Synthesis and some properties of carbazole modified polyvinylchloride and the cation exchange resin therefrom

The chlorine displacement reaction between PVC and N-methylcarbazole-3,6-diamine affords a condensate which is insoluble in all possible solvents of PVC. The overall thermal stability of this condensate is appreciably higher than that of PVC. The dielectric behavior is also significantly different from that of unmodified PVC. Sulfonation of the PVC-carbazole condensate affords a cation-exchange resin with ? SO₃H and ? COOH functional moieties.     

Inhibition of steel corrosion by potentiodynamic deposition of poly(N-methyl carbazole)

Poly(N-methyl carbazole) (PNMeCz) coating was deposited on 304 type stainless steel (SS) by electropolymerization of N-methyl carbazole monomer in tetrabutylammonium perchlorate containing acetonitrile solution using cyclic voltammetry. PNMeCz coating was characterized by attenuated total reflectance-Fourier transform infrared spectroscopy, scanning electron microscopy, thickness, conductivity, and contact angle measurements. Corrosion performance of the polymer-coated steel electrodes was investigated in 1 M H₂SO₄ solution using open circuit potential–time (E_ocp–t) curves, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques. PNMeCz coating was found to provide anodic protection to the substrate and significantly reduce the corrosion rate of SS in acidic medium.     

The mechanical properties of some filled polymer cements

The tensile and compressive strengths and the elastic moduli of sand and asbestos filled polymer cements, based on the aluminosilicate/poly(acrylic acid) (ASPA) system, have been measured. A progressive decline in property with increasing volume fraction of filler (in the range 5 to 12%) was observed. The decline is interpreted in terms of dilution, lack of matrix-filler interaction and void content.     

Synthesis and polymerization of amphiphilic itaconate monomer and some properties of the polymer

A β-2-methoxyethyl α-3-[tris(trimethylsiloxy)silyl]propyl itaconate (1) was synthesized successfully as a novel amphiphilic itaconate monomer, and its radical homopolymerization and copolymerization with styrene (St) were investigated. The polymerization rate (Rp) is expressed with Rp = k[1]^2.73[AIBN]^0.51. Overall activation energy in the radical homopolymerization was determined to be 52.9 kJ/mol. The 1 copolymerized with St in bulk in a highly alternating tendency. The Q, e values of the 1 were obtained to be 1.05 and 0.69, respectively, and the 1 was found to be a conjugative and electron-accepting monomer. Membranes containing the 1 unit, prepared by the copolymerization of 1 with N-vinylpyrrolidone (NVP) and by the terpolymerization of 1, NVP, and 2-hydroxyethyl methacrylate, showed higher oxygen permeability than corresponding ones without the 1 unit, and also they have better transparency than membranes containing 3-[tris(trimethylsiloxy)silyl]propyl methacrylate unit.     

Preparation and properties of some wood/(co)polymer composites

Beech and spruce samples which were impregnated with acrylonitrile (AN), methyl methacrylate (MMA), allyl glycidyl ether (AGE), AGE + AN, AGE + MMA monomers and monomer mixtures were subjected to (co)polymerization by gamma radiation. The dimensional stabilization and resistance against biodegradation of wood/(co)polymer composites was investigated. The water uptake capacities of wood/(co)polymer composites were observed to decrease by more than 70% as compared to untreated samples. There were no noticeable changes in the structure of the wood/(co)polymer composites after treatment with artifical acid rain. It was found that the wood/(co)polymer composites were stable against the biological attacks of microorganisms like mould and bacteria.     

Synthesis and properties of helical polyacetylenes containing carbazole

Novel acetylene monomers containing carbazole with chiral menthyl and bornyl groups, 9-(1R,2S,5R)-menthyloxycarbonyl-2-ethynylcarbazole (1), 9-(1S,2R,5S)-menthyloxycarbonyl-2-ethynylcarbazole (2), 9-(1R,2S,5R)-menthyloxycarbonyl-3-ethynylcarbazole (3) and 9-(1S)-bornyloxycarbonyl-2-ethynylcarbazole (4) were synthesized and polymerized with a Rh catalyst to give the corresponding polymers [poly(1)-poly(4)] with moderate M_n value of (11.5-92.2) × 10³ in good yields (77-89%). CD spectroscopic studies revealed that poly(1), poly(2) and poly(4) took predominantly one-handed helical structure in CHCl₃, THF, toluene, and CH₂Cl₂, while poly(3) did not. Addition of methanol to CHCl₃ solutions of poly(1) and poly(2) resulted in the formation of aggregates showing smaller CD signals at 275 and 320 nm. The helical structure of poly(1) and poly(2) was very stable against heating. The polymers emitted fluorescence in 0.40-2.90% quantum yields. Poly(4) exhibited an obvious oxidation peak at 1.10 V. The polymers were thermally stable below 300 °C.     

