最新刊期
卷 ， 期 2 ， 1999
- 摘要：Bisphenol A epoxy resin was emulsified to be waterborne system by incomplete phase inversion technique at low concentration of the emulsifier (233wt%),and both stress sweep and dynamic frequency sweep tests were performed to characterize the rheological behavior of the system during phase inversion evolution.It is shown that the system is a Newtonian fluid with an almost constant viscosity independent on stress before the phase inversion point.At the phase inversion point,the viscosity of the system at low stress increases slightly and the dynamic rheological parameters(storage modulus,loss modulus and complex viscosity) reach their minimum values.After the phase inversion point,the dynamic rheological parameters increase greatly with adding water.It is suggested that the lubrication of water phase among the waterborne particles cominates at the phase inversion point,and phase inversion progress still continues with adding more water.
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发布时间：2021-03-19 - 摘要：Melting behavior of poly(ethylene terephthalate) industrial fibres from various domestic and overseas factories is studied by differential scanning calorimetric (DSC) measurements.The thermograms of polyester fibres often show double melting endotherms.This behavior has been attributed to melting of less stable crystallites followed by recrystallization during scanning in differential scanning calorimetry experiment.Combined with data obtained from wide-angle X-ray diffraction,small-angle X-ray scattering,birefringence and density, it is pronounced that the continuous network structure plays an important part on melting behavior of industrial poly(ethylene terephthalate)fibers in addition to the effect of crystal size,crystal perfection and crystal size distribution.In addition,the degree of crystallinity fwc(DSC) calculated from the heat of fusion is not very satisfying for describing crystalline weight fraction of industrial PET fibres.
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发布时间：2021-03-19 - 摘要：The PS specimens were subjected to three point bending under different loading rate.Through the analysis of experimental results,the forming process of the mirror zone and the rib zone is the principal process of energy consumption.With the increase of loading rate,the size of mirror zone decreases and tends towards constant progressively.At the same time,the rib width decreases while the roughness of rib zone increases.A minimum appearing at the loading rate 2.5m/min exists in the relationships between energy consumption and loading rate.When loading rate below 2.5m/min,the fracture surfaces were chiefly made up by the mirror zone and the last fracture zone.The change of break energy is mainly decided by the change of the size of mirror zone.When the loading rate beyond 2.5m/min,the fracture surfaces were conposed of the mirror zone,the rib zone and the last fracture zone.The change of energy consumption is primarily decided by the roughness of rib zone.
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发布时间：2021-03-19 - 摘要：This paper describes the application of atom transfer radical polymerization for the synthesis of controlled copolymer of styrene and butyl methacrylate by using 1 phenylethyl chloride (1PECl),CuCl and bipyridine in a mole ratio of 1∶1∶2 at 130℃. The block copolymers of butyl methacrylate(BMA) and styrene(S) with predicted molecular weight (1×104～4×104) and narrower molecular weight distribution (1.1～1.5) were obtained.The random copolymer compositions were determined by 1H-NMR spectroscopy and the reactivity ratios,γSt=0.91,γBMA=0.32,were evaluated by the extended Kelen-Tudos method.It was found that St is more reactive than BMA in atom transfer radical copolymerization.
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发布时间：2021-03-19 - 摘要：The influence of catalyst on the copolymerization of epoxy and cyanate was investigated,and the mechanism of their copolymerization was discussed.The catalyst can obviously accelerate the curing of the resin to decrease the curing temperature.The three kinds of reactions(cyclotrimerization,co reaction and polyetherification) in their copolymerization are not simultneous and independent to each other.In the lack of cyanate functional group,the main structures are oxazoine and polyether structure in the cured resin,and the triazine ring structure is of miner importance.
