最新刊期
卷 ， 期 4 ， 1991
- 摘要：Two polyethylene/rubber blends, LLDPE/NR and LLDPE/SBR, were examined by FTIR-ATR spectroscopy and dynamic Tg measurements. It was found that the 835 cm-1 band of the NR and the 964cm-1 band of the SBR became higher and narrower as a result of blending with LLDPE, indicating certain extent of interaction between the amorphous molecular segments of PE and the rubber molecles. The Tg changes determined by dynamic techniques supported the result obtained by IR spectroscopy.
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发布时间：2021-03-19 - 摘要：The component distribution, cpmpatibility and crystallization behavior of the polyolefin blends of isotactic polypropylene (IPP), high density polyethylene (HDPE) and ethylene-pro-pylene-diene terpolymer (EPDM) were investigated by means of differential scanning calori-metry (DSC), 13C-nuclear magnetic resonance (13C-NMR), scanning electron microscopy (SEM) and wide-angle X-ray diffraction (WAXD). EPDM with high ethylene content was more compatible with PE component than PP component in the blends and its molecular seg-ments mostly distributed in PE component. The ternary blend containing 15% of EPDM had hest best compatibility,exhibiting a interconnecting structure of domains of crystals in the SEM micrograph. The overall crystallinity (Xc) decreased with increasing EPDM content,which was ascribed to the facts that the crystallinity of PE component (XCE) decreased significan-tly and that of PP component (XGP) was almost unchanged. The results were explained on the basis of the difference in compatibility of EPDM with PE and PP as well as the different cry-stallization behavior of semicrystalline components in the course of cooling.
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发布时间：2021-03-19 - 摘要：It is reported that a variety of trimethylsilyl enol ethers which are not ketene silyl acetals can be used to initiate GTP of methacrylates and acrylates. The new initiators are easy to be prepared using Et3N as catalyst from the reaction of ketones or aldehydes with Me3SiCl. PM-MA and PMA with controlled molecular weight and low polydispersity were obtained by using 1-trimethylsiloxy cyclohexene, 2-trimethylsiloxy butene-2, 2-methyl 1-trimethylsiloxy pro-pene-1 in the presence of bibenzoate, bifluoride and HgI2. The living nature of polymeriza-tion is shown by the correspondence of theoretical and observed molecular weight and the pre-paration of block copolymer. This initiator system provides a very sueful method for the syn-thesis of A-B-A triblockcopolymer of MMA and BA by using GTP.
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发布时间：2021-03-19 - 摘要：The toughened epoxy resin/castor oil polyurethane IPN(TEP/PU(CO) IPN) having some crosslinked points between the two networks possesses excellent damping properties. The half width of the tan δ-T curve at TEP/PU(CO) ratio being 30/70 reaches to about 100℃ and the maximum value of tan δ is about 1. The morphology of the IPN shows that it has two-phase structure of toughened epoxy resin within the IPN.
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发布时间：2021-03-19 - 摘要：By using PLM (polarized light microscopy) with heating stage, SEM, IR, and DSC techniques, the spherulitic structure of polyetheretherketon (PEEK) has been studied. It has been found that the spherulite of PEEK shows radiated morphology or banded morphology in some case, and the two morphologies can interchange reversi'blely in thermal process. The interchanging characteristics and the microstructure of them have been investigated. Basing on the results a spherulitic model of PEEK has been given.
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发布时间：2021-03-19 - 摘要：Polymerization of acrylamide initiated by the combination of 2-N-morpholinoethyl me-thacrylate (MPEMA) or 2-N-morpholinoisopropyl methacrylate (MPIPMA) with potassium persulfate were studied kinetically. The rate equations for AAM polymerization were given asRp=Kp[K2S2O8]0.5[MPEMA]0.5[AAM],Rp=Kp[K2S2O8]0.5[MPIPMA]0.5[AAM] and the overall activation energies for the above polymerizations were obtained to be 11.1 Kcal/ mol and 13.6 KCal/mol respectively. The UV analysis for the AAM polymer initiated by the above initiation systems showed that the polymerizable amines, MPEMA and MPIPMA not only join the redox initiation but also incorporate to the acrylamide polymer chains. A super high molecular weight,,107 of PAAM were obtained by using these initiation systems. The water-absorptivity of hydrogels prepared from MPEMA and methylenebisacrylamide as cross-linking agent was undertaken. It was also observed that the transparency f concentrated PMPEMA aqueous solution was sensitively depended on the tempeerature. Under room temperatu-re the sollution was transparent,when the temperature raised to 60℃,the solution became opa-que and completely lost its transparence when temperature raised to upper 80℃.
