最新刊期
卷 ， 期 6 ， 2007
- 摘要：A multifunctional macromolecule poly(N-isopropylacrylamide-co-methylacrylate-co-hydrazide)(PNMH) was prepared and used to cross-link oxidized sodium alginate (OSA) to form biodegradable and thermosensitive gels.Thermo-sensitivity and degradable properties of the gels were evaluated by measuring the transmittance at different temperatures and the time dependence of the swelling ratio in phosphate buffered saline,respectively.FTIR and LCRS were applied to characterize the samples.It is showed that gels are cross-linked by the forming of CN bonds.The macromolecule PNMH shows thermo-sensitivity.With increasing PNMH content,the thermo-sensitivity of gels is improved,and degradation time of gels becomes longer.In addition,the PNMH content has great effect on the temperation dependence of swelling and degradation of hydroels.
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发布时间：2021-03-19 - 摘要：The monodisperse submicron-size polystyrene(PSt) microspheres were prepared by emulsifier-free emulsion polymerization of styrene (St) using potassium persulfate (KPS) as initiator in ethanol-water mixed solvents.The effects of the concentration of KPS and St,polymerization temperature and the composition of the solvent on the size and morphology of PSt microspheres were investigated by scanning electron microscopy (SEM).The results indicate that the above factors evidently affect the diameter of the microspheres.The petal-like composite polymer particles were produced by emulsifier-free seeded emulsion polymerization in the presence of PSt seeds,styrene and acrylonitrile (AN) monomers using poly (ethylene glycol) (PEG) which has a methacryloyl group in the polymer end as reaction stabilizer.Such nonspherical shapes were controllable by change the ratio of St to AN.Such a surface morphology may provide a valuable information to elucidate the formation mechanism of the petal-like particles prepared by emulsifier-free seeded emulsion polymerization in the presence of PEG macromonomers.The result ulteriorly proved the formation mechanism of the unusual morphology for dispersion copolymerization system.
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发布时间：2021-03-19 - 摘要：Inverse gas chromatography (IGC) is a new characterizing method for surface properties in polymer field.The main difference between GC and IGC is that the interested species is the polymer material acting as the stationary phase in IGC column.Probe solvents with known properties are injected in column.For the interactions between probe solvents and polymer stationary phase are different,the surface properties of polymer can be determined from the retention volume of probe solvents.In this work,surface properties of soluble polyimide HQDPA-DMMDA were quantitatively analyzed by the IGC method.Four n-alkanes (C6,C7,C8 and C9) were chosen as non-polar probes to characterize the dispersive component of free energy.Trichloromethane (CHCl3),ethyl ether and acetone were chosen as polar probes to detect the Lewis acid-base parameters.It was found the dispersive component of free energy of HQDPA-DMMDA was 34.37 mJ/m2,31.80 mJ/m2,29.50 mJ/m2 and 27.64 mJ/m2 at 50℃,60℃,70℃ and 80℃,respectively.The surface free energy decreased linearly with increasing temperature.The Lewis acidic number Ka of HQDPA-DMMDA was 0.4115,and basic number Kb was 0.5812.The result meant that HQDPA-DMMDA was a weak Lewis amphoteric polymer.
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发布时间：2021-03-19 - 摘要：The poly(styrene-co-acrylonitrile) supported palladium catalyst bearing a nano-fibrous morphology was prepared via electrospinning technique,and the catalyst was characterized by IR,SEM,TEM and XPS.The nano-fiber supported catalyst has high activity and good recycling property for hydrogenation of α-olefin at room temperature under 101.3 Pa.hydrogen pressure.In addition,it was found that the hydrogenation reaction of α-hexene was accompanied with the isomerization reaction.The experimental results show that the yield of the α-hexene to hexane catalyzed by the nano-fiber supported palladium catalyst was 4.7 times higher than that of PdCl2/γ-Al2O3 catalyst.The hydrogenation of α-tetradecylene,cyclohexene,nitrobenzol and styrene by the nano-fiber supported palladium catalyst was also studied,the selectivity to primary products of the hydrogenation of cyclohexene,nitrobenzol and styrene was 100%.
