最新刊期
卷 ， 期 6 ， 2006
- 摘要：A series of polyesters PBSBS,Poly(butylene succinate—co-butylene phenylsuccinate),were synthesized from the polycondensation of succinic acid and phenylsueeinic acid with 1,4-butanediol．The compositions and thermal properties of resulted homopolyesters and copolyesters were investigated by 1H—NMR,differential scanning calorimetry(DSC)and X-ray diffraction．The results suggested that the introduction of the comonomer containing a phenyl side-group led to a change in thermal properties and crystallization behavior．The glass transition tomperature increased with the increasing of the comonomer composition,while the equihbrium melting temperature obtained by the Hoffman—Weeks plot decreased significantly．Furthermore,an Avrami method was used to analyze the kinetics of isothermal crystallization of PBS and PBSBS-10．The Avrami exponents,estimated by Avrami plots,ranging from 2．8 to 3．0 for PBS and 2．7 to 2．9 for PBSBS-10,indicated that the mechanism of crystallization for both homopolyester and copolyester was a tridimensional growth with heterogeneous nucleation．Meanwhile,X-ray diffraction showed that there was almost no effect of the phenyl succinate unit on the crystal structure．
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发布时间：2021-03-19 - 摘要：Organic—inorganic hybrid UV—curable coatings were synthesized through blending the UV—curable components and the stabilized titania sol prepared via sol—gel process of tetrabtyl titanate(TBT)with three different stabilizers,acetoacetone(acac),isopropyl tri(dioctyl)pyrophosphato titanate coupling agent(TTPO)and a polymerizable organic phosphoric acid (MAP)．FT-IR was employed to fllow the sol process and the photopolymerization of the hybrid systems．The SEM observation of etched photocured hybrid film showed that the size and dispersion of titania particle in the organic matrix were dominated by the properties of these stabilizers．The inorganic particles in the hybrid cured film uniformly dispersed with the diameter of about 20 nanometers iT TTPO used as stabilizer during sol—gel process．Physical properties of the hybrid cured film were determined．it is interesting that the hardness and flexibility of the photocured hybrid films were improved simultaneously contrasted to those of pure organic UV—curable formulation．
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发布时间：2021-03-19 - 摘要：Chitosan(CS)is suggested for using in orthopedic applications to provide temporary mechanical support for the regeneration of bone cell ingrowth due to its good biocompatible,non-toxic,biodegradable,and inherent wound healing characteristics．In the present study magnetic iron oxide／hydroxyapafite(HA)／chitosan rods were prepared by blending magnetic iron oxide／hydroxyapatite with chitosan via in situ precipitation．Magnetic iron oxide／hydroxyapafite was obtained by co—precipitation method．X—ray diffraction(XRD),size distribution and magnetic measurements were performed to characterize the as—prepared magnetic iron oxide／hydroxyapatite,the results confirmed the formation of magnetic iron oxide／hydroxyapatite with particle size of around 1380 nm,and its saturated magnetic intensity(Ms)was about 33．3 emu When the total inorganic and CS content kept constant,effect of the rafto of magnetic iron oxide and hydroxyapatite on the mechanical properties was invested,the reults showed that the best ratio of magnetic iron oxide and hydroxyapatite was 3：17,and the effect of the ratio of magnetic iron oxide／HA and chitosan on the mechanical properties was also investigated,9：91 was the best ratio．It could be also concluded from the three point bending test that the mechanical properties improved as the inorganic content decreased.Bending strength and bending modulus of the magnetic iron oxide／HA／CS composite were 87．0 MPa and 1．57 GPa,respectively．The mechanical pmperties of magnetic iron oxide／HA／CS composites were stronge while compared to those of human bones,due to the special performances of magnetic iron oxide and hydroxyapatite,this composite could have potential use in bone repair domain．The microstructure studies of magnetic iron oxide／hydroxyapatite／chitosan rods were carried out by scanning electron microscopy(SEM),and SEM mierographs supported the results of the three point bending test．
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发布时间：2021-03-19 - 摘要：PP／EPR in situ blends were prepared by the sequential polymerization technique using a Ziegler-Natta catalyst MgCl2,TiCl4／BMF(BMF is 9,9-bis(methoxymethyl)fluorine as an internal donor)．The content of ethylene unit in blends was adjusted by modifying the time of ethylene—propylene copolymerization．The structure and morphology characters of the blends obtained were investigated by nuclear magnetic resonance(NMR),gel permeation chromatography(GPC),dynamic mechanical analysis(DMA),differential scanning calorimetry(DSC),scanning electron microscopy(SEM)and polarized light microscopy(PLM)．The results suggested that PP/EPR is a complex multiphase mixture including PP,EPR and EP block copolymer The presence of EP block copolymer greatly improved the compatibility between the PP matrix and the EPR dispersed phase in the muhiphase system．The compatibility between the PP matrix and the EPR dispeersed phase in the muhiphase system．The change of the ethylene unit content in PP／EPR remarkably influenced the crystalline morphology of PP with increasing the content of ethylent unit in the blend,the PP spherulites became smaller and irregular．
