最新刊期
卷 ， 期 2 ， 2001
- 摘要：The metallocene complexes(tBuC5H4)2MCl2(M=Ti(1a),Zr(1b),Hf(1c)) and (tBu2C5H3)2MCl2(M=Ti(2a),Zr(2b),Hf(2c)) were synthesized by the reactions of Li tBuC5H4 and Li tBu2C5H3 with metal tetrachloride in THF solution.The complexes were characterized by their IR, 1H-NMR and EI-MS.The molecular structure of 1c was determined by X-ray single-crystal structure analysis.The complexes(1a～2c) exhibited high activities for ethylene polymerizatin (up to 3.2×106gPE/mol·h) in the presence of methylaluminoxane (MAO) at room temperature.
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发布时间：2021-03-19 - 摘要：Tensile properties of poly(β-hydroxybutyrate)/poly(ethylene oxide)(PHB/PEO) blends were reported in this paper.It was found that the blends of PHB with different molecular-weight PEO exhibited different mechanical properties.The mechanical properties of the blends of PHB and PEO3(Mw=0.3×106) were very poor.However,the blends of PHB and PEO5(Mw=5×106) showed compatible in mechanical properties.Excellent synergism was observed not only in tensile stress and tensile elongation but also in modulus.Moreover,the ductility of the blends could be improved further under proper heat-treatmen.
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发布时间：2021-03-19 - 摘要：In this article,study on the aggregation structure of polypropylene (PP) material with IAS4 image analysis system was reported．The result indicated that the form of spherulite or filling particle in the matrix of crystalline polymer can be quantitatively described by IAS4 Image Analysis System．Through the measurement of aggregation structure,the transformation of mechanical properties can be explained．With the increase of filling quantity of nucleating agent,the spherulite size(Dn) and its distribution(Cd)tends towards decline．Under different heat treatment technology,Dn and Ca has little changed．It was showed that,with the decrease of Dn,the notch impact strength increase．To the PP／talc composite,the aggregation of talc panicle has relation with the original size of particle,filling quantity and the surface treatment level．With the decrease of particle size,the notched impact strength goes up．So,the image analysis is a kind of effective method to study the relationship between structure and properties of polymericmaterials.
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发布时间：2021-03-19 - 摘要：Three typical styrene-butadiene rubbers(SBR)were chosen:emulsion-SBR(ESBR)and two kinds of solution-SBR(SSBR(C)) and (SSBR(B)). Fourier transform infrared(FTIR) was used to analysis the chain structure; dynamic mechanical analysis (DMA) and differential scanning calorimeter (DSC) were used to study the compatibility of these three SBR with NR. The results show that:the blend system of SSBR(B) with NR is compatible. The blend systems of ESBR and SSBR(C) with NR exhibit two-phase morphology. The differences in compatibility among the three kinds of SBR with NR can be well explained by comparing their chain structure.The content of cis-1,4 polybutadiene (PB) in SSBR(B) is more than that in the other two SBRs and the content of 1,2-add PB is the lowest.
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发布时间：2021-03-19 - 摘要：A novel type of conjugated poly[pyrrole-2, 5-diyl(4-hydroxy-3-methyloxybenzylidene)](PPHMBE) was obtained by condensation of pyrrole with vanillin.The precursor poly[pyrrole-2,5-diyl(4-hydroxy-3-methyloxybenzylidane)](PPHMBA) is soluble in common organic solvents. Their structures were characterized by FT-IR、1H-NMR and UV-Vis spectroscopy. The molecular weight of the synthesized polymer is 46200. The thermal behavior of the synthesized polymers was evaluated by TGA and DSC analyses. The glass transition temperature (Tg) of PPHMBA and PPHMBE is 140.3℃ and 188.5℃,respectively.UV-Vis spectroscopy reveals that introducing quinoniod pyrrole rings in polymer chain can decrease the bandgap of conjugated polymers,and the energy bandgap of PPHMBE is 1.14eV. The conductivity of products doped with iodine is in the range of semiconductors.
