最新刊期
卷 ， 期 2 ， 1985
- 摘要：The radical homo- and eopolymerization of TMPM with various initiators have been studied．It was found that，with azo-type initiators，the polymerization proceeded readily．and an increase of the concentration of TMPM in the TMPM-styrene system raised the rate of copolymerization．While with acyl peroxied initiators，the polyme-rization was inhibited effectively because of the formation of the stable TMPM-oxyl radical．identified by ESR．This observation was further confirmed by the adsenee of inhibition effect on the addition of 2，2，6，6-tetramethyl 4-piperidinol to the poly-merization system，whereas remarkable inhibition was observed on the addition of the stable 2，2，6，6-tetramethyl 4-piperidinol N-oXyl radical．The reaction mechanism was discussed．We also found that when TMPM reacted with BPO in petroIeum ether．N-benzoy-loxy 2，2，6，6-tetramethyl 4-piperidinyl methaerylate was formed，and this novel com-pound has been characterized with IR．ESR and NMR and MASS Spectroscopy．
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发布时间：2021-03-19 - 摘要：The radical copolymerization of 2, 2, 6, 6-tetramethyl-4-piperidinyl methacrylate (TMPM) with styrene has been studied in various solvents: benzene, chlorobenzene, pyridine, dimethyl formamide and petroleum ether. The reactivity ratios were calculated by the linear graphical method of Kelen-Tudos. It is observed that in all these systems there is a marked solvent effect on both r1 and r2, which can be correlated to the difference in chemical shifts of β-olefinic protons of TMPM.
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发布时间：2021-03-19 - 摘要：With the aid of the theoretical relationship between the calibration relation of a SEC column for the monodisperse polymer species under ideal working condition and the effective relations between the molecular weight and the elution volume for characterized polymer samples, a computational procedure for simultaneous calibration of molecular separation and column dispersion is proposed. From the experimental chroma-tograms of narrow MWD polystyrene standards and broad MWD 1, 2-polybutadiene fractions the spreading factors of a SEC column was deduced by the proposed method. The variation of the spreading factor with the elution volume is independent of the polymer sample used.
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发布时间：2021-03-19 - 摘要：Beads of acrylonitrile polymer of low crosslinking were first heated in the presence of oxygen and then pyrolyzed under nitrogen atmosphere in a cracking furnace. The spherical carbonaceous adsorbent thus obtained had a diameter of 0.4-0.6mm. The physical properties of the carbonaceous beads were measured. The surface area of the beads is near 600 m2/g and the distribution of pore diameters is 800-40,000 A. The adsorption of the creatinine, uric acid, or vitamin B12 is all over 98%,As the pyrolysis temperature for adsorbents was over 650℃,the spherical carbo-naceous adsorbents,whether activated or inactivated,had good adsorption for creati-nine and uric acid.
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发布时间：2021-03-19 - 摘要：The thermotropic nematic-isotropic equilibria in an undiluted system of polydis-perse rod-like molecules obtained by melt polycondensations has been investigated both theoretically and experimentally. In this paper, effects of the polydispersity and orientation-dependent (i.e. anisotropic) interactions between rod-like molecules on the phase equilibria are included. It was shown in the experimental part of this work that the thermotropic nematic-isotropic equilibria will appear in the wide range of temperature for poly(p-hydroxybenzoates) samples with the average D.P. equal to approximately 3.
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发布时间：2021-03-19 - 摘要：A new catalyst system composed of neodymium complex supported on styrene-acrylic acid copolymer (SAAC) SAAC-Nd-Al(C2H5)2Cl-Al(i-C4H9)3 for the stereospe-cific polymerization of butadiene is described. The effects of the components, the component ratio, the different alkylaluminium halides, as well as alkylaluminiums and the characterzation parameters of polymer-supported neodymium complex on its activity have been studied. It shows that the system possesses good activity and high stereos-pecificity giving pol polybutadiene with 98% cis-1,4 content.
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发布时间：2021-03-19 - 摘要：The effect of temperature on the Monomer Beactivity Eatios(MRR) of copolymerization of acrylonitrile with methyl acrylate in aqueous solution was studied by means of gas chromatography. We obtained r1 = 0.96, r2 = 1.18 at 30℃; r1 = 0.83, r2 = 1.17 at 40℃; r1 = 0.70, r2 = 1.17 at 50℃; r1 = 0.68, r2 = 1.10 at 60℃.The relationship between MRR and temperature is as follows:Inr1 = -4.043 + 1207/T, Inr2 = - 0.01360 + 51.68/T.It has been discovered that the temperature dependence of MRR is considerably affected by the adsorption on the deposit particles of the copolymer for this copolymerization system.
