最新刊期
卷 ， 期 5 ， 2012
- 摘要：The synthesis and structural characterization of a series of 2,6-dimethylnaphthalene-based novel heterocyclic poly(aryl ether ketone)s (3a~3d) were studied.These heterocyclic poly(aryl ether ketone)s (3a~3d) were synthesized by the NC coupling polymerization of 1,5-bis-(4'-fluorinebenzoyl)-2,6-dimethylnaphthalene (1) and bisphenol-like monomers (2a~2d).The structure of the polymers was characterized by FTIR and 1H-NMR,the properties of the polymers were investigated by DSC,TGA and GPC,and the solubility and inherent viscosities (inh) were also investigated.The results indicated that the polymers easily dissolved in aprotic polar organic solvents at room temperature,such as chloroform,DMAc,NMP,pyridine, m-cresol and so on,and the chloroform solution of these polymers could be cast into colorless,transparent and flexible fllms.The inherent viscosities (inh) of the polymers were in the range of 0.76~1.40 dL/g.The number average molecular weight (Mn) and polydispersity index (PDI) of polymers 3b~3d were in the range of 78000~104000 and 1.66~2.21,respectively.Moreover,the glass transition temperature (Tg) of the polymers were all above 280℃, and the residual weight were in the range of 53%~69% at 800℃ in nitrogen.The 5% and 10% weight loss temperatures of these polymers were in the range of 423~440℃ and 434~467℃ in nitrogen,respectively.关键词：2,6-Dimethylnaphthalene;Heterocyclic poly(aryl ether ketone)s;Solubility;Thermal properties
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发布时间：2021-03-19 - 摘要：New polymer-supported catalysts were developed by common synthetic polymer poly(vinylidene chloride)(PVDC) grafting with natural cinchona alkalicinchonine. Seven polyvinylidene chloride-bound catalysts were synthesized by cinchonine which activated by p-toluenesulfonyl chloride reacted with polyvinylidene chloridepolyamine resin. And they were tested in the challenging conjugate Michael addition between 1,3-dicarbonyl compounds and N -benzylmaleimide, forming quaternary carbon and tertiary carbon centers. After the investigation of solvent, amount of catalyst and temperature, the optimal catalyst PVDC-tetraethylenepentamine-cinchonine (PVDC-TEPA-CN) obtained good yield (80%), excellent enantioselectivity (72%) and diastereoselectivity (80 ∶20) at the optimized reaction conditions which were toluene medium, 10 mol% catalyst and room temperature. In addition, the catalyst which was applied to six kinds of challenging substrates had a wide scope of substrates, and it can be recovered and reused for at least 3 cycles without loss of its enantioselectivity.关键词：Cinchona alkaloids;PVDC-supported catalyst;Asymmetric Michael reaction;Adjacent quaternary and tertiary stereocenters
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发布时间：2021-03-19
Rapid Communications
- 摘要：High performance and functionality modification is always one of the issues in polymeric materials field.Based on our researches,this paper reviews some new nanoparticles (such as silicate short nanofibers,graphite nanosheets and Mg(OH)2 nano-particles) reinforced rubber nanocomposites involving compounding methods to get good dispersion and interface,as well as structure-property relations,which help to understand the nano-reinforcement of rubbers.Meanwhile,the preparation and functionality of dielectric elastomers and anti-bacteria ultrafine elastomeric fibers are also reported.关键词：Polymer materials;Elastomer;Modification;High performance;Functionality
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发布时间：2021-03-19
Feature Articles
- 摘要：Through pseudo-high dilution technique,the new electrode materials of aqueous dispersed polyaniline nanowires with diameter of 78~90 nm,18~30 nm and 16~25 nm are prepared employing acidic phosphate ester containing one ethylene glycol unit as dopant acid,in which ammonium persulfate,ferric nitrate and ferric chloride are used as oxidant,respectively.Accordingly,electrical conductivities of polyaniline films can reach 18, 32 and 35 S cm-1,and their surface areas are 65, 70 and 82 m2 g-1,respectively.As an eco-friendly active electrode material for supercapacitor,nanofiberous polyaniline can be well dispersed into water.Specific capacitance as high as 110, 140 and 152 F g-1 at discharge rate of 0.4 A g-1 from -1 V to 1 V in 1 mol L-1 tetraethylammonium tetrafluoroborate/propylene carbonate solution is obtained,which is affected strongly by the surface area and electrical conductivity and the values increase with the increasing surface area and conductivity.Polyaniline nanowire provides high discharge/charge efficiency above 98%,indicating that nanofibrous polyaniline possesses good electrochemical reversibility and discharge/charge rate-control capability.关键词：Supercapacitor;Electrode material;Aqueous dispersed polyaniline nanowire
