最新刊期
卷 ， 期 2 ， 1995
- 摘要：Eight new polycondensates of phenolics and crown ethers are preparedby the condensation of 2,6-dihydroxymethyl-4-methylp (or4-sulfophenol) withdibenzo-18-crown-6 (2B18C6), dibenzo24-crown-8 (2B24C8),benzol 5-crown-5(B15C5),benzols-crown-6(B18C6) respectively and charaterized by IR HNMR DSC.The polymeric crown ethers can' be used as complexing resin to collect differentionsand as stationary phases in gas chromatography for separation of mixed organiccompounds.
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发布时间：2021-03-19 - 摘要：rystallization behavior of ultrahigh molecular weight polyethylene polymerized with HE--1 type catalyst has been studied by means of small angle X--rayscattering (SAXS), wide angle X--ray diffraction(WAXD) and differential scanningcalorimetry(DSC). It was found that crystallinity, long periods, crystallite regionthickness and amorphous region thickness formed in dilute solution are independentof molecular weight and are related with crystallization temperature. If crystalswere obstained from melt crystallization. Its long periods are independent of mo-lecular weight,but related with crystallization temperature and time. Crystallinity and crystallite region thickness decrease with molecular weight increase. Amorphous regions increase with molecular weight and the melting temperature increases with molecular weight. The nascent crystals have higher melting points than those from melt,but the long period of nascent crystals has not been found.
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发布时间：2021-03-19 - 摘要：y using TG and DTA, the processes and kinetics of the thermal degradation of nylon 1010 in N, or air have been studied. The effects of the atmosphereson the process, degradational temperatures, degrees of degradation, kinetics of reaction and the difference of the reactive mechanism have been analysed. It has beenfound that the process of the thermal degradation in N2 is one step reaction, butthe oxidative degradation in air is composed of multiple small steps. The temperatures, degrees of degradation in N2 are higher than those of in air. The apparent degradation reaction orders of are 1.0 and 1.1 in N2 and air respectively.
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发布时间：2021-03-19 - 摘要：Block copolymers of polybutadiene and polydimethylsi fo-cane, poly (Bdb--DMS), were prepared by sequential addition of butadiene and octomethylcyclotetrasi fo-cane(D4), using potassium α-methylnaphthalenide as initiator. Results show thatfinal conversion of D4 varies significantly with its initial concentration, but not changewith the molecular weight and living chain end concentration of polybutadieneblocks; and also not with the polymerization temperature within 10-40oC. Studieswere also made on the ring-openingkinetics of D4 during block copolymerization initiate by polybutadiene living chains. It is shown that the kinetic procedure is similar to that initiated by small molecular anionic initiator. And the apparent rate constant for D4 propagation is found to be 10 kg/mol·h in THF at 30℃,and the corresponding apparent activation energy to be 28.3kJ/mol.
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发布时间：2021-03-19 - 摘要：he block coplymers of polybutadiene and Polydimethylsiloxane, poly(Bd-b-DMS), were critically characterized using FTIR, 1H-NMR,DSC,TGA, WAXD.GPC, TEM etc. modern analytical and determing methods. Results verify that Poly(Bd-b-DMS) is block copolymers with the morpholgy of microphase separation. Studies on the membrane-forming property and gas-selective permeabilities show Poly(Bd-b-DMS) membranes properly vulcanized have good properties for oxygen enrichment. A sample containing 17.8wt % of PDMS has an oxygen permeation coeffi-cient (Po2) of 4.7×10-9cm3.cm/cm2·s·KPa and a separation coefficient (Po2/PN2)of 4.3. The dependence of permeabilities upon vulcanization time and solvents for cas-ting the membranes were investigated and the interrelation of the morphology of Poly(Bd-b-DMS) to permeabilities was also preliminarily discussed.
