最新刊期
卷 ， 期 5 ， 2004
- 摘要：The degree of ionization of polyacrylic acid and pure sodium polyacrylate solutions covering a wide concentration range was deteremined by measuring the pH values of these solutions. The results show that the degrees of ionization are very sensitve to the location of the concentration range of polyelectrolyte solutions．The concept of dynamic contact concentration proposed by Qian Renyuan and the principle of division of flexible neutral polymer solutions into four concentration ranges namely extremely dilute,dilute,semidilute and concentrated solutions are confirmed to be universally applicable to polyelectrolyte solutions．
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发布时间：2021-03-19
Rapid Communications
- 摘要：Four derivatives of substituted polythiophenes (Pt) such as poly (3-dodecylthiophene) (Patl2),poly(3,4-didodecylthiophene) (Patl212),poly(3-octoxylthiophene) (Paot8) and poly [3-(dodecyl-co-octoxyl) thiophene](CoPt12-o8) have been synthesized using Fe(Ⅲ) as catalyst．All polymers exhibit excellent solubility in common organic solvents．Molecular weight and chemical structure of each polymer have been characterized by gel permeation chromatography (GPC) and 1H-NMR,respectively．The absorption and emission properties of polymers in chloroform solutions and spin-coating films have been studied．Except the film of Paot8,in the solution and the solid state,the polymers display different color from red to green photoluminescence. The absorption and emission maximum of Pat1212 was blue shifts more than that of Pat12 and absorption and emission maximum of Paot8 was more red shifts than that of Pat12．The band gapdata of four polymers were 2.2 eV,2.6 eV,2.1 eV and 2.1 eV,respectively,estimated from the edge of absorption spectra of spin-coating films．Single layer polymer LEDs(ITO／Polymer／Al) have been fabricated and it was found that the Pat12 emitted strong red light,the Paot8 emitted weaker red-orange light and the Pat1212 also emits weaker yellow light．The emitted wavelength was 670 nm,640 nm and 560 nm,respectively．No EL (electroluminescence) properties of CoPt12-o8 were found in our studies.
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发布时间：2021-03-19 - 摘要：The AB3 type monomer was synthesized by use of succinic anhydride and tri(hydroxymethyl)-aminomethane under the condition of ice-bath．The polymerization was performed at different temperatures,and the analysis techniques FTIR,viscosity and end-grous were used to characterize the products,which have hydroxyl end-groups at the chain extremities．The reaction kinetics was examined to give the reaction rate constant at 130℃,140℃ and 150℃,respectively,and then the activation energy was obtained．The results showed that the synthesis route was practicable without gelation,and the polymerization process was self-catalytic,and the reaction was a third order.
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发布时间：2021-03-19 - 摘要：A novel elastomeric polyurethane／montmorillonite nanocomposite based on poly(propylene glycol),4,4′-diphenylmethane diisocynate and 1,4-butanediol was synthesized by intercalative polymerization technology．Octadecylamine was used as swelling agents to treat Na- montmorillonite and form organomontmorillonite through ion exchange. Nanoscale dispersing of clay in the nanocomposite was analyzed by X-ray diffraction and Molau experiment．At the same time,X-ray diffraction result showed that the intercalated nanocomposites were formed Hydrogen bonding in the hard segments of the synthesized polyurethane／montmorillonite nanocomposite was found to decrease with the increasing amount of montmorillonite,but reached a minimum at 5 wt％ montmorillonite concentration,as was evidenced by FTIR studies．DMA and DSC results showed that the glass transition temperature was reduced with increasing of montmorillonite concentration．Introducing 3％ organomontmorillonite in the composites resulted in a 45％ increase in the tensile strength and a 35％ increase in the elongation as compared to thoee of pure PU．
