最新刊期
卷 ， 期 3 ， 1990
- 摘要：A new way of dissolving isotactic polypropylene (PP) in cyclohexane, by putting the samples in cyclohexane under a pressure of 3-4 atm. at 140℃ for 2-3 hrs is introduced. By using a specially designed hermetic viscomter, intrinsic viscosities [η] of PP samples were measured at 60℃ and 70℃- The data viscosity are reproducible and show that PP samples were not degraded even without antioxidant added and cyclohexane is a good solvent of PP at this measuring condition. The values of Huggin's constant are within the range of 0.36+0.02 Mark-Houwink equations [n]=1.23×10-1M0.61(60℃) and [n]=9.20×10-2M0.63(70℃) are obtained. Molar mass distributions of six PP samples are measured by GPC byusing an Apple II personal computer and iterative technique.
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发布时间：2021-03-19 - 摘要：In this paper, the poly(4,4'-diethynyldiphenylmethane) is synthesised by the thermo-polyme-rization and catalysis polymerization (using (Ph3P)2PdCl2 as catalyst) of 4,4'-diethynyldiphen-ylmethane in bulk, and the copolymers of 4,4 -diethynyldiphenylmethane and phenylacetypene is also synthesised using (Ph3P)2 PdCl2 as catalyst. The density, the swellability and, the solubility parameter, Huggins parameter and the average molecular weight between crosslinks (Mc) of crosslinking products are measured. And the thermogravimetric analysis of crosslinking products and Infrared Spectra of all polymers are also done.
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发布时间：2021-03-19 - 摘要：The ultrasonic heterogeneous copolymerization of poly (ethylene oxide) (PEO) in its aqueous solution with hexyl methacrylate (HMA) was studied. The experimental results show that the macroradicals praduced in the ultrasenic degradation of PEO can initiate the polymerization of HMA. The copolymer (PEO-HMA) thus formed will be degraded further as the irradiation goes through. The structure of the copolymer was idontified by IR, PGC and NMR, it is a block one.
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发布时间：2021-03-19 - 摘要：Two kinds of multiblok poly (ether-ester) copolymers with different properties have been synthesized. One of them consisted of poly (ethylene terephthalate) as hard segment and poly-(ethylene glycol) (PEGT), as hydrophilic soft segment while, another consisted of poly(ethy-lene terephthalate) as hard segment and poly (tetramethylene glycol) (PTMGT) as soft segment,, which is a relatively hydrophobic one.Relationship between the microstructure and blood ooknpatibility has been observed by changing the composition of blends.M icrophase separated structure of blends has been determi-ned by means of VES.DSC, SEM and TEM. Blood compatiobility of the blends was evaluated by column beads method. The experimental results indicate that microphase separated structure and hydrophilic-hydrophobic balance of materials are important factors which affect the compa-tibility of these materials with blood.
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发布时间：2021-03-19 - 摘要：There are two kinds of methods to measure the crystallinity of polymers by WAXD-the relative method (CCI, ICI) and the absolute method (HWM, CPRM, Ruland-M). The results of various methods in the literature are often different. Results of WAXD also disagree with those of other methods (p, DSC, NMR FT-IR etc.). The present work investigated systematically on the differences between WAXD and DSC, p, the choice of 2θ range, the effects of various corrections, the separation of amorphous scattering and the comp arison between the relative method and the absolute methods etc. It is concluded that WAXD is better than DSC and σ,the absolute methods are better than the relative methods and each absolute method has its advantage and shortage. The key problem still isthe separation of amorphous scattering from the total scattering.
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发布时间：2021-03-19 - 摘要：The effects of fire retardants on PP crystalline morphology have been studied in fire reta-rdant-polypropylene (FRPP) systems by wide angle X-ray diffractometry (WAXD), light microscopy (PLM and PCM), small angle light scattering (SALS) and differential scanning calo-rimetry (DSC). It was revealed that some fire retardants can act as nucleating agents in PP crystallization, some fire retardants can act as a barrier to PP crystallization, While some fire retardants are inert additives in FRPP systems.According to PLM and PCM results. it appeared that PP crystallization process was a re-dispersion process of fire retardants in the FRPP systems.