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发布时间：2021-03-19 - 摘要：The propagation rate constants and active center concentration were evaluated for the polymerization of butadiene with LnCl3-C2H5OH-AlR3 catalysts(Ln=La,Nd,Sm,Gd,Dy,Ho or Y; AlR3=Al (C2H5)3 or Al(i-C4H9)3. Both the propagation rate constant and active center concentration varied with the rare earth element used in the catalyst. The former lies in the range of 6-100 l/mol · sec at 30℃ and decreases in the order of: kp(Nd)-Kp (Sm)-Kp(Gd) > Kp (La) > Kp (Dy) > Kp (Ho) > Kp(Y). The active center concentration formed by Nd-catalyst has an order of 2—3×10-2mol/mol Nd which is much higher than any other six rare earth catalysts. The nature of propagation rate constant was discussed.
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发布时间：2021-03-19
Research Article
- 摘要：PPTFB has been synthesized using a EF external capacitively coupled discharge apparatus. The binding energy shifts of C1s in the PPTHE was calculated by means of both Seigbahn's charge potential model through CNDO/2 method and Pauling'svalence model. The results have proved that there exist CH2(Ⅰ), CH2(Ⅱ)),CF(CHF), CF2 and CF2 groups in the polymer. From the calculated results of the model compounds. An empirical formula of calculating energy shifts:ΔEi = aα + bβ + cγ, was deduced. In addition, on the basis of characterizatition of the structures of the products formed in glow discharge a structural model of the PPTFE is proposed.
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发布时间：2021-03-19 - 摘要：The relaxation behavior of epoxy with different thermal history was studied by means of stress telaxation DSC，dynamic mechanical measurement and thermo-meeha-nical analysis (TMA) methods．According to stress relaxation measurement，the internal stress of epoxy samples with different thermal history relaxed rapidly，when quenched samples were kept at room temperature．The phenomena of physical aging，i．e．enthalpy or volume relaxation of quenched and annealed samples，observed from DSC testing，are different．For quenched sample an additional physical aging peak shifted to higher temperature and the peak area in-creased with increasing storage time at room temperature．On the contrary for anneal-ed samples，the additional peak shifted to lower temperature and the peak area decreas-ed and disappeared gradually．The Tg of quenched samples，measured by TMA，decreased at first and then in-creased With increasing storage time at room temperature． It shows that there are at least two relaxation processes，internal stress and volume relaxation，which influence the mechanical properties，and the formerone changes faster than the later one．
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发布时间：2021-03-19 - 摘要：The pyroelectric behaviour of VDF-TFE copolymers, obtained by using different initiators, were compared. The effects of corona polarization on the pyroelectricity were also investigated. Two current peaks were obtained in TSC curve from the corona discharged sample. The first peak in TSC curve is found to be mainly attributed to the depolarization current of the space charge.
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发布时间：2021-03-19 - 摘要：The "living" polydienes with broad molecular weight distribution(MWD) have been synthesized by means of the continuous addition of initiator (sec-Buli). The investigations on the dependence of molecular weight upon conversion, the kinetic analysis on polymerization and the block polymerization of butadiene and isoprene have been made in order to confirm the fact that the detectable termination and transfer reactions are absent in the polymerization with the continuous addition of initiator. It has been found that the MWD of polymer can be controlled and varied over a wide range when the technique of continuous addition of initiator used and polymerization conditions,(such as the initiator amount,its addition rate,monomer concentration and polymerization temperature) changed.
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发布时间：2021-03-19 - 摘要：Segmented copolymers have been prepared from dihydroxyl terminated polyaryl-cardosulfone oligomer and diisocynate terminated polydimethylsiloxane-polyether ure-thane block prepolymer through hydrogen transfer reaction. The main aspects of the reaction were investigated. The segmented copolymers obtained are of low crystallin-ity, and with twomicrophase morphology.
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发布时间：2021-03-19 - 摘要：Two new polyphenylquinoxaline-platinum and rhodium complexes indentified by X-ray photoelectron spectroscopy were synthesized. Their catalytic properties on hy-drosilylation and hydrogenation of unsaturated compounds have been investigated. It was found that these polymer complexes possessed high calalytic activities and could be easily recocvered after each reaction and repeatedly used for several times while maintaining the same effectiveness.
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发布时间：2021-03-19 - 摘要：The influence of strain rate on three dimensional orientation of polyethylene tere-phthalate (PET) films has been studied by means of refractometry in the case of un-iaxial and biaxial (including simultaneous and sequential) stretchings.Two birefringence values ΔXY=nX-nYand A(Xy)Z=(nX+nY)/2--nZ (where Z axis perpendicular to the film plane, X and Y are axes within the film plane) have been suggested to evaluate the orientation of film specimens. It is shown that the uniaxial stretching mainly results in the anisotropy within the film plane,while the biaxial stretching technique is conducive to improving the degree of planar orientation in the films.
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发布时间：2021-03-19
Research Bulletin
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