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发布时间：2021-03-19 - 摘要：Thermo-stable anthraquinone chromophores were covalently introduced into high performance polymer poly(arylene ether sulfone) via nucleophilic polycondensation reaction using 4,4'-difluorodiphenyl sulfone,4,4'-biphenol and 1,5-dichloroanthraquinone.The content of anthraquinone chromophores could be well controlled by the feed ratio of anthraquinone monomer,1,5-dichloroanthraquinone.This series of novel poly(arylene ether sulfone) colorants containing 10%,20% and 30% anthraquinone units (PAES-An 10,20 and 30) have high molecular weight and show good solubility in high polar aprotic solvents.FTIR and NMR characterizations confirmed the structures of these obtained polymers.A preliminary study of their spectroscopy characteristics was conducted by UV-Vis method.PAES-An polymers show similar spectroscopy behavior but a little red-shift compared to the anthraquinone monomer due to the change of substituent groups after being introduced to PAES.Thermal properties of PAES-An polymers were investigated by DSC and TGA measurements.The introduction of anthraquinone chromophore can increase the glass transition temperature of PAES for its rigid plane structure.It is worth noting that they all show high thermal stability with degradation temperature above 500℃,much higher than the processing temperature of poly(arylene ether sulfone) polymers.High thermal stability and good compatibility make them show potential use for the dying process of high performance plastic poly(arylene ether sulfone).关键词：Poly(arylene ether sulfone);Nucleophilic polycondensation;Anthraquinone;Polymer dyes
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发布时间：2021-03-19 - 摘要：In order to achieve fabrics with both good warmth retention at low temperature and fine sweat volatility at high temperature,a novel semi-interpenetrating polymer network (semi-IPN) based on polyurethane (PU) and poly(N-isopropylacrylamide) (PNIPAM) was synthesized via the strategy of in situ crosslinking polymerization,and the semi-IPNs were fabricated into microporous membranes by immersion precipitation phase inversion method.The relationship of the morphology and porosity of the membranes with the chemical structure of the semi-IPNs and fabrication parameters of membranes was investigated.The hydrophilicity,swelling properties and water vapor permeability of the membranes at various temperatures were then evaluated and compared.Generally,the water contact angle decreases with the introduction of PNIPAM content in the semi-IPN.Therefore,the PU/PNIPAM semi-IPN membranes have better hydrophilicity than the membranes prepared from pure PU.On the other hand,the surface hydrophilicity of the semi-IPN membranes is inhibited at high temperatures.The temperature-sensitivity was also found in the swelling properties of the semi-IPN membranes.The equilibrium swelling ratio (ESR) of PU membrane increases slightly with temperature.But with the increase of PNIPAM content,the membrane ESR decreases significantly with temperature,revealing the obvious volume contraction of the semi-IPN material at high temperatures,which is endowed by the hydrophilic-hydrophobic transition of PNIPAM with temperature.The pore diameter of the semi-IPN membranes is therefore enlarged.The enlargement could be confirmed by the results in water vapor permeability (WVP).The WVP of PU membrane at 50℃ is about 2 times of that at 25℃,which is caused by the enhancement of vaporization rate and molecular mobility of water vapor.In contrast,the WVP of semi-IPN membranes at 50℃ can reach more than 4 times of that at 25℃.These results prove that by the method proposed in this paper,membranes with fine temperature-sensitivity and high water vapor permeability can be prepared,and such membranes are highly valuable in the applications of intelligent garments.关键词：Material physics and chemistry;Temperature-sensitive membranes;Interpenetrating polymer network;Polyurethane
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发布时间：2021-03-19 - 摘要：A lightweight material based on PVC/TPU blend was studied,which was prepared by incorporation of DCP as cross-linking agent,AC forming agent,hollow glass microsphere and other accessory ingredients via melt blending, and foam materials were prepared via molding method.The effects of the composition ratio of PVC/TPU,DCP content and hollow glass microsphere content on the properties of PVC/TPU lightweight materials were investigated by the density,impact,tensile and flexible test.FTIR analysis showed that groups of materials were changed in modified material.Bubble quality,size and the topology were studied by SEM.Polyester TPU modified the impact and flexible strength,the lowest density was 0.30 g/cm3,as TPU content was 10 phr.With addition of DCP content the lightweight material density declined first and then increased.The results observed by FTIR and gel content test indicated that cross-linking network formed in PVC/TPU lightweight materials.Addition of hollow glass microspheres made the density and mechanical properties of PVC/TPU light material improved obviously,but density was still less than 1.0 g/cm3. SEM showed that the bubbles were intact,hardly be broken and bubble walls were thickened with addition of DCP.Hollow glass microspheres were distributed in the bubble wall,which could cause foam and support more strength.关键词：PVC;TPU;Cross-linking;Foaming
