed lower values, which were also slightly dependent on the substitution degree of polymers. The mesomorphic temperature ranges of odd members were wider than those of even members. The decomposition temperatures of copolymers were near 230°C. 相似文献
Soluble aromatic and carboxyl- and hydroxyl-containing polyimides, mixed polyimides, and polyquinazolones of various chemical structures, as well as a series of new dicyanoazobenzene chromophores, are synthesized. From 20 to 80 mol % of chromophore groups are incorporated into side chains of the polymers. The thermal, photosensitive, and nonlinear optical properties (second-harmonic generation) of the chromophore-containing polymers are investigated. The polymers with covalently attached groups of the dye DR-13 or azo-derivatives of 4-phthalonitrile demonstrate the highest nonlinearity. The Tg values of the polyimides vary from 165 to 215°C; their temperatures corresponding to 5% weight loss lie in the range 290–350°C; and the measured coefficients of second-harmonic generation, d33, for a number of polarized films based on chromophore-containing polymers attain several tens of picometers per volt. The incorporation of chromophore groups into the side chains of the polymers causes an increase in the photosensitivity of polyimides by an order of magnitude relative to that of the parent polymers (S0.1 = (3?4) × 105 cm2/J in the range of dye absorption). 相似文献
A novel combined main-chain/side-chain liquid-crystalline polymer based on an ethyl cellulose main chain containing azobenzene
mesogens (AzoEC) was successfully synthesized. Molecular characterization of the resulting polymers with different degrees
of substitution (DS) was performed with proton nuclear magnetic resonance (1H NMR), Fourier-transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC). Thermal stability was investigated
by thermogravimetric analysis (TGA). The phase transitions and liquid-crystalline behavior of these polymers were investigated
by differential-scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). The
results indicate that DS has substantial effect on the liquid-crystalline behavior of these polymers. AzoEC with low DS only
shows the cholesteric phase similar to ethyl cellulose (EC). However, when DS increases to a specific value, AzoEC begins
to show fascinating supramolecular structures. The supramolecular structure of AzoEC with maximum DS consisted of a large-scale
ordered lamellar structure formed by EC main chains and a small-scale ordered structure formed by azobenzene mesogens. 相似文献
Diselenide‐containing polymers are facilely synthesized from polymers prepared by atom transfer radical polymerization (ATRP). Benefiting from the ATRP technology, this protocol provides a flexible route for controlling the polymer structure, which allows for a great variety of architectures of selenium‐containing polymer materials for applications in various fields. The oxidative and reductive responsive behavior of the obtained diselenide‐containing polymers is also investigated.