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发布时间：2021-03-19 - 摘要：The purpose of this article is to explore the methods preparing biodegradable microspheres delivery system of vaccines by oral targeting administration.A series of polymers of DL lactide and polyethylene glycol(PEG) with different contents of PEG were synthesized and the microspheres containing human serum albumin(HSA) were prepared by a solvent evaporation method using a W/O/W emulsion.The scanning electron micrograph of microspheres showed a smooth and spheric surface.The size of microspheres could be controlled between 0.5～10μm,which is essential for microspheres to reach the target sites.The amount of protein in microspheres was 2.5% determined by CBB method and the entrapemnt ratio achieved approximately 80%.It was concluded that the properties of polymers,stabilizer system and solvent in oil phase and great effect on the formation of microspheres,particle size and the protein entrapment ratio.In vitro studies indicated that protein-carrying microspheres of PLA had a larger burst-effect than that of PELA-10.
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发布时间：2021-03-19 - 摘要：A novel aliphatic polycarbonate based polyurethane (PPCPU) was synthesized with various amounts of crosslinking agent and isocyanate.The prepolymer used was poly (propylene carbonate),which was prepared by copolymerization of carbon dioxide and propylene oxide.PPCPU was characterized by FTIR,DSC,TG,TEM,water absorption and mechanical property measurements.It is found that PPCPU had tensile strength as high as 20 MPa,water resistance better than conventional polyether polyure thane,and thermostability higher than the starting aliphatic polycarbonate.
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发布时间：2021-03-19 - 摘要：C-NMR spin lattice relaxation times ( T1), line widths, nuclear Overhauser effcts (NOE) at room temperature have been measured for radiation induced crosslinked cis 1,4 polybutadiene. As crosslinking increases T1 is almost invariant, line width of —CH2— group increases markedly, NOE ratio of —CH2— group decreases significantly too.This implies that long range chain segment motion is hindered and —CH is produced in crosslinking cis 1,4 polybutadiene.
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发布时间：2021-03-19 - 摘要：Fibres of ultra high molecular weight polyethylene(UHMW PE) were prepared with the gel fibre drawing method, in which the solvent and extraction solvent used were a general kerosene and gasoline respectively. The structural changes in the fibres during drawing process were examined by wide angle X-ray diffraction(WAXD),polarising optical microscopy(POM) and density gradient column.During drawing process,folded chain structure transformed into extended chain one in the fibre,the density of fibres increased,and the dimensions of orthorhombic crystallite size trended towards a narrow distribution with the increasing draw ratio simultaneously.The orthorhombic unit cell dimensions for the fibre with a draw ratio of 40 were a=0.732nm,b=0.491nm,and c=0.254nm.In the fibre with a draw ratio of about 40,kink bands were observed.They are suggested to correspond to the local crystalline slip due to the effect of winding tension,and the smaller the winding roller diameter,the more clearly they can be observed.In present work,the effect due to the existence of kink bands on the structure of orientation and crystallinity of fibre bulk was not observed.
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发布时间：2021-03-19 -
FREE RADICAL OLIGOMERIZATION OF STYRENE WITH 2,4 DIPHENYL 4 METHYL 1 PENTENE AS CHAIN TRANSFER AGENT
摘要：The polystyrene oligomers(PS) with M w =1,500～15,000, Mw/Mn≈2 were prepared by free radical oligomerization with α methylstyrene dimer ( α MSD,2,4 diphenyl 4 methyl 1 pentene) as chain transfer agent.The relationship between α MSD and the molecular weight of the oligomers was studied through thermal oligomerization and BPO initiated oligomerization.It is shown that the molecular weight of PS obviously decreases with the increase of [α MSD] but keeps in almost constant when [α MSD] becomes larger than 10% tither in thermal or BPO initiated oligomerization.The molecular weight of PS was determined based on intrinsic viscosity,1H-NMR,13C-NMR and GPC.It is confirmed that there is a active -C=C- terminal unit in PS by 1H and 13C-NMR spectrometries.- 19
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发布时间：2021-03-19 - 摘要：Cosolvent effect on micelle formation of PEO PPO PEO block copolymer in aqueous solutions were studied by fluorescence probe method in the work. The cosolvents used included methanol(MOH), ethanol(EOH), 1 propanol(POH), 2 methoxyethanol(ME), ethylene glycol(EG), ethanolamine(EA) and ethylenediamine(ED) that were introduced to the aqueous solution of block copolymers as a component of solvent. It was found that the introduction of some cosolvents which were compatible well with both water and PPO segments prevented the micelle formation and made the CMT increase,while other cosolvents were favorable for micelle formation and CMTdecreased.The cosolvents with difunctional group and smaller size were benefited for the formation of micelle with closed packaging unclei.It was also found,in condition that there was a little cosolvent introduced,the polarity of internal nuclei of micelle was mainly determined by the degree of packaging,but little relevant with the polarity of cosolvents.