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发布时间：2021-03-19 - 摘要：A new near-infrared(NIR) absorption filter with good optical and mechanical properties was prepared by injection molding method.It was made by NIR-dyes and polycarbonate.This NIR absorption filter can be applied on light apparatus for night vision imaging system (NVIS) compatible lighting.The optical performance of the filter was studied.The filter material offers sufficient transmittance in the visible spectrum along with excellent extinction in the NIR region.The results also showed there was a good linear relationship between its absorbance and NIR-dye dosage.This means that the optical property of the filter can be easily controlled by changing the amount of NIR-dyes.A NIR absorption filter with optimal dye dosage was prepared.The filter has a transmittance not higher than 0.15% in the NIR region in the wavelength range of 660~930 nm; a 16% value of transmittance in the wavelength range of 400~630 nm.The filter is excellent in environmental stability that after being left to stand in the air atmosphere at temperature of 85℃ and exposed to light condition at 1120 W/m2 for 200 h,the filter can maintain its spectral property in the said range.Its bending strength is 107 MPa,shock strength is 54.4 kJ/m2. Therefore the filter can stand strong mechanical impact in the actual application environment.关键词：NVIS compatible;Optical filter;NIR absorption;Injection molding;Polycarbonate
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发布时间：2021-03-19 - 摘要：Silica/poly(methyl methacrylate) grafting composites (SiO2/PMMA) with higher silica content were used as pre-dispersed masterbatches and melt-mixed with PMMA resin to prepare a series of SiO2/PMMA composites with lower silica content.The dispersion evolution of accumulated silica particles during melt-mixing process was monitored by section-TEM.It was found that the effect of grafting states of pre-dispersed masterbatches on the dispersibility of accumulated silica particles was obvious.Non-grafted silica particles were easily agglomerated into sub-micron level aggregation in PMMA melt due to their poor compatibility.Taking silica particles as cross-linking points,three-dimensional cross-linked structure was generally formed in complex grafted pre-dispersed masterbatche, and as a result the accumulated silica particles cant be released and then diffused into the matrix phase.Only the simple grafted pre-dispersed masterbatche can be swelled by the matrix polymer and then be torn by the strong shear field force, in this case the accumulated silica particles can constantly migrated from pre-dispersed masterbatche phase into matrix phase,and finally can be uniformly dispersed in the entire matrix phase at a primary-particles size level.This high silica dispersion was of benefit to improving the composite properties.关键词：Nanosilica particle;Grafting state;Melt-mixing;Dispersibility
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发布时间：2021-03-19 - 摘要：Polymer dispersed liquid crystal (PDLC) films were prepared by photopolymerization induced phase separation (PIPS) with living macro-initiator (MI) of different molecular weights,synthesized by RAFT and iniferter polymerization.The effect of molecular weight of MIs on electro-optical properties of PDLC based on graft polymers was investigated.The effects of molecular weight of MIs on morphologies,transmittance,switching voltage and memory effect of PDLC films were studied in detail.It was found that the decrease in the molecular weight of MIs in the films led to the formation of larger liquid crystal droplets.The threshold voltage decreased from 15.9 V to 4.2 V and the off-state transmittance showed an increase tendency,which could be contributed to the increase of liquid crystal droplet diameter.In addition,the saturation voltage also decreased from 36.5 V to 16.4 V while the memory effect increased because of the decreased interface anchoring strength induced by the lower molecular weight of polymer matrix and weaker entanglement that polymer flexible main chain exerted on liquid crystal molecules.Therefore,the decrease decrease of molecular weight of MIs successfully improved the electro-optical properties of PDLC films based on graft polymers.关键词：RAFT;Iniferter;Macro-initiator;Molecular weight;Polymer dispersed liquid crystal
