最新刊期
卷 ， 期 5 ， 1982
- 摘要：Cohesion energy density of 1,2-polybutadienes with various content of 1,2-unit was obtained from solubility parameter which was measured in mixed solvents of cyclohe-xane and toluene.It was found that with increasing in the content of 1,2-unit of the polymer, its glass transition temperature increases but the cohesion energy density decreases, due to the stiffening of the molecular chains of 1,2-polybutadienes.
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发布时间：2021-03-19 - 摘要：The effect of the addition of carboxylic acids to the benzophenone/tertiary amine initiation system containting oxygen was studied. The experimental results show that the polymerization can be accelerated to a greater extent by the addition of carboxylic acids to the system. The rate of polymerization is dependent on the concentration of acids, content of oxygen in the system, chain length and acid value of the carboxylic acid etc. The mechanism of promoting effect of carboxylic acids in this system are discussed. Using this system to initiate bulk polymerization of MMA results in an in-crease of the quantum yield to 8.7×102.
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发布时间：2021-03-19 - 摘要：The valence state of the active center of the nickel catalytic system in the synthesis of cis-polybutadiene has been studied by ESR. It was found that Ni0 and Ni+ always coexist with each other during the course of polymerization.
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发布时间：2021-03-19 - 摘要：Under high temperature, dehydration occurs between the sulfonyl group of Resin 4006-170 and the benzene ring resulting in the formation of sulfone groups which are more stable toward heat than that of Resin 4006.At higher temperature, a trace of reactive gases, such as oxygen, water vapor, etc. is adsorbed by and reacts with the carbonaceous adsorbent at the active point C* to produce CO, CO2, and H2. As a result of this, the closed ppres become open, and the surface area and porosity of the carbonaceous absorbent are increased gradually-Therefore,the activation process increases the rate and efficiency of the adsorption.
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发布时间：2021-03-19 - 摘要：Bheological properties and morphology of the title polyblends were studied by using Instron capillary rheometer, examination of photomicrographs and labelling.It was found that the PDS is dispersed in the polypropylene as t separate phase of typically spherical globules, and that the particle size varies with shear rate of extrusion, length/diameter ratio of the capillary and molecular weight of the PDS.
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发布时间：2021-03-19 - 摘要：Segmented polyurethanes (SPU) have been used as an important biomedical material, the biocompatibility of which will be strongly influenced by the surface properties of the polymer. ESCA has been used in the present study to characterize the surface morphology of SPU samples with different degree of phase segregation. Our experimental results show that (1) the ratio of O/N on polymer-air interface is greater than that in the bulk, i.e. more soft segment is found on the suface than in the bulk average; (2) the soft segment is more abundant on the surface for the samples with better phase segregation,and (3) the compositional variation of the samples with better phase segregation is higher than the samples with less phase segregation.
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发布时间：2021-03-19 - 摘要：Morphology and growth mechanism of spherulite crystallized from nematic meso-phase of poly-p-benzamide in 100％ H2SO4 have been studied by hot-stage polarizing microscopy and transmission electron microscopy．It is shown that nematic mesophase of PBA possesses a supercooled state．The degree of supercooIing reached 30—40℃ whereby spherulites were formed．It was f ound that there are three types of PBA spherulites formed from a 20 wt％ solution．The orientational arrangments of domains which play the role of fundamental structu ral units of PBA spherulite are different when spherulites arc formed from various supercooled states of the nematie mesophase．The morphology of PBA spherulites has been found to be dependent on the degree of su-percooling only，being independent of the eoncentration of the solution．Various growth mechanisms of PBA spherulites have been discussed．
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发布时间：2021-03-19 - 摘要：The investigation on the molecular weigth and its distribution of 1,2-polybuta-diene prepared with MoCl4OR-i-Bu2AlORn catalyst system has been performed by viscosity and GPC methods and the way for regulation of the molecular weight and distribution has been searched. 1,2-polybutadiene with Mw/Mn = 1.2-2.0 can be prepared with MoCL4OR-i-Bu2AlOR' catalyst system at 30-70℃. There is a linear relation between the Mw/Mn and polymerization temperature. It was found by extrapolating that this catalyst system can possibly initiate living polymerization at about -18℃. The molecular weigth and its distribution can be regulated by polymerization temperature or presence of polar additive compounds. Allyl halides are very effective for this purpose and allyl iodide is the best.
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发布时间：2021-03-19 - 摘要：The carboxylated polypropylene composite cation exchange resin is obtained by heterogeneous graft copolymerization of a mixture of acrylic acid and methacrylic acid onto the particles of polypropylene. Each of the branched chains is linked together with the tertiary carbon atom of polypropylene through primary valence bond, but with no cros-slinking between them. They are therefore almost completely extended and rotate freely in ionic solution and thus confer good exchange and chelating adsorption properties on the resin.
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发布时间：2021-03-19
Research Article
- 摘要：A new polymeric tetraphenylporphyrin (p-TPP) and its manganese complex were synthesized. Their structures were identified from examining the viscible absorption, IE, 1H-NMR spectra.
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发布时间：2021-03-19 - 摘要：Pyrolysis-laser optoacoustic spectra of different polymers werr measured and the layout of the apparatus was described. It was shown that this technigue is a useful alternative for determining the molecular structure and elucidating the pyrolysis mechanism of mang polymers.
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发布时间：2021-03-19 - 摘要：Poling PVDP films with different crystal phases show that only the samples which are of β-phase and in direct contact with the poling electrodes can demonstrate strong piezoelectricity (E31*). The samples poled in contact with negative electrode during the poling process display stronger piezoelectricity (e31*) than the samples poled in contact with positive electrode. It is suggested that piezoelectricity of PVDF electrets arises from injected charges especially negative charges. During the poling process only PVDF samples which are of β-crystal phase can accept a large number of injected charges.
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发布时间：2021-03-19 - 摘要：The photostabilizing effect of 1, 2, 2, 6, 6-pentamethyl-4-hydroxy-piperidine(PMP) on polypropylene (PP) films has been investigated. Experimental results further confirm the two step stabilizing mechanism of PMP as suggested in our previous paper.In PP film PMP is first transformed into its N-oxide, and this is then transformed into 2, 2, 6, 6-tetramethyl-4-hydroxy-piperidine-N-oxyl.
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发布时间：2021-03-19 - 摘要：Polymethacryloyl 2, 2, 6, 6-tetramethylpiperidine and polyacryloyl 2, 2, 6, 6-tetra-methylpiperidine and copolymers of styreneacryloyl 2, 2, 6, 6-tetramethylpiperidine were preprared. Corresponding polymeric nitroxyls were obtained by .oxidation of these polymers containing tetramethylpiperdine. When these polymeric nitroxyls used as inhibitor in the synthetic process of unsaturated ester, allylmethacrylate and glycol bis-roethacrylate were prepared with high yield.
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发布时间：2021-03-19 - 摘要：Polysulfone was decomposed thermally in an inert atmosphere, leaving 30-40% by weight of the initial sample as residue. It was found that the residue has good conductivity and good crystalline structure.
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发布时间：2021-03-19 - 摘要：Polymerization of 4-(N, N-dimethylaminobenzyl)methacrylate (DMABMA) initiated by LPO has been studied. The rate equation of the polymerization which was determined at 20, 30, 40 and 50℃ was found to be Rp=Kp [DMABMA]1.5 [LPO]0.5, and the overall activation energy of this polymerization system was determined as 12.2 Kcal/mol. Owing to the above results and the monomer containing tertiary aromatic amino group, the redox nature of LPO with the monomer itself has been suggested.
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发布时间：2021-03-19
Research Bulletin
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