Dynamic mechanical properties of some polyurethane-acrylic copolymer interpenetrating polymer networks

Dynamic mechanical properties have been investigated for interpenetrating-network systems based on polyol-cured polyurethanes (PU) and 2 to 1 n-butyl acrylate-n-butyl methacrylate (Ac) networks. The systems were formed simultaneously (SIN) from all of the precursors and reactants for both networks in the same vessel, and sequentially (SIPN) by swelling a precured PU with the reactants that will form the Ac network. If the Ac network is formed after gelation of the PU, the IPNs are transparent and appear to have single T (tan δ_max) between those of the homonetworks; visible-phase separation occurs if the Ac is intentionally polymerized prior to PU gelation. Damping curves were lower and broader and the T (tan δ_max) and rubber moduli were higher for the SIN than for the SIPN systems. Up to 65 percent Ac, the T (tan δ_max) data for both SIN and SIPN fit the Gordon-Taylor equation if a T (tan δ_max) for the Ac homonetwork 7°C higher than observed is used, suggesting a higher crosslink density for the Ac network under these conditions. The differences in properties of the SIN and SIPN are assumed to be dependent on sample homogeneity and upon the presence of a tin catalyst in the SIN preparation. This can result in limited Ac-network formation and consequent phase separation before PU gelation has occurred, and the catalyst may also increase the extent of interaction, such as grafting or hydrogen-bond formation between the networks.     

Synthesis and luminescent properties of perylene bisimide-cored dendrimers with carbazole surface groups

A group of perylene bisimide (PBI) cored dendrimers were designed and synthesized. The polyphenylene dendrons containing carbazole functional groups at periphery were attached to the PBI core with expectation to control the intermolecular interaction and to tune the charge transporting ability of dendrimers. Their photophysical, electrochemical and thermal properties were investigated. The spectral data showed that energy transfer and photoinduced charge transfer coexist between the carbazole peripheries and the PBI core, competing to influence the luminescent properties of these dendrimers. The red OLEDs were fabricated with these dendrimers as non-doped emitting layer by solution method. The dendrimers bearing carbazoles exhibited improved EL performance than those model compounds. The improved charge balance state caused by these carbazole units is suggested to be responsible for the EL performance.     

咔唑加氢性能研究

咔唑是一种含氮的芳香杂环化合物,文中以Raney-Ni为催化剂,对咔唑的加氢储氢性能进行了研究。实验发现溶剂、温度、压力及催化剂用量等条件的改变均对咔唑的吸氢过程产生影响。溶剂十氢萘的加入有利于咔唑加氢反应进行;在443—563 K咔唑的加氢量随着温度的上升呈现先增加后减小的趋势,并在523 K达到最大值;在3MPa—6 MPa咔唑的加氢量随压力的增大而增大;催化剂用量的增加在低用量范围内明显影响咔唑的吸氢量,在高用量范围内对咔唑吸氢量的影响不大。在咔唑/十氢萘质量比为1/5.9,523 K,5 MPa和催化剂用量为0.5 g的条件下,咔唑的加氢量达到较佳值0.27 mol。GC-MS分析结果表明:咔唑的加氢产物以四氢咔唑、十二氢咔唑为主,此外还含有少量的六氢咔唑及八氢咔唑。     

A novel,conjugated polymer containing fluorene,pyridine and unsymmetric carbazole moieties: Synthesis,protonation and electrochemical properties

An optically active, conjugated polymer bearing unsymmetric pendant carbazole chromophores was prepared via the Suzuki coupling of 9,9-dioctylfluorene-2,7-diboronic acid and a novel pyridine-containing compound. The polymer had a T_g of 192 °C and T_d10 at 437 °C under a nitrogen atmosphere and exhibited absorption bands at 320–400 nm and displayed an additional absorption bands at 380–480 nm after protonation with aq. HCl solution. The photoluminescence of the polymer shifted from 360–460 nm to 460–560 nm after protonation and the photoluminescence quantum yield of the polymer in THF solution was 0.88. The emission color of the polymer film changed from blue (439 nm) to yellow (551 nm) under an applied bias voltage of 2.5 V.     

