最新刊期
卷 ， 期 3 ， 1984
- 摘要：Allyl group-capped polystyrene macromers (PS-allyl)，anicnically synthesized with n-BuLi，were copolymerized，using vanadium compounds as catalysts，with ethylene and pro-pylene to form graft copolymers EPR-g-PS with polystyrene (PS) branches randomly distribu-ted along the E-P copolymer (EPR) backbome．The highest efficiency in macromer incopora-tion was about 70％．Copolymerization parameters affecting mobility of the macromer，such as MW and dosage of the macromer，concentration of catalyst，and reaction temperature，strongly affect copolymerization and structure of the copolymers．The unreacted macromer was successfully separated from the graft copolymer by selective precipitation with MEK．The composition and MW of the purified copolymers were measured by Uv，NMR，osmo-mertry and GPC methods．Characterization results showed that PS-content of the copolymers ranged from 5 to 45％ by weight，MW of PS branches being 1.0一7.8×104 and Mw／Mn of the branches 1.05—1.17．Average number of branches per molecule was 1—4．
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发布时间：2021-03-19 - 摘要：Without chemical crosslinking，the graft copolymer EPR-g-PS of ethylene．propylene (EPR) backbone with polystyrene (PS) branches possesses mechanical properties comparable with those of vulcanized EP terpolymers．A tensile strength of 198 kg／cm2．300％ modulus of 113 kg／cm2．and an elongation at break of 705％ were achieved with the sample contain-ing 37.5％ PS (molded speciment)．The tensile strength of specimens (cast film) is higher than that of Kennedy’s EPR-g-PS prepared by cationic grafting reaction．PS-content in the copolymers and average number of branches per molecule are main factors affecting the me-chanical properties of EPR-g-PS．Highly dispersed microdomains，formed by PS branches，act as a thermoplastic network and energy-absorbing“reinforcing filler”，actually undergoing deformation under stress，and are responsible for the thermoplastic elastomeric properties of EPR-g-PS．
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发布时间：2021-03-19 - 摘要：Based on the results of earlier work, the effect of PVA on polymerization of N-substi-tuted acrylamide has been studied. It was found that the rate of polymerization of N-methy-lacrylamide decreased proportionally with the amount of PVA added in the system of polymerization. And there was no effect of PVA on polymerization of N, N-dimethylacrylamide. The interaction between N-methylacrylamide and 1,3-propanediol as a model of PVA has been investigated by means of (Chemical lonization) Mass Spectrometry. It showed a com-plex formation between them. The change of viscosity of PVA solution in presence of acry-lamide gives further evidences.The mechanism of complex formation was discussed.
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发布时间：2021-03-19 - 摘要：Two new polytriazines：poly [2-methyl-4，6-(4’，4”-diphenylene)-1，3，5-triazine] (I) dan poly [2-phenyl-4，6-(4’，4”—diphenylene)-1，3，5-triazine] (II) were synthesized from the solution condensation of biphenyl-4．4’-diamidine dihydrochloride with acetic anhydride and biphenyl-4．4’-diamidine with benzaldehyde respectively．These two polymers were characterized by TGA，DTA，elemental analysis and IR spectroscopy．They exhibRed good thermal oxidative stability as shown by the fact that the powders of these polymers suf-fered 5.4％．2.4％ weight loss after isothermal aging in air at 300℃ for 200 hours. The decomposition temperature of (II) was 583℃ in air and 590℃ in N2．In comparison，the linear poly．1，3，5-triazine as mentioned above were soluble in concentrated sulfuric acid，phosphoric acid and trifluoroacetic acid whereas the crosslinked poly-1，3，5-triazines which have been reported in the literature were insoluble and infusible It is interesting that these polymers can be formed into complexes with PdCl2 as de-termined by X-ray photoelectron spectroscopy (XPS)．The polymer complex (III) PdCl2，where (III) is poly[2-methyl-4，6-(1,4-phenylene)-1，3，5-triazine]，possesses catalytic activ-ity for hyarogenation．
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发布时间：2021-03-19 - 摘要：[η]-M relationships for cis-l,4-polybutadiene in tetrahydrofuran, methyl cyclohexane, n-heptane and mixture of butanone and n-heptane (2:1, volume) at 30℃were determined and were found as follows:MW was measured by light scattering method. The mixed solvent at the given temperature was found to be aθ solvent. The unperturbed dimension of cis-1 ,4-polybutadiene was estimated with KS, SF, and IP equations to be 0.0901nm, 0.0928 nm and 0.091 5nm respectively and the value obtained at θ condition is 0.0896nm.
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发布时间：2021-03-19 - 摘要：Carboxyl-terminated polytetramethyleneoxides, the adducts of hydroxyl-terminated poly-tetrahydrofuran and maleic anhydride, were used as toughener for epoxy resins. The mor-phologh of the toughened resin was investigated by means of turbidity measurment, dynamic mechanical testing and scanning electron microscope observation. It turned out that the molecular weight of the polyether and the curing temperature are important factors, which affect the particle size of the polyether domcain and, in turn, the mechanical properties of the toughened resin.
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发布时间：2021-03-19 - 摘要：Chemical shifts relating to methyl carbon of central group in the undecad situated within an otherwise isotactic polypropylene chain were calculated by using Gamma effects, Suter and Flory's rotational polypropylene model. All meso, single, double and tetra racemic (r) defects in the undecad were designed.By comparing the chemical shifts calculated from experimental 67.8 MHz 13C-NMR spectra data indicated that the main stereo-defects are isolated rr triads in predominantly isotactic polypropylene chain and the long rrrr sequence,but do not isolated rrrr pentad distri-buted in the isotactic polypropylene chain.