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发布时间：2021-03-19 - 摘要：A series of new polyimide oligomers and resins terminated with 4-phenylethynylaniline were synthesized using 4,4′-oxydiphthalic anhydride (ODPA),3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA),3,4′-oxydianiline (3,4′-ODA),and 1,4-bis(4-amino-2-trifluoromethylphenoxy) benzene (BTPB).The phenylethynyl terminated polyimide oligomers and resins were evaluated by their chemical structure,thermal properties and rheological properties.Experimental results showed that all these oligomers were crystal line.The PETI oligomers based on ODPA dianhydride exhibited lower melt viscosity and low-viscosity temperature range,which made PETI oligomers have more wide process window.After cured at 371℃ for 1 h,all PETI resins showed good thermal stability,and PETI resins based on BPDA have high glass transition temperatures.The diamine composition of BTPB and 3,4′-ODA has effect on both melt viscosity and thermal stability of oligomers and resins,especially on the melt viscosity of PETI oligomers based on BPDA.In addition,the thermal cure reaction of 4-phenylethynylaniline terminated oligomers occurred obviously at about 300℃.
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发布时间：2021-03-19 - 摘要：Film morphology and orientation of poly(dimethylsiloxane-co-methoxydodecylsiloxane) (DDPS) on different cellulose models,such as natural cotton fiber and the regenerated cellulose substrates,were investigated and studied by atomic force microscope (AFM),field emission scanning electronic microscope (FESEM),X-ray photoelectron spectroscope (XPS) and other instruments.Experimental results showed that DDPS formed hydrophobic,macroscopic smooth but actually microscopic inhomogeneous structural films on these cellulose model substrates.The hydrophobic property and characteristic AFM morphology demonstrated that DDPS molecules took such an orientation in forming films on cellulose models so that the Si—CH3 and Si—C12H25 groups pointed outward to the film surface,while the dipolar Si—O bonds pointed to the interface with the cellulose model substrates.
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发布时间：2021-03-19 - 摘要：Three N-propargylamide monomers with different pendent groups were synthesized and characterized with NMR,IR and elemental analysis techniques.These monomers were polymerized with Rh-catalyst in high yields (nearly 100%),and the obtained polymers demonstrated high steroregularity.The secondary structures of the resulting polymers were examined by UV-Vis spectroscopy.The different pendent groups in the polymers' side chains placed different effects on the stability of the helices adopted by the corresponding polymers.It was concluded that the pendent groups affected largely both the formation of intramolecualr hydrogen bonds between the neighboring amide groups and the rigidity of the polymer main chains.These two factors are exceptionally important for poly(N-paropargylamides) to take the configuration of stable helices.
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发布时间：2021-03-19 - 摘要：Polyaniline films on Ti-based metal substrates with granular,fibrillar and tube-slice surface morphology were prepared in a 0.2 mol·L-1 aniline solution in 0.5 mol·L-1 sulfuric acid by using the cyclic voltammetry method with scanning valtages in the range of -0.1 V～0.9 V at a scanning rate of 50 mV·s-1.The electrochemical properties and structure of polyaniline film electrodes were characterized by SEM,cyclic voltammetry(CV) and electrochemical impedance spectra (EIS).The result show that the different surface morphology of polyaniline films has different nucleation and growth mechanism,and polyaniline on Ti-based metal has prodigious surface area and good electrical conductivity.The tube-slice polyaniline has the least film impedance and the best electrical conductivity.
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发布时间：2021-03-19 - 摘要：Based on molecule designing,poly(2,5-dioctyloxy-p-phenylene vinylene)-Br(PPV-Br) oligomer with bromine(Br) as end group had been successfully synthesized for the first time.Using the PPV-Br oligomer as a macroinitiator to initiate the polymerization of methyl methacrylate(MMA),a novel well-defined PPV-b-PMMA rod-coil diblock polymer,which consist of PPV oligomer as its rod block and PMMA as its coil block,respectively,had been successfully prepared by ATRP.It had been confirmed by the measurements of FTIR,UV-Vis,1H-NMR and gel permeation chromatography(GPC),the structure of the synthesized PPV-b-PMMA diblock polymer and the PPV oligomers with various end active groups such as CHO,OH and Br,were well consisted with the structure predicted by the molecule designing.A 96.2% substitution degree of CHO by OH was determined from the integral height of CHO proton peak at δ 10.45 and that of CH2OH proton peak at 4.69 in the 1H-NMR spectra of PPV-CHO and PPV-CH2OH,respectively,while those of the other active functional groups were determined from the of the corresponding characteristic proton peaks.The polydispersity indices(PDI) of PPV macroinitiator and PPV-b-PMMA diblock polymer were 1.3 and 1.2,respectively according to the measurement of GPC.Upon drop casting a 0.2 wt% CS2 solution of PPV-b-PMMA diblock polymer onto a glass slide when the temperatrue was 22℃,the relative humidy was 85%,a moisture argon stream was floweed through the sample at a speed of 0.2 m3/h,a highly ordered hexagonally honeycomb-structured film of the copolymer was obtained,as identified by an optical microscope.The average diameter of the hole is 1.7 μm.
