最新刊期
卷 ， 期 2 ， 2006
- 摘要：The area of“polymer blends”has interested many scientists since the 1960s．This is because the polymer blends provide many special and desirable properties．The thermodynamics of the phase behavior and the kinetics of phase separation／dissolution processes play an important part in these applications．In recent years,lots of advancement have been made in both theories and experiments．The statics part of the phase behavior studies are mostly started from the Flory—Huggins mean—field theory．and the kinetics ofphase separation are mostly based on the Cahn-Hilliard-Cook(CHC)linear theory．Many new developments and improvements on theories and new verifications and extensions by experiments have been achieved,including some theoretical and experimental developments in nonlinear phase separation behavior．In this paper,the authors review the scientific development in both the static and kinetic aspects of the spinodal decomposition(SD)．Then,we describe the static scattering experiment,which measures the concentration fluctuations of a binary mixture．After that we present some recent theoretical calculations on the SD of binary polymer system．First,the derivation of CHC theory from generalized Langevin equation is reviewed to provide a microscopic pietore for the phenomenological mean-field theory of CHC．Then a mold—coupling calculation Was used to extend the SD theory into the nonlinear region．The quantitative nature of the calculation is demonstrated by a comparison with the dissolution study of a polymer blend subjected to SD for a short period．Finally,some recent studies on shear dependence of the phase behavior and possible future potentials and directions in this field have also been discussed.
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发布时间：2021-03-19 - 摘要：Sulfonated poly(phthalazinone ether nitrile ketone)s(SPPENK)with pendent sulfonate groups were synthesized by direct polycondensation from 4-(4-hydroxyphenyl)-1(2H)-phthalazinone(DHPZ),disodium 3,3'-disulfonate-4．4’-difluorobenzophenpne (SDFB),4,4’-difluorobenzophenone (DFB)and 2,6-dicholobenzene (DCBN)．The intrinsic viseosity of SPPENK was in the range of 0．58～2．0 dL／g．FT—IR,1H—NMR and wide—X—ray scattering were used to characterize the structures of the eopolymers．The thermo—stability of the eopolymers was detected bv DSC and TGA．Tough films were cast successfully from N—methylpyrrolidone solutions．The ion exchange capacity (IEC) values were 0．91～2．06 meq·g-1．The swelling ratios of resulted membranes were 9％～21％, which is much lower than those of Nafionll35 and other reported sulfonated poly(aryl ether ketone)8 and poly(aryl ether sulfone)s membranes with the same ion exchange eapacity．
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发布时间：2021-03-19 - 摘要：Competitive and cooperative simultaneous adsorptions of phenol and aniline from aqueous solutions by hyperemsslinked potymerie adsorbents(NDA103、NDA101、NDA100)were investigated．The results indicated that adsorption isotherills for them in both single and binary systems can be well fitted by the Langmuir equation．At the lower equilibrium concentrations,the individual adsorbed amounts of phenol or aniline on macroreticular adsorbents in single systems is higher than those in binary systems because of the competition between phenol and aniline towards the adsorption sites．It is noteworthy that at higher concentrations,the total uptake amounts of phenol and aniline in binary systems are obviously larger than the pure uptake amounts in single systems,and a large excess was noted on the particle surface at saturation,which is presumably due to the cooperative effect primarily arisen from the hydrogen bonding or weak acid—base interaction between phenol and aniline．Increasing temperature from 293 K to 313 K enhanced the cooperative effect on simultaneous adsorption of aniline and phenol on NDAl03；while,the cooperative coefficients on NDA101 and NDA100 almost kept unchanged．
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发布时间：2021-03-19 - 摘要：The properties and features of nano-scale futile TiO2 and bulk phase rutile TiO2 were gained by some methods．suchas TEM,UV-Vis,IR and so on．Polypropylene／POE,polypmpylene／nano—TiO2／POE composites and polypropylene／bulk—TiO2／POE composites were prepared by a melt—blending process．Polypropylene and composites were degradated in a 28 days accelerated aging test with a laboratory xenon arc lamp(GB／T 16422．2-1999)．It was shown that,with the UV shielding capability of nano-scale futile TiO2,the ageing resistance of polypropylene was improved．the survice life of polypropylene was prolonged and the tougheness of PP was increased to a great extent too．The ageing resistance of polypropylene／nano—TiO2／POE composites was better than that of polypmpylene／bulk—TiO2／POE composites．After 28 days exposure to xenon arc lamp the IZOD unnotched impact strength of polypropylene／(1.0 wt％)nano．TiO2／POE composites was 80．45 kJ·m-2which was more than four times as high as that of pure PP．At the sanme time the impact strength of polypropylene／(1．0 wt％)bulk—TiO2／POE composites was only 47．88 kJ·m-2 after 28 days exposure to xenon arc lamp．