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发布时间：2021-03-19 - 摘要：Polyaluminocarbosilane(PACS) was synthesized by reaction of polysilocarbonsilane(PSCS)with Al- (AcAc)3,(AcAc：acetylacetonate)at normal pressure and high temperature,then PACS fibers were prepared through melt spinning of PACS．The composition and structure of PACS fibers were examined by measurements of element analysis,GPC,XPs,IR,29Si-Solid NMR and27Al一Solid NMR；the properties of PACS fibers were studied by TG,IR,weight gain and SEM．PACS synthesiznd through the reaction of AI(AcAc)3 with PSCS by mass ratio of 6：100 was best fitting for preparing PACS fibers．Its empirical formula was SiC2.0 H7.5O0.13Al0.018 and the molecular weight was about l700．The chemical structure unit included SiC4,SiC3H etc,and si—O—A1 bonds also existed in the PACS fibers．Under nitrogen atmosphere,the ceramic yield of PACS fibers was about 52％；during the curing process of PACS fibers in air．the Si--H bond reacted with oxygen,and Si—O—Si bond was formed．The ceramic yield of cured PACS fibers was about 80％ and the properties of SiC(OA1)and SiC(A1)ceramic fibers were excellent．It was proved that PACS fibers were very fitting for making SiC(OA1) and SiC(A1)ceramic fibers．
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发布时间：2021-03-19 - 摘要：The mini-emulsification and mini—emulsion polymerization of methyl methacrylate(MMA)／nanosilica dispersion were investigated．The rnimi-emulsification was carried out by ultrasonic treatment．It was found that more than 90％ silica particles would be escaped from submicren MMA droplets to water phase after ultrasonic treatment when MMA/unmedified silica dispersion was used．Almost all silica particles stably stayed in MMA droplets when silica particles were treated by 3-(trimethoxysilyl)propyl methacrylate(MPS)coupling agent at 40℃ for 24 h before being dispersed in aqueous phase．This was caused by the effective grafting of MPS onto silica particles．and the decrease of hydrophilicity of silica particles．Poly(methyl methacrylate)／nanosilica composite latex particles were prepared by mini—emulsion polymerization of silica-containing MMA using sodium lauryl sulfate(SDS)as the surfactant and hexadecane(HD) as the costabilizer．The composite latex particles were dispersed stably,the surfaces of composite latex were sleek and the silica particles could hardly be found in the water phase．It was considered that the silica particles had been encapsulated in the composite particles．
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发布时间：2021-03-19 - 摘要：Supported initiator was synthesized by exchange of Na+ and initiator 2,2'-azobis(2-methylpropion-amidine)dihydrochloride(AIBA)．The MMT-supported initiator was used to initiate the emulsion polymerization of styrene and prepare PS／MMT nanocomposite．The clay-supported initiator and the structure of PS／MMT nanocomposite were characterized by XRD,TGA,DSC,TEM and extraction method．The results indicated the successful intercalation of initiator molecules in the galleries of clay layers since the MMT-supported initiator showed increased d-spacing values and more weight loss in the temperature range of 200～600℃．During polymerization,the initiator intemalated in the layers of MMT decomposed to produce radicals that initiated the polymerization of styrene．The decomposition of initiator also caused the exfoliation of MMT layers．In the PS／MMT emulsion,the layers of MMT were adhered on the surface of polymer particles．The final nanocomposites were formed by coagulation and melting．In nanocomposites,the layers of MMT were uniformly dispersed in polymer matrix．Some MMT layers were fully exfollated into individual ones,and the others dominantly existed as nano—aggregates with thickness of around 10～20 nm．The results of extraction experiment showed that a great deal of PS chains was grafted on the layers of MMT．The molecular weight and molecular weight distribution of PS grafted on the layers of MMT were different from those of tlle freeps polymer．
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发布时间：2021-03-19 - 摘要：A series of poly(ethylene oxide)(PEO)／LiClO4 complex samples with different molar ratios were studied systematically by solid-state high—resolution 13C and 7Li—NMR spectroscopy．It was found that with the presence of a small amount of water(9％～16％by weight),the initial increase of LiClO4gradually destroys crystals formed by PEO,whilc further increase of LiClO4 brings about the crystals formed by PEO and Li+．When the molar ratio of PEO to LiCl4 is in the range of 6／1 to 8／1,the complex samples are completely amorphous．The7Li-NMR results indicate clearly that the existence of water hinders the formation of Li+-PEO crystals．