Synthesis and blue luminescence of a soluble newly designed carbazole main-chain polymer

A new electroactive polymer with alternating conjugated-nonconjugated repeating units in the main chain was synthesized by step growth polymerization of α,ω-bis(N-carbazolyl)octane in chloroform solution with excess of iron trichloride, and in the presence of N-ethylcarbazole as a terminating agent. The resulting α,ω-N-ethylcarbazole terminated poly(3,3′-bicarbazyl-N,N′-octylene)s are readily soluble in common organic solvents and have good film-forming capabilities, partly because of the special design of the polymer backbone constituted by stiff bicarbazyl chromophores linked by flexible eight-carbon segments. Soluble materials with molecular weights up to 105 g/mol and polydispersity indices around 3.3 were obtained. Purified samples exhibiting quite low polydispersity indices (in the range 1.5-1.7) can be prepared by a selective fractionation of the crude polymer from benzene/methanol mixtures. Structural analysis of these new ‘stairs-like’ polymers disclosed their well-defined character with an aromatic linkage exclusively at position 3 on the carbazole moieties. Electrochemical studies of polymer films exhibited two reversible redox processes between 0 and 1.5 V vs saturated calomel electrode. The photoluminescence (PL) of the polymer in solution and as cast films revealed an intense blue emission and the same intensity level than that of the N,N′-diethyl-3,3′-bicarbazyl molecule, taken as a model of the aromatic segment of the repeating unit. Such a processable and purifiable polymer with bicarbazyl-isolated fluorophores is quite promising for the fabrication of efficient blue light-emitting devices.     

Synthesis and electrochromic performance of a novel polymer based on an oxidative polymer derived from carbazole and thiophene

A polymer derived from poly-9-bis[4-(thiophen-3,4-yloxy)biphenyl)]-9H-carbazole containing a carbazole and thiophene group, abbreviated as B2, was synthesized via the oxidation method by using FeCl₃ as an oxidant. Additionally, the electrochemical polymer of B2 was synthesized and coated onto an ITO–glass surface via electrochemical oxidative polymerization. The electrochemical synthesis of the polymer was performed in 0.05 M AN/LiClO₄ solvent/electrolyte solution containing 0.1 M concentration of B2 between +0.3 and +1.4 V potentials. The compounds were characterized by FT-IR, NMR, and elemental analysis techniques. The spectroelectrochemical and electrochromic properties of this polymer were also investigated in 0.05 M AN/LiClO₄ solvent/electrolyte solution for 200 s and at a constant potential of +1.4 V. Switching ability of this polymer was measured as the percent transmittance (?T%) at its changing point of maximum contrast. Additionally, the scan rate study was performed at different scan rates: 400, 300, 200, 100, 50, 20 mV/s. According to the electrochromic measurements, the synthesized polymer had a light blue color when it was oxidized, and when it was reduced, it had a transparent color. As a result, the synthesized polymer P(B2) can be used to produce new polymeric electrochromic devices, and it can be considered a good candidate for applications of electrochromic devices (ECDs) because of its short response time of 3.5 s.     

Plasma modification of cellulose fibers: Effects on some polymer composite properties

Cellulose fibers have been surface-modified by selected cold, microwave plasma treatments. Inverse gas chromatographic (IGC), XPS, and SEM analyses showed surface treatment to be incomplete, but, nevertheless, effective in controllably altering the acid/base interaction balance of fiber surfaces. Surface-modified fibers were used in composites with polystyrene (PS), chlorinated polyethylene (CPE), and polypropylene (PP) as, respectively, basic, acidic, and neutral matrices. Favorable acid/base interactions led to enhanced mechanical properties and increased glass transition temperatures of composites. Acid/base interaction appears to be an important, though not the sole consideration, in the design of superior systems using cellulose fibers as reinforcing agents. As expected, in the case of PP composites, acid/base considerations proved to be irrelevant. © 1994 John Wiley & Sons, Inc.     

The influence of a high polymer on some properties of fused-quartz slips and castings

Conclusions A water-soluble polymer added to quartz glass slip in the proportion of 0.02% (on the solid phase) increases the viscosity of the slip by a factor of three to four without changing the rheological behavior of the slip. The polymer produces a significant increase in the kinetic stability of slips of low apparent density.The loose packing of the solid phase in a system stabilized with a polymer helps to accelerate the building-up of the casting.Slips stabilized with a high polymer can be recommended for the production of castings of porosity 17–27%.Translated from Ogneupory, No. 5, pp. 50–52, May, 1976.     

