最新刊期
卷 ， 期 4 ， 1984
- 摘要：Molecular motions in PVDF were investigated by dielectric measurement, dynamic mechanical measurement, TSC and piezoelectricity. In the temperature range of -150-120℃, four relaxations were observed and their mechanisms were explained.Our experimental results showed that there are 2 peaks above room temperature and are quite different from those reported in literatures but same as the results of Kakutani.The relation between dielectric polarization and piezoelectric polarization was compared. The results indicated thet d'31 increases linearly with e'3. The slop at high temperature is greater than that at low temperature. It indicates that the piezoelectricity may be originated from orientation of dipoles.
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发布时间：2021-03-19 - 摘要：Radical polymerization of methyl methacrylate (MMA) initiated by various diacyl peroxide-amine systems wore studied．Benzoyl peroxide (BPO) and lauroyl peroxide (LPO) were used as diacyl peroxide component，N，N-dimethyl aniline (DMA) and its para substituted derivatives，i.e.，N，N-dime thyl-p-toluidine (DMT)，P-hydroxymethyl-N，N-dimethyl aniline (HDMA)，p-nitro-N，N-dimethyl aniline (NDMA) and p-dime-thylamino benzaldehyde (DMAB) were used as amine component．It was found that the diacyl peroxide．DMT aystems always give higher rates of bulk polymerization Rp of MMA than the organic hydroperoxide．DMT systems with the following descending order：BPO-DMT>LPO-DMT>CHP (cumene hydroperoxide)．DMT>TBH (tertbutyl hydroperoxide)-DMT．The aromatic tertiary amines posses obvious structural effect on the Rp values in the diaeyl peroxide-amine system．Thus．the para．substituted electron-do-aating groups on the ring of the，aromatic amine molecule increase Rp while the elee-tron-withdrawing groups decreased it with the following descending order as DMT> HDMA>DMA>NDMA≈DMAB．The overall aetiration energies E of MMA polyme．rization were determined．the kineffcs of polymerization of MMA initiated with BPO-DMT system were studied and its rate equation was determined as Rp=K『BPO]0.5[DMT]0.5[MMA].
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发布时间：2021-03-19 - 摘要：The Kc(s) and K,(f) values, the fracture toughness of subcritical and unstable crack propagation, of PS and two types of HIPS (HIPS-A, a blend of PS with 10% rubber; HIPS-B, graft polymer of styrene with 6.5% rubber) were determined by using single edge notched samples. The experimental results showed that after limiting the crack length to a narrow range, the linear elastic fracture mechanics may be used to determine the Kc value of HIPS.
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发布时间：2021-03-19 - 摘要：The photopolymerization of acrylonitrile (AN) initiated With phenylhydrazine (PHZ) and its derivatives under irradiation of UV light and polymerization initiated with the combination of PHZ and quinone in the absence of light have been studied．Ftom the kinetics of photopolymerization．the initiator and monomer exponents were calculated to be 0.66 th and 2.1th respectively and the overall activation energy was 33.4 kJ／mol for the PHZ-AN system．The mechanism of photopolymerization has been proposed．It shows that the exciplex between PHZ and AN will be formed under ir-radiation and then it decomposes to produce the free radical species for initiation．The occurence of exciplex has been verified through fluorensence spectrometry．On the other hand the mechanism of polymermization in the dark has also been proposed that the charge transfer complex (CTC) between PHZ and quinone will be formed at first and then it decomposes to produce an initiation species．The occurence of CTC has also been verified through．UV spectrometry．
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发布时间：2021-03-19 - 摘要：The energy of regular adjacent reentry conformations as well as that of all trans-conformation in polyethylene chain segment was calculated by means of EHMO method. Their results were compared and discussed. In comparison with the latter, the elevation of energy in the former case is less than 3%. Thus, the authors believe that it is quite possible for polyethylene to have regular adjacent reentry.
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发布时间：2021-03-19 - 摘要：The dependences of rheological properties on concentration．temperature and she-ar rate have been investigated experimentally for the water．based sols of hydroxyethyl zaorenjiao i.e．the gum from Chinese honey locust．bean)．The apparent viscosity of the sol as a non-Newtonian fluid was modified by means of,the single-bob method．Over the higher shear rates used．the variation of apparent viscosity with the shear rate for the fluids can be described quite accurately by the power law model．It has been shown that the relationship between the zero-shear viscosity obtained according to Spencer-Dillon equation and the concentration can be represented by the Onogi for-mula．For the solvent (water containing a certain amount of salts) and the dilute (0.6--2.0％) solutions，the temperature effect of zero-shear viscosity obeys Andrades equ-ation．For the；more concentrated solutions，however，the experimental data was not in agreement with Andrades equation．
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发布时间：2021-03-19 - 摘要：γ-Aminopropylheptamethylcyclotetrasiloxane (Ⅰ) and γ-aminopropylmethyldiethoxy-silane (Ⅱ) were synthesized.Emulsion copolymerizations of octamethylcyclotetrasiloxane with (Ⅰ) and (Ⅱ) were carried out respectively in the presence of cationic and anionic emulsifiers.The effects of the amount of the catalyst, the molar ratio of the copolymerization monomers, the concentration of the monomers and the temperature on the experimental results were discussed.
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发布时间：2021-03-19 - 摘要：Polyvinylidene chloride beads were first heated at 185℃ and then pyrolyzed at 960℃ under nitrogen atmosphere in a cracking furnace. The surface area of the spherical carbonaceous absorbent exceeds 1,000M2/g, and its capacity for adsorbing crea-tinine is over 99%. The mechanical strength of the spherical carbonaceous adsorbent 0.6-0.8 mm in diameter is quilt good.
