最新刊期
卷 ， 期 6 ， 1989
- 摘要：Pulsed Nuclear Magnetic Resonance measurement is presented for three series of the block polymer of styrene and isoprene. The solid echo measurement was made on a Bruker MSL-300 NMR Spectrometer operating at 300 MHz. The solid echo signals were decomposed by means, of linear least square regression into a fast Gaussian and a slow exponential components associated with the rigid and mobile phase respectively, using PASCAL language and lealed with on the Aspect-3000 computer which is equipped on the spectromeeter. The qualitative and quan-titative informations of the phase structure and molecular motion can be obtained by means of this method.
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发布时间：2021-03-19 - 摘要：The relationships between the refractive index increment, SEC response area and weight fraction of the monodisperse species of oligomers are analyzed mathematically. The molecular weight dependsncye of the refractive index increments is originated solely from the end group effect. A theoretical formula is proposed for the refractive index increment correction of SEC chromatogram of polymer, which involves the molecular formula weights and the ratio of dn/ dc of the end group and the structural repeating unit. The refractive index increment ratio could be evaluated a priori by Lorenz-Lorentz or Gladstone-Dale equations. The theoretical judgements have been confirmed exprimentally by the HPSEC data of styrene oligomer.
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发布时间：2021-03-19 - 摘要：The singlet oxygen (1O2) oxidation of polybutadiene (PB) in presence of polymeric hindered amine light stabilizer (HALS) was studied by determination of viscosity, ESR., lR., GFC.. The results show that polymeric HALS can inhibite 1O2 oxidation of PB and the effectiveness is 944 > PDS > 770 > 622. The quenching rate constants of 1O2 by HALS were determined by Monroe's method(19) They are:944(3.2×106),PDS(8.2×105),622 and 770 5M-1S-1.The determination of ESR. shows that 944 and PDS can produce stable nitroxy free radi-cal in this experimental condition and 622 does not. This is associated with the steric effect of 622. The determination of GPC also shows that PDS possesses an effect of grafting-crosslin-king to PB in this experimental condition. The mechanizm of grafting-crosslinking has be-en proposed.
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发布时间：2021-03-19 - 摘要：Resonance Raman spectra and its dependence on the excitation photon energy of partially isomer ized and all trans-polyacetylene prepared by rare-earth catalyst were compared with that of polyacetylene prepared by Shirakawa's catalyst. Resonance Raman spectra have been reported firstly for soluble polyacetylene prepared by rare-earth catalyst. The observed results seem to support the consideration of that the observed Raman anomaly for trans-polyacetylene is originated from dispersion of conjugation length in polyacetylene chain.
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发布时间：2021-03-19 - 摘要：Five new poly-co-condensale of pheaolic and crown ethers were prepared by the condensation of 2,6-dihydroxymethyl-4-phenylphenol with dibenzo-18-crown-6(B18C6), dibenzo-24-crown-8(2B24C8), dibenzo-30-crown-10(2B30C10), benzo-15-crown-5(B15C5), benzo-18-crown-6(B18C6) respectively and cationbinding abilities were evaluated by extraction of poly-co-con-densates solution in chloroform from aqueous alkali metal picrates solution. The results indicate that the extractability and cation-selectivity of polyco-condensates (PB15C5) and (PB18C6) are more effective than the corresponding monobenzo or dibenzo-crown ethers.
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发布时间：2021-03-19 - 摘要：Using the characteristic peaks in H-spectra for the different functional groups of ethyle-ne terephthalate-caprolectone segmented copolymer, We have calculated and proved that two kinds of the intensity formulas reflect the quantitative relationships of the coresponding functional groups in the hard and soft segments, and the chemical structure of the chain is confirmed.On the basis of this, utilizing the contribution of the different functional groups to their characteristic peaks in H-spectra, the formulas for the number of soft and hard segments,for the average length and molecular weight of the soft and hard segments and for the con-tent of the hard segents have been found directly. The H-spectra and C-spectra have been analysed by the method of the probability of the triad and the result reconfirmed the chain structure of segmented copolymer that we got be-fore.