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发布时间：2021-03-19 - 摘要：Waterborne raspberry—like PMMA／SiO2 composite microspheres were synthesized by a soapless one-step method in the presence of aqueous silica sols and cationic monomer 2-(methacryloyy)ethyhrimethylammonium chloride(MTC)．MTC was eopolymerized with MMA via radical polymerization and then nanosilica particles were deposited onto the surfaces PMMA particles in the aqueous medium thransh electrostatic interaction between negatively charged nanosiliea particles and positively charged MTC．The whole process neither required surface treatment for nanosiliea particles nor additional surfactant or stabilizer．TEM indicated that electrostatic interaction between silica and MTC was strong enough for the formation of long-stable nanocomposite microspheres with raspbetry-like morphology．The average particle sizes of the obtained composite microspheres ranged from 180—300 nm,depending on the precise formulation．Thermogravimetric analysis indicated silica content in the nanocomposite microspheres ranged from 16．4％～40．8％．Some influencing parameters such as initial silica amount and MTC amount on the diameter,silica contents and morphologies of the composite microspheres were investigated in detail.A possible formation mechanism of the raspberry—like composite microspheres was proposed．
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发布时间：2021-03-19 - 摘要：Poly(1,5-diaminoanthraquinone)(PDAAQ)was synthesized by a chemical oxidation method and used as cathode material in rechargeable lithium batteries．IR spectrum confirms its molecular constitute．Experiment results show that the particle size d0.5 is 7．9 μm and PDAAQ has the specific surface area of 8．9 m2·g-1,also its conductivity is 0．8 S·cm-1．All of these properties satisfy the requirement of being used as cathode material．When used in rechargeable lithium batteries,the capacity and cycle performance are contributed by the cooperating effect of the quinonc group and polyaniline skeleton,which is proved troush the charge—discharge experiment．It is found that in Li(CF3SO2)2N／PC-DGDM electrolyte system PDAAQ’s first discharge capacity is 221 mAb·g-1 which reduces to 177 mAh·g-1 with 80％ capacity retention after 40 cycles．Therefore PDAAQ is a very promising cathode material for rechergeable lithium batteries．
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发布时间：2021-03-19 - 摘要：Organic—inorganic hybrid(SAV)supported zirconocene was synthesized and its catalysis on ethylene polymerization was examined．The SAV was synthesized by eopolymerization of 4-vinylpyridine with vinyl silica monomer(SA),which was modified by reacting silica with allyltrimethoxysilane(APS)．After treated by MAO．the SAV was reacted with Cp2ZrCl2 to form organic—inorganic hybrid supported metallocene．The chemical structure and the composition of SA and SAV have been characterized by sdid—state13C-NMR,XPS,and elemental analysis (EA)．The SAV supported zirconocene catalyst was effective in ethylene polymerization at a relatively low MAO level (A1／Zr=600)giving higher activity than that supported by SiO2．
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发布时间：2021-03-19 - 摘要：The blends of novolac cyanatc ester and bisphenol A epoxy rosin weie expected to attain the high thermal resistance of novolac cyanate ester and the excellent processsablity of epoxy．Little work has been done on novolac cyanate ester／epoxy systems before because the high purity novolac cyanate esters wwas very difficult to synthesize．In this work,a high purity novolac cyanate ester(Mn=900)and a bisphenol A epoxy(E-51)with an equal molar ratio co-cured system was selected to study the reaction pathway and mechanism by FTIR trace method in the molten state．Isothermal cure conditions include 150,180,200,220℃ were used to conduct the co-cured reactions．The reaction was found to be complex and involve several pathways．When cured below 150℃,trimerization of novolac cyanate ester was the main reaction and the trimerization rate was accelerated after the addition of epoxy．An open ring co-polymerization between epoxy and carbamate,which is an impurity contained in novolac cyanate ester or induced by reaction with water from environment or from epoxy,can always occur．This made a slow dissipation of epoxy in the conversion-time plot．No reactions between epoxy and novolac cyanate ester was found in this stage. When temperature was raised up to and over 180℃,oxazolidinone ring was formed and such a reaction increased the dissipation of epoxy function．As in the case of cyanate function,the transformation of triazine rings quickly reaches it’s maximum value and then descent．It was found that increased temperaturos facilitated the formation of oxazolidinone．The transformation rate of triazine ring can easily reach 1．0 while the α that value of oxazolidinone formation is less than 0.5.