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发布时间：2021-03-19 - 摘要：Long—chain branched polyethylene was prepared by a bianary catalyst system[Cat 1：bis(α— naphthalidine)-butanediimine)NiBr2 and Cat 2：bis(2,6-diisopropylphenyl)-acenaphthenediimine NiBr2]．The binary catalyst system showed a good synerglc effect．Its polymerization activity(4．6×105g PE／mol Ni·h) was higher than that of either single catalyst．The resultant highly branched(94．8～144．5／1000C)PE was confirmed by 13C-NMR to contain a significant amount(27～42／1000C)of long chain branches(n≥6)．The GPC results showed that the molecular weight distribution of the polyethylene obtained with this binary catalyst system was very narrow．The explanation for this is that ethylene oligomerizes in the Cat 1 active site,and the produced vinyl end group oligomers serving as comonomers in shu copolymcrize with the growing polyethylene chain in the active site of Cat 2．
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发布时间：2021-03-19 - 摘要：Ferric ethoxide．ferric n—propoxide．ferric iso—propoxide and ferric n—butoxide were used as initiators respectively for bulk ring-opening polymerization of lactides．The effects of initiator content and polymerization time on the polymerization were investigated．It was showed that these ferric alkoxides were efficient initiators for the ring—opening polymerization of lactides with higher than 90％ of monomer conversions polymerized at 130℃ for 36 h．Maximum molecular weights were achieved at 1／1000 of initiator／monomer mole ratio for the four ferric alkoxides and then decreased gradually with increasing the amount of initiator and prolonging polymerization time．Poly(D；L-lactide)and pely(L-lactide)withthe maxium viscosity-arerage molecularweights(Mv)of 7．28×104 and 19．00×104 respectively were synthesized by using ferric ethoxide as initiator．It was found that the ligands of the ferric alkoxides had significant influence on the molecular weight and molecular weigth distribution of the polymerization products．With increasing the volume of the ligands of the ferric alkoxides,the molecular weight decreased and the molecular weight distribution broadened．1H and 13C-NMR analyses indicated that the ferric alkoxides studied here had no racemization on the ring-opening polymerization of L—lactide,but exhibited isotactie stereoselectivity addition on the ring—opening polymerization of D,L-lactide．Intermolecular tranestefificafion took place during polymerization of D．L-lactide for the four ferric alkoxides as evidenced by the results of MALDI-TOF MS analysis．and quantitative evaluations by 13C-NMR were made for the four initiation systems．However,no regularity of ligands of the ferric alkoxleds on both of isotactic stereoselectivity addition and intemaolecular tranesterification was found due to incomplete resolution of the13C-NMR spectra．
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发布时间：2021-03-19 - 摘要：A novel series of main chain liquid crystalline copolyesters with X-shaped two-dimensional mesogenic units and crown ether cycles of cis-4,4'-bis(4-hydroxyphenylazo)dibenzo-14-crown-4 was synthesizeed via solution cocondensation polymerizations from 4,4’-(α,ω-octanedioylxy)dibenzoyl dichloride(M1),2,5-bis(P—dodecyloxybenzoyloxy)hydro-quinone(M2)and cis-4,4'-bis(4-hyaroxyphenylazo)dibenzo-14-crown-4(M3)as the monomers．Monomer M1 was synthesized by esterification and substitution reaction of P—hydroxybenzoic acid and octanedioyl chloride．Monomer M2 was synthesized by esterfieation and reduction reaction of 2,5-dihydroxybenzoquinone and P—dodecyloxybenzoyl chloride．Monomer(M3)was synthesized by diazotization and coupling reaction of cis-diaminedibenzo-14-crown-4 and phenol．The molecular weights of copolyesters are not high, and the[η]of the copolyesters ranges from 0．35～0．25 dL／g．The monomer structures were identified by using elementary analysis,IR,UV,1H—NMR and MS etc．All the copolyester samples aie yellowish powders and insoluble at room temperature in THF and CHCl3 except for sample CP9．The properities of copolyesters were investigated by using GPC、[η]、DSC、TG、WAXD and POM．It was found that all the copolyesters went into liquid-crystal phase when they were heated over their melting temperature(Tm)．The thread texture and sehlieren texture Can be observed．Their melting temperature and isotropic temperature(Ti)change regularly with varying the cis-4,4'-bis(4-hydroxyphenylazo)dibenzo-14-crown-4 unit content in the copolyestem．The WAXD study illustrated that the copolyesters are liquid crystalline with a nemafic phase．A dispersive peak at 2θ near 20°appeared in their WAXD patterns,which is a typical character for quenched nemafie liquid crystal eopolyesters．