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发布时间：2021-03-19 - 摘要：he complex dielectric constants of as-cast, quenched, slowly-cooled andallnealed copolymers of vinylidene fluoride with trifluoroethylene (VDF/TrFE) (73/27, 65/35, 52/48 mold )are measured by an improved dielectric relaxation spectrometer in the range of-120-130℃, 10-2-104Hz.The Curie point (Tc) of slowlycooled and annealed samples is lower than that of quenched ones because of a disordered ferrophase in the former and an ordered one in the latter. The dielectricconstant around T. increases with the rise of crystallinity. The frequency spectra od copolymers below the room temperature consist of β-relaxation ascribed to the micro-Brownian motions of molecular segments in the noncrystalline regions and γ-relaxa-tion designated as the local motions of small-scale segments. With increasing the crystallinity,β-relaxation peaks of low-frequency part diminish and γ-relaxation pe-aks of high-frequency part enlarge, the relaxation strength of noncrystalline decrea-ses and that of crystalline increases.
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发布时间：2021-03-19 - 摘要：pure dimer were prepared by GPC from the products of selective dimerization of α-pinene, then with HPLC the number and the relative content ofdimeric isomers in the dimers were measured. And the effect of catalysts and polymerization conditions on the mumber and the relative content of dimeric isomer inthe dimers was investigated. Generally,four peaks of dimeric isomer were observed,but the relative ratio of these peaks changed with the catalysts and reaction conditions. Besides the regular dimers with molecular weight(MW)272, several dimeric isomers with 270 and 274 of a-pinene were observed for the first time by GC-MS combine analysis. On the bases of the datas of the 1H-NMR,13C-NMR,UV and the fragment ions of MS. main molecular structures of these dimeric isomers were proposed.
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发布时间：2021-03-19 - 摘要：n this paper, viscoelastic spectra of PET/alcohol, PET/ketone and PET/ester were determined by dynamic mechanical method. The data proved that thesolvent-induced crystallization is the result of the depression of glass transition temperature.
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发布时间：2021-03-19 - 摘要：series of silicon-containing polyaramide were synthesized by methodof interfacial polycondensation, and the relationship between their chemical structure and gas transport property was discussed. It is found that the permeability forgases used in this experiment, which is hydrogen; oxygen; nitrogen; carbon dioxide; and methane, is fit for ordinary glassy polymer. Gas permeability increases byintroducing flexible segment into rigid polymer chain. Polyaramide with easily rotational backbone has higher gas permeability, For two polymers with the same backbone, gas permeability is higher for one with methyl side group in its aroma-tic ring. The polyaramide with phenyl side group on silicon atom has higher dif-fusivity, but lower solubility than that with methyl side group on silicon atom. These results indicate that in addition to intrachain motion,interchain spacing difference is a contributing factor in understanding various transport behavior of gas through these silicon-containing polyaramide.
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发布时间：2021-03-19 - 摘要：The specific refractive index increments (dn/dc) of short chain polymer exhibit pronounced molecular weight dependency due to the fact that end group contributes much to the optical property of whole polymer chain．From the weight fraction additivity rule．(dn/dc) of the whole polymer chain is the sum of those of corresponding structural units and it is indicated that changing the end group of a given polymer，the molecular weight and(dn/dc) of the polymer chain stem cou-ld be determined simultaneously by measuring (dn/dc) of the whole polymers．It is also possible to estimate the composition of the copolymer from (dn/dc) of the cha-in stem．This principle especially applicable to short chain polymers with pronoun-ted end group effect．This principle is checked by quantitative size exclusion chro-matography to measure (dn/dc) of the benzene solution of oxyethylene-oxypropylene copolymer with different end groups and satisfactory results are obtained．A method for simultaneously estimation of the molecular weight and composit-ion of short chain copolymer by measuring (dn/dc) of the sample solution with quantitative SEC was proposed．
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发布时间：2021-03-19 - 摘要：The surface hydrophobicity and structure of blend coatings of hydroxyl terminated polydimethylsiloxane (PDMS) and chlorosulfonated polyethylene(CSP) are studied. There is a knee point at the curve of the hydrophobicity of the coatings-CSP percent. By XPS,it is demonstrated that the nature of this phenomenon is the function of chlorine-content at the coatings surfaces. The conditions in.which the uniform hydrophobic blend coatings form are described.