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发布时间：2021-03-19 - 摘要：A series of novel Shish-Kebab type liquid crystalline copolyeaters with chiral smeetic C phase was synthesized by low temperature solution polycondensation with terephthaloyl chloride,2,5-bis[4-((s)-2-methylbutoxy) benzoyloxy] hydroqunone,ethylene glycol,diglycol,triethylene glycol,tetraethylene glycol and polyethylene glycol as the monomers．The copolyesters were characterized by GPC,DSC,TG,WAXD,polarizing macroscope(POM)with a heating stage and romtmnal analysis instrument．It was found that the copolyesters entered into liquid crystal phase when heated to above their melting temperature．The focal-conic mxture was observed．All the chiral compounds and copolyesters showed high optical activity．Temperature-variable X-ray diffraction study together with the POM and polarimetric analysis revealed that the copolyesters synthesized exhibited a chiral smectic C phase．Both Tm and Ti of all the copolyeaters decreased with the increase of the length of polyethylene glycol flexble spacers in copolyesters,while the temperature range of the liquid crystal phase of the copolyesters becfllne wider．
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发布时间：2021-03-19 - 摘要：The hydrolysis of the chelate of acetylacetone of aluminum,which is prepared by aluminum-iso- propanol and acetylacetone,results into alumina sol An organic-inorganic sol (OIS) can thus be prepared by the alumina sol crosslinking with the residual hydroxyl groups of poly(vinyl butyral)．The OIS,after molding and drying,gives easily transparent,solvent-resistant membrane and high-elastic fiber,those are actually the organic-inorganic hybrid polymers．When coated on carbon fibers,followed by drying and heat treatment,the OIS forms very fine and thin amorphous alumina-carbon film,which obviously improves the fibers’resistance to oxidation at high temperature and fiber’s surface properties．
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发布时间：2021-03-19 - 摘要：A novel liquid crystalline polymer—hydmxyethyl chitosan(HECS) was synthesized in alkali system．The degree of molar etherification(DME) of HECS was controlled by both the amounts of ethylene oxide and the reaction time．DME of HECS specimens was from 0.2 to 5.4 measu~d by element analysis and NMR．All specimens formed typical cholesteric texture—fingerprint texture while dissolved in formic acid．HECS with DME>1.9 was water soluble．and the HECS aqueous solution also formed eholesterie phase with typical texture．The mesophase texture was detected both by polarized optical microscopy and scanning electron microscopy．Samples for SEM studies were treated by permanganic etching in order to increase the contrast．The studies were focused on the effect of DME on the eritical concentration(C*) of mesophase formation for HECS／formic acid solutions．The results indicated that c* sharply increased with DME at first．and became independent as SDME variedfrom 0.2 to 1.9．Mterthat(DME>1.9),it regain obvious rise as DME continuously heightened．These results were explained by the variation of both persistencelength q andmoleculardiameter d in Flory’s semi-experience equation c*≈8q／x(x=2q／d)．The variation of DME of HECS related with two structural factors．i．e．the Rumbet and Iength of the substituent．the former affected c* slightly,hut the latter affected c* evidently．
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发布时间：2021-03-19 - 摘要：In the synthesis process of nanometer-size PS particles,functional polyperoxides(PPX) was used as an inisurf.The chemical composition and the structure of nanometer-size PS particles wese studied carefully by differential scanning calorimetry,thin-layer chromatography,solubility measurement,infrared spectrum etc.It was found that the product is predominantly composed of PS-PPX crosslinked polymer with trace of un-reacted peroxo-groups on its chains.
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发布时间：2021-03-19 - 摘要：Polystyrene(PS) was submitted to CO2,N2 and air plasma.The chemical composition of the modified polymers was investigated by X-ray photoelectron spectroscopy (XPS) It was found that the surface of the modified polymers had some functional groups,besides the original bonds.These groups may improve the soakage and adhesion of the polymere.In addition,the amounts of the oxygen and the nitrogen combined with the PS surface are heavily effected by the plasma conditions.