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发布时间：2021-03-19 - 摘要：Polystyrene single-capped with halogen,PS-X,was synthesized by atom transfer radical polymerization (ATRP) method using ethyl-α-bromopropionate(EPN-Br) as initiator and CuCl／2,2′-bipyridine (bpy) as catalyst and ligand at 110℃．By using PS-X as macroinitiator and CuCl／1,1,4,7,7-penta-methyldiethylenetri-amine (PMDETA) or bpy as catalyst and ligand at 110℃,ATRP of N,N-dimethylacrylamide(DMAA) was realized and functional amphiphilic block copolymers of poly(styrene-block-N,N-dimethylacrylamide) (PS-b-PDMAA) were synthesized. Furthermore,some factors including the molecular weight of macroinitiator,various solvents and ligand that influence the polymerization of DMAA have been studied. The properties of the PS--b-PDMAA copolymer were characterized by using GPC．IR and 1H-NMR analysis．
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发布时间：2021-03-19 - 摘要：Sodium-montmorillonite (Na+ -MMT) was organically modified by cetyltrimethyl-ammonium bromide．Using the organically modified montmorillonite (OMMT),a high impact polystyrene (HIPS)／OMMT composite was prepared by a melt intercalation method．X-ray diffraction patterns revealed that the spacing distances between the layers of the MMT were 1.51 nm for Na+ -MMT,2.18 nm for OMMT and 3.44 nm for HIPS/OMMT(at 5 phr) composite respectively while for the HIPS／Na+ -MMT (at 5 phr) composite the spacing was 1.48 nm,showing that the HIPS chains were intercalated into OMMT by the melt intercalation process．The cone calorimeter was used to assess the flammability of the HIPS／OMMT and the HIPS／Na+ -MMT composites．The results demonstrated that comparing to the pure HIPS the heat release rates (HRR),the mass loss rates (MLR) and the smoke production rates (SPR) for the HIPS／OMMT composites are all reduced dramatically,e. g. peak HRR of the HIPS／OMMT composite with only 5 phr OMMT decreases by 44.8％．In contrast,the properties of HIPS／Na+ -MMT composites changed only slightly except in cases of high loadings．Meanwhile,the HRR of the mixture of HIPS and cetyltrimethyl-ammonium bromide,and the HRR of the mixture of HIPS,cetyltrimethyl-ammonium bromide and Na+ -MMT were also measured and compared. It was found that the ammonium salt alone did not reduce flammability of HIPS significantly．The flame retardant mechanism of the HIPS／OMMT composite was discussed based on the analyses of the cone calorimeter data and the burnt residues. It was concluded that the resulted flame retardancy of the composite was mainly due to the char layer which acted as both a barrier to mass transport of the degraded products and a thermal barrier to the feedback of the combustion heat．The study shows that the HIPS／OMMT composite is a promising environmental friendly flame retardant material.
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发布时间：2021-03-19 - 摘要：3-Allyl -5-chloro substituted salicylaldimine(6) was prepared and then reacted with trans-[NiCl(Ph)-(PPh3)2] to give the salicylaldiminato nickel(II) complex(7) {[O-(3-Allyl)(5-Cl)C6H2-ortho-C(H)=N-2,6-C6H3(i-Pr)2]Ni(Ph3P)(Ph)}. These compounds(6),(7) were characterized well by MS,1H-NMR and element analysis. The complex (7) activated by Ni(COD)2 can catalyze ethylene polymerization effectively. At 8.08×105 Pa pressure,the polymerization activity can reach 6.31×105g PE／(mol Ni·h),the polymer product’s Mη ranged from 1.57×104 to 4.34×104. However,addition of THF,ethyl acetate and ethyl ether,the activity does not decrease evidently．Addition of MMA,the polar monomer is not incorporated into polymer,and the polymerization activity decreases markedly．