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发布时间：2021-03-19 - 摘要：Cd(MA)2 was synthesized. Through the copolymerization of Cd(MA)2/Styrene/Methylacrylic acid, transparent optical resins containing Cd2+ were obtained. The monomer solubility and polymer transparency phase diagram of this kind of copolymer were determined and discussed. The study of optical properties indicated that fix the content of MA, with the ratio of Cd(MA)2 increasing, the refractive index ( n D) of the resin decreased but Abbe number ( v D) increased linearly. In the transparent region,the nD of the copolymer were determined,and the refractive index of polymer component nD(P Cd(MA)2)=1.5788、nD(PMA)=1.4992 were obtained indirectly.
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发布时间：2021-03-19 - 摘要：The paper described the synthesis of a new monomer containing spiro orthoester groups using epoxy resin(E54) and γ butyrolactone with a catalyst of BF3·OEt2. This spiro monomer was used to modify epoxy resin (E44). It was found that the addition of the monomer into epoxy resin system enhanced the conversion of epoxy groups during plymerization in the presence of ethylamine trifluoroborane (BF3·NH2Et). This proved that they could undergo a copolymerization. The adhesive tensile and shear strengthes of the modified epoxy resin increased obviousely as the content of the monomer increased.The above observed phenomena were discussed,and the relationship between shrinkage and adhesive strengthes was investigated.The mechanical properties of the modified epoxy resin matrix were also measured.
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发布时间：2021-03-19 - 摘要：Seed latex S1 consisting of styrene(St) and methyl methacrylate(MMA), and S2 consisting of St. MMA and AA(acrylic acid), were first prepared by batch process, then a series of St MMA-AA or MAA(methyl methacrylate) terpolymer latexes containing different amount of unsaturated acid monomers were synthesized by continuous seeded emulsion copolymerization in the absence of emulsifiers, and the composite latexes were then treated by alkali and acid subsequently at 90℃ for 3h. Particle size and morphologies were characterized by TEM using phosphotungstic acid as staning agent.The influence of swelling agent MEK(methyl methacrylate) and the initial pH value in the alkali treatment on the formation of multihollow were investigated.Experiments showed that multihollow particles,accompanied by the largest volume expansion,were observed after treatments for S1/P(St-MMA-AA) using 8.0% mole of AA in the second step monomers.At the present conditions.AA is more suitable than MAA to prepare the desired multihollow latexes particles,and seed latex S1 is more effective than S2 on the forming multihollow structure in latex particles.
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发布时间：2021-03-19 - 摘要：Visible light photopolymerization of triethyleneglycol dimethacrylate (TEGDMA)initiated by camphorquinone(CQ) and peroxide (PO) combination systems were studied with photocalorimetry for the purpose on dental materials. As comparison with CQ alone, the systems composed of CQ and peroxides PO are more effective. The results obtained indicated that the peroxide added, such as dicumyl peroxide (DCPO), di tertbutylperoxide(DBPO) greatly accelerates the polymerization rate( R p) and shortens the time of R maxp reached(tmax),however their corresponding hydroperoxide,such as tert-butylhydroperoxide(TBPO) and cumyl-hydroperoxide(CHHP) appears a less efficient.The reaction mechanism of the synergistic effect for CQ/PO system was suggested to be a energy transfer process from excited CQ* to peroxide,which results in a significant facilitation of the active radical generation from peroxide.The rate-enhancement of polymerization was also found in the presence of oxygen.