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发布时间：2021-03-19 - 摘要：The miscibility of reactive blends of PN(Propargyl novolac)resin and PAA(Polyarylcetylene)resin was studied．Evaluation on the storage stability,processability of the blends and thermal stability of the cured blends were also presented．As evidenced from phose observation,DSC analysis,SEM and TEM investigation,PN—PAA reactive blends were completely homogeneous．Compared with PAA,the blends exhibited improved storage stability at room temperature．The blends could be cured in a controllable way,thus the processability of the blends was marginally improved comparad with that of PAA resin．DMA and TGA analyses indicated that the blends possessed high thermal stability(glass transition temperature as high as 380℃)．Owing to the low viscosity of the blends and a proper gel time,as well as the elimination of volatiles during the curing process,the reactive blends are suitable for many processes including RTM(Resin transfer mold)．The reactive blends of PIN resin and PAA resin are amongst novel matrices of advanced materials for high temperature ablative and thermo—structural applications．
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发布时间：2021-03-19 - 摘要：A polyimide containing main-chain isosorbide units has been synthesized by polycondensation of an isosorbide-based diamine monomer and a dianbydride monomer(6FDA)in solution through a thermal imiderization reaction．The chemical structure and properties of the polyimide were characterized by using FTIR,1H-NMR,UV-Vis spectroscopy and thermal analysis．The polyimide thus obtained can be dissolved in polar organic solvents．such as DMF,NMP,DMAc,THF and CHCl3．The glass transition temperature(Tg)and the decomposition temperature (Td)of the pelyimide were measured to be 302℃ and 414℃(5％decomposed),respective．The polymer doesn’tshow absorption for the light with wavelength longer than 400 nm．These results indicate that the polyimide pessesses good thermal stability and optical transparency in visible range．The polyimide is considered to be promising-for applications in optical and microelectronic devices．
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发布时间：2021-03-19 - 摘要：Throuugh ultrasonic emulsifier-free emulsion polymerization,no chemical initiator and emulsifier,a eopolymer latexes of BA(butyl acrylate)／St(styrene)／AM(acrylamide)was prepared．The influence of ultrasonic time on monomer conversion,latex particles size and latex viscosity was investigated．A polymerization mechanism of ultrasonic emulsifier-free emulsion polyrnerization also was proposed,which indicated that AM was as an initiator and stabilizer in the reaction system．TEM photographs showed that the size of latex particles was about 80 nm,which was less than that(about 140 nm)of the particles prepared by conventional emulsifier-free emulsion polymerization method．And FTIR spectrum showed that after extracted in turm by water,CCl3 and THF for 48h,respectively,the sample obtmned by this way was a ternary copolymer of BA,St and AM,but not the blend of poly(butyl acrylate),polystyrene and polyacrylamide．
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发布时间：2021-03-19 - 摘要：Partition of acrylonitrile(AN)between aqueous phase and oil phase and its effect on the copolymer composition in AN／St suspension polymerization were investigated．The result shows that the composition of copolymer in suspension polymerization differs from thatin bulk polymerization at the same monomer feed ratio．It is because the AN／St monmer ratio in the oil phase is lower than the fed one due to the significant phase partition of AN between aqueous phase and oil phase．In order to predict accurately and then control the copolymer composition in AN／St suspension polymerization,a model for calculating AN／St copolymer composition was proposed on considering phase partition of AN between the two phases．The results calculated by the model were in agreement with the experimental data．The real reactivity ratios in oil phase used in the model were the same as that in the bulk polymerization,but the apparent reactivity ratios in suspension polymerization varied with the water／oil ratio significantly．
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发布时间：2021-03-19 - 摘要：Ethyl cellulose fibers containing tetracycline were produced by electrospinning,and the release process of tetracycline in aqueous solutions was measured and investigated by the ultraviolet-visible spectrometer method．It was found that the release of the tetracycline in water Was delayed when the drug distributed inside the ethyl cellulose fiber．The drug delivery late was controlled by the diameter of fibers and the tetracycline concentration in the fiber．The fiber with large diameter was better than that with small diameter in the controlled drug delivery．
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发布时间：2021-03-19 - 摘要：Studies on the dynamic theological behaviors and electrical properties for multiwalled nanotubes filled high-density polyethylene composites were carried out．An obvious shear thinning phenomenon in η*vs ωwas found for composites of MWNTs content beyond 3％．A specific viscoelastic behavior．i．e．the so-called“second plateau”,appeared at low frequency region in cases of ψ>3％．This phenomenon could be regarded as a rbeological threshold,and could be attributed to the formation of some kind network structure due to MWNTs aggregation and the interaction between MWNTs and polymer matrix．A miulmum was found in the Iow ω region for the tanδ～ω curves．which also was believed to be induced by the formation of network structure．Results of dynamie frequcncv sweep after heat treatment of different time length and results of dynamic time sweep approved the previous postulation．Ultimately．the rheological threshold coincided with the electrical percoloation threshold which was found for the composites containing MWNTs of 2 wt％and 3 wt％．