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发布时间：2021-03-19 - 摘要：The inverse gas chromatography (IGC) was used to determine the heat of mixing of SPU with some organic compounds. The miscibility behavior of these systems and the surface properties of SPU was discussed based on this result. We also observed the phenomenon of soft segment enrichement on the surface of SPU film by IGC, and the results were compared with those obtained from the ESCA experiments.
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发布时间：2021-03-19 - 摘要：The kinetics of the polymerization of isoprene in hexane in the presence of Ln naph-thenate-Al(i-Bu)3-Al2Et3Cl3 catalyst was studied in a specially designed dilatometer. The polymerization showed to be Ist-order in monomer and 1.75 th order in catalyst, respectively. In a typical polymerization, the concentration of propagating chain has been calculated to be 3×10-6mol/l. Thus, the efficiency of lanthanide catalyst is 2.8% and the rate constant of absolute propagations is 411/mol/sec (50℃).
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发布时间：2021-03-19 - 摘要：Using the parameters which were obtained by ab initio HF(STO-3G) MO method，the mechanism of the reaction of t-butyl hydroperoxide(BHP)with N，N-dimethyl aniline (DMA) was discussed．The reaction is composed of three different reactions as follows： 1．Attack of N of DMA on O1 of BHP to give a N-oxide(Scheme 1，in Text)， 2．Formation of a hydrogen bond type complex (Scheme 2，in Text)． 3．Attack of N of DMA on O2 of BHP to give free radicals (Scheme 3，in Text)． The perturbation energies which were calculated by the klopman’s equation(Eg．(1) in Text) were 0.2276，0.1687 and 0.2065 eV in the cases of (1)，(2) and (3)，respectively．Accordingly，it was concluded that all the reactions may proceed simultaneously．
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发布时间：2021-03-19
Research Article
- 摘要：Saturated urushiol, obtained from the Chinese Lacquer by direct catalytic hydrogenation, was condensed with polyethylene glycol dichloride or 1,2-di (polyethylene chloride) benzene to form the saturated urushiol crown ethers. Three new crosslinked polymeric saturated urushiol crown ethers were synthesized via reaction of these monomeric crown ethers with formaldehyde or formaldehyde and phenol in the presence of H2SO4 as a catalyst. The complex-ing capacity, catalytic acitivity and thermostabililty of these polymers have also been investi-gated.
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发布时间：2021-03-19 - 摘要：The polymerization of methyl methacrylate with N-vinylcarbazole and halogenated compounds as initiators have been investigated. The initial activity of the new initiator systems, the influence of irradiation, temperatures and solvents on polymerization were examined. The induction periods increase with increase of DPPH concentration. The molecular weight and dispersivity of poly (methyl methacrylate) obtained were measured.
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发布时间：2021-03-19 - 摘要：Kinetics of butadiene polymerization with C5H5NdCl2.THF(or C9H7NdCl2.HCl.THF)-i-Bu3Al catalyst systems were studied at 50℃. When [Al]/[Nd]=30, the process of polymerization using both catalytic systems belongs to the type of slow initiated, non-steady state reaction. If [Al]/]Nd[ 60, the polymerization process by G9H7NdCl2. HCl.THF system becomes the type of rapid initiated, steady state reaction, while the process induced by C5H5NdCl2.THF system under this condition remains unchanged. When [Al]/[Nd] = 60 and at polymerization temperature 30 or 0℃the polymerization process in these two sys-tems changes to slow initited,non-steady state reaction again. The above results were veri-fied by the molecular weight distribution curves.
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发布时间：2021-03-19 - 摘要：The 13C-NMR spectra of radical and anionic polystyrene have been studied. Resolution of the aromatic C1 spectra has been made by computer. The resolced peaks have been assigned as pentad sequences and their probablities have been calculated. Experimental and cal-culated resultes show that the sequence distributions of radical and anionic polystyrene obey first order Markovian statistics. The polymers observed are all syndiotactic-rich.
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发布时间：2021-03-19 - 摘要：The halogenated aromatic polyamide, which contains halogenospacer in main chain, was obtained by the reaction of 3,3-dichloro-4, 4'-diamino-diphenyl-methane and terephtha-loyl chloride. For comparison analogous nonhalogenated polymer and copolymer were prepared. The effect of chlorine substitution on the benzene ring on flammability, solubility, melting point, thermal stability, was studied by limited oxygen index (LOT), DSC, TGA and solubility measurements.
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发布时间：2021-03-19 - 摘要：The kinetics of the polymerization of methyl methacrylate (MMA) initiated with initiator system of benzoyl peroxide (BPO) combined with N-(4-N', N'-dimethylaminophenyl) acrylamide (DMAPAA) or N-(4N' N'-dimettylaminophenyl) methacrylamide .(DMAPMA) have been investigated. The rate equations are given asRp = Kp,[DMAPAA]1/2[BPO]1/2[MMA] and Rp = Kp [ DMAPMA]1/2 [ BPO ]1/2[ MMA],respectively. The overall activation energies of these polymerization were determined as low as 8.4 and 7.2 kcal/mol, respectively. The monomers containing teritiary amino groups not only initate the polymerization by redox nature,but also incorporate into the polymer chains.
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发布时间：2021-03-19
Research Bulletin
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