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发布时间：2021-03-19 - 摘要：To study the water solution properties of hydrophobically modified poly(N isopropylacrylamides), the copolymers of NIPAM and a series of acrylic ester and cholesteryl acrylate were synthesized. The surface activity and micelle behavior of the copolymers in aqueous solution were deterimned by surface tension methods. Simultaneously, the Lower Critical Solution Temperature (LCST) of the copolymers was studied by fluorescence probe method. Results shows that the LCSTs of the copolymers have no obvious change with the change of the alkyl length of acrylic ester and the molar ratios of acrylic ester for the copolymers,but they are all lower than the homopolymer of Poly(N-isopropylacylamide)(PNIPAM).The microviscosity of the copolymers in aqueous solution was studied by fluorescence polarization.Results show that their microviscosity do not change with the change of the alkyl length of acrylic ester and the molar ratios of acrylic ester for the copolymers.It indicates that at room temperature the copolymers can almost form the indetical micellar structure.
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发布时间：2021-03-19 - 摘要：Optically active polyesters based on L+ diethyl tartrate and terephthaloyl chloride (TPC),isophthaloyl chloride (IPC),o phthaloyl chloride (OPC) are synthesized and characterized by using model compound,computer simulation for the geometric minimization,UV spectra and circular dichroism.The optical activity of obtained polyesters has close relationship with the diacid chlorides used,i.e:TPC>IPC>OPC.The morphology of the polyesters have been discussed by DSC and X ray methods.
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发布时间：2021-03-19
Research Article
- 摘要：Cellulose can be easily oxidized to oxycellulose with periodic acid,which can serve as a carrier for the immobilization of hemoglobin acting like a bionic gill,to extract oxygen from sea water,which may provide a source of oxygen for human life support in an undersea environment.The present paper studied the mechanism of hemoglobin immobilization on periodate oxycellulose.It was found that only by the unique activation procedure,that the cotton was first oxidized with NaIO 4,then treated with 5.0mol/L NaOH and again oxidized with NaIO4,the carrier thus obtained was able to immobilize a very high amount of Hb,i.e.1.0g Hb/g cellulose.When cellulose was oxidized only once with NaIO4,although the aldehyde group content was rather high,the linking amount of Hb was very low.The mechanism was studied by means of X-diffractioin,infrared spectrum and determination of functional groups.It was found that Hb was immobilized by the interaction between the aldehyde groups in the oxycellulose and the amino groups on Hb.And the microcrystalline structure in cellulose was the main hindrance in immobilization process.Alkaline degradation of periodate oxycellulose led to destruction of the microcrystalline structure.The alkaline degradation and Cannizzaro reaction also resulted in a complete loss of aldehyde groups.In order to obtain maximum amount of immobilized Hb,a second oxidation with NaIO4 was necessary to produce aldehyde groups.
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发布时间：2021-03-19 - 摘要：Two new polymides with aliphatic group were synthesized.The aims are to break through the limit which aromatic polyimide is primarily material as gas separation membrane in polyimide membrane materials,and to look for gas separation membrane materials with good permeability and selectivity.Meantime,the gas permeate behavior of the new polyimides was also discussed.The relationship between permeation and structure of membranes were discussed.A preliminary probe into the mechanism of CO2 and CH4 permeating through polyimide membrane was done.
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发布时间：2021-03-19 - 摘要：Two novel electroluminescent copolymers have been synthesized,in which there are three functions:1,8 naphthalimide as emitting moiety,oxadiazole as electron transporting moiety and PVK as hole transporting moiety.The dyad monomers were characterized by 1H-NMR and MS spectra.Their UV Vis spectra indicate that there is little or no interaction between the two chromophores in their ground state.However,the fluorescence emission of oxadiazole and vinylcarbazole were quenched in these copolymers,which shows in the excited state there exists very effective intramolecular singlet-singlet energy transfer(Intra-SSET) from oxadiazole and vinylcarbazole to1,8-naphthalimide.