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发布时间：2021-03-19 - 摘要：Weakly basic resin ND-900 and modified hypercrosslinked polymeric adsorbent AL-8 were selected to remove 1-amino-2-naphthol-4-sulfonic acid (1,2,4-acid) from aqueous media,and the comparison study on the static adsorption performance and thermodynamics was developed. Both of the tested adsorbents exhibited an endothermic and favorable adsorption process．The Langanuir and Freundlich equations both can give well fits to the adsorption data of 1,2,4-acid on ND-900,while only the latter can be used for AL-8．The negative value of ΔG indicates the spontaneous nature of the adsorption process,and the positive value of ΔS shows the closely relationship to the phenomena of “solvent exchange”,and the positive value of ΔH proves the presence of chemical adsorption．The much larger values of ΔH for ND-900 than those for AL-8 inform the predominant adsorption mechanism：a chemical adsorption for ND-900,whereas a physical one for AL-8．
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发布时间：2021-03-19 - 摘要：The synthesis of six novel poly(schiff-base)s,such as PBTGZ,which is obtained by polycondensation of 2,4-diamino-6-phenyl-s-triazine and 2,2′-diamino-4,4′-bithiazole (DABT) with glyoxal．The polycondensation was processed under acidic condition with the effect of acetic acid．The preparation of two complexes of Fe2+ are described. Their structures were determined by FTIR and 1H-NMR,The values of [η] were obtained at 300℃ by using an Ubbelodhe viscomter with capillary diameter of 0.55 mm. The decomposition temperatures of DAPTPA,DAPIPA and DAPA obtained by thermogravimetic analysis were all above 300℃,indicating good thermal stability．The temperature dependence of magnetization at an applied field 2.39×106 A／m and the applied field dependence of magnetization at 5 K for the Fe2+ complexes were measured by PPMS (physical property measurement system)．The saturation values of magnetization of PBTPZ-Fe2+ and PBTGZ-Fe2+ were 5.4 Am2／kg and 2.6 Am2／kg,and the coercive force of the complexes were 7564 A／m and 75876 A／m,respectively. The “S” shape of magnetic hysteresis loop for PBTPZ-Fe2+ and PBTGZ-Fe2+-and their values of residual magnetization 0.165 Am2／kg and 0.011 Am2／kg indicated they were soft magnets. The existence of benzenes ring enlarges the distance of two adjacent Fe2+ ions,which causes the difference of the magnetic properties of the two complexes．
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发布时间：2021-03-19 - 摘要：Poly(tert-butyl methacrylate) (PBMA) macromononer with one vinyl end group per polymer chain was synthesized by using free radical polymerization in the presence of 2-mercaptethanol and end capping reaction with p-chloromethyl styrene．The PBMA macromonomer was selected as reaction stabilizer to prepare core-shell polymeric microspheres. The PBMA grafted polyacrylamide (PAm-g-PBMA) microspheres were obtained by dispersion copolymerization of acrylamide (Am) with PBMA macromononer using 2,2′-azobis (N,N′-dimethyl-eneisobutyramidine) (VA) as a free radical initiator in the presence of N,N′-bismethyleneacrylamide (Bis-A) as crosslinking agent in the different ethanol／water mixed solvents at 60℃ for 24 h．Also,the poly(methylacrylic acid) graft polyacrylamide (PAm-g-PMAA) microspheres were obtained by hydrolysis of PAm-g-PBMA microspheres in HCl. The monodisperse polymeric microspheres were studied by using transmission electron microscopy (TEM) and laser light scattering (LLS)．It was found that the microspheres have a hydrophilic core and a hydrophobic shell based on the analysis results of X-ray photoelectron spectra. The morphology and diameter of the microspheres can be controlled by changing reaction conditions such as the volume ratio of ethanol to water,the molecular weight of PBMA macromononer,the mole ratio of Am to PBMA macromononer and Bis-A concentration in feed. lt was found that the PAm microspheres can be swollen in water greatly and their size distribution remains narrow.