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发布时间：2021-03-19 - 摘要：SEM,XRD and TGA were used to study the characteristics of fire residues of high-impact polystyrene/arganic montmorillonite (HIPS/OMMT) nanocomposites formed during cone calorimeter tests,including residue cross-section morphology,montmorillonite platelet distribution,thermal stability and pyrolysis characteristics of the residues.The results show that the residue formed after the peak heat release rate (HRR) is composed of a thin and dense skin layer at the surface of the residue and a cellular layer beneath the skin layer.It is the skin-cellular layer structure that makes the residue layer perform a good insulation effect.XRD data and SEM observations show that the intercalated structure in the original nanocomposite is not found in the skin and cellular layers,while randomly distributed montmorillonite platelets aggregate and form a network-like structure.TGA analysis shows that both the skin layer and the cellular layer formed in the half burnt samples are mainly composed of montmorillonite with a certain amount of carbonaceous char,which not only form a protective layer,but also reduce the volatile due to the formation of carbonaceous components.Although the cellular layer is not as good as that of the skin layer in terms of permeability,the cellular layer considerably augments the thickness of the residue.It is the good combination of the skin and cellular layers that reduces the flammability of the nanocomposites.关键词：HIPS;Flame retardance;Nanocomposite;Fire residue structure
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发布时间：2021-03-19 - 摘要：A series of radiopaque polyurethanes used for prosthetic disc nucleus were prepared via polycondensation between polyurethane prepolymer and N,N'-bis(1,3-dihydroxypropyl)-2,3,5,6-tetra iodoterephthalamide (BDTIP),which was synthesized as crosslinker and X-ray contrast agent.The structure of BDTIP was characterized by 1H-NMR.Infrared spectroscopy was used to monitor the reaction degree of BDTIP.The developing effect of modified polyurethane was characterized by X-radiography.Meanwhile,the cytotoxicity was tested by the method of thiazolyl blue tetrazolium bromide (MTT) colorimetric assay using mouse fibroblast,and the mechanical properties of radiopaque polyurethanes with different iodine contents were also studied.The results of 1H-NMR showed that the hydrogen atoms on benzene ring were replaced by iodine completely and expected structure was obtained.Polyether polyurethane structure,demonstrated by FTIR,was also obtained.The X-radiography results showed that polymer had a good radiopacity which is almost equivalent to that of a 2 mm thick aluminum wedge when the iodine content was very small,while the mechanical properties were still excellent.There was nearly no change of compression modulus when the iodine content is low and within half an hour after the compression test the shape of prosthetic disc nucleus were restored to the state before compression,which demonstrated that the addition of BDTIP had little effect on the mechanical properties of prosthetic disc nucleus of polyurethane.The cell proliferation rate (RGR) of all modified polyurethanes was more than 75%,they were all biomaterials without cytotoxicity.This study provides a new modification way for preparing radiopaque polyurethane used for prosthetic disc nucleus.关键词：Polyurethane;Iodine-containing polyol;X-ray radiopacity;Prosthetic disc nucleus
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发布时间：2021-03-19 - 摘要：A novel aromatic diamine containing fluorine and thioether groups,4,4'-bis(4-amino-2- (trifluoromethyl)phenylsulfanyl)diphenyl sulfide (6FSDEA),was synthesized by the condensation and reduction reaction with 1-chloro-4-nitro-2-(trifluoromethyl)benzene and 4,4'-thiobisbenzenethiol as starting material.Then it was polymerized with six various dianhydrides,including BPDA,ODPA,BTDA,6FDA,DSDA and DTDA via one-pot polycondensation to produce a series of novel polyimides.The polyimides are soluble in conventional polar organic solvents,such as NMP,DMF,DMAc, m-cresol,and some of them are even soluble in CDCl3 and acetone.The glass transition temperatures of plyimides were in the range of 197.1~235.1℃ (DMA) and 199.8~231.7℃ (DSC),respectively.Moreover in nitrogen atmosphere the 5% and 10% weight loss temperatures were in the range of 491~535℃ and 517~557℃,respectively.And the char yields at 800℃ were between 30 wt%~63 wt%.In addition,the PI films showed good optical transparency in the visible light region (400~700 nm) with the cutoff wavelengths range of 380~417 nm,and little absorption at the optical communication wavelengths of 1310 nm and 1550 nm.Furthermore,the average refractive indices (nAV) of the polyimide films at 1310 nm and 1550 nm were 1.5401~1.6142 and 1.5389~1.6124 respectively,measured by using a Variable Angle Spectroscopic Ellipsometer.The birefringence (n) of the polyimide films at 632.8 nm were in the range of 0.0012~0.0043 obtained by the prism coupling device.The above results showed that these PIs could be used as candidates for optical waveguide materials.关键词：High transparency;Polyimide;Thioether;Trifluoromethyl;Waveguide