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发布时间：2021-03-19 - 摘要：Partial hydrolyzed polyacrylamide(HPAM)and associating partial hydrolyzed polyacrylamide(AHPAM) were compared focusing on the structure and rheology relations,which play important roles in enhanced oil recovery.The molecular associating state in AHPAM aqueous solutions is studied in terms of molecular weight measured by intrinsic viscosity and static light scattering method,associate size and behaviors by the dynamic light scattering and viscosity method,as well as the rbeologlcal properties at various concentrations,temperature and salinity.The results on AHPAM aqueous solution reveal that the association exists in broad concentrations．It is suggested that the concept of crifical association concentration should be related to the range of semi-dilute to entangled region rather than the starting concentration of bydrophobic association．The change of the associating structure under shear was reflected in the shear viscosity which dropped down suddenly,when the shear rate was up to 10 s-1,but this phenomenon became less evident at highly entangled concentrations．In addition,the elongational viscosity of AHPAM in converging flow decreased with flow rate and also reflected the intrinsic feature of short range interaction of the association．The relevant influences of polymeric hydrophobic association on the enhanced oil recovery were discussed．
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发布时间：2021-03-19 - 摘要：The complex of BDIE·[zn—Al]is a cheap catalyst for copolymerizatrion of carbon dioxide,which was prepared by using zinc acetate anhydrous,aluminum isopropoxide and precursor N,N’-bis(2,6-diisopropylphenyl)-2．4-ethyldiimine(BDIE)．It is nonsensitive to moisture and easy to handle in the copolymerization．However,its low catalytic efficiency limited its application．In this paper novel technologies for the copolymerization of CO2 and cyclohexene oxide were developed using BDIE·[Zn-Al]catalyst．These new processes include：(1)aging BDIE·[Zn-A1]with all appropriate amount of cyclohexene oxide(CHO)as a catalyst；and(2)CO2 and cyclohexene oxide are fed in three batches during whole reaction．Effects of aging conditions such as aging time and temperature,the molar ratio of CHO／BDIE·[Zn-Al]were investigated in detail．The hishest catalytic efficiency 69．9 g／g was obtained with feeding monomere in three batches,molar ratio of CHO／BDIE·[Zn—Al]=1．5：1,aging time of 4 h,aging temperature of 25 ℃,reaction temperature of 80℃,catalyst concentration of 0．1 g／mL and CO2 pressure of 2 MPa．
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发布时间：2021-03-19 - 摘要：A nonlinear optical(NLO) azo polyimide has been synthesized by post-polymerization azo coupling reaction．In the process,a new diamine monomer,([2-(N—ethylanilino)-ethoxyl]P—phenylenediamine),was synthesized and then reacted with 2,2-bis(3,4-dicarboxyphenyl)hexafluomisopropylidene dianhydride(6FDA)to obtain a potyimide—based precursor polymer．The precursor polymer owned excellent solubility in DMSO,DMF and other polar organic solvents．Through post—polymerization azo—coupling reaction of the precursor polymer,the NLO azo polyimide was obtained．This synthetic scheme can avoid exposure of the ago chromophore to the rigorous imiderization conditions required in the synthesis of polyimide．By the scheme,the degree of functionalization of the azo polyimide can reach abort 100％ under mild reacting condition and the product can be easily separated from the solution．The polymer synthesized was characterized by using spectroscopic methods and thermal analysis．The polymer shows good solubility,processibility and thermal—stability．The d33 of the polymer film is 39．2 pm／V．
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发布时间：2021-03-19
Research Article
