最新刊期
卷 ， 期 1 ， 1985
- 摘要：The molecular size distributions of poly (p-hydroxybenzoates), briefly called PHB or PHBA, have been studied theoretically in this paper. It is impossible to investigate these distributions by experiments since no solvent for PHB has been found. As shown in the theoretical analysis, the molecular size distribution of PHB based on the polyconden-sation of phenyl p-hydroxybenzoate is slightly different from Flory distribution, by which that of PHBA obtained from p-hydroxybenzoic acid is characterized. This form of molecular size distribution for the former PHB can be regarded as a modified Flory distribution.
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发布时间：2021-03-19 - 摘要：This paper reports the influenee of two different feeding ways in preparation of segmented polyether ureihane (SPEU) by a two-step method on dynamic mechanical Properties of SPEU．Experimental results indicate that (1) when chemical composition and nlolar ratio of reactants were kept unchanged，the extent of microphase separation in SPEU was affected by the feeding ways．The extent of mierophase separation of bulk SPEU polymer Prepared by the first reaction feeding way，i．e．[PTMEG—DMI]—Extender，is better than that obtained by the seeond reaction feeding way，[PTMEG—MDI] —Extender．(2) The effect of reaction feeding ways on dynamic mechanical properties of the SPEUS is more evident in 1,4-butanediol (BDO) extending samples．(3) The samples extended with 1,2-ethylenediamine have better phase separation that the samples extended with BDO．
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发布时间：2021-03-19 - 摘要：The thermally stimulated current method (TSC) has been used to study the relaxation behavior of styrene/butadiene copolymers. All copolymers exhibit three current peaks which are labeled designated as β, α and p peak in the order of increasing temperature. The experimental results show that polymerization method markedly influences the position of the peak resulting from glass transition of polybutediene phase.Moreover, the specimen obtained from two-step polymerization exhibits two a peaks. In addition, there is a shoulder for the segmented copolymer,while there is no shoulder for the random copolymer. The TSC result can be explained with the sequence structure which depends on the polymerization method.
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发布时间：2021-03-19 - 摘要：The random copolyesters (PET-PHB) of Polyethylene terephthalate with different amounts of p-acetoxybenzoic racid have been investigated by several methods sueh as po-larizing microscopy，scanning electron microscopy，X-ray diffraction，DSC，etc.，The experimental results show that the nematie liquid crystal begins to appear at the com-position of copolyester 30(mol)％ PHB，and at which the reek beeomes turbid．Further-more，an abrupt change can be found in the composition dependence of quenehed-melt density, equilibrium melting point，the extant of super-cooling or the extent of super-heating．And it can be related to the onset of liquid crystallinity．It has been proposed that the duple beliees with reversed tail-to-head PHB-PHB segments exist in liquid erystal and arrange in a nematic pattern．
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发布时间：2021-03-19 - 摘要：A radiation-crosslinking method to determine the molecular weight of a fluoropoly-mer is suggested and described. For PEP copolymer with different melt indices, its dose of gelation increases with the melt index. G value of erosslinking is 1.2 as determined by elastic modulus measurement of the radiated samples at a temperature above its melting point. The molecular weight (Mw) of this copolymer calculated from the G value of erosslinking and the dose of gelation relates to its melt index aslog Mw ∝ 3.5 log This is quite consistent with awell-known relation between melt viscosity and molecular weight determined with aconventional method.
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发布时间：2021-03-19 - 摘要：In order to investigate syntherie route of polyperfluorotriazine elastomer，2-tri-fluoromethyl-4，6-bis (4'-iodo．2'-oxa-hexafluorohutyl)-1，3，5-triazine (IX)，a novel tria-zine monomer．was synthesized from 5-iodo-3-oxg-octafluoropentanesulfonyl fluoride (I) in eight-steps．I was reduced by potassium sulfite to the sulfinat (II)，which was treared with hydriodic acid to yield 5-iodo-3-oxa-hexafluoropentaaVie acid (III)．Compound III was transformed to 5-iodo-3-oxa．hexafluotopentanenitrile (VI) through the correspond-ing esfer IV and amide V．The desired product IX was prepared by acylationcyclode-hydration of the imidoyIamidine ⅥII．obtained by condensation of the nitrile VI with the amidine VII．The various methods for the esterification of perfluoro-carboxylie acid were studied and a possible mechanism for the transfarmativn of perfluorosulfina-te to the eorresponding perfluorocarboxylic acid by hydriodie acid was proposed．
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发布时间：2021-03-19 - 摘要：The purification and polymerization of the monomer I were studied. Crude Ⅰ contained compounds Ⅱ, Ⅲ and Ⅳ as impurities, whivh were removed by low temperature crystallization followed by filtration throudh a short alumina column. The monomer I was polymerized by UV-irradiation in the presence of Hg with or without solvent. Polyperfluorooxaalkyl triaizne Ⅴ thus obtained showed good thermal stability. In the main chain of the polymer there was no weak unit of uncyclized ring. polymer Ⅴ had an average molecular weightof ca.1.33—2.0×104(D.P.=27—42) and the temperature of 10%weight loss in nitrogen was 340℃.