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发布时间：2021-03-19 - 摘要：Conduction behaviors of carbon black(CB)filled poly(methyl vinyl siloxane)(PMVS)vulcanites in loading and unloading processes were investigated．The results revealed that the resistance decreased with time after loading under constant stress and also after unloading,exhibiting a typical relaxation behavior．According to the resistance relaxation time and the most extent of resistance relaxation,relationships between the structure change of conductive network and the resistance relaxation were analrsed．Simultaneously,the effect of CB content on resistance relaxation was discussed．It was found that under 2～4 MPa stress．tWO relaxation times were detected independent of the content of CB．which were related to tIle structure change of conductive networks in different dimension．After unloading the recovery of matrix deformation resulted in the occurrence of structure relaxation．and the relaxation times incleased with the content of CB．
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发布时间：2021-03-19 - 摘要：This paper reports a technique to fabricate the stationary phase for high—speed protein flowthrough chromatography．Using glycerol aqueous solution(20 wt％)and n-heptane／toluene organic solvent as the porogenic agents,a novel type of bipomus matrix(BiPB)has been prepared by ultraviolet photo—polymerizing monomers (glycidyl methacrylate and ethylene glycol dimethacrylate)by a(W／O)／W emulsification technique．It was found that there were two types of pores(micropores and superpores)in BiPB,but there was only micropores in the micropomus beads(MiPB)created by O／W emulsification．The pores of BiPB were in the range of 10—100 nm and 1000～7300 nm,whereas those of MiPB were mainly 10～100 nm in size．The specific surface alea,hydrated density and particle size of BiPB were 41．9m2/g,1．08 g/mL and 42．8 μm,respectively,similar to those of MiPB(52．1m2／g,1．11 g/mL and 42．4 μm)．The static adsorption capacity of BiPB for bovine serum albumin(BSA)was also similar to that of MiPB．At a low flow rate(5cm／min),the dynamic adsorption eapacity(DAC)of BiPB for BSA was close to that of MiPB．At high flow rate(40 cm／min),however,the DAC of BiPB Was about three times as high as that of MiPB．The results indicate that BiPB columns were promising for high—speed protein chromatography．
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发布时间：2021-03-19 - 摘要：Electron beam(EB)curing of polymer matrix composites offers many particular advantages compared to conventional thermal curing．There has been a considerable development about the EB curing advanced composites for the use of aerospace and other industries in recent years．Most variety of epoxy resin has been confirmed to possess radiation reactivity and have alreody become chief resin matrices used in EB curable composites．The influences of initiator variety and concentration on the curing characterizations of epoxy resin system containing co-initiator benzophenone and isopropanol were analyzed．The variation regularities of temperature during the radiation,the gel fraction,damping factor and dynamic modulus of samples were studied．The experimental results indicate that under the same condition of epoxy resin content and absorbed dos,the addition of co—initiator can enhance the gel fraction of system,hat the enhanced extent of gel fraction does not increase with the increase co—initiator content,there exists an,optimal content of the co-initiator．With the increase of onium salt initiator,the enhanced extent of gel fraction induced by co—initiator will decrease．A temperature peak appears during the radiation,and the influences of co—initiator on the peak temperature and the glass transition temporature are the same as those on the gel fraction． The room temperature modulus and high temperature modulus of cured samples with low content of onium salt initiator have little change before and after the addition of co—initiator．When the diphenyliodonium hexafluorephosphate initiator content is high,the room temperature modulus of samples with co—initiator increases,while the hish temporature modulus has little changes．
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发布时间：2021-03-19 - 摘要：Monodispersed bismaleimide resin microspheres with diameter of 3／μm were prepared by chemically induced phase separation in polyetherimide and bimaleimide resin blends．The morphology of bismaleimide resin microspheres was investigated by SEM,and BMI resin micmsphere particle sizes and their distribution were characterized by LPS．The resuhs showed that the morphology of bismaleimide resin microspheres has evident relations with the structure of the used polyethefimide and polyesterimide．With increase of polyetherimide content,the microsphere size decreased．but the size distribution variation showed a wide-narrow-wide process．The DSC measurements showed that Tgof bismaleimide resin microsvheres was 215～218℃ slightly lower than that of the neat bismaleimide resin.