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发布时间：2021-03-19 - 摘要：By using a three-step introduction of initiator at different time of polymerization,the emulsion copolymerization of methyl methacrylate(MMA),ethyl acrylate(EA) and acrylic acid(AA) was carried out in the absence of emulsifier first at 80℃ for 7.5 h and then at 90℃ for 0.5 h．The distribution of —COOH in the latex was determined by conductometric titration,and effects of ingredients on the distribution of —COOH and the density of surface —COOH(Sd) were investigated. Results showed that N4HCO3 is a key material：with the increase of N4HCO3,the amount of surface —COOH(Sa),water —COOH(Fa) and Sd increased,while the amount and percentage of embedded —COOH(Ea and Ep) decreased．Sa,Fa,Eaand Sd increased whereas Epdecreased with AA increase．It was found that Fa increased and then remain constant,and Sd deceased with the increase of initiator.
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发布时间：2021-03-19 - 摘要：The degradation process of aniline on glassy carbon electrode during polymerization was investigated by electrochemistry and spectrum electrochemistry．Cyclic voltammograms showed four redox peaks within the potential limit of -0.2 to 1.0 V．The cyclic voltammetric curves of the PAn films in H2SO4 aqueous solution with／without containing PAP were compared,and the absorbance of the aniline electrolyte during polymerization was in situ measured by UV-Visible absorption spectrum．The results displayed the existence of PAP,which was the degradation product of the PAn films．The kinetic degradation process of aniline during polymerization was also in situ preliminarily investigated by UV-Visible absorption spectrum．
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发布时间：2021-03-19 - 摘要：The residue-residue contacts contribute more function to the protein folding and play an active role in the stability of proteins．we calculate the number of medium-and long-range contacts for 90 (α/β)8 barrel proteins with considering the distance between the centers of two residues in defining residue-residue contacts．The ability to forming contacts in each (α/β)8 barrel protein was discussed through calculating the number of long- and medium- ranges contacts for different residues in proteins．The relationship between the average numbers of medium-and long-range contacts with Fauchere-Pliska hydrophobicity value (FPH) for 20 amino acid residues was studied,and it was found that the average number of long-range contacts had a linear relation with the Fauchere-Pliska hydrophobicity value (FPH),however,it had not valid for medium-range contacts．The dimension of (α/β)8 barrel proteins has a good relation to the long-range contact of proteins,and the characteristic ratio of mean-square radius of gyration 〈S2〉 can be expressed as 〈S2〉／N=a′+b′×LRO is where LRO is the long-range order,N is the number of residues,and a′=2.32,b′=-0.131．When a protein has a large LRO value,the structure is compact and it has a small dimension value. These investigations can provide some insights into structure of (α/β)8 the barrel proteins．
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发布时间：2021-03-19 - 摘要：The degradation behavior of a novel functionalized biodegradable poly(L-lactide-co-β- malic acid) in pH 7.4 PBS was studied,and mice 3T3 fibroblasts were cultivated on copolymer films to evaluate the cell affinity of copolymers．The variation of weight loss,surface morphology,composition and molecular weight of copolymers were investigated. The results showed that the degradation of poly(L-lactide-co-β-malic acid) was bulk degradation,the malic acid could accelerate the degradation rate,the ester bonds near PMA segments hydrolyzed prior to the ester bonds in PLLA．The cell attachment rate of 3T3 fibroblasts on the surface of PLLA,PLMA96／4,PLMA92／8 and PLMA87／13 was 43％,71％,80％ and 43％,respectively when cultivated for 5 h,the morphology of 3T3 fibroblast was berter on the surface of PLMA96/4 and PLMA92／8 than that on the surface of PLLA and PLMA87／13 when cultivated for 24 h.
