最新刊期
卷 ， 期 5 ， 1983
- 摘要：During solid-state polycondensation of crystaHine nylon 66 salt(Hexamethylenediam-monium adipate) the mechanism of reaction，crystalline morphologies and the relations of thermal behaviour to the thermal history for the nasent nylon 66 have been studied by the use of a number of techniques including determination of conversion rate and of intrinsic viscosities，IR，polarized light microscopy，SEM and DSC．The results indicate that the de-fects in crystals of nylon 66 salt may introduce the nucleation of the reasulting polymer phase, and there are epitaxial crystallization processes in the polycondesation．It was found that the morphologies of fibril-like structure are formed in nascent nyIon 66．and the orien-tation of fibrils is dependent on the conditions used．Double melting peaks duHng DSC ana-lvsis for the nascent nylon 66 in this system are discussed．
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发布时间：2021-03-19 - 摘要：Investigation on the chain transfer in the polymerization of butadiene with MoCl4OC6 H17-(i-Bu)2AlO as catalyst has been carried out. In this catalyst system it was foundthat the monomer and MoCl4OC8H17 played a main part in the chain transfer. The rate of transfer is first order with respect to the concentration of both monomer and MoCl4OC8H17 and 1/2 order with respect to the concentration of the aluminium alkyl.
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发布时间：2021-03-19 - 摘要：Based on the methods reported by Ambler and Kraus, a method was developed for the determination of long-chain branching in polymers by GPC-intrinsic viscosities of polymer fractions. In this method, gi, λi, Gimi, the weight percentage of polymer that is branched, etc. were used to express the distribution, degree and content of branching in polymers. Some relations between molecular weight polydispersity and branching polydisper-sity were disscussed. It was concluded that this method can be used for comparsing of long-chain branchins in Nicked-based cis-polybutadiene more reasonably and comprehensively.
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发布时间：2021-03-19 - 摘要：A polybutadiene of 99% cis-1,4 content with [η]tol30℃ in the range of 3.0-3.5 (dl/g) is prepared for the first time using rare-earth coordination catalyst. It is postulated that the microstructure of polybutadiene is controlled by relative rate of propagation to isomerization of living chain which is assumed to have a structuer of π-allyl neodymium complex.
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发布时间：2021-03-19 -
STUDIES ON THE MORPHOLOGY STRUCTURE AND PROPERTIES OF POLYETHYLENE OBTAINED WITH RARE EARTH CATALYST
摘要：The physical properties of polyethylene obtained with rare earth catalyst have been studied by various methods. The morphology of nascent polymer powder shows strip structure by scanning electron microscope. Branched content, crystallinity and crystallite size are similar to those of high density polyethylene. The melting point of polyethylene powder and its molecular weight ate higher than those of high density polyethylene. The experimental results indicate that the polyethylene synthesized with rare earth cata-lyst shows characteristics of extended molecular chain.- 38
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发布时间：2021-03-19 - 摘要：The pore structure of the super-macroporous styrene-divinylbenzene copolymer, which was prepared by applying a mixture of polystyrene and other solvents as a porogenic agent, have been determined. Some of the matrix have been aminated after the chlorome thylation of the copolymer giving an anion exchange resin. Basing on experimental results, the formation of the macropores of the copolymer was discussed.
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发布时间：2021-03-19 - 摘要：A new type of polymeric adsorbent possessing both high specific surface area and certain polarity was made of chloromethylated cross-linked polystyrene and phenol by Friedel Crafts reaction. Dichloroethane and nitrobenzene were used as mixed solvents and aluminium chloride was used as catalyst. The reaction temperature was kept at 40℃to 125℃. Results showed that the capacities of the resins for adsorbing phenol from waste water were two times as high as that of Amberlite XAD-4 made by the Rohm and Haas Co. in the U.S.A. Besides,its kinetic property and adsorptability were better than that of XAD-4. The adsor-ption capacities of the resins after 50 cycles remain unchanged.