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发布时间：2021-03-19 - 摘要：A series of sodium humate/polyacrylamide/clay (SH-PAM-Clay) hydrogels was synthesized by solution polymerization and crosslinked using acrylamide,sodium humate(SH) and clay Laponite RD as raw materials,potassium persulfate (KPS) as the initiator and N,N′-methylenebisacrylamide (MBA) as the cross-linking agent.The morphology of the hydrogels was characterized by field emission scanning electron microscope (FESEM),and their rheological and water-absorption properties were also examined.Experiments showed that SH/PAM/Clay hydrogels have homogeneous network structures and high water-absorbent properties.Swelling experiments show that the swelling rate decreases with the increase of SH content,and the introduction the hydrophilic clay improves the water absorbency properties of SH/PAM/clay hydrogel systems.Relaxation of polymer chains of the hydrogels controls the swelling process.Rheological experiments show that the elastic response of the hydrogel system is stronger than the viscous response.Chemical cross-link due to chemical cross-linker and physical cross-link due to weak interactions coexist in the hydrogel network.The interactions between SH and polymer chains are very weak,and SH acts as lubricant.While the contents of clay in the hydrogels play an important role in affecting rheological properties of the hydrogel system.The Han plot proves that clay and SH are compatible with PAM,and SH/PAM/clay hydrogels are homogeneous.
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发布时间：2021-03-19 - 摘要：A novel dark brown polyacenaphthene film has been electrodeposited on platinum electrode by direct anodic oxidation of acenaphthene in mixed electrolyte of boron triflouride diethyl etherate (BFEE) and polyethylene glycol oligomers with a molecular weight of 400 (PEG 400).The oxidation potential of acenaphthene in this medium was initiated at approximately 0.95 V versus SCE,which was much lower than that determined in acetonitrile containing 0.1 mol\5L-1 Bu4NBF4 ( 1.38 V versus SCE ).The introduction of PEG 400 improved the solubility of the monomer in the mixed electrolytes.The structure of the polymer was investigated by UV-Vis,FTIR and 1H-NMR.Fluorescent spectral studies indicated that polyacenaphthene film was a blue light emitter both in DMSO solutions and in solid-state.
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发布时间：2021-03-19 - 摘要：The chloromethylation of polystyrene (PS) was performed high effectively in a homogeneous system using self-made 1,4-bis(chloromethoxyl)butane (BCMB)as the chloromethylation reagent and adopting Lewis acid catalysts.The reaction mechanism was investigated,the effects of various factors on the chloromethylation reaction were examined,and the optimum reaction conditions were determined.The chemical structure and composition of the products were characterized with infrared spectrum and Volhard method.The experimental results show that the reaction mechanism consists of two kinds of reactions possibly,electrophilic substitution on benzene ring and nucleophilic substitution accompanying by ether linkage fission.All the used amount of BCMB,the property and used amount of the catalysts,the property and used amount of solvents and temperature influence distinctly the chloromethylation of polystyrene.There are two types of effects of reaction conditions on the chloromethylation of polystyrene,one is the influence on PS chloromethylation degree,and the other is the influence on the remaining linearity for PS.The chloromethylated polystyrene (CMPS) with 80% of chloromethylation degree and complete linearity was obtained under the optimum reaction conditions.
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发布时间：2021-03-19 - 摘要：A series of novel carbazole/aminoalkyl-substituted fluorene based main chain copolymers (poly［3,6-(N-(2-ethylhexyl)carbazole)-(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-4,7-(2,1,3-benzoselenadiazole)］(PCzN-BSeD)) with different contents of 2,1,3-benzoselenadiazole (BSeD) were synthesized by Suzuki coupling reaction.Through a postpolymerization treatment on the terminal amino groups,corresponding quaternized ammonium polyelectrolyte derivatives (poly［3,6-(N-(2-ethylhexyl)carbazole)-(9,9-bis(3′-((N,N-dimethyl)-N-ethylammonium)propyl)-2,7-fluorene)-4,7-(2,1,3-benzoselenadiazole)］ dibromide (PCzNBr-BSeD)) were obtained. It was observed that the efficient energy transfer occured under optical and electrical excitation on the narrow band gap BSeD site for both the neutral and the quaternized copolymers.Devices with poly(3,4-ethylenedioxythiophene)/poly(vinylcarbazole) (PEDOT/PVK) as an anode buffer,the external quantum efficiencies of the copolymer show similar devices performance to those by using poly(3,4-ethylenedioxythiophene) (PEDOT) only.It indicated that introduction of a carbazole segment into polymer main chains offered the enhanced hole-injection and transport properties.It was also found that devices from these polymers with a high work-function metal cathode such as Al showed similar devices performance to that by using the low work-function cathode such as Ba,indicating the excellent electron injection ability of these polymers.