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发布时间：2021-03-19 - 摘要：Group transfer polymerization of C7-C9 methacrylates was investigated by using 1-trimethyl-siloxy cyclohexene (TSCH) as initiator and tetrabutylammonium bibenzoate (TBABB) as catalyst. Polymer with higher molecular weightand low polydispersity was obtained. It is one kind of viscosity index improver.GTPof the monomer must be carried out above 80t. The dependences of the polymerization rates, molecular weights and polydispersity, conversion on the polymerizationconditions had been investigated.
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发布时间：2021-03-19 - 摘要：The infrared spectra of Gutta-Percha with different degree of crosslinking have been measured at room temperature and by heating. It was discoveredthat 5 special peaks corresponding to deformation vibration at low wave numberregion have disappeared by heating but are not effected by the change Df crosslinking degree eventhough the crystalline in Gutta-Percha has disappeared completelyand it has changed into a high elastomer at high degre of crosslinking. Thus wemay deduce that the existance of 5 special peaks should be relative to theconfor-mation regularity of the chain segments between crosslink junctions in network of Gutta-Percha.
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发布时间：2021-03-19 - 摘要：The lamellar structure in the oriented films with and without bandedtexture of a lyotropic aromatic polyamide sheared from the anisotropic solutions hasbeen investigated by mean of'transmission electron microscopy. The lamellar structure of 20 urn in thickness for poly (1,4-phenylene terephthalamide) (PPTA) and of40 urn in thickness for poly (1,4-benzamide) (PBA) was observed. These periodicities of lamellar structure are corresponding to the persistance length of both polymers. The molecular chain is only in extended comformation for these rigid poly-mers. Amodel was suggested to describe the packing arrangement of the molecular chain in the crystalline region of the rigid polymers.
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发布时间：2021-03-19 - 摘要：The absolute viscosity and the intrinsic viscosity were measured forCDA/PVP solutions. The experimental results suggested that molecular chains ofCDA and PVP were strongly associated together. FTIR was used to investigate onthe nature of the association of molecular chains of CDA and PVP. Hydrogen bondswere formed between hydroxy groups of CDA and carbonyl groups of PVP.Themiscibility of CDA with PVP were introduced by the specific interaction of hydrogen bonds.
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发布时间：2021-03-19 - 摘要：Ring-opening polymerization of D. L-lactide (D.L-LA) have been successfully carried out by using rare earth isopropoxides as catalyst for the first time.The effects of different rare earth isopropoxides different solvents LA/Ln molar ratio time and polymerization temperature on the polymerization reaction were investigated. It was found that the catalytic activity of different rare earth isopropoxides is as follows: La> M>Nd>Dy>Y, and the optium conditions of the ring-opening polymerization of D. L--LA were:[LA]:1.95mol/l,[Ln(OiPr)3]:6.5×10-3mol/l,90℃,toluene. A kinetic study has shown that the polymerization is first order in both monomer and catalyst. The apparent activation energy of the polyme-rization of D.L-LA with La(OiPr)3 is 67.7KJ/mol.
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发布时间：2021-03-19 - 摘要：The nematic-isotropic (N-I) transition of nematic polymers with semiflexible spacers was examined. The pseudo second order phase transition temperature,T*, of this transition was analytically expressed as a function of length of mesogens and spacers, persistence length of spacer chains and the interactions of andbetween mesogens and spacers. The hinge effect on T* of mesogens and spacersalong nematic polymer chains was envisaged, based on above theory. The predictions were in agreement with experiments.