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发布时间：2021-03-19 - 摘要：The morphology and mechanical properties of nylon 1212／nylon 6 blends were investigated using a maleated triblock copolymer of styrene-(ethylene-co-butene)-styrene (SEBS) as a compatibilizer．The results showed that when the minor phase was nylon 1212,with the addition of MA-SEBS,the compatibility between the nylon 6 and nylon 1212 was greatly improved,and the size of dispersed particles decreased．TEM showed that “shell-core” structures were formed in this system．MA-SEBS at the interphase between nylon 6 and nylon 1212 played an important role in improvement of compatibilization of these two components．At the fixed ratio of nylon 1212／nylon 6 as 30／70,super-toughness was achieved with 15％ MA-SEBS in weight.
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发布时间：2021-03-19 - 摘要：Polymethylsilane (PMS) is the simplest polysilane；it can be synthesized by Wurtz reductive coupling reaction of methyldichlorosilane in different solvent systems. The FT-IR,UV,1H-NMR,29Si-NMR spectra of PMS indicated that the resulting polymers showed Si—CH2—Si segments formed by the Kumada rearrangement when THF／n-hexane was used as solvent,and the Kumada rearrangement can be avoided by the stabilization effect on the silyl radicals when toluene was used as solvent．End-group of the polymer is changeable,and it is optimal to use Me3SiCl as end-blocking agent at a ratio of Me3SiCl／MeHSiCl2=0.045:1.
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发布时间：2021-03-19 - 摘要：The preparation of titania (TiO2)／polyvinylidene fluoride(PVDF) composite hollow fiber membrane by phase transition process was introduced. The separation property,microstructure,thermal stability and crystalline phase of composite membranes were characterized by rejection experiment,scanning electron microscopy (SEM),thermogravimetric analysis (TGA) and X-ray diffraction (XRD),respectively．The results show that bovine serum albumin(BSA)rejection ratio and breaking stress of the composite membrane are 86.67％ and 4.70 MPa,which are improved greatly compared to those 3.27％ and 3.35 MPa of the pure PVDF membranes．Moreover the pore size and its distribution of the composite membrane characterized by nitrogen isothermal absorption measurement are smaller and narrower than those of the pure PVDF membranes’.
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发布时间：2021-03-19 - 摘要：Linear low-density polyethylene (LLDPE) has been prepared by in situ copolymerization of ethylene with a dual functional catalyst,which was composed of rac-Et(Ind)2ZrCl2 supported on montmorillonite (MMT) and {[(2-ArN=C(Me))2C5H3N]FeCl2}(Ar=2,4-C6H4(Me)2) oligomerization catalyst．A series of LLDPE with different branching degrees were obtained by adjusting the molar ratio of Fe and Zr (Fe／Zr),the molar ratio of Al and (Fe+Zr) (Al／(Fe+Zr)) as well．The kinetics curves of polymerization show that the two catalysts exhibit respective catalytic characterizations,and the activity of copolymerization catalyst is more smoothly after supported on MMT. As increasing the Fe／Zr ratio,the densities of polymers measured by density gradient method and the melting points of polymers obtained from DSC decrease. 13C-NMR shows that the polymers are LLDPE,and their branching degrees increase as the increasing of the Fe／Zr ratio．At the same time,there are some unreacted α-olefins in polymers,which were confirmed by 13C-NMR and GPC．The SEM shows that the polymerization catalyst supported on MMT may produce LLDPE with better morphology than that produced by the catalyst in homogeneous.
