最新刊期
卷 ， 期 5 ， 1994
- 摘要：he effect of CH2 = CH - CH2X (X=Cl,Br and I ) on polymerization activity and molecular weight of polymer has been studied in molybdenum catalyst system for 1,2-- polymerization of butadiene. The functions of CH2=CH -- CH2Br among three kind of allyl--halogen are the best for the catalytic activity and the regulation of molecular weight of 1, 2-- polybutadiene from Mn= 3. 5 × 105 to 17. 5×105. From the data obtained by 13C--nmr and UV spectra of CH2= CH -- CH2X and butadiene molecules as well as parameters of polymerization activity and kynetics it was proposed that a frequency mechanism which was under the control of the molecular weight of polymer existed in the reac-tions between complexing reaction and discomplexing reaction, i.e.
- 2
- |
- 9
- |
- 0
发布时间：2021-03-19 - 摘要：y means of FTIR, elemental analysis, X--ray diffraction , SEM and other analytical methods, the redox mechanism of amidoxime chelate polyvinyl-- formal nonwoven fabric (Ac-- PVFF ) recating with An3+ was investigated and some valuable ideas were propose in mis paper. It can be proposed from experimental resuits that when An-- PVFF reacts with Ans+, almost amidoxime groups are oxidized to amide groups, while some are oxidized to carboxyl groups, At the same bine, the small molecular weight nitrogen--containing compounds released from the redox process are found to be mainly nitrogen oxide (NOx). As well as, H+ ion is produced in the redox process. Au3+ ions are finally reduced into ele-mental gold in redox process although some of them may be chelated by Ao-PVFF in the beggining at lower temperature. The produced gold crystallizes on Ao-PVFF in the rose-shaped and the mount of crystallite increase with the lengthning of redox duration.
- 37
- |
- 8
- |
- 5
发布时间：2021-03-19 - 摘要：The complexation and the electrochemical behavior of Eu2+ and Eu3+ in poly (ethylene glycol) (PEG) oligomers were studied．Eu3一PEG complexes were pre-pared by dissolving EuCl3 into PEG with various molar masses．They showed strong excitation and emmision bands at 394 and 614nnl，respectively．The intensi-ties of both bands increased with the increase in PEG molar mass．Eu2+一PEG complexes were formed by the reduction of corresponding EuCl3 solutions at一2.0V (VS Ag) and under N2，by using indium／tin oxide (ITO) coated glass sheet as working electrode．Their luminescence properties very like that of the complex formed by Eu2+ and 18-C-6 crown ether (ex. =326—328 nm，em．=440—1445nm)，which demonstrated that the chemical environment of PEG was very similar to that of large ring poly—oxygen ligand．The redox process of trivalent europium in PEG is very irreversible，and its behavior could be strongly affected by adding supporting electrolytes．The complexation and the electrochemical behavior of Eu2+ and Eu3+ in poly (ethylene glycol) were studied by using IR，fluorescent spectroscopies and cyclic voltammetry．
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：The dispersed relaxation time spectra of materials were evaluated direct from the conventional experimental stress—relaxation curves by means of data—operation instead of overlaborate function—analysis procedure．The principal relaxation time τ0 was determined from the single Maxwell model．and another relaxation times were appointed at about 10-2 τ0 10-1 τ0, 101 τ0 103 τ0 The stress-relaxation equation was expressed in the form as a model with 5 parameters，and the spectrum intensities ai (or Ai) were determined from the linear multielement regression and the least square method．The relaxation curves of NR (nature rubber) samples at different temperatures were handled，a comparison of the calculated data with experimental curves shows good agreement．The obtained spectra represent the activation of relaxation process due to heating，and that the spectrum intensities are stronger in short—time region，means that the main micro-scopic relaxation depends on the motion of segments，but not of molecular chain．
- 3
- |
- 8
- |
- 2
发布时间：2021-03-19 - 摘要：Through using interfacial condensation, a series of new organo-tin polyether-esters,polyamine esters were obtained, by dialkyl tin dichlorides, his (β- alkoxycarbonylalkyl) tin dichlorides reacted with hydroxy-acids and amino -acids. Experimentalparameters were studied. A part of the polymers was tested for their effeCt on theheat-stabilization of PVC resins. The results are interesting in this area of application.
- 29
- |
- 8
- |
- 1
发布时间：2021-03-19 - 摘要：he paper report the synthesis and strcture charactritic of waters-soluble aCrylic resins which have the better properties of dyeing and retanning for leather. Theresults of the spectums show that the cationic groups were linked to themacromoleculer chain and the ￣ reSins have had the 'observable amphotericcharacteristic.