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发布时间：2021-03-19 - 摘要：Polyphenylacetylenes were synthesized by [Rn(nbd)Cl]2 and WCl6／Ph4Sn catalyst systems in N2 at room temperature．Polymers with high yield and high molecular weight were obmined．Thdr structures were characterized by UV,IR,NMR and GPC,respectively．The fluorescence of the polymer solution with different concentration was investigated using variabh exci~tmn wavelength from UV to visible region．The relation between fluorescence and polymer structure Was studied．The results showed that the molecular chain structure has great influence on fluorescence of the polymers．The emitting peak wavelength of fluorescence for the polymer of high stereoregularity is independent of solution concentration and excitation wavelength．The emitting peak wavelength of fluorescence for the polymer with disordered molecular chain arrangement varies with changing the solution concentration and excitation wavelength,and different emission sites in molecular chains and loW emitting yield are shown．The measurement and analysis of fluorescence spectroscopy of polyphenylacetylenes may provide some useful information to judge the molecular chain arrangement in some conjugated polymers．
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发布时间：2021-03-19 - 摘要：The catalyst MgCl2／TiCl4／BMMF-AlEt3 prepared with a novel complex 9,9-his(methoxymethyl) fluorene(BMMF)as internal donor was applied to propene polymerization without any external donors and the isotacticity of polypropene obtained was over 95％．In comparison with the catalyst MgCl2／TiCl4／Phthalate-AlEt3／DDS,the catalyst of MgCl2／TiCl4／BMMF·AIEt3 showed high activity．The effects of polymerization conditions such as temperature and Al：Ti ratio on the activity of catalyst,on the molecular weight,the isotaticity and the melting point of polypropene were studied．Polypmpene Was characterized by 13C-NMR spectroscopy and the structure of polypropene Was studied．
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发布时间：2021-03-19 - 摘要：The spherulite morphology of syndiotactic polystyrene and the formation condition in isothermal crystallization have been studied by the polarizing microscope．There are eight kinds of spherulite formed as crystalline temperature(Tc)changed from 200℃ to Tm. The spherulite is feathered and the lamellae structure is bulking as Tc lower than 240℃．The feathered soherulite is positive ss 230℃>Tc>220℃ and becomes optically positive-negative mixed as 240℃>Tc>230℃．In addition,the shish-kebab and four- sectional positive soherulite with a helical matting ring ean form when crystallized isothermally nest 230℃．Most spherulites crystallized at Tc>240℃ are eight-sectional,the distribution of the eight sections varies with the rotation of the samples．There are also very few Four-sectional positive and negative spherulites which coexist with the eight-sectional spherulites as Tc>240℃ and Tc>250℃,respectively．
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发布时间：2021-03-19 - 摘要：A series Semi-interpenetrating polymer networks(SIPN) of PU／PS polymer composites were prepared by PU／St concentrated emulsion polymerization．The effects of the dispersed phase content and polymerization temperature on polymerization kinetic and stability were studies respectively．The size and distribution of polymer latex particles,morphology of latex particles,polymer Tg and tensile strength have been determined．The powder resin of PU／PS polymer composites was obtained．The particle size and distribution of the polymer latex can he easily controlled by controlling the monomer cell size．The obtained powder polymer composites can be more easily reprocessed,so their usefulness area will be increased．
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发布时间：2021-03-19 - 摘要：Novel water insoluble sodium sulfonate-functionalized poly(ether ether ketone)s containing cydohexylidene in the main chain with degree of sulfonation up to 2.0 were synthesized from nucleophilicpelycondensation of 5,5'-carbonylhis(2-fluorohenzenesulfonate),4,4'-difluorohenzophenone and 4,4'-cyclohexylidenebisphenol．The polymers showed excellent thermal stability and good water resistance aswell The DSC diagrams and WAXD patterns indicated an amorphous morphological structure of thesepolymers．A comprison of some properties between these copolymers and polrmers derived from bisphenol A was giyen．