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发布时间：2021-03-19 - 摘要：Comb-like biodegradable polylactide-grafted dextran copolymer (Dextran-g-PLA) was synthesized in a bulk lactide polymerization reaction using dextran derivative as macroinitiator and stannous octoate as catalyst．The Dextran-g-PLA copolymers were characterized by 1H-NMR,GPC and intrinsic viscosity measurements,and their molecular architecture was confirmed as PLA segments attached to dextran backbones．Compared to pure PLA,the copolymers showed higher hydrophilicity and faster degradation rate due to the incorporation of hydrophilic glucose units and comb-like structure,which resulted in shortened PLA chain length. This Dextran-g-PLA copolymer was envisioned having good cell affinity and being a good candidate as cell scaffold materials for tissue engineering applications．
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发布时间：2021-03-19 - 摘要：To investigate the changes in structure of cohesional state of poly(lactic acid)s with different chain tacticities,poly(D,L-lactic acid) (PDLLA),a low optical activity poly (L-lactic acid) (l-PLLA) without crystallinity,and poly(L-lactic acid)(PLLA) were physically aged at O℃,25℃ and 37℃ for up to 6 months．Their glass transition behavior after physical aging was monitored by means of modulated temperature DSC(MDSC)．The results showed that the glass transition behavior of PDLLA and l-PLLA is sensitive to physical aging as indicated by the non-reversing thermal enthalpy (ΔHnon) generated in the physically aged samples．The rates of physical aging were higher in the early stage of aging and slowed down after aging for one week. At a given temperature,the Tg’s of PDLLA and l-PLLA shifted to higher temperatures and the ΔHnon increased with increasing aging time．The increasing rates of Tg and ΔHnon were speeded up as aging temperature raised．It was found that good linear relationships between ΔHnon and logarithm of aging time for PDLLA and l-PLLA existed at different aging temperatures．Linear dependences of the changing rates of ΔHnon as functions of reciprocals of aging temperatures were obtained for both PDLLA and l-PLLA,and the absolute value of the slope for l-PLLA was slightly larger than that of the PDLLA,indicating that macromolecular chains with higher tacticity need higher activation energy to form physical entanglements. No obvious glass transition was observed for PLLA whether it was aged or not due to its high degree of crystallinity．
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发布时间：2021-03-19 - 摘要：A silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex was prepared by treatment of poly-γ-chloropropylsiloxane with potassium diphenylarsenide in THF,followed by palladium chloride in acetone,and then the reduction with hydrazine hydrate in ethanol．The X-ray photoelectron spectroscopy(XPS) was used to characterize the palladium complex．It was found that the title complex is an efficient catalyst for the cross coupling reactions of aryl halides with olefins,acetylenes and Grignard reagents．This polymeric palladium (0) complex catalyst is stable and can be reused without noticeable loss of activity．Hence this paper presents a simple and practical method for the synthesis of stilbenes,arylacetylenes and biaryls.
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发布时间：2021-03-19 - 摘要：The copolymerization of acrylamide(AM),sodium 2-acrylamido-2-methyl-propane-sulfonate(NaAMPS) and styrene(St) was carried in microemulsion madium,and tercopolymer AM／NaAMPS／St containing strong anionic group —SO3Na and hydrophobic association group St was synthesized. The structure and composition of the copolymer were characterized by FTIR spectrum,UV spectrum and element analysis．The solution viscosity of the copolymers was determined using an Ubbelohde viscometer,and the intrinsic、riscosities by which molecular weight can be indicated relatively were determined with the method of dilute extensional method．The apparent viscosities of aqueous solutions and brine of the copolymers were measured using a low shear rotational viscometer．The hydrophobically associating property and influence of ionic groups on the hydrophobic association property were investigated. The experimental results are as follows．After incorporating strong anions and hydrophobic groups at the same time in the backbone of polyacrylamide,the viscosity of the copolymer aqueous solution will increase obviously under coordination of electric viscosity of ions and hydrophobic association property of hydrophobic group and the salt resistance of the copolymer will increase evidently under the combining of strengthening hydrophobic association by salt and greater tolerating salt of strong anions. The hydrophobic association property of hydrophobic association group St is weakened and the critical associating concentration of the copolymer is increased due to existing of strong anionic groups in macromolecular chains.