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发布时间：2021-03-19 - 摘要：Ultrafine fibrous membranes of pely(vlnyl alcohol)(PVA)were prepared by electrospinning from aqueous solutions of fully hydrolyzed PVA．The morphology of the electrospun PVA fibere was observed under a scanning electron microscope．The crystallization behavior was investigated by X—ray diffraction(XRD)．Mechanical properties and water up—take of the fibrous PVA membrane were also evaluated．Results suggested that the average diameter of ultrafine PVA fibers was(184±26)nm．XRD analysis exhibited poor development of crystallinity in electrospun fibrous PVA membranes．The tensile strength．tensile modulus and elongation at broak of the fibrous PVA membrane wero(5．10±0．77)MPa,(236±27)MPa and(8．28±2．38)％ respectively,indicating weak mechanical properties compared with the casting PVA film．Water up—take of fibrous PVA membranes was more than 300％,hisher than that of the casting PVA film．Crosslinking of the fibrous PVA membrane did not show significant influence on its water up-take．
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发布时间：2021-03-19 - 摘要：Isophthaloyl chloride(IPC),1,3,5-benzenetricarbonyl chloride(TMC),and l,2,4,5- benzeneteraearbonyl tetrachloride(BTTC)were used to polymerize with l,3-benzenediamine(MPDA),l,2- dimethylenediamine(DMDA) and piperazine(PIP)respectively on the surface of thermal stable copolymer poly(phthalazinone ether sulfone ketone)membranes．The components and characteristics of the composite membranes including their IR spectra,morphdogy,polymer crystallinity of the active layers and permeation properties,were carefully studied with various analytical methods such as infrared (IR) spectroscopy,atomic force microscopy(AFM),X-ray diffraction and permeation testing．Results indicated that when MPDA was used as the diamine monomer,the NaCl salt rejection of the composite membranes increased and the flux decreased with the increasing of the crosslink degree of the active layer．When TMC was used as the chloftde monomer,the same tondency was exhibited with the increasing of the tight degree that molecules of the active layers were packed．Thus．according to the special separation system,the molecular stmcture of the function layer can be designed to acquire the best separation properties．
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发布时间：2021-03-19 - 摘要：4,4'-bis(stearolamino)diphenyl methane(BSDM)can aggregate and self-assembly in vinyl monomers． As a result,the molecular gels of monomers,such as styrene,butyt acrylate,metbyl methaerylate and 2-hydmxyethyl methacrylate can be formed by BSDM aggregates．The temperature of gel／sol transition(TGS)was related to the concentration of BSDM．Increased mass fraction of BSDM resulted in an increase of hydrogen bonds andπ-π stack in the system,which need more energy to destroy．TEM pictures showed that BSDM self-assembled into long fibres by non-covalent interactions in vinyl monomers．POM pictures showed the formation of spherulites undergoing aggregation of self-assembled fibres before and after polymerization of vinvl monomers．
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发布时间：2021-03-19 - 摘要：Using cobaloxime boron fluoride(COBF)and AIBN as catalyst and initiator respectively,the catalytlc chain transfer bulk polymerization of 2-hydroxyporpyl methacrylate(HPMA)was carried out at 60℃and the low molecular weight polymer with a terminal double bond was prepared．The evolution of the apparent chain transfer constant(Capp)of COBF during the polymerization was determined by the Mayo equation and the CLD(chain length distribution)equation respectively．At the beginning of the reaction,the chain transfor constant showed values of up to about 2000,but with the increasing of the monomer conversion,the chain transfer constant decreases and keeps at a value of about 600 for sometime and then decreased again．The most likely cause for the catalyst deactivation is the stable cobalt-carbon bond formed at the first period of the reaction and then roached equilibrium point．When the polymerization proceeds up to middle and high conversion,the chain transfer polymerization is further manipulated by diffusions of polymeric propagating chain and catalyst molecules,and the apparent chain transfer constant fell to value of below 300．It has been found also,that the data determined by the CLD equation are usually lower than those by the Mayo equation．especially at high conversion stage．It is because that both original equations are available for the instantaneous produced polymer or the case of very lower conversion stage．However,the GPC measurements give molecular weight distributions of the cumulated products rather than the instantaneous produced polymer．The number-average polymerization degrees for the instantaneous produced polymers were obtained from the GPC data,and used in the Mayo equation method together with the modification of the monomer concentration．It was believed that the apparent chain transfer constants from the modified Mayo equation method are more available for the middle and high conversion cases．