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发布时间：2021-03-19 - 摘要：The macroreticular copolymer of a-methyl methaerylatedivinylbenzene with high strength was prepared under various conditions．It was found that the extent of hydrolytic reactions was influenced by the reaction conditions，such as the swelling agents，hydrolytic agents，reaction temperatures，reac-tion time and structure of the copolymers etc．A weakly acidic cation exchange resin of exchange capacity 9 meq／g was obtained bythe hydrolysis of a copolymer of a-methyl methaerylate-divinyl,benzene swollen in 10—100％ of furfuryl alcohol with a hot 60％ sodium hydroxide solution at 150℃ for 4— 10 hours．The copolymer was made by the suspension polymerization of 87.5—-79.2％ of methyl methaerylate and 6—10％ of divinylbenzene (48％ pnrity) with 40—60％ (based on monomers) of # 200 petrol as porogenic agent The percentage of hydrolysis of the copolymer was 90—95％．The cation exchange resin thus prepaxed possessed good me-chanical property and its principal properties is closed to that of the Amberlite IRC-50 made by Rohm and Haas company of the United States．Weakly acidic cation exchange resin was prepared by the hydrolytic reaction of the MMA-DVB nmeroreticular copolymer．The extent of hydrolysis of the ester was 90一95％ and was influeneed by the reaction condittons．The capacity of the resin was ab-out 9 meq/g．The mechanieal strength of the beads is good．The principal properties of the resin are closed to that of the Amberlite IRC-50 made by Rohm and Haas com-pany of the United Staites．
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发布时间：2021-03-19
Research Article
- 摘要：The thermodynamic parameters of fusion of polyepichlorohydrin were investigated by Flory's method based on the melting point decrease for polymer diluent mixtures. Toluene, α-chloronahthalene and nitrobenzene were used as diluents.The equilibrium melting temperature was obtained by extrapolating the "kinetic" melting points, measured on polymers crystallized at various temperatures.The equilibrium melting temperature, fusion enthalpy and fusion entropy obtained are 116℃, 10.6 KJ/mol asd 27.2 J/mol. K resp.
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发布时间：2021-03-19 - 摘要：The characterization of the degree of crosslinking of methyl methacrylate-divinyl-benzene (MMA-DVB) copolymer was studied by means of pyrolysis chromatography. Linear relationships were obtained between (hEVB/hm-DVB)average and the degree of crosslinking (in the range of 4-24%) when different samples of DVB were used as raw material. Refinement of the data made it possible to determine the degree of cross-linking directly from the averages chromatographic peak height ratio mentioned above and the composition of DVB used. The mechanism of the pyrolysis of the copolymer was also discussed and a comparatively satisfactory explanation was proposed.
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发布时间：2021-03-19 - 摘要：The elemental analysis data and their gas chromatography indicated that the empirical compositions of the intermediate compounds obtained by reducing Ti (OC4H9)C13 with AlEt2Cl are Ti(OC4H9)Cl2 (Ⅰ), and the catalysts obtained through the heat treatment of Ti(OC4H9)Cl2 by means of TiCl4, have the formula of TiCl3·0.02 AlCl3,·0.05 (n-C4H9)2O ·0.02 C4H9O (Ⅱ). X-ray diffraction pattern showed that (Ⅰ) is an amorphous material, and (Ⅱ) is δ-TiCl3. (Ⅱ) has almost the same crystal modification (20 (deg) = 15.13, 33.03 and 51.52) and average sizeof crystallites (～100A) as the Solvay catalyst (III)prepared from TiCl4.