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发布时间：2021-03-19 - 摘要：Acoustic emission has been studied for a wide range of polymers induding amorphous-glasses，semi-ciystalline polymers，copolymers，polymer blends and a crosslinked rubber du-ring the course of uni．axial stretching at room temperature．For noncrystalline polymers acoustic emission occurred in rather small number of events accompanied by crazing and micro-crack formation．Strong acoustic activity appeared during yidding and necking of cry-stalline polymers．Rather small number or none of acoustic bursts occurred during the initial stage of neck drawing but numerous strong bursts appeared when drawing proceeded appro-aching specimen break．Specimens of the same polymer but of different fabrication history may be reflected in their acoustic emission behavior．Acoustic emission during stretching crosslinked poIybutadiene rubber was very weak but observable when the force-dongation curve started to deviate from the linear region．No Kaiser effect was observed for the rub-bet．Very strong and numerous acoustic emission was observed during stretching specimens of polymer blends．High impact resistant polymer modifications showed no sharp increase-of acoustic activity before specimen break．So long aS the polymer and conditions of sped-men fabrication are the same quite reprodudble acoustic emission behavior could be obser-ved．
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发布时间：2021-03-19 - 摘要：The mdecular weight of high 1,2-content polybutatienes obtained with Mo-catalyst system decreased with the amount of allyl bromide added．The vinyl content and the syndio-tafic configuration of the polybutadienes also increased with the addition of allyl bromode．On account of the increase in both vinvl content and syndiotacticity the glass transition temperature of the polymer is raised and the polymer becomes partially crystalline and shows a higher yield strength．With or without addition of allyl bromide，the plots of yield strenght against [n] show linear relation．The two lines are paralled to each other．The molecular weight effects the extruding properties of the polymer，whereas the molecular weight distribution exerts only a minor effect under our experimental conditions．The phy-sicomechanical properties of the valcanized rubber ate nearly equivalent to that of cis-1，4-polybutadiene．
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发布时间：2021-03-19 - 摘要：The sodium amides of telechelic polytetranydrofuran with secondary amine as endgroup (PTHF-NHR，where R represents benzyl, n-butyl or phenyl group)synthesized by termina-ring the dicationicaUy living polymerization of tetrahydrofuran (THF) with a large excess of primary amine were used as polymeric catalysts for anionic block copolymerization of vinyl monomers (methyl methacrylate，styrene or acrylonitrile)．When R is a phenyl group，the PTHF-NHR can be almost completely metallated by sodium naphthalene．On the poly-meric anion from the subsequendy formed sodium amide a quantitative polymerization of MMA leads to the formation of a block copolymer，poly(MMA-b-THF-b-MMA)，which ex- hibits the general properties of thermoplastic ehstomer with a tensile strength of 157 kg／cm2 and dongation of 700%．
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发布时间：2021-03-19
Research Article
- 摘要：Palladium complexes of silica-poly-γ-cyanopropylsiloxane and silica-poly-γ-aminop ropylsiloxane have been found to catalyze the heterogeneous hydrogenation of aldehydes and ketones at room temperature under an atmospheric hydrogen pressure. The rates of hydrogenation of aldehydes and ketones by these two polymer complexes are found to be markedly affected by N/Pd gram atomic ratio in the complex and temperature. These two catalysts are considerably stable and can be reused.
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发布时间：2021-03-19 - 摘要：An investigation was conducted on the morphology of diglycidyl-4.5-epoxycyclohexane -1, 2-dicarboxylare with emphasis on the effect of curing temperature. A heterogeneous two phase network structure was observed on the etched surfaces of all the samples cured at different temperatures. The sample cured at 110℃ showed the most pronounced inbomogenei ty under SEM and has two peaks in the broad damping curve, whereas the degree of in homogeneity tended to decrease again as the curing temperature was further raised. The re-sults obtained has been interpreted in termsof the specific suring process arising from the unequal activity of epoxide rings on the same molecules.
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发布时间：2021-03-19 - 摘要：Two new polyphenylquinoxaline-Rh and polyphenylquinoxaline-Pt complex catalysts have been identified by X-ray photoelectron spectroscopy. This investigation showed that a dative bond was formed by transferring the lone-pair electron on nitrogen atom of poly-phenylquinoxaline to the rhodium atom of Rhcl3 or the platium atom of H2PtCl6·6H2O respecdvely. It was also shown that the conjugated rings of this polymer play an important role in the transition of the lone-pair electron on the nitrogen atom.
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发布时间：2021-03-19 - 摘要：The combination effects of 1,2,2,6,6-pentamethyl-4-hydroxy-piperidine (PMP) with several UV absorbers and quencher during the photo-oxidation of polypropylene film have been examined. It was found that PMP gives a synergistic effect with 2-hydroxy-4-n-octy loxy-benzophenone (UV-531), an additive effect with nickel (3,5-di-tertbutyl-4-hydroxy ben-zylphosphonate monoethylate) (Irgastab 2002) and a weak antagonistic effect with 2-(2'-hydroxy-3', 5'-di-tert-butyl-phenyl)-5-chlorobenzotriazole (UV-327). The difference be-bween the combination effects of tetramethyl piperidine derivatives and pentamethyl pipe-ridinol with these UV absorbers and quencher was compared.
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发布时间：2021-03-19 - 摘要：A vinyl monomer having tertiary aromatic amino-groups，4-N，N-dimethylaminosty-rene (DMAS) has been synthesized from 4-N，N-dimethylaminobenzaldehyde with mal-onie acid by knoevenagel reaction and then decarboxylated．Although the DMlAS bardly proceeds the radieal polymerization initiated with or-ganic peroxide such as BPO, LPO，bet it was found that DMA8 under lower concentra-tion would form redox system with BPO to initiate the polymerization of some vinyl monomers such as MMA readily．The rate equation of the polymerization of MMA ini-tiated by DMAS-BPO system is given as Rp=Kp [MMA][DMAS]0.5 [BPO]0.5 The rate constants of the polymerization were determined at 30．40，50 and 60℃，and the overall activation energy was caleulated as low as 7.4 kcal／mol．The UV-analysis of the obtain-ed polymers confirmed that DMAS not only initiated the polymerization of MMA by combining with BPO，but also entered into the polymer chains．
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发布时间：2021-03-19
Research Bulletin
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