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发布时间：2021-03-19
Research Article
- 摘要：A study of viscoelastic properties of graphite (GP) filled high density polyethylene composites was carried out.The Mooney equation was modified to evaluate the formation and development of agglomerate structure for high filled suspension system.The apparent filler concentration (φ) was substituted by the effective volume fraction,φeff.It is believed that in the case of high filler concentrations the viscoelastic properties of the composites are mainly related with φeff.Here,we define φeff＝fφ,in which f(f≥1) is the experiential factor of effective volume,corresponding to the microstructure with different relaxation time in HDPE/GP system.In the low φ region,the viscoelastic properties of the composites can be described by the original Mooney equation,while the viscoelastic properties of the high loading composites can be described by the modified Mooney equation considering the effective filler volume in the case of ω＝0.1 rad/s,experientially postulate f＝1.55.
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发布时间：2021-03-19 - 摘要：A new initiator for atom transfer radical polymerization (ATRP),(Cl2HCCOO)3-C6H3,(TrDCAP),has been designed and successfully synthesized.ATRP of styrene was carried out by using TrDCAP as hexafunctional initiator and the CuCl/bpy catalyst at 130℃ in 30% THF via core-first strategy.The Arm-6 PS-AAP was synthesized by etherealization of Arm-6 PS and 4-(4′-methoxyphenylazomethine)phenol (AAP).The initiator and the architectures of the Arm-6 PS were confirmed by 1H-NMR,FT-IR,UV-Vis and GPC.
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发布时间：2021-03-19 - 摘要：3-Chloro-2-(chloromethyl)-1-propene (CCMP) was synthesized and used to initiate atom transfer radical polymerization (ATRP) of styrene catalyzed by copper (Ⅰ) chloride/2,2′-bipyridine at 125℃.As a difunctional initiator,CCMP can initiate ATRP of styrene with two living end sites at the same time.The structure of the obtained α,ω-chloropolystyrene was confirmed by 1H-NMR spectra.The living character of the ATRP process is indicated by narrow molecular weight distributions of the obtained polystyrene (Mw/Mn1.5),a linear ln(［M］0/［M］) versus time profile and predictable molecular weights proportional to monomer conversion.
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发布时间：2021-03-19 - 摘要：1,4-Bis-(4-bromobenzoyl)benzene as the monomer has been synthesized and characterized by Friedel-Crafts benzoylation reaction.Novel poly(imino ketone)s (PIKs) as high performance polymers have been obtained by the condensation polymerization of 1,4-bis-(4-bromobenzoyl)benzene and aromatic diamines via palladium-catalyzed aryl amination reaction.The strcture of PIKs is characterized by means of FT-IR and 1H-NMR spectroscopy,and the results show an agreement with the proposed structure.DSC and TG measurements show that PIKs possess high glass transition temperature(Tg＞230℃) and good thermal stability with high decomposition temperatures(TD＞500℃).PIKs also exhibit the excellent solubility,PIK-3 can be dissolved in common organic solvent CHCl3 at room temperature (20℃).
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发布时间：2021-03-19 - 摘要：A new kind of amorphous molecular materials containing azobenzene chromophors has been synthesized.The precursor molecule was prepared by esterification between 1,3,5-benzenetricarbonyl chloride and N-ethyl-N-hydroxyethyl-aniline.The precursor molecule was then reacted with the diazonium salts of 5-aminoisophthalic acid to introduce donor-acceptor azobenzene chromophores at the peripheral groups.The azobenzene amorphous molecular material was characterized by the spectroscopic methods and thermal analysis.The azo compound synthesized can form stable amorphous glass.The amorphous molecular material was used to fabricate surface relief gratings (SRG) by exposing spin-coated thin films of the azo compound to an interference pattern of Ar+ laser beams at modest intensity (120 mW/cm2).The surface modulation was about 390 nm and the first order of diffraction efficiency was up to 23%.
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发布时间：2021-03-19
Research Bulletin
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