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发布时间：2021-03-19 - 摘要：Fe-Zn double metal cyanide (DMC) complexes are relatively cheap and effective catalysts for the ring-opening polymerization of propylene oxide．Polyoxypropylene diol oligomer is used as the initiator． Polyoxypropylene diols having Mn within the range of about 3000 to 12000 are prepared with Fe-Zn DMC catalyst under mild condition．The polymer is characterized by GPC and VPO．Effect of polymerization condition on molecular weight(MW) and molecular weight distribution(MWD) is investigated．The MW of polymer may be controlled by monomer／initiator molar ratio(M/I)．It is assumed that each activated catalyst site is related with many different molecules during polymerization．Polymerization proceeded at 80℃ and 60℃ gives polymers with a bimodal MWD(at least two kinds of active centers) and a unimodal MWD,respectively．When polymerization proceeds at temperatures lower than 65℃,the active center associated with Fe(CN)64- may not act because of its low activity．Two types of anion Fe(CN)63- and Fe(CN)64- coexisting in Fe-Zn DMC catalysts,which possibly result in the bimodal MWD,have been proved by IR spectra and X-ray diffraction．
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发布时间：2021-03-19 - 摘要：Responsive hydrogels based on N,N-dimethylaminoethyl methacrylate were synthesized in aqueous medium by photopolymerization．H2O2 was used as the photosensitive initiator and N,N-methylene-bis-acrylamide was used as a crosslinker．Effects of the monomer concentration,the initiator concentration,the crosslinker concentration and the radiation time on gel fractions and swelling ratios were investigated．The optimum condition of synthesis was given．The resulting hydrogels were transparent and possessed good elasticity．It WaS found that the gels displayed both thermosensitive and pH-sensitive behaviors．The equilibrium swelling ratios of the hydrogels changed abruptly at 40℃ in water．Swelling ratios would decline abruptly at pH 3．Ionic strength has only a small influence on swelling and the swelling ratio decreased gradually when the ionic strength increased．
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发布时间：2021-03-19 - 摘要：The phase forming and development of polystyrene／poly(cis-butadiene) rubber (weight ratios were 70／30 and 50／50,respectively) blends during mixing were investigated by pattern analysis of scanning electron microscope．For the blend with composition 70／30,the average diameter(PDav) of the dispersed phase[particles(PeBR)] decreased in the initial stage of mixing,and fluctuated in the metaphaze and later stage．The distribution of the particles trended to uniform with the blending process．But for the blend with composition 50／50,which is near the phase inversion composition,the calculation of PDav is difficult because of the co-continuous structure of the two components,thus two parameters,the characteristic length A and the average characteristic length Am are used to characterize the size of the dispersed phase．The characteristic length was defined es the measuring distance of black area(dispersedphase) when scanned the binarized SEM images along a direction．The changes of m was similar to that ofPDav andthe A and Amcould reflectthe size and size distribution of the dispersed phase whether or not the composition is near the phase inversion．Furthermore,the histograms of Am obtained at various time in the metaphase and later stage of mixing fell on a master curve．demonstrating the self-similar growth of the phase structure．Thus a scale function P(A/Am) was defined to study the fractal behavior of the mixing．The results showed that the fractal dimension D could be used to characterize the mixing process of the polymer blend．
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发布时间：2021-03-19 - 摘要：Pure polyaniline(emeraldine base form) Langmuir-Blodgett(LB) films and polyaniline and aceticacid mixed LB films with various layers are prepared．The LB films with various layers are characterized byultraviolet／visible(UV-Vis)spectroscopy．The gas-sensitivity to NO2 of polyaniline based LB films with different layers are studied．It is found that pure polyaniline LB films show higher sensitivity,responsivity and reversibility to NO2 gas than those of polyaniline and acetic acid mixed LB films．The response time of 3-layer and 15-layer pure polyaniline LB films to 20×16-6NO2 gas is about 10 seconds and 30 seconds．respectively．The recovery time of the latter is about 4min．