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发布时间：2021-03-19 - 摘要：A series of AB2-type miktoarm star azobenzene polymers carrying one polystyrene(PS)arm and two poly[6-[4-(4’-methoxyphenylazo)phenoxy]hexyl methacrylate}(PMMAZO)arms were prepared by combination of atom transfer radical polymerization(ATRP)and chemical modification of the termini of ATRP derived polymers．The synthesis involved thme steps．The first step involved the preparation of ω-bromopolystyrene(PS)chain by ATRP using ethyl 2-bromoisobutyrate as initiator．Next,the bromo end groups of the resulting PS chains were derivatized into ω．ω-bis(bromo)-PS chains．The last step consisted of growing two PMMAZO arms by ATRP in chlorobenzene These precursors and miktoarm star polymers were characterized by proton nuclear resonance (1H—NMR),and gel permeation chramatograpy(GPC)．The information of PS(Br)2 and PS(PMMAZO)2 star pdymers confirmed the expected structure．The liquid crystailline(LC)behavior of these eopolymers was studied by DSC and POM．It was found that the miktoarm star copolymem had LC properties similar to PMMAZO those of homopdymer,and their thermal stability of the mesophases was improved,while the phase transition enthalpies were reduced.
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发布时间：2021-03-19 - 摘要：Nano carbon／poly(methyl methacrylate)sols were prepared by a method of pulsed laser ablation at the interface of target submerged in flowing liquid(PLA—IT／SFL),and the corresponding composite films were prepared by solution-casting．Spectrum studies indicated that there existed interaction between nano carbon particles and the PMMA matrix．which was consistent with the decrease in glass transition temperature of the composites with carbon content．TEM images revealed that a carbon encapsulated core／shell structure was formed in the composites,which could ensure good dispersion of carbon nanopartieles within PMMA matrix．The heat decomposition of the composites was less infiuenced by the introduction of nano carbon．
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发布时间：2021-03-19 - 摘要：Highly reflective and surface conductive silvered polyimide films have been prepared via single-stage self-metallization techniques．Polyimide was synthesized by copolyeondensation of a dianhydride(3,3’,4,4’-benzophenone tetracarboxylic acid dianhydride(BTDA))and two diamines(4,4'-oxydianiline(4,4’-ODA)and 4,4’-thiodianiline(4,4'-SDA))．The information of the silver particle was recorded by XRD．It explained that the silver particles were reduced and then aggregated during curing cycle．The influence on the optical properties．electrical properties and structural morphology resuhed from the incorporation 4,4’-SDA has been systematically investigated by UV—Vis,four—point probe and SEM．The results suggested that the introduction of 4,4’-SDA could facilitate silver reduction and migration．also could improve the surface conductivity．The metallized film achieved its optimum reflectivity at a mole ratio(4,4'-ODA and 4,4’-SDA)of 1．The thermal stabilities of the films were investigated by TGA．it showed that the silvered film Was better than its matrix．
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发布时间：2021-03-19 - 摘要：Poly(D,L—lactide)-grafted β-cyclodextrin as a biodegradable graft copolymer was synthesized by the ring-opening polymerization of D,L-lactide onto β-cyclodextrin(β-CD)usingtriethylamine(Et3N)as the catalyst．The graft eopelymers were characterized by means of IR、1H—NMR、DSC、WXRD and GPC measurements．The number average molecular weight was determined and the effect of feed ratio on the graft polymerization was also investigated．The results showed that the graft polymerization of D,L-lactide onβ-CD was successful．The graft ratio (G％)and graft efficiency(GE％)were 182．9％and 21．4％,respectively,when the molar ratio of D,L-laetide to structural glucose unit ofβ-CD was 30：1 and the reacting time was 10 hours．Compared with polylactide,the hydrophilieity and biocompatibility of the graft copolymer might be improved by the introduction of βcyelodextrin units．The obtained graft copelymer would be widely useful in drug delivery system,tissue engineering and surgical repairs．