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发布时间：2021-03-19 - 摘要：Using poly (4-merhylpentene-l) (PMP) as a membrane material and cyclohexane, irich-loroethylene, tetrachloroethylene, mixture of cyclohexane and trichloroethylene or tetrachloro-ethylene as solvents, the solution were cast to form homogeneous dense membranes, and the crystalline properties and surface morphology were investigated by DSC and TEM. The results, showed that the crystalline form, crystallinity, and surface morphology of PMP membrane are closely related to the solubility and evaporation rate of solvents. A new type of PMP crystal-line form,named VI-form crystal,was observed in PMP membranes formed by tetrachloroe-thylene or trichloroethylenecontaining solutions.
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发布时间：2021-03-19 - 摘要：Using Poly(4-methylpentene-1) (PMP) as a membrane material, and cyclohexane, trichlo-roethylene, tetrachloroethylene, and the mixture of cyclohexane and trichloroethylene as solvents, these solutions were cast to form homogeneous dense membranes, and the membrane permeation behavious for oxygen, nitrogen, hydrogen, and carbon dioxide were investigated. The results showed that gas permeation mainly occurs in amorphous region of the PMP, but also in the crystalline region. The gas permeation activation energy in VI-form crystal of the PMP was lower than that in I-form crystal.
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发布时间：2021-03-19 - 摘要：The Brillouin scattering was used to investigate the effect of crosslinking on the dynamic mechanical properties and the relaxations of polystyrene. It was found that there is a new relaxation in the cross-linked polystyrene besides the high temperature (T>Tg) amorphous relaxation. The effect of crosslinking on this relaxation was examined. The activation energy of this relaxation was determined to be about 12 kcal/mol. The molecular origins of this relaxation were proposed.
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发布时间：2021-03-19 - 摘要：The photoprotecting behaviour of PDS and two UV-absorbers for PP film has been studied by determination of infrared and ultraviolet spectroscopy and scanning electron microscopy. The results have shown that PDS synergises effectively with 2-hydroxy-4-n-octyloxybenzopheno-ne (UV-531) and antagonises weakly with 2-(2-hydroxy-3, 5-di-tert-butyl-phenyl) -5-chloroben-zotriazole (UV-327). It has also been shown that PDS had protected them from photolysis. In addition, it was found that a nonuniform dispersion of UV-327 was formed in PP matrix in pre-sence of PDS. The mechanisms of the synergistic and antagonistic effects under these condi-tion have been proposed.
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发布时间：2021-03-19 - 摘要：Based on the successful isolation of polynuclear Nd-Al bimetallic complex which alone can initiate diene polymerization without the presence of the co-catalyst trialkyl aluminium, the effects of active speecies, additional trialkyl aluminium, and monomer concentrations as well as temperature on butadiene polymerization were studied in detail. The results indicate that there is a relationship between the molecular weight and the microstructure of obtained polybutadiene, that is, the lower the molecular weight and the microstructure of obtained polybutadiene,that is,the lower the molecular weight,the lower the cis-1,4 content and the higher the trans-1,4 content. To explain the experimental results, a new view which involves the reaction of the propagating polymer chain on polymerization process was put forward and some explanation according to syn-anti isomerization of π-allyl mechanism was given.
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发布时间：2021-03-19 - 摘要：Compatibility of natural rubber (NR)/low density polyethylene blends was calculated and it was predicted that compatibility existed between the amorphous part of polyethylene and NR. Based on above calculation and prediction, an interaction model of polyethylene and NR was suggested. Effective network chain density measurement, dynamic mechanical spectrum measurement, wide angle X-ray diffraction and density measurement have been used to verify the compatibility of natural rubber/low density polyethylene blends (NR either unvulcanized or vul-canized) as predicted by the calculation and proposed model. Experimental results show that there exist certain interaction between amorphous LDPE and NR.