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发布时间：2021-03-19 - 摘要：The crystallization and melting behavior of mellocene-catalized branched and linear polyethylenes of low molecular weight was studied．It was found that the crystalline lattice of branched polyethylene is larger than that of linear polyethylene because of the existence of branched chains．The melting behavior of branched polyethylene is similar to that of linear polyethylene since the branched chains can not enter the lattice．However．the crystalline behavior of low molecular weight branched polyethylene is the same as that of high molecular weight linear polyethylene, but different with that of low molecular weigh linear polyethylene．Kinetics theory analysis evidenced that the transition temperature of growth regime of the branched polyethylene is about 20℃ lower than that of linear polyethylene with the same molecular weight.It may be attributed to the existence of short branched chains．
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发布时间：2021-03-19 - 摘要：Copolyesters based upon ethylene glycol (EG),terephthalic acid (TPA) and 2,6-naphthalenedicarhoxylic acid(NPA) or isophthalie acid(IPA) of different composition were synthesized by transesterification polycondensation of monomers or polymers．With the involvement of IPA or NPA moieties in the chains,the copolyesters became less crystallizable or amorphous,and the isothermal crystal growth rate decreased rapidly．Tlhe H1-NMR studies of the copolyesters NPA／TPA／EG showed that the samples prepared by different method exhibited a similar random sequence distribution．DSC measurements indicated that the copolyesters NPA/TPA／EG or IPA／TPA／EG are amorphous if the contents of moieties NPA of IPA are higher or equal to 20 mol％．The WAXD of the copolyester sample containing 20 mol％ NPA moieties,after an anneal at 140℃ for 2 hours,exhibited some weak diffraction peak．which is attributed to the crystals of PET moiety in the eopolyester．Due to the introduction of IPA or NPA moieties,the melting temperatures and the cooling crystallization temperatures of the copolyesters were changed．
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发布时间：2021-03-19
Research Article
- 摘要：The influence of composition on the curing kinetic parameter,electrical,mechanical,thermal properties and the glass transition temperature of cured compound of epoxy and cyanate ester co-curing system catalyzed by transition metal acetylacetone was studied by means of DSC．dielectric and dynamicmechanical methods in this paper．The results showed that the reactive energy and frequency factor of co-curing is found to increase with enhanced concentrations of cyanate ester of co-curing system．The glass transition temperature and thermal stability of cyanate ester and epoxy cured system is found to increase with enhanced concentrations of the cyanate ester under the same cured condition,addition of the cyanate ester will decrease the loss factor and dielectrieal constant value aS well．
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发布时间：2021-03-19 - 摘要：For the aim of getting macromolecular flocculant,we studied the copolymerization of acrylic acid onto Rhi．oryzae cell wall structural polysaccharide by the initiation of cefic ammonium nitrate．The effect of concentration of initiator and monomer,reaction temperature and reaction time on grafting percentage was investigated．To Rhi．oryzae cell wall structural polysaccharide the maximal grafring percentage of 135．5％ was achieved at [Ce+4]=5mmol／L,[AA]=lmol／L,T=60℃,t=3h．Then choosing organic dyes as the flocculated substances,by comparing with the chitosan,polyacrylamide and Rhi．oryzae cell wall structural polysaccharide hefore grafting,we studied the flocculent capability of Rhi．oryzae cell wall structural polysaccharide after grafting acrylic acid．The grafting product had excellent flocculent effect on basic and neutral dyes．
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发布时间：2021-03-19 - 摘要：The CaSO4 whisker／polyurethane elastomer composites with high strength and high toughness are fabricated．The CaSO4 whisker reinforcing and toughening mechanisms for polyurethane elastomer are stMied．The observation of the fracture surface by SEM and TEM shows that CaSO4 whisker reinforcing mechanism for polyurethane elastomer is mainly load transfering,while its toughening mechanism involves crack deflection and whisker pullout．The effects of dispereity of CaSO4 whisker and the interfacial bonding state on reinforcement and toughness are discussed．The re8ults indicate that compooites with 5％～10％ CaSO4 whisker exhibit the best mechanical properties among the materials tested．Good bonding interface is formed between whisker and matrix after the surface of CaSO4 whisker being treated by silane coupling agent(KH-550)．Better interracial bonding state contributes to strength and toughness being fairly improved．