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发布时间：2021-03-19 - 摘要：The formation mechanism of a band texture of ethyl cellulose acetate (ECA) in dichloro-acetic acid (DCA) which exhibits a cholesteric mesophase has been investigated by using a parallel plates shearing apparatus. A critical shear rate of the band texture formation can be measured to be about 1.5 sec-1 for 30 wt% solution of ECA. The result obtained indicates that the band texture of ECA/DCA is not formed during shear, but it is formed during relaxation of shear orientation. The variation of the formed band texture was also studied during heat-ing,and found that the formedband texture will vanish at heating,but the macromolecular chain orientation persists in solution.If the temperature is lower the isotropic temperature of the solution the band texture will reappear during cooling.Finally,a model was suggested to describe the formation mechanism of band texture for liquid crystalline state of polymers by shear.
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发布时间：2021-03-19 - 摘要：The structure of a novel side chain liquid crystal polymer, poly-2,5-bis (4-methoxyben-zoyloxy) styrene, was studied by spectroscopic methods including FTIR, FT-RAMAN, 1H-NMR and 13C-NMR. The molecular structure was proved by both IR and RAMAN. However, unexpected results were given by the NMR methods. In the 1H-NMR spectrum, the peaks for the protons on the back-bone carbons are much smaller than that they would be if the numbers of different protons are considered. In addition, the 13C-NMR signals for the back-bone carbons are even undetectable if a pulse lepetition time of 1.5 seconds is used,which can,ho-wevar,be seen in the spectrum whena ionger pulse repetition time of 3 secends is used. A somewhat plausible explanationis given for these unusual observations. The temperature depen-dence of the spectroscopic properties is also discussed in terms of molecular interactions.
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发布时间：2021-03-19 - 摘要：The blends of poly(vinylidene fluoride) (PVF2)and methyl methacrylate-styrene random copolymer (MS) of different styrene (St) mol% were investigated.This paper deals with the miscibility of PVF2/MS blends by differental scanning catori-meter, scanning electron microscope and cloud point measurement.The LCST curve of the blends was also determined.
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发布时间：2021-03-19 - 摘要：Copolymerization of o-methacryloyl polyoxyethylene macromers with ethyl acrylate (EA) in benzene using AIBN as initiator was studied. The effects of molecular weight of the macromers, charging ratio of the macromer to EA, total monomer concentration and amount of initiator on the grafting efficiency and molecular weight of the copolymers were reported. The highest grafting efficiency can reach above 90% and molecular weight of the copolymers varied from 5×104 to 15×104.Reactivity ratio of EA with the macromer was determined to be 0.83.The graft copolymers were purfied with extractions and the purified products were cha-racterized with IR,1H-NMR,PGC,GPC and membrane osmometry. The average grafting number of the copolymers varied from 2 to 11.
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发布时间：2021-03-19 - 摘要：Pyrrole(PY) was electrochemically polymerized on Ni electrode by using Et4N(TsO) as electrolyte in ethyleneglycol/acetonitrile solvent with constant current or constant voltage. The electrical conductivity is around 10 s/cm. TGA results show that the film is stable under 300℃. Results of elemental analysis, FTIR, SEM are also reported.
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发布时间：2021-03-19
Research Article
- 摘要：Characterization of ethyl cellulose and its derivative membranes EC-SiMe3 was studied by 1H-NMR, 13C-NMR, solids-state 13C-NMR(CPMAS) and IR spectra. The permselectivity for oxygen and nitrogen of EC-SiMe3 membranes was determined.
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发布时间：2021-03-19 - 摘要：The DSC melting curves of lthylene/propylene copolymers double melting peaks, and he crystallite melting process was a wide temperature range. The ether and hexane fractionation gave randomly distributed low crystallinie ethylene/propylene copolymers, whereas the heptane fractionation gave copolymer containing long ethylene sequences with high ethylene content and high crystallinity. The latter has showed longest ethylene sequence length () (5.156) and largest r1,r2 value for 13C-NMR results. These results can be attributed to the inter-molecular non-homogeneity and can be explained by the existence ofmulti active-centers in the catalytic system.
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发布时间：2021-03-19 - 摘要：Microstructures of graphite/poly-phenylene sulphide compounds are studied by means of X-ray diffraction, transmission electron microscopy and fractography. It shows that the crystals of poly-phenylene sulphides have three kinds of structures, and no new phases are formed when graphite is added. Conductive polymers with different conductivties may be prepared by mixing different amount of graphite in it, forming conductive networks. The distribution- of graphite networks is a main factor to influence the conductive polymers.
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发布时间：2021-03-19 - 摘要：Acoustic emission during sub-Tg annealing fort amorphous polyethylene terephthalate (PET) sheet quenched from melt has been observed. The mechanical properties, texture and glass transition of annealed specimens have been studied. It is shown that some of PET chains change from non-equilibrium state to equilibrium state during sub-Tg annealing, which leads to stress concentration in specimen. When the level of internal stress approaches to the limit, the acoustic waves are emitted due to sudden releasing of stress and the micro-defects are for-med. This is one of the important reasons,the causes the loss of mechanical properties to an-nealed specimens.