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发布时间：2021-03-19 - 摘要：In that paper, an improved MP method is described Pore size distribution for carbonized resins containing both micropores and mesopores were calculated by using the improved MP method and model method, respectively. The complete pore structure analysis results can be expressed by the sum of the results from these two methods.
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发布时间：2021-03-19 - 摘要：This paper reports on some first results on the group transfer polymerization (GTP) of several methacrylates, with ethyl 3-ethoxy-3-trimethylsiloxy acrylate (ETSA), ethyl 2-butyl-3-ethoxy-3-trimethylsiloxy acrylate (BTSA) and dimethyl ketene methyl trimethylsilyl acetal (MTS) as initiator and Et4 NHF2 as catalyst. Polymers with narrow molecular weight distribution and predetermined molecular weight were obtained. PMMA with higher polydispersities are obtained when highl levels of the catalyst are used. The effect of the catalyst concentration onmonomer conversion was studied. Some PMMA of high molecular weight (Mn>2×105) were obtained.
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发布时间：2021-03-19 - 摘要：A series of UV-cured AB crosslinked polymers (ABCP) based on vinyl-terminated polyethylene adipate polyurethane and methyl methacrylate were prepared. The dynamic mechanical properties, glass transition, morphology and crosslinking density of the AB crosslinked polymers were studied by using Rheovibron, TEM and equilibrium swelling. Two glass transition temperatures, Tg, corresponding to these of polyurethane and PMMA phases were observed and mic-rophase separation was eventually evident with TEM. The two Tgs were shifted inwardly in ABCP indicating that the chemical crosslinking between wo components increased the mutual miscibility. IPN with similar composition to ABCP have much larger phase domains than ABCP. Hydrogen bond influenced greatly the compatibility,morphology and dynamic mechanical pro-perties of ABCP.
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发布时间：2021-03-19 - 摘要：The conformation of xanthan molecule in aqueous solution was investigated by GPC. It is indicated that two states of xanthan exist simultaneously in aqueous solution at low ion-intensity. One of the two states is polyassociated double-stranded helix, and the other is single molecular state. These two states can transform each other under some conditions.
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发布时间：2021-03-19 - 摘要：Laccase-catalytic oxidations of urushiol and its analoglues have been investigated in various aqueous solutions of ethanol. Alkyl substituted pyrocatechol will favor the enzymatic oxidation. The results suggest that the reaction consists of formation of yellow quinones and then coupling of them to produce polyphenylphenols.
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发布时间：2021-03-19 - 摘要：A series of polymeric carrier drugs were prepared by linking 5-fluorouracil to chitosan as a carrier. The conversion of H2N- group in chitosan was estimated by the determination of nitrogen content, and the structure of polymeric carrier drugs was confirmed by IR, UV and 13C-NMR. Hydrolytic release of 5-fluorouracil or its derivatives from these new polymeric carrier drugs was also investigated. The preliminary results of the in vitro testing against Ehrlich Asci-tes Carcinoma cell showed that I and II type of polymeric drugs have good antitumor activity.
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发布时间：2021-03-19 - 摘要：The crystallization and mutiple-melting behavior of PBT crystals in PSF/PBT blend films, the influence of blend compositions on these behaviors were studied by DSC, IR and viscoela-stometer. The experimental results show that the double-peaks in DSC plots are owing to mutiple-melting behavior but not to polymorphy in PBT crystals. The crystallinity of PBT is not affected by addition of PSF component but mutiple-melting behavior is by this. This is due to the influence of the addition of PSF on the perfection of PBT crystals.
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发布时间：2021-03-19
Research Article
- 摘要：The effect of electron beam on the crystallinity of irradiated sulphite cellulose have been investigated by X-diffraction. When two methods of making the X-ray diffraction samples were used, contradictory results were obtained. It is thought that at high dose, the crystallinity of cellulose might be destroyed by radiation and decreased with increasing the radiation dose. Our experiments have proved that when the irradiated cellulose is pressed by mechanical force in procedure of making the X-ray diffraction sample,the crystalliinity of irradiated cellulose will be recovered because of its recrystallization. The aforementioned phenomenon could be explained with models. A method to determine the crystallinities of irradiated cellulose was suggested.