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发布时间：2021-03-19 - 摘要：It has been found that the strain gage adhesives (SGA) with larger range of plastic strain. (e>8%) and sensitivity (k>1.85) can be used in the range of RT to 300℃.The thermal imidization of SCA had been studied in solid phase at RT to 300℃ by measuring their adhesion, solubility, creep properties and by TMA, TBA, TGA. and IR etc. The results showed that polymer was glassy (Tg>280℃) after rapid imidization of SGA at 125-155℃, and reaction was slow with the deeping of imidization. The maximun degree of imidization. The maximun degree of imi-dization and molecular weight were achieved at 225℃ in the flexible glass state of polymer. The imidization temperature is at 250-260℃ for obtaining optimun integrative properties of polymers.
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发布时间：2021-03-19
Research Article
- 摘要：The ring-opening photopolymerization of cyclohexene oxide using o-nitrobenzyltriphenyl-silyl ether (NBTE)-Tris(acetylacetonato) aluminium (TAA) as catalyst has been studied. The conversion of polymerization and the molecular weight of polymer as well as the photolysis of NBTE were determined. The tentative mechanism of polymerization was preliminary proposed.
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发布时间：2021-03-19 - 摘要：The photochemical graft copolymerization of isoprene on the surface of tetrafluoroethylene-propylene copolymer was effected by external magnetic field. The graft ratio of the system using benzophenone as initiator in the presence of 1.2 Tesla of external magnetic field is more than three times than in the absence of magne tic field. The 3,4-polymerized contents in po-lyisoprene were increased greatly. The causes which led to above-mentioned phenomena were discussed.
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发布时间：2021-03-19 - 摘要：The supported Zeigler-Natta catalyst TiCU/MgCl2 Al(i-Bu)3 have been used to synthesize low molecular weight hydroxyl-tipped ethylene and propylene copolymer in conjunction with diethylzinc (as transfer agent). The funclionality value of the prepolymer were depended on the experimental conditions. The most of functionality was over 70%. Diethyl-zinc was used to control the molecular weight of the prepolymer, in the meantime, the functionality of the prepolymer also be dropped.
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发布时间：2021-03-19 - 摘要：Silk sericin is a natural protein which consists of 18 kinds of aminoacids. The prepara-iion and catalytic activity of silk sericin-Cu, Mn complexes have been studied. The grafting copolymerization of silk sericin is not reported up to now. In this paper, the effects of temperature, time and concentration of initiator on the graft copolymerization of styrene onto silk sericin were investigated in aquous media. The grafting copolymer was characterized by IR, DSC and TG. It is insoluble in wafer and possessed of intension. The grafting copolymer was able to absorb metallic ions such as Co2+,Ni2+,and Cu2+.It is possible to use the grafting copolymer in disposing waste water.
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发布时间：2021-03-19 - 摘要：Polyazoester has been obtained by the catalyzed polyreaction of azobisbutyronitrile with PEG 400 according to Pinner reaction. The structure and the kinetice of decomposition of the product were researched. The polyazoester was used to initiate radical polymerization of acrylamide limiting the decomposition of the initiator to 37%. By use of the resulting po-lyacrylamide as an emulsifying initiator system stable emulsions of polymers (polyvinylacetate, styrene-ethyl acrylate copolymer) were obtained without additional use of a tenside.
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发布时间：2021-03-19 - 摘要：A new kind of UV-absorber-a-Substituted hexadecyl-dibenzoyl methane was synthesized in this work. Its protective efficiency and compatibility to polymers have been studied preliminarily.
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发布时间：2021-03-19 - 摘要：Infrared spectra (1800-1450 cm-1) were studied for CPVC stabilized with Pb stearate(Ⅰ), dibutyltin dilaurate (Ⅱ) and di-sodium hydrophosphate (Ⅲ) as a secondary stabilizer along with(Ⅰ) or (Ⅱ), and previously subjected to different degree of thermal degradation. Infrared spectroscopy made it possible to follow the consumption of the effective ingredient of the primary stabilizer during thermal, decomposition by means of a band assigned to the stretching vibration of RCOO- (1510 or 1590 cm-1). The secondary stabilizers slow down the consump-tion. Conductometric measurments and Brabender torque rheometer tests confirmed the above results.
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发布时间：2021-03-19
Research Bulletin
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