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发布时间：2021-03-19 - 摘要：Because the concentration in reaction part is different from that in feed mixture, the reactivity ratios of styrene and acrylonitrile emulsion copolymerization obtained from Mayo-Lewis differential equation are called apparent reactivity ratios by us and rst= 0.536,rAN=0.0199, respectively, and their azeotropic composition is St/AN = 80/20 (wt ratio).
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发布时间：2021-03-19 - 摘要：19F-NMR studies of the nickel catalyst system, Ni(naph)2-Al (i-Bu)3-BF3OEt2 (abbr. Ni-Al-B), has been tested. In Ni-B system contained "F-B-Ni" complex,19F chemical shift moves to downfield from-153.55 ppm to -148.85ppm, because of the magnetic diploe-dipole interaction between unpaired eelectrons in the 3d8 orbital of N1(II) and fluorine nucleus as a ligand bonded with Ni(II). In B-A1 system the value of coupling constant 1JE-A1 was measured to be equal to 19.2 Hz, the over range of 19F is about from -145 pp, to -155 ppm. And in the real nickel catalyst system,one of 19F resonances is from -135 ppm to -136 ppm at the downfield,which might be assigned to the resonance of fluorine-bridged nucleus on the bimeta-lic complexes,such as due to the presence of dipole-dipole interaction between Ni(I) and Fnuclei,which has been identified by the equation.
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发布时间：2021-03-19 - 摘要：Low molecular weight polydienes were obtained with Nd-Al bimetallic complex isolated from the NdCl3 3P350 (or TBP)-Al(i-Bu)3 system. IR and 13C-NMR data show that there is-CH2CH (CH3)2 group at the molecular end of the polydiene. Based on the results, it was proposed that the activce species composition of the Nd-Al bimetallic complex is Nd-CH2CH(CH3)2. The diene polymerization may be in accordance with the process that the monomer inserts into Nd-C bond. A possible diene polymerization mechanism was proposed.
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发布时间：2021-03-19 - 摘要：Tertiary aliphatic amines containing methyl substituents on the nitrogen atom such as N-methyl diethylamine, N-methyl di-n-propylamine, N,N-dimethyl n-propylamine, N-methyl di-n-butylamine, N,N-dimethyl n-butylamine and the other trialkyl amines such as triethylamine, tri-n-propylamine, tri-n-butylamine were coupled with persulfate as redox initiators in acry-lamide polymerization. The rate of polymerization and the over all-activation energies of polymerization were determined respectively. It was found that the tertiary aliphatic amines con-tining methyl substituents exhibited higher promorting activities in polymerization of acryla-mide than those of trialkyl amines with larger alkyl substituents. The results of spin trapping adn ESR spectroscopy study showed that the tertiary amines having methyl substituents were oxidized by persulfate to form the corresponding dialkylamion methyl free readicals nad they were reponsible for initiating of vinyl polymerization and became the amino end groups of the resulting polymers as confirmed by end group analysis.
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发布时间：2021-03-19 - 摘要：Carboxyl vinyl terminated polytetrahydrofuran macromers and telechelic oligomers were synthesized from hydroxyl terminated polytetrahydrofuran by end group conversion. From these macromers or telechelic oligomers and styrene polytetrahydrofuran/polystyrene segmented and graft copolymers were synthesized and the effects of molecular structure on the damping properties of those copolymers were also studied.
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发布时间：2021-03-19 - 摘要：The reactions of Solvay TiCl3-AlR3 (R=C2H5,i-C4H9) catalysts with acetyl chloride were studied. The main reaction, which is much faster than the reactions between A1R3 and CH3COC1, is as follows:It is found that when CH3COC1 was introduced into 1-octene polymerization systems catalyzed by TiCl3-AlR3 for 5-15min, it reacted selectively and completely with the active centers to produce acetyl-ended polymer chains.With CH3COC1 as a quenching agent, the number of active centers in .these polymerization systems were determined by measuring the content of carbonyl in the polymer,and the results consist with those obtained by kinetics-molecular-weight method.
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发布时间：2021-03-19 - 摘要：Two kinds of polymeric stabilizer containing benzophenone and hindred amine group have been synthesized. The effect of compatibility of polymeric stabilizer in polypropylene on the light stable efficiency has been studied. We found that the light stable efficiency depends on the difference of solubility parameter betweeh polymeric stabilizer and polypropylene. The smaller the difference of solubility parameter it has, the higher the light stable efficiency it becomes.
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发布时间：2021-03-19
Research Bulletin
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