- 22
- |
- 7
- |
- 1
发布时间：2021-03-19 - 摘要：el-- films of ultrahigh molecular weight polyethylene (UHMWPE) were prepared from tri -- dilute solutions. The films were composed of lamellarcrystals oriented parallel to the film surfaces and could be ultradrawn (λ > 200) at the temperatures ranged from 129℃ to 134℃. When the undrawn films were annealed atthose temperatures, the morphologies in the lamellar crystals had change. WAXDand iR studies shown that the crystallinities incrcand, dimensions in (002) and(020) normals increased while that in (200) fold had slight decreases. The rela-tionship between the orientation of the drawn UHMWPE gel-films and the struc-ture changes and the optimum drawing temperature had been disscussed.
- 3
- |
- 7
- |
- 3
发布时间：2021-03-19 - 摘要：A new initiation system for aqueous polymerization of acrylamide is presented.The effects of the contents of ammonia, urea, EDTA--2Na, pH value, concentration of monomer, polymerisation temperature in a Na2CO3 polymerization sysytem on the molecular weight of polymer and water-- soluble property were studied. Amethod to obtain the product with high molecualar weight which easily is dissolvedin water was found. A product in the form of powder with [η] = 22dl/g was obtained by Na2CO3 method.
- 4
- |
- 11
- |
- 12
发布时间：2021-03-19 - 摘要：Monte Carlo method for studying the molecular weight distribution (MWD)and the kinetics of polymerization has been developed in this paper. This methodallows for simulation of the kinetics of polymerization and the evolution of MWDsimultaneously. By using this method for the AB--AA type condensationpolymerisation of unequal functional group reactivity, the simulation results agreewith the experimental results quite well. The results reveal that the AA monomerwith high funCtional group reactivity can promote the reaction and narrow the MWD of the products. Therefore, a practical method for accelerating the conden-sation polymerization and modifying the MWD of polyphenyl ether sulfone has been suggested.
- 39
- |
- 9
- |
- 6
发布时间：2021-03-19 - 摘要：he conventional two-component condensation -type RTV silicone rubbervulcanized by novel crosslinking agent of polysilazane was studied. The experimental results showed that RTV silicone rubber samples vulcanics by theKH--CL crosslinking agent had the resistant temperature up to 350 ℃and theactivation energy of thermal degradation reaction of the vulcanizates increased to330KJ/mol. This Aught be attributed the elimination of the degradation ofsilo-cane chain initiated by the residual catalyst and the silanol groups in the vulcanizates.
- 4
- |
- 8
- |
- 10
发布时间：2021-03-19 - 摘要：A novel polyazoinitiator── polyazoamide was synthesized by reacting AIBNwith trio-cane in the presence of concentrated suffurid add. The conversions effected by the amount of catalyst, reaction time and solvent were also discussed.The structure of polyazoaAnde was characterics by IR, 1H--NMR and UVspectra and the results of GPC showed that the average of polydegree ofpolyazoamide was about 4. The kinetic of themal decomposition of PAA was investigated by DSC resulting in: Ea= 149. 1 KJ/mol, A = 3. 8 × 1016s-1.
- 31
- |
- 7
- |
- 1
发布时间：2021-03-19 - 摘要：he correlation between the interphasial interaction and microstructure in sixpolyblend systems containing thermotropic liquid crystalline polymers (TLCP ) hasaam investigated by means of dynamic mechanical spectrometry and scanning electron microscopy. The large or small inward shift of loss peaks of ingredientsshows strong or weak interphasial interaction existing in these blends. The TLCPdispersion phase in corresponding samples has its morphology from spheric,through ellipsoidal and elongated, to fibrilar.These results indicate that no direct correlation exists between the interphasial interaction and fibril formation in incompatible polyblends containing TLCP.
- 2
- |
- 7
- |
- 5
发布时间：2021-03-19 - 摘要：Microcomposites of a rigid rod-like poly (p-hydroxy benzoic add ) (PHB) anda poly (butylene terephthalate) -- poly (tetramethylene glycol ) multiblock copolymer (PBT-- PTMG) were synthesize by in-- situ direct polycondensation. The effectof PHB contents and the concentrations of matrix polymer solution on themorphology and mechanical properties of the microcomposites obtained have been studied. The microcomposites prepared by in-- situ polycondensation exhibit much better uniform morphology and mechanical properties than those prepared by in-situ blend method.
- 3
- |
- 10
- |
- 0
发布时间：2021-03-19
Research Article
- 摘要：This paper deals with the swelling properties of the hydrogels synthesized byirradiation method. The swelling dynamics of hydrogels and the effeCt of structurein hydrogels were also studied'
- 6
- |
- 10
- |
- 0
发布时间：2021-03-19 - 摘要：his paper deals with synthesis of mesogenic condensation monomer, bis- (3- methoxy - 4 -- hydroxybenzylidene ) -- 4, 4' -- diimidobiphenyl (biphenol ), seven main chain thermotropic polyazomethine-- ethers made from biphenol and a, ω -dibromoalkane by phase -- transfer--catalysis polyetherification reaction are discussed.Ther structure have ho characterics by 1H--NMR, IR spectra and element analysis. The effect of alkali aqueous concentration on solubility has been investigated. The banded texture of oriented specimens remains almost unchanged dur-ing the melting transition but birefrngent weakens and the banded texture gradually disappears with increasing temperature.