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发布时间：2021-03-19 - 摘要：Three carbazole containing methacrylates,i.e. 2-(N-carbazolyl)ethyl methacrylate(CzEMA), 6-(N-carbazolyl)hexyl methacrylate(CzHMA) and 11-(N-carbazolyl) undecyl methacrylate(CzUMA), and their model compounds 2-(N-carbazolyl)ethyl isobutyrate, 6-(N-carbazolyl)hexyl isobutyrate and 11-(N-carbazolyl) undecyl isobutyrate were synthesized.These monomers can be easily homo and copolymerized with MMA by the initiation of AIBN.UV absorption spectra show that there is no or negligible interaction between methacrylate and the carbazolyl chromophore in the ground state.Fluorescence spectra of these monomers,their model compounds and copolymers show that CzEMA exhibits fluorescence structural self-quenching effect(SSQE),but CzHMA and CzUMA does not.This result indicates that SSQE expressed by CzEMA is caused by intramolecular charge transfer interaction between the excited carbazolyl chromophore and the electron-accepting carbon-carbon double bond of acrylic group.
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发布时间：2021-03-19 - 摘要：A series of polyesters based on triad aromatic ester mesogenic unit but different length of poly(ethylene oxide) flexible spacers in the main chain was prepared by solution polycondensation and its chemical structure and mesogenic behavior were examined.The intermediates of each step and assynthesized polymers and monomers containing mesogenic unit were characterized by elementary analysis,IR, 1H-NMR and melting point measurement.
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发布时间：2021-03-19 - 摘要：The reaction behavior of water in tetrahydrofuran polymerization initiated by a heteropolyacid,H3PW12O40 in the presence of ethylene oxide was studied.The variation of components during polymerization was monitored by gas chromatography.Most of water was converted in the earlier stage of the polymerization into ethylene glycol,which was consumed in the subsequent reaction process through chain transfer reaction.Water could not take part in the initiation reaction to start a polymer chain and might reduce the activity of the polymerization.Low molecular weight glycol such as ethtlene or butylene or butylene glycol has a similar effect with water on controlling the molecular weight of the polymer.The molecular weight of the product can be predicted by an equation based upon concentrations of molecular weight controller and heteropolyacid,and conversion of polymerization.
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发布时间：2021-03-19 - 摘要：The interaction of cetyltrimethylammonium bromide (CTMAB) and anionic copolymer derived from 3 sulfopropylmethacrylate,potassium salt(SPMS) and styrene(St) in aqueous solution has been studied.It was found that the viscosity of anionic copolymer/CTMAB solution rise suddenly in a specific molar ratio region of CTMAB/anion.The maximum value of the solution viscosity is closely related to the concentration of sulfo group in copolymer dissolved in solution.A gelation has been observed in a system composed of CTMAB and copolymer having less concentration of sulfo-group and the gelation is reversible according to the CTMAB/anion molar ratio or the water containing in system.A term "micelle crosslinking"was proposed for explaining the reversible gelation.
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发布时间：2021-03-19 - 摘要：Polystyrene spheres are widely used in radioimmumoassay kit,but it is limited by weak physical adsorption of proteins and the hard control of the amount of adsorpted proteins.The acrolein was grafted on the surface of polystyrene spheres via gamma induced pre irradiation technique.The induced aldehyde groups could react with the amino groups of proteins to form Schiff base,through which trypsin and 125 I-labeled antibody were successfully immobilized on the polystyrene spheres by chemical bond.Comparing with the polystyrene blank,the acrolein grafted polystyrene spheres obviously enhanced the amount of immobilized proteins.So by using this method,the radioimmunoassay kit could be improved,but it is better to change to another monomer with aldehyde group because acrolein is irritant and easy to induce oxo-addition reaction with polystyrene.
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发布时间：2021-03-19
Research Bulletin
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