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发布时间：2021-03-19 - 摘要：Amphiphilic graft copolymer polystyrene-graft-nonylphenoxy-poly(ethylene oxide) (PS-g-NPEO 40) has been synthesized by the radical solution copolymerization of macromonomer NPEO-MA with styrene．By the method of coating-evaporating,amphiphilic graft copolymer films were prepared with THF or toluene as solvents on PET matrix．By means of SEM,XPS,ATR and contact angle measurements,effects on the surface morphology,the surface composition and the surface wetting were investigated．The results showed the formation of regular micropores in amphiphilic graft copolymer films under different conditions. With the increasing of NPEO content,the size of micropores increased and the wetting of polymeric film became better．With the increasing of the solution concentration,the diameter of micropores increased,which makes the wetting of polymeric film better. While in toluene,the influence of the solution concentration on surface morphology was weak,but the relationship of contact angle and concentration was opposite to that in THF,i．e．,with the increasing of concentration,the wetting of amphiphilic graft copolymer film became worse. In the same solution concentration,the diameter of micropores of polymeric film in THF was bigger than that in toluene and the hydrophilic composition in THF was less than that in toluene.
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发布时间：2021-03-19 - 摘要：A monomer of tetrachloroterephthaloyl chloride (TCTPC) was prepared by the chlorination of terephthaloyl chloride catalyzed by ferric chloride at 175～180℃ for 10 h,and confirmed by FTIR,MS and elemental analysis. A soluble polychloro substituted poly(aryletherketoneketone) (C-PEKK) was prepared by low temperature solution electrophilic Friedel-Crafts reaction of TCTPC and diphenyl ether (DPE) in 1,2-dichloroethane in the presence of AlCl3 and N-methyl-2-pyrrolidinone (NMP)．Effects of the molar ratio of monomers and the amounts of AlCl3 and NMP on the polycondensatlon were investigated．Some propersites of the polymer was characterized by FT-IR,DSC,TGA and WAXD,etc. The results shown that the glass transition temperature(270℃) of the polymer is higher than that of pure PEEK and PEKK,and the polymer was noncrystalline. The polymer was soluble in common organic solvents such as DMF,DMSO,NMP,CHCl3 and THF at room temperature and showed excellent thermal stability at temperature over 500℃ in air,high char yields of 61％ in nitrogen and 54％ in air at 700℃.
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发布时间：2021-03-19 - 摘要：Poly(4-diazosulfonate styrene-co-4-vinylpyridine) (P(DSS-co-VP)),containing both H-acceptor moieties of pyridine and photosensitive diazosulfonate groups,was synthesized and has been used for self-assembly as a new component．The layer-by-layer deposition between P(DSS-co-VP)and m-methyl phenol formaldehyde resin (MPR) on a substrate via H-bonding interaction was investigated．After UV irradiation the stability of the multiplayer ultra thin film toward polar solvents is improved dramatically. The improvement of the solvent stability of the film should be attributed to the bond conversion between the layers of the film from H-bond to covalent bond under UV irradiation.
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发布时间：2021-03-19 - 摘要：H2PtCl6 was coordinated with the carboxyl-terminated G4.5PAMAM dendrimer molecules (PAMAMC) in aqueous solution,followed by reduction using NaBH4 as reducer,and formed Pt-PAMAMC hybrid nano-particles．The stable multilayer films were obtained by fabricating diazo resin (DR) with these hybrid nanoparticles (Pt-PAMAMC) and PAMAMC,respectively．The films were subsequently irradiated under UV-light．It was found that the films from Pt-PAMAMC as polyanions exhibit stable frictional responses under the applied load,and the lubricative property of the films from Pt-PAMAMC hybrid nanoparticles is obviously superior to that of the films from dendrimer without platinum inside．
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发布时间：2021-03-19
Research Article
- 摘要：On the basis of former reports,C60Cln was used as a novel coupling agent to react with active polymer chains in anionic polymerization of styrene and copolymerization of styrene and isoprene initiated by n-BuLi,respectively. The UV-Vis spectra of coupling products showed that C60Cln was bonded to the polymer chain．The various samples were analyzed by GPC using a refractive index(RI) detector and an ultraviolet(UV) detector set at 340 nm for the absorption of C60 and its derivatives. The results revealed that there is a new peak containing C60 after coupling reaction between C60Cln and polymer chains,and the polydispersity of the coupling products is broadened,which demonstrated that coupling reaction has taken place and polymer chains are covalently bonded to the molecule of C60Cln. It was calculated that about two polystyrene chains are attached to a C60Cln molecule,and it demonstrated that two mechanisms,i. e. substitution reaction and addition reaction,have taken place simultaneously during the coupling reaction.