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发布时间：2021-03-19 - 摘要：The effect of different sulfonation degree on properties of sulfonated syndiotactic polystyrene (SsPS) was investigated by 1H-NMR,13CNMR,FTIR,DSC and WAXD．The results of 13C-NMR showed that a peak at δ=145.5 appeared in all SsPS spectra．which proved that the syndiotactic structure of syndiotaetic polystyrene(sPS) still eximed in SsPS．With increasing degree of sulfonition。the chemical shifts of C-1 and C-3 for sulfonated benzene ring turned out to be wider．1H-NMR spectra showed that C-3 for sulfonated benzene ring had a chemical shift of 7．66．FTIR spectra showed that sulfonic acid groups were introduced on the para position of benzene rings and with increasing sulfonation degree,the absorption strength of 612／1600 cm-1,834／1600cm-1 increased,but the absorption strength of 1078／1600cem-1 decreased．The absorption of ～1030cm-1,～1179cm-1,～1217cm-1,appeared when the sulfonation degree was higher that 6％．sPS and SsPSH-2．2 had absorption at 975 and 943cm-1 and also had doubh peaks around～1175cm-1；DSC showed that with increasing sulfonation degree,the glass transition temperature increased, the melt temperature,crystallization temperature and crystallization degree decreased；SsPS eouldn’t crystallize when sulfonation degree was higher that 6mol％；WAXD proved that sPS had the a and βcrystal types,however,SsPS with 2．2％ sulfonation degree only had the β crystal type,and SsPS with 6．1％ sulfonation degree didn’t crystallize．
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发布时间：2021-03-19 - 摘要：The characteristics and structure of the titled copolymer are presented and discussed in the present paper．The eopolymer is characterized by IR and 1H-NMR．The copolymer is a product of high alternation．The content of meleie anhydride is 47％ in the copolymer．The copolymerization can be realized in solvents such as aromatic hydrocarbon and alkane．The yield is higher in aromatic hydrocarbon than that inthe others．The suitableAl/Fe emolar ratiois 2～6．The suitableFe／a,a'-dipyridylmolar ratioisl．From kinetic studies the activation energy of eopolymerization is evaluated to be 89．6 kJ／mol．
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发布时间：2021-03-19 - 摘要：In order to obtain the inviseid dendrimers with more terminal amino-groups than those of ω,ω'- polyethylene glycol diamine,in the meanwhile to untihze the fine biocompetibi|ity of polyethylene glycol,aseries of polyamidoamine dendrimers with polyethylene glycol core were synthesized by Tomalia’s divergentmethod which invovled a repeated two-step process：(1) exhaustive Micheal addition of ω,ω'-polyethylene glycol diamine as the initiating core,with methyl acrylate and (2) exhaustive amidation of the resulting esters with a large excess of ethylenediamine．The structures of all generations of the dendrimer was identified by FT-IR and elemental analysis,and the numbers of the terminal aminogroups of the integral generations of the dendrimer were determined by potentiometer titration．Although PEG-NH2 and the integral generations had adsorption at ～3300 cm-1 in FT-IR,the half generations did not have．It indicated that all the steps of Micheal addition took place thoroughly On the other hand,the conversion of the half generations into their corresponding integral generations made the adsorption of the ester’s carbonyl at 1735～1740cm-1 disappear, it suggested that the conversion was complete．The results of lemental analysis also affirmed the above discussion．However the data of elemental analysis and potentiometer titration of PEG-5.0 and PEG-6.0 didn’t entirely coincide with their theoretical values,that may be due to the residue of the ingredients such as ethylenediamine which were bundled up by larger generations with more branches and difficult to remove．Except that PEG-1.0 and PEG-2.0 are solids,the other integral generations are viscous．Influences of the integral generations on coagulation and hemolysis were examined,and the results showed that the properties of coagulation and hemolysis of the integral generations of thedandrimer were similar to those of po|yehylene glycot．