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发布时间：2021-03-19 - 摘要：The influence of polyolefin elastomer(POE)content of polypmpylene(PP)／POE blends on fracture behavior has been studied using the essential work of fracture(EWF)method．Each matefial was iniected for preparing double edge—notched tensile(DENT)specimens of about 1．3 mm thickness．It was established that the essential work of fracture approach worked well for the PP and PP／POE(100／5)blend．The specific essential work of fracture,we,increased remarkab|y with adding POE．Some limitations of the EWF method was found with PP／POE (100/10 and 100／15)blends,which showed the necking phenomenon with DENT specimens studied．The specific essential work and plastic work of fracture required for yielding,we,y and β'Wp,y of each material were obtained．It was found that the We,y values of the PP／POE blends all increased remarkably,over two times larger than that of pure PP,and the β'Wp,y values increased gradually with increasing content of POE for the PP/POE blends．
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发布时间：2021-03-19 - 摘要：A series of tetrapolyamides were synthesized by low temperature solution polycondensatian of terephthaloyl dichloride with 1,2-dihydro-2-(4-aminophenyl)-4-[4-(4-aminophenonxyl)phenyl]-phthalazin-1-one (DHPZ-DA),4,4’-methylanedianiline(MDA)and p-phenylene diamine(PPD)．The synthesized polyamides were charaeterized by FHR and 1H-NMR．The polymers exhibitedinherent viscosities of l．24～2．32 dL／g and some were soluble in several organic solvents such as N-methyl pyrrolidone,N,N—dimethylacetamide and N,N— dimethylformamide．when the three kinds of diamines were in proper ratios．These polymers had glass transition temperatures above 301℃ and 5％ weight loss above 438℃ in nitrogen．Some polyamide films were prepared from their NMP solutions and had tensile strength of 64～72 MPa,elongation at break of 4．9％-8．1％ and tensile modulus of 1．7～2．1 GPa．The results showed that these polyamides showed the combination of excellent thermal properties,solubility and mechanical properties．
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发布时间：2021-03-19 - 摘要：The preparation of carbon fibers based on phenol formaldehyde by electrospinning was reported． Synthetical A-stage resol and PVA salutions of different mass ratios were used for electrospinning．After solidified at 150℃ for all hour,phenol formaldehyde(PF)fibers were obtained．When the PF fibers(mass ratio of PF and PVA as 1：2)were calcined at different temperature,the fibers based on PF were obtained,whose diameters were less than 200 nm．By field emission scanning eleotron microscopy(FESEM),the diameter and morphology of the fibers were observed and compared．The IR spectra showed that the fibers calcined at 600℃ were carbon fibers with expected morphology．
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发布时间：2021-03-19 - 摘要：The resin mixed PES-based fibrous adsorbents with open pore structure on the surface were prepared, and their adsorption behavior with BSA was studied．The edsorption isotberm demonstrated that the adsorption was well fitting the Langmuir model．The maximum adsorption capacity was about 139 mg BSA／g adsorbent．The resin Lewatit CNP80ws mixed PES—based fibrous adsorbent with more open pore structure on its surface had much more adsorption capacity with high adsorption rate for BSA．The effective diffusion coefficient of BSA in different resin mixed PES—based fibrous adsorbents Was in the range of l．82×10-14～8．7×10-14m2／s．The values of diffusion coefficient of BSA in these fibrous adsorbents were comparable with those in resins reported in the literatures．The influence of operation parameters on the behavior of adsorption and desorption of BSA for the weak acidic type cation exchange resin mixed PIES—based fibrous adsorbent in different strucyures was also investigated in this work．The pH of BSA buffer solutions was a very important parameter when the ion—exchange adsorbent was used for separation of proteins．The result indicated that the adsorption capacity was very low when the pH of BSA solutions was above the isoelectric point of BSA．