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发布时间：2021-03-19
Research Article
- 摘要：new series of sulfur-containing side chain liquid crystalline polymerswere described. Mesomorphic side chains with different terminal groups have beensynthesized and their structures were identified by NMR, FTIR and MS. The polymers have liquid crystalline nature
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发布时间：2021-03-19 - 摘要：he stability of mixed liposomes containing β-eleostearic acid (β-ESA>and dimyristoylphosphatidylcholine (DMPC) have been studied by measuring therelease of trapped 5(6)-carboxyfluorescein (5(6)-CF) from the inner phase of liposomes. The results showed that the stability of the mixed liposomes decreased withthe increase of the content of β-ESA in liposomes. Addtion of ethanol and TritonX-100 into the liposome suspensions could damage the liposome structure or induceliposome aggregation, followed by the release ofdye;but less release was observed for the polymerized liposomes when thesame amount of ethanol or Triton X-100 were added, which revealed the increase of stability by polymerization.
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发布时间：2021-03-19 - 摘要：The effect of the smectic and isotropic phase on the photopolymerization of the chiral liquid crystal acrylate 4--acryloyloxyundecanloxy-4'-[thylbutyloxyl-biphenyl (monomer(I)) was studied using -FT--IR. In the meantime,the effect of temperature on the birefringence of surface-oriented monomer(I) andits polymer obtained by in-situ photopolymerization was investigated, too. The results show that the photopolymerization in the isotropic phase is conducted at ahigher rate than in the smectic phase when monomer conversion is less than 60%, however,the polymerization rate is independent of the initial phase state of the monomer when conversion is above 60%, and the highlyoriented liquid-crystalline polyacrylate film can be prepared by in-situ photopolymerization of the surface-ori-ented chiral acrylate(I).
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发布时间：2021-03-19 - 摘要：The blend films of PAn/PVC and PAn/PMMA were prepared by meansof casting from the solutions. The characterization and the transmission of thefilms were determined with UV-Vis absorption spectra.The third-order nonlinearsusceptibility X(3) of the films was measured by using single laser beam technique.The results indicate that it is easy to obtain the qualified optical films with PAn/PVC and PAn/PMMA blends.The transmission of the films in visible range is above 40% that is unable to be reached by pure PAn films with the same thickness. The third-order nonlinear susceptibility X(3) is up to 10-8 esu which corresponds to the values for pure PAn films.
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发布时间：2021-03-19 - 摘要：riphenylalkyl borates (ph,RB) are a new.class of activator for visiblelight induced polymerization of vinyl monomers sensitized by photoreducible dyes,such as methylene blue(MB) used in this paper. Under irradiation (MBph3RB), theborate cleaves rapidly via electron transfer to give an alkyl radical that is capableof initiating the polymerization of acrylates. The results obtained show that therate of electron transfer reaction for MB borate in the tight ion pair form (ket1012s-1) is far faster than that observed in the solvated free ion form whose proper-ty strongly depends on the solvent polarity and concentration. The polymerization can not take place in acetonitrile with MB borate alone but readily occurs by MB borate(MBph3RB)/TEA borate (Et4Nph3RB) combination and polymerization rate inc-reases with increasing TEA borate. The rate inhancement was also observed by ad-dition of methanol to the system.
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发布时间：2021-03-19 - 摘要：he surface properties of polycaprolactone (PCL)-poly (ethyleneglycol) (PEG) block copolymer(PCE) and blend(B-PCE) of PCL and PEG obviouslyeffect on drug release behavior of the polymer. In this paper, both-surface propertiesof PCE and B--PCE are studied and compared by measuring their water sorption.contact angle and XPS technique. The effect of polyether segment content in PCEand B-PCE on the hydrophilicity is discussed. The results show that hydrophilicpolyether segment moves towards the surface and enriches on the surface for either PCE or B-PCE. The enrichment content of polyether segment of PCE and the hydro-philicity of its surface are higher than that of B-PCE. The reason of different drug release rate for the PCE and B-PCE has been suggested.
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发布时间：2021-03-19
Research Bulletin
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