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发布时间：2021-03-19 - 摘要：Aroylhydrazones,formed by condensation of benzoylhydrazine with benzoylaldehyde,2-methoxybenzoylaldehyde and 2,4-dimethoxybenzoylaldehyde,reacted with TiCl4 to form their corresponding complexes. The titanium complexes were characterized by elementary analysis,IR,and 1H-NMR．Their catalytic properties for ethylene polymerization performed up to 104gPE／(molTi·h)．The resultant PE was studied by DSC,GPC,WAXD,FT-IR analyses．The results reveal that the product obtained is a typical linear polyethylene.
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发布时间：2021-03-19 - 摘要：A series of bridged ligand 4,4′-methylene-bis [2,6-dialkyl-N-(2-phenylmethylene)-anil] was efficiently synthesized by the condensation reaction of 4,4′-methylene-bis(2,6-disubstituted aniline) and salicyl aidehyde. They easily coordinated with Ni (Ⅱ) to form the title complexes,which were characterized by IR spectroscopy and elemental analysis．The complexes show good activities for vinyl polymerization of norbornene with methylalumoxane (MAO) as co-catalyst．The variations of complexes and catalytic parameters were investigated along with viscosimetric measurement of resultant polynorbomenes．
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发布时间：2021-03-19 - 摘要：The adsorption of serum proteins on polymer microspheres is very important for their application in many fields．Various amounts of sulfonate groups were introduced to PMMA microspheres,and the adsorption behaviors of BSA on them was studied．The apparent rate constants of various microspheres increased with the increase amount of sulfonate groups on the surface of microspheres. Adsorption isotherm curves were fitted to the Langmuir-Freundlich model. With the increase of sulfonate groups on the surface of microspheres,cm values increased,however,K showed an opposite tendency to cm．It is indicated that the electrostatic interaction plays a dominant role in the adsorption process,and adsorption based on electrostatic interaction is higher than that due to hydrophobic interaction,but the adsorption due to electrostatic interaction has a lower rate than that of the latter.
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发布时间：2021-03-19 - 摘要：Polyaniline／fractionized carbon nanotube composite was prepared with the polymerization of aniline in the FCNTs dispersed liquid．The SEM micrographs indicate that carbon nanotubes ale coated with polyaniline；the thickness of the polyaniline on carbon nanotubes is about 5～10 nm；and carbon nanotubes were dispersed well in the composite on the nanometer scale. The apparent density and the electrical conductivity of the polyaniline／fractionized carbon nanotube composite are 440 kg／m3 and 173 S／m,respectively．As compared with polyaniline,the apparent density and the conductivity of the composite increased by about 82％ and 1400％,respectively．TGA tests indicate that the composite has better thermal-stability than that of polyaniline.
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发布时间：2021-03-19 - 摘要：A new catalyst,iron(Ⅱ) chelate of the schiff base derived from β-Ala and picoline,was successfully used for atom transfel radical polymerization．The reaction was carried out at 90℃ in bulk with ethyl 2-bromo-2-ethylpropionate as the initiator．The molecular weight of the resulting polymer increases with increasing monomer conversion．The molecular weight distribution is not narrow(PDI=1.5～1.7),and the value of molecular weight detected is in good accordance with the calculated. The molecular weight distribution is 1.13 with the addition of 10％ DMF.
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发布时间：2021-03-19
Research Bulletin
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