- 摘要：Poly(arylene ethynylene)s,P1 and P2 containing 1,3,5-triazine and chalcone unites respectivdy,were synthesized by Sonogashira coupling reaction．These polymers exhibited good solubility in common organic solvents,such as dichloromethane,chloroform,and tetrahydrofuran．The molecular weight Mw of P1 was 6390 with polydispersity(PDI)being 2．33 and that of P2 was 6870 with polydispersity(PDI)being 1．85 characterized by GPC．The photophysical properties were analyzed by solution and solid state photoluminescence spectroscopy．P1 emitted blue fluorescence at around 441 nm in CH2Cl2 or THF solutions under UV excitation．The photoluminescence behavior of P2 was dependent on the solvent,with green emitting light at around 550 in CH2Cl2 solution and 500 nm in THF solution．Powder photoluminescence spectra of P1 and P2 showed that the peak wavelengths respectively shifted to 530 and 605 nm．
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发布时间：2021-03-19 - 摘要：Linear low-density polyethylene(LLDPE) was melt blended with styrene-maleic anbydride copolymer (SMA)．The blending films were then immersed in pely(ethylene glycol)400(PEG400)at room temperature．The surface composition of the blend films was determined by Fourier transform infra-red spectroscopy coupled with an variable incidence angle attenuated total reflection accessory(ATR—FTIR)．It has been found that PEG400 was grafted onto the surface of the films via esterification with SMA．PEG immemion promoted enrichment of SMA onto the surface of the films．The water contact angle data show that grafting of PEG400 can greatly improve the hvdrophilicity of the PE surface．These experiments show that surface functionalization of polyethylene films by blending SMA and then surface grafting of PEG is a feasible process,which suggest a viable and simple route for PE surface modification via blending and grafting．
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发布时间：2021-03-19 - 摘要：A series of polyimide／SnO2 hybrid membranes supported on TiO2／kieselguhr-mullite(K-M)were prepared via a sol-gel process．Their morphologies,chemical structures,thermal performances,pore distribution and gas permeability were characterized by means of TEM,FTIR,TG／DTA,DSC,N2 adsorption and gas permeability measurements．The results showed the SnO2 phase was well dispersed in polyimide matrix．The SnO2 phase connected with the polyimide through the pendant carboxyl groups along the polyimide chain．The polyimide／SnO2 hybrid membranes possessed finely thermal stability．The hybrid membranes showed better separation properties for H2,CO2,N2 and H2O when compared to those of pure polyimide．The separation factors of the polyimide／SnO2 hybrid membranes with 25 wt％ SnO2 are 58．2,42．4,51．2 and 68．8 for H2／N2,CO2／N2,CO／N2 and H2o／N2 contents, respectively．
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发布时间：2021-03-19 - 摘要：A modification of natural rubber latex(NRL)grafted with perfluoroalkylethyl methacrylate(Zonyl TM) under sensitizer butyl acrylate(BA)by60Co gamma ray emulsion copelymefization was presented in this paper.The components of the NRL films were studied by Fourier-transfer infrared(FT-IR)spectrometry．The contact angle (CA)analysis showed that the NRL films exhibited a high water contact angle after modification,which changed of 81．1 degree to 1 10 degree．The surface analysis of X-ray photoelectron spectroscopy(XPS)revealed that the fluorinated segments were preferentially self-organized at the film—air surface．Furthermore,the effect of the Zonyl TM and BA contents 0n the preperties of NRL films was discussed by CA in detail．It showed that the NRL films with 0．94 wt％ ZonvJ TM and 2．77 wt％ or 4．55 wt％ BA had better modification effect than the others.
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发布时间：2021-03-19
Research Bulletin
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