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发布时间：2021-03-19 - 摘要：This paper reports the effect of shear rate, temperature and composition on the apparent viscosities of CPVC/CPE blends. The major results obtained are: 1. The variation of apparent viscosity with the shear rate for all blends can be described quite accurately by a modified power law model; 2. The activation energy (E) of CPVG or CPE at constant shear rate for flow is not constant, its value dependence of shear rate follows the simple exponential relationship; 3. The effect of temperature on the apparent viscosity of CPVC/CPE blend get smaller as CPE content increased; 4. Accoring to Utracki's work,the viscosity-composition relationship of CPVC/CPE blends isin agreement with "negative deviation".
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发布时间：2021-03-19 -
KINETIC STUDIES ON THE POLYESTERIFICATION OF ETHYLENE GLYCOL WITH MALEIC ACID AND PHTHALIC ANHYDRIDE
摘要：Kinetic studies of polyesterification of ethylene glycol and dibasic acid (maleic acid and phthalic anhydride) were investigated. The kinetic data obtained from reactions are agree with the corresponding equations proposed by Lin, but when the concentration of ethylene glycol is higher, the kinetic processes do not fit with Lin's view. In all reactions, two reactive rate constants are existed obviously.- 33
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发布时间：2021-03-19 - 摘要：The effects of electron irradiation on the rubber elasticity of electron-irradiatedn-polyethylene filaments were studied. The results showed that the dose of gelation is about 2.4 ~ 3.0 Mrad.The experiments also infered that the average molecular weight between entanglements in the linear polyethylene with Mn= 28000 is about 15000.
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发布时间：2021-03-19 -
FACTOR ANALYSIS APPLIED TO X-RAY DIFFRACTION SPECTRUM STUDY OF PE/(PE-EPR) AND PE/(PE-EPR-PE) BLENDS
摘要：The feasibility of applying the method of factor analysis to X-ray diffraction spectra of PE/(PE-EPR) and PE/(PE-EPR-PE) blends was examined. The result of mathematical treatment is satisfactory. The number of species and compositions for eight kinds of both PE/(PE-EPR) and PE/(PE-EPR-PE) were determined. The separation of spectra peaks of each species in two kinds of blends contributing spectra intensities was carried out.- 3
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发布时间：2021-03-19 - 摘要：Dilute solution properties of the poly(butyl-acrylate) were studied by means of low angle laser light scattering, membrane osmometer, viscosity and high performance size exclusion chro-matography. The limiting viscosity number-molecular weight relationship of this polymer in THF at 25℃ was determined. The data of SEC show that both PBA and PS have identical hydrody-namic volume universal calibration curve.
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发布时间：2021-03-19 - 摘要：Polyvinyl alcohol solution in water-dimethyl sulphoxide will automatically change into gel. Auramine O as a fluorescence probe was added into the system. A self-catalytical curve, from which a gelation rate was taken out, of the gelation process was obtained by measuring fluorescence spectra of Auramine O. The effects of various component ratios in system on the gelation rate were examined. Kinetics of gelation was also studied by this method. It is found that the mole fraction of DMSO in the mixture solvent affected the rate of gelation. When the mole frac-tion of DMSO is 0.25,the rate of gelation reached the maximum. This phenomenon may be in-terpreted from the view of hydrogen bond formation. It is concluded that fluorescence probe method is efficient and easy for study of gelation process.
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发布时间：2021-03-19 - 摘要：The polymerization of e-caprolactone (CL) or propylene oxide (PO) with tetra-phenylporphyrin (TPP)-diethylaluminium chloride (et2AlCl) as catalyst in toluene gives the polymer with narrow molecular weight distribution and is living polymerization in nature.From the living polymerization of CL or PO the block compolymers of PCL-PPO or PPO-PCL were prepared, The M, and Mw/Mn of homo-or copolymers were determined by GPC and showed that the M, increased linearly with the increase of conversion and the value of Mw/Mn was 1.19-1.25,indicating the narrow distributi-on of the molecular weights. The ratio of CL/PO (mole/mole) in the block copoly-mers were estimated by GPC or NMR spectroscopy.
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发布时间：2021-03-19 - 摘要：The effect of molecular weight (MW) on the isothermal crystallization of polypropylene (PP