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发布时间：2021-03-19 - 摘要：The morphology of films of isotactie polypropylene poly(3-dodecylthiophene) and iPP／P3DDT blend formed in electrostatie fields has been investigated by using scanning electron microscope．The experiment results show that the micro-crystal morphology of polymer films was strongly dependent on electrostatic fields．It was found that the effect of the electrostatic field led to the formation of dendrite crystals aligned in the field direction,and some branches of P3DDT ruptured．However, the micro-crystals in these films grew into spherulites without electrostatic field,and have no crystal orientation．
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发布时间：2021-03-19 - 摘要：A novel blue-light-emitting functional copolymer containing alternating rigid eonjugated PPV and flexible ionic conductivity PEO blocks in the main chain was synthesized by using the Wittig reaction．The copolymer was characterized by FT-IR,1H-NMR,UV-Vis,DSC,GPC,etc．The resuIts show that the copolymer can be soluble in chloroform and tetrahydrofuran,with Tg=50．5℃,Td=20℃,amaximum absorption peak in UV-Vis spectrum at 354nm and an emission peak in the photolumineseent spectrum at 438nm for solution in chloroform and at 475nm for film It is a good blue emitter for fabricating LED or LEC．
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发布时间：2021-03-19 - 摘要：Polyether triol with molecular weight distribution index being 1.3～1.5 was prepared in yield around 50% by tetrahydrofuran polymerization using heteropolyacid-H3PW12O40 and ethylene oxide as initiator system and 1,1,1-trihydroxymethylenepropane(TMP) as molecular weight controller.The average hydroxyl functionality was estimated by end-group analysis and VPO to be close or equal to 3. The 1H NMR spectra showed that about 1/3 hydroxyl of TMP did not react with the propagating chains in the THF polymerization.Each of the unreacted hydroxyl groups of TMP attached to the middle or to the end of a diol chain as a pendent primary hydroxyl proup forming the obtained polyether triol.All the hydroxyl of polyether triol were verifid to be active enough towards 4,4'-methylene bis (phenyl isocynate) in the preparation of polyurethanes.
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发布时间：2021-03-19 - 摘要：Poly(4-vinyl phen01) (PVPh) was synthesized from anisaldehyde via Perkin-Doebner and deearboxyl reactions to form 4-methoxy styrene．It was then polymerized by free-radical polymerization following dealkylation to forrtl PVPh．A kind of Stable multilayer utra—thin film was successfully fabrieated via self-assembly technique from PVPh and diazoresin (DR) followed by UV irradiation．The driving foroe of self-assembly was confirmed to be the hydrogen bending attraction from diazonium group(-N2+) of DR and phenolic hydroxy group(一Ph—OH) of PVPh．The film becomes very stable towards polar solvents after UV irradiation and it is believed that the H-bonds between the lalters of the film converts to coValent bonds following the decomposition of —N2+ groups when the multilayer film underwent UV irradiation．
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发布时间：2021-03-19 - 摘要：A novel unsymmetrical dianhydride containing 4-(4-hydroxylphenyl)-2,3-phthalazin-1-one was svnthesized in order to improve the solubility of aromatic polyimides according to the principle of designing new monomers．This article reported a series of polyimide random copolymers derived from 4,4’-diamino diphenyl sulfone(DAPS),4,4'-oxyl dianiline(ODA)and the new dianhydride-2-(3,4-dicarboxyl-phenyl)-4-(3’,4’-dicarboxyl．phenyl-oxyl)．phenyl-2,3-phthalazine-1-one dianhydride (DAH4) by“one-step”solution DolyoDndenSation in m-cresol with catalystic amount of isoquinoline at 200℃．Some properties of the copolymerS were investigated by DSC,TG and mechanical analysis．The result shows that the ηinh of copolymers is between 0.64 to 0.71 dL／g in m-cresol at 25℃,and the Tg of the copolylTters are higher than that of Durt poliymides containing 4,4'-oxyl dianiline(polymer 5)．The relationship between Tg and mole percent of DAPS is not obvious．Degradation temperature for 5% weight loss (Td5)of the copolymers occurs all above 470℃ in air．The mechanical properties of the copolymers age lower owing to introducing suIfone groups into polymer’s backbone．In sharp contrast, the copolymers have good solubility and can he easiIv soluble in 1,1,2,2．tetrachloroethane (TCE),N,N-dimethylacetamide(DMAc),N- methyl-2-pyrr01idinone (NMP),m-cresol and pyridine．Furthermore,the copolymers have better solubility in dimethyl sulfoxide (DMSO) and chloroform than the polyimide derived from DAH4 and ODA．
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发布时间：2021-03-19
Research Bulletin
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