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发布时间：2021-03-19 - 摘要：A series of transparent ABS(T-ABS)resins have been prepared by emulsion in situ suspension polymerization process It was found that the transparence of T-ABS was satisfactory but the impact strength was lower when smaller SBR particles was used as rubber phase．The transparence of T-ABS was lowered when larger SBR particles were used as rubber phase．When SBR bi—modal particles(S70 nm／S400 nm=4／6～6／4,total rubber content 15％ to 18％)were used as the dispersion phase,the transparence of ABS resin was higher then 80％and the impact strength was between 90 J／m and 120 J／m．The brittle-toush transition of T-ABS resin using different SBR particles as rubber phase was preliminarily discussed．Synergistic toughening effect of different SBR particles on T-ABS resin was studied．The basic conditions under which the prepared T—ABS resin showed high transparence and satisfactory mechanical properties were found．
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发布时间：2021-03-19
Research Article
- 摘要：Dynamics of protein-like chains arc investigated by using Monte Carlo simulation method based on the modified ofientation．dependent monomer-monomer interactions model(ODI)．The diffusion coefficients for different chain length are calculated,and some comparisons with self-avoiding chains are also made．There exists a relationship between the diffusion coefficient D and chain length N for both protein—like chains and SAW chains．i．e D—N -a。．Here the valtie of αfor SAW chains is 1．02．however．the value of αfor protein-like chains iS 4．75,which iS 4～5 times larger than that of SAW chains．Therefore,dynamics of protein-like chains is different from SAW chains completely．These investigations may provide some insights into dynamics of proteins．
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发布时间：2021-03-19 - 摘要：A new kind of supramolecuIar building unit(defined as SBU)having two phenolic hydroxyl groups (proton donors)and two aromatic earbexyl groups(proton acceptors)was synthesized from 1,2,4,5-benzene tetraearboxylic acid and 4-hydmxy pyridine by a simple procedure．Based On1H—NMR,IR,EA and XRD analyses,the structure of SBU was defined．Under suitable conditions,supramolecular gels and fibers were formed from the building unit through multiple hydrogen bends between the donors and the aceeptors．These supramolecular structures demonstrated strong temperature dependant features．
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发布时间：2021-03-19 - 摘要：Polyesters with silanes in their main chains were synthesized．These polyesters possess interesting pmporties such as hish thermal stability,oxidative stability,low surface energy,water repellency and good dielectric properties．Thermal properties of these silane—containing polyesters were tested by differential scanning calorimety (DSC)and thermal gravimetric analysis(TGA)．The results show that the polyesters without substitutents have exeeUent thermal stability and excellent chemical resistance．While polyesters with substituents have good solubility in polar organic solvents such as THF,DMF,DMSO,NMP,DMA and could be made into membrane material easily．These novel silane--containing polyesters could be processed as conveniently as other thermo-plastics and have high application temperature．
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发布时间：2021-03-19 - 摘要：Soluble polymeric ehiral binaphthol(BINOL)ligands have been synthesized thmugh copolymerizafion of 3,3'-bis(hydroxymethyl)-2,2’-bis(methoxymethy leneoxy)-1,1’-binaphthyl,1,6-dihydmxyhexane and 1,4-benzene diearbonyl chloride followed by deprotection of methoxymetbyleneoxy groups by‘PrOH／HCI,and their application in the enantioselective addition of dietbylzinc to benzaldehyde was investigated．All soluble polymeric chiral BINOL ligands were characterized by IR、1H—NMR、GPC and elemental analysis．which clearly demonstrated the formation of polymeric ehiral BINOL ligands．These soluble polymeric chiral ligands were found to be effective in the addition of diethylzinc to benzaldehyde either in the presence or in the absence of i(OiPr)4 with higher catalytic activities and lower enantioseleetivities．In the latter case,the dendritic chiral BINOL ligands showed much higher catalytic activity and a little higher enantioselectivity than BINOLs．
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发布时间：2021-03-19
Research Bulletin
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