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发布时间：2021-03-19 - 摘要：Radical polymerization of methyl methacrylate (MMA) initiated with organic pero-xide-ditertiary amine binary systems was studied in this paper. In order to study the effects of organic peroxide and amine respectively, benzoyl peroxide (BPO), lauroyl peroxide (LPO), t-butyl hydroperoxide (TBH), and t-butyl peroxybenzoate (TBPB) were used as organic peroxide component, and aromatic ditertiary amine 4,4'-tetramethyldia-minodiphenylmethane (TMDAPM), and aliphatic ditertiary amine tetramethylethylene-diamine (TMEDA) were used as amine component. It was found that in the bulk poly-merization of MMA using organuc peroxide-TMDAPM binary initiation systems,the ef-fect of organic peroxide on the polymerization rate of MMA Rp was in the following order:BPO>LPO>TBH>TBPB. However,in the organic peroxide-TMEDA binary systems,the order of Rp was LPO-TMEDA>TBH-TMEDA,and BPO-TMEDA,TBPB-TMEDA system could not initiate MMA polymerization. The values of Ea,overall activation energa of polymerization,of MMA initiated with organic peroxide-TMDAPM systems were determined. According to the kinetic studies of MMA polymerization initiated with BPO-TMDAPM,LPO-TMDAPM system,the foll-owing equations were obtained.
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发布时间：2021-03-19 -
EFFECT OF THE STATE OF MACROMOLECULAR AGGREGATION ON THE URANIUM NUCLEAR FISSION TRACKS IN PET FILMS
摘要：235U fission track observations have been performed for PET samples stretched and heat treated under different conditions.These damage tracks may be revealed and made visible in an ordinary optical microscope by treatment with KOH solution that rapidly and preferentially attacks the damaged material.As the stretching and annealing of PET films caused change in the state of mae-romolecular aggregation in the film, the diffusion-etching rate of KOH solution will be accordingly changed. Anisotropy in the diffusion-etching rate gives usanisotropy in the diameter of track cross-section.- 2
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发布时间：2021-03-19 - 摘要：A sulfochlorides-heavy metal staining method is developed for morphology studies of rubber-modified PVC (PVC/CPE, PVC/EVA, PVC/MBS, PVC/ACE, etc.) The staining procedure is as follows: Specimens react with HSO3Cl below -5℃, then are em-beded in epoxy resin and microtomed. The ultrathin sections are stained with UO2Ac2 or OsO4 for TEM. This method is simpler and more effective, and the period of staining is much shorter than those reported in literature.
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发布时间：2021-03-19 - 摘要：Polyacrylonitrile (PAN) fiber was activated at various temperature for varying lengths of time in different flux of CO2. In this experiment, it is good for activation that the tmperature is 850℃ and periods of time 2 hrs, flux of CO2 4 1/min. In this way the ACF which has a specific surface area 900-1000 m2/g and absorbs CCl4 60-70% (in weight) was obtained. It has been found that the PAN ACP posses same properties as viscose ACF made in Japan through the determination of absorption, desorption and pore diameter distribution. In addition,the pore diameter distribution is narrow and the peak of distribution is about 30 A. It has larger specific surface,enabling easy absorption and quick desorption as compared with the conventional activated carbon.It is beingnoticed as a new absorbent.
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发布时间：2021-03-19 - 摘要：The Polymerization of acetylenes have been extensively studied, for the polymers obtained are a kind of prospective material of organic conductor and semiconductor.We Found that in the presence of molybdenum complexes, propargyl alcohol and propargyl chloride copolymerized with vigorous reactions. We obtained polymer Ⅰ insoluble in all solvents studied, and polymer Ⅱ, solubel in methanol, chloroform, acetone etc., with molecular weight 700-1000.We have tried using 9 complexes of Ti, Zr, Fe, Co, Ni as catalyst,but no reaction has taken place.
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发布时间：2021-03-19 - 摘要：Six new polyphosphoric esters containing 5-fluorouracil in the main chain: were synthesized by condensation polymerization of 1,3-dihydroxyalkyl-5-fluorouracil with etho-xyphosphoryl or phenoxyphosphoryl diohloride. The polymers are powdered materials with molecular weight 2400-3600 and easily soluble in water. The antitumor activity of some of these polymers were tested on mice against tewis, it shoewd good antitumor activity.
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发布时间：2021-03-19
Research Bulletin
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