- 2
- |
- 7
- |
- 1
发布时间：2021-03-19 - 摘要：he block copelymer of 6-- methyl-- morpholinedione and caprolactone have been synthesized based on the stepwise addition of 6 -- methyl -- morpholinedione to the hydroxyl end group of prepolymers using stannous octoate as a catalyst. Themolecular weight of pre-polymer of caprolactone was determined by the molar ratio of caprolactone and 1, 4-butanediol. The block structure was confirmed andcharacterized by means of 1H-- NMR, 13C-- NMR, IR, and GPC. The thermal analysis were also reported and compared with the random copolymers.
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：ssignment of Peaks of 13C nuclear magnetic resonannce spectra ofpropylene/pentene-- 1 and propylene/das-- 1 copolymers and determination ofcomposition of these copelymers by 13C NMR method were studied. The moreconvenient infrared method for determining composition of these copolymers, together with that of reported propylene/octene-- 1 copolymers, was established by construing curves of IR absorption ratios A720cm--1/A970cm--1 (A733cm--1/A970cm--1 forpentene copolymers) against ratios of two component ofcopolymer calculated from 13C-NMR spectra of experimental samples and blends of PP.respective homopolymer of known compositions. Linearity of these calibration cruves testifies the rationality in selecting the IR absortion peaks.
- 2
- |
- 7
- |
- 1
发布时间：2021-03-19 - 摘要：he morphological characteristic such as layer structure, layer thickness and the content as well as the aspect ratio of the in-situ formed liquid crystalline polymer fibers by injection molding was investigated and quantitatively measured. According to the inhomogeneous distribution of the fibers, a three-layer-model was set up. It's very difficult to determine the mechanical properties of the LCP fibers becausethey were in-situ formed and always embedded in the matrix. In this paper, amicromechanical model based on Cox model has been established to determine the Young's modulus of the fibers. It has been shown that all the shear induced in-situ fibers seem to have same Young's modulus as material related constant,in-dependent upon the processing conditions,even though the different processing con-ditions result in significant change of the fiber content and the aspect ratio. There-fore,for in-situ formation of the LCP fibers, shear condition may only influence the geometric structure, but not the mechanical characteristics.
- 2
- |
- 8
- |
- 2
发布时间：2021-03-19 - 摘要：Eventhough C60 does not display the fluorescence at room temperature, it canact as a quencher to the fluorescence of electron -- donor such as dimethyltoluidine,N, N, N ', N' -- tetrs methylbenzidine (TMB) and N, N, N ', N' -- tetramethylstilbene (TMStDA), etc.In this article, the fluorescence quenching of two copolymers of styrene having electron -- donating chromophore--moiety, i. e. poly(styrene -- co -- N' -- vinylmethylene-- N, N -- dimethyl -- 1, 4 -- benzenediamine ) andpoly (styrene-- co -- N -- dimethylaminophenyl maleimide) by C60 is reported. It was found that C60 could also act as a quencher to the fluorescence of these copolymers. Having no distinct curvatures in the Stern- Volmer plot indicated that there was no ground state charge transfer complex formed, and the photo-induced charge transfer was resulted between C60 and the electron-donating copolymer.
- 23
- |
- 10
- |
- 4
发布时间：2021-03-19 - 摘要：igh performance crystal/crystal blends of poly (phenylene sulfide) and poly (ether ether ketone) (PPS/PEEK) have ho prepared by dry mixing and melhng at different temperatures. The crystallization and melting behavior of PEEK component in quenched blends have ho investigated by differential scanningcalorimetry (DSC). As melt temperature (Tmelt) increases, the crystalline andmelting behavior of PPS and PEEK is different due to the difference of thermalproperty of PPS and PEEK. The temperature of melhng (Tm) and crystallization (Tc) and crystallinity (Xc) of PEEK component in blends increase as the content of PPS increases up to 50%. However. this action of PPS is suppresed with increasing of Tmelt.
- 51
- |
- 9
- |
- 2
发布时间：2021-03-19 - 摘要：Polystyrene and polyacrylamide prepared by BDC (benzyl diethldithiocarbamate )could be ed as macromolecular iniferter and they initated styrene or acrylamidepolymerization further. The results shoWed that chain enlargement reaction inhomogeneous systems had the character of living radical polymerization and theprodusts still contained iniferter functional groups. Polystyrene macromoleculariniferter can initiate acrylamide polymerizahon in dioxane and thepolystyrene-- block-- polyanylamide copolymers were obtained. Blocking efficiency and polymerization activity were high.
- 31
- |
- 8
- |
- 2
发布时间：2021-03-19
Research Bulletin
- Postal code：100190
- Tel：010-62588927 Email：gfzxb@iccas.ac.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备05002797号-8
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0