一种新型不对称咔唑衍生物的合成和光电性能

通过Ullmann偶联和Suzuki偶联等反应合成了一种新型不对称咔唑衍生物9-苯基-3-[4-(9H-9-咔唑基)苯基]-9H-咔唑,其结构经1HNMR、13CNMR和FT-IR分析表征。利用紫外-可见吸收光谱、荧光光谱和循环伏安法对其光电性能进行了研究,研究结果表明,该化合物的最高占有轨道(HOMO)和最低空轨道(LUMO)能级分别为5.69和2.21 eV,具有良好的空穴传输性能。     

Studies of nylon 6/PET polymer blends: Structure and some physical properties

The structure, morphology, and some physical properties of nylon 6/polyethylene terephthalate (PET) blends (PET varying from 10 to 50%) have been reported here. Various techniques such as SEM, X-ray diffraction, birefringence, density, DTA, and DSC have been used. SEM studies revealed that in the blend PET is dispersed as spheres in the nylon 6 matrix. On melt spinning these are elongated in the form of rods and a fibril matrix-type morphology is developed. PET reinforces the (202, 002) lattice planes of nylon 6 up to a certain composition, resulting in increased crystallinity. Both nylon 6 and PET aid each other in mutual nucleation. The highly oriented and extended PET chains hold the nylon 6 molecular chains along their length resulting in increased orientation of the blend fiber system. All these studies further revealed that the improvement in some of the observed properties is due to the fibril-reinforced morphology and the crystallization behavior of the two components, especially that of nylon 6 in the presence of PET.     

Polycondensation of squaric acid with N-alkylcarbazoles

Summary 1,2-Dihydroxycyclobutene-3,4-dione (squaric acid) was polycondensed with N-ethyl- and N-(1-butyl)carbazole in polyphosphoric acid to give polymers having 36–43% of 1,2-oriented squarate units. The polymers are insoluble in organic solvents or sulfuric acid. Condensation of 1,2-dichlorocyclobutene-3,4-dione (squaryl dichloride) with N-1-butyl-carbazole in nitrobenzene gave 100% of 1,2-oriented squarate units. This polymer is soluble in most organic solvents, and the molecular weight (¯Mw) is 1900 (DP=6). The electrical conductivity was low, <10^–9 (ohm cm)^–1, and did not increase on treatment with iodine.     

Polycondensation of bismaleimides with aromatic diamines

Summary The polycondensation (Michael addition) of a bismaleimide (BMI, N,N-4,4-[(1-methylethylidene) bis (phenyleneoxyphenylene)] bismaleimide) with an aromatic diamine (DA, 4,4-[1,3 phenylene bis (1-methylethylidene)] bisaniline), in a 1:1 molar ratio, was followed using SEC and FTIR techniques. The polycondensation followed a 2nd-order kinetics with an activation energy, E=51 kJ mol^–1. The mass fraction of dimer varied with conversion following the statistical prediction for an ideal A₂+B₂ polycondensation. At 60% conversion, gelation was observed. This was ascribed to a small advance in the BMI homopolymerization. Thermal degradation took place at T>200 °C. The first step was, possibly, a reversal in the Michael addition reaction as revealed by the decrease in the concentration of CH₂ groups observed in FTIR spectra.This paper is dedicated to Prof. Eloisa B. Mano (IMA, UFRJ, Brazil) for her pioneering work in the development of the polymer field in Latin America.     

Polycondensation of structurally divergent tetraamine monomers with dicarboxylic acids to synthesize polybenzimidazole copolymers for polymer electrolyte membranes

In our effort to promote 2,6‐bis(3,4‐diaminophenyl)‐4‐phenylpyridine (Py‐TAB) as an alternative tetraamine monomer to conventionally used 3,3′,4,4′‐tetraaminobiphenyl (TAB) for synthesizing readily processable pyridine bridged polybenzimidazoles (Py‐PBIs), two series of random copolymers (PBI‐co‐Py‐PBI) were synthesized by polymerizing Py‐TAB and TAB with isophthalic acid or terephthalic acid to produce meta (mPBI‐co‐mPy‐PBI) and para (pPBI‐co‐pPy‐PBI) connected copolymers, respectively. For the first time in the PBI literature, copolymers were synthesized by varying the relative compositions of tetraamines (TAB and Py‐TAB) in the polymerization feed with a single dicarboxylic acid (DCA) instead of the traditionally used method where two DCAs with variable compositions were polymerized with a single tetraamine. The solubility and hence the processability of the copolymers were improved significantly upon introduction of Py‐PBI in the copolymer. The detailed characterizations of both meta and para series copolymers compellingly established that thermal, chemical and mechanical stabilities can be easily modulated according to need by altering the relative compositions of PBI and Py‐PBI. The phosphoric acid (PA) loading of the copolymers increased gradually with increasing Py‐PBI content since the bulky pyridine moiety facilitated the absorption of PA. The presence of pyridine functionality and a larger PA loading caused a higher proton conductivity of PA doped copolymer membranes. © 2014 Society of Chemical Industry