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发布时间：2021-03-19
Research Article
- 摘要：The structure of polysulphone-nylon 6 block copolymer film was studied by inverse GC, electron microscope and polarizing microscope. The heat of adsorption of water on the surface of this block copolymer was determined by IGC. Experimental results show that the crystallinity of nylon 6 is decreased by the addition of polysulph-one component, and the copolymer formed is composed of nylon 6 crystal domains and amorphous domains comprising both nylon 6 segments and polysulphone segments. IGC results also show that the compatibility of the two components is relatively poor.
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发布时间：2021-03-19 - 摘要：The effect of various aluminium alkoxides in match with the same molybdenum alkoxide on the activity in the polymerization of butadiene has been studied. The order of activity of R2AlOR' with varied R is as follows:(i-Bu)2AlOPh > Et2AlOPh ≥ Me2AlOPh, when R' = Ph; (i-Bu)2AlOC8Hl7 > Et2AlOC8H17, when R' = C8H17. The order of activity of R2AlOR' with avried R' is as follows:(i-Bu)2AlOPh > (i-Bu)2AlOC8H17, when R = i-Bu; Et2AlOPh > Et2AlOC8Hl7, when R = Et.The active valence state of molybdenum as determined by ESR is three.
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发布时间：2021-03-19 - 摘要：The compositions of ethylene-propylene copolymers prepared in this work were determined by in'frared spectroscopy. Atactie polypropylene with head-to-tail linking, 2,5-dimethylhexane, squalane and tetradecane were used as model compounds to determine the sequence distribution of ethylene-propylene copolymers according to the method used by Bucci et al.. The effects of various catalyst systems, with or without organic compounds as activators, on the sequence distribution of ethylene-propylene copolymers have been discussed.
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发布时间：2021-03-19 - 摘要：The oxidative thermal stability of two series of thirteen model compounds Ⅰ-XIII containing benzothiazole, benzoxazole, benzimidozole, phthalimide, benzoxazinone and quinoxaline ring was measured:The results indicated that the order of oxidative thermal stability of these two series of model compounds arc Ⅰ > Ⅱ Ⅶ, Ⅳ, Ⅵ > Ⅲ > Ⅴ and Ⅷ > Ⅸ > Ⅺ > XIII, Ⅻ > Ⅹ, respectively. Compound with benzothiazole ring possesses the best oxidative thermal stability, and the next is that with benzoxazole ring, then that with phthalimide ring,The oxiative thermal stability of compounds with teh other three heterocyclic ring is not so good.
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发布时间：2021-03-19 - 摘要：Possibility was studied of synthesizing polypropylene-ethylene propylene copoly-mer-polypropylene (PP-EPR-PP) triblock copolymer with RR-TiCl3-Et2AlCl in slurry polymerization in heptane. Molecular weight (Mn)of PP increased with polymerization time; [η] of product in polymerization according to PP-EPR-PP scheme also increased with addition of successive blocks. In spite of evidence of chain-transfer (negligible with Et2AlCl), especially through the isolation of a nonerystalline low MW fraction, it is suggested that block structure is obtainable on assumption of the presence of two di-fferent active centers.
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发布时间：2021-03-19 -
POLYMERIZATION OF EPICHLOROHYDRIN WITH TRIISOBUTYLALUMINUM-ETHYLENEUREA- TRIPHENYLPHOSPHINE CATALYST
摘要：A catalyst system consisting of triisobutylalumimum, ethyleneurea, and triphenyl-phosphine for the polymerization of epichlorohydrin (ECH) has been investigated. This system showed high polymerization activity for ECH and it was confirmed by inherent viscosity and crystallinity that the resultant ECH polymer has high molecular weight (Mη =70-130×104) and is completely amorphous. As the initiation reaction of this polymerization needs only very low activation energy, this new ternary catalyst can be used to polymerize ECH at room temperature.- 35
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发布时间：2021-03-19 - 摘要：The compatibilities of polysulfone (B)-nylon 6(N) block copolymers with the ble-nd．of homopolysulfone and homonylon 6 and the properties of the block capolymers and their．blends in various solvents were studied．The phenomenon that different viscosities and molecular conformation when the copolymers were dissolved in O-chlorophenol and in formic acid were observed．The B-N (or N-B-N) block copolymers can play a role of the emulsifier in these solvents pai-rs：formic acid-chloroform．formic acid-chlorobenzene and formic acid-dichlorometha-ne．Stabilities of these emulsions depend on composition of copolymers (as emulsifiers) and the ratios of volume of these solvents pairs in each system．The presence of two phase in the B-N (or N-B-N) block copolymers were characterized by PM and SEM．The results show that B-N (or N-B-N) block copolymers can be a compatible agent for polymer-polymer systems and solvent—solvent systems．
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发布时间：2021-03-19 - 摘要：The structure of poly-γ-mercaptopropylsiloxan-carbonylrhodium catalyst has been investigated by X-ray photoelectron spectroscopy (XPS).The experimental results indicate that the catalyst is formed by substituting two bridged chlorine atoms in tetracarbonyl- μ -dichlorodirhodium molecule with two sulfur atoms in si-licasupported poly-γ-mercaptopropylsiloxan. Thus, the structural formula of catalyst can be pictured as (A).
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发布时间：2021-03-19
Research Bulletin
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