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发布时间：2021-03-19 - 摘要：A novel Pb(Ⅱ) ion-imprinted composite membrane with microporous polypropylene membrane (MPPM) as support was successfully prepared by covalent surface modification and ion-imprinted technology.First,carboxyl groups (COOH) were introduced onto the MPPM surface by UV-induced grafting polymerization of acrylic acid (AA).Subsequently,chitosan (CTS) was immobilized onto the surface of MPPM based on the reaction of carboxyl groups with amino groups (NH2) of CTS.Finally,ion-imprinting was realized by coordination bond effects using Pb(Ⅱ) as template ions and epichlorohydrin (ECH) as crosslinking agents.The preparation process was verified by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS).The morphologies and elemental distribution of the surface and cross-section of membranes were analyzed by scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX).Static water contact angle and pure water flux measurements were also conducted.Results show that the imprinted composite membranes have satisfactory surface hydrophilicity and water flux.When the grafting rate of the Pb(Ⅱ) ion-imprinted polymer reaches 174.4 g/cm2,the water flux is (265958) L/(m2 h).The adsorption affinity and permeation selectivity of the imprinted composite membranes were evaluated by equilibrium binding experiment and competitive permeation experiment,respectively.The imprinted composite membranes show higher adsorption affinity,faster adsorption rate and better permeation selectivity towards Pb(Ⅱ) ions than the non-imprinted counterpart,and the permeation selectivity coefficients relative to Cu(Ⅱ) and Zn(Ⅱ) are 3.43 and 3.93,respectively.关键词：Ion-imprinting;Microporous polypropylene membrane;Chitosan;Selective separation;Pb(Ⅱ)
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发布时间：2021-03-19 - 摘要：The stereospecific polymerization of isoprene (Ip) was carried out with a modified rare-earth catalyst system which consisting of neodymium tricarboxylate (Nd),triisobutyl aluminium (Al),chlorinating agent (CE) and alcohol (OH),in which CE includes chlorinated hydrocarbon (CE1) and chlorinated carboxylic ester (CE2).The effect of chemical structure of OH and CE2,molar ratio of Al/RE on Ip polymerization,molecular weight,molecular weight distribution and microstructure of the resulting polymers was investigated.The kinetic study on the polymerization was conducted via in situ characterization by Fourier transform infrared spectroscopy in combination with a diamond tipped attenuated tota1 reflectance immersion probe (ATR-FTIR) during polymerization.Detailed characterizations including microstructure,molecular weight and its distribution,sequence and heat capacity of PIp have been carried out by FTIR,GPC,NMR and DSC.The results show that polymerization rate was first-order with respect to monomer concentration,and the apparent propagation activation energy (Ea) was determined to be 69.5 kJmol-1 when polymerization temperature was in the range from 0℃ to 30℃.The catalytic activity and content of cis-1,4 configuration of PIp could be improved and molecular weight distribution could be narrowed by introducing a small amount of CE2 and OH.The monomer conversion increased and molecular weight decreased with increasing Al/RE ratios.Polyisoprene with high cis-1,4-content of more than 98% and narrow molecular weight distribution (Mw/Mn= 1.6 ~2.4) could be achieved by adjusting component ratio and polymerization conditions.关键词：Rare earth catalyst;Polyisoprene rubber;Stereospecific polymerization;ATR-FTIR
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发布时间：2021-03-19 -
INFLUENCE OF DEGREE OF FUNCTIONALIZATION ON THE PHOTOINDUCED ORIENTATION OF EPOXY-BASED AZO POLYMERS
摘要：This investigation studied the orientation behavior of one kind of epoxy-based azo polymers (BP-AZ-CA) containing carboxyl as the electron-withdrawing group on the azobenzene unit with different degree of functionalization (DF).The orientation behavior was studied by photoinduced birefringence measurements and polarized infrared spectroscopy.The effect of degree of functionalizaiton on the orientation behavior of azo chromophores and polymer main-chains of BP-AZ-CA were observed.The results show that the orientation rate,relaxation rate and saturated orientation level of BP-AZ-CA are significantly influenced by the degree of functionalization.With the increase of DF of BP-AZ-CA,the orientation rate of both azo chromophores and polymer main-chains decrease.The influence of the DF on the orientation rate of polymer main-chains becomes weak when the DF of BP-AZ-CA is higher than 69%.With the increase of DF of BP-AZ-CA,the relaxation rate of both azo chromophores and polymer main-chains decrease,indicating the increasing molecular interaction has positive impact on the stability of the orientation of BP-AZ-CA induced by exciting polarized laser.The saturated orientation level of azo chromophores and polymer main-chains increases with the DF increase,but the DF has a more significant influence on azo chromophores than on polymer main-chains.The hydrogen-bond strength also plays an important role in enhancing the orientation behavior of BP-AZ-CA,increasing with the increase of DF.关键词：Azo polymer;Epoxy-based;Photoinduced orientation;Polarized FTIR;Degree of Functionalization- 20
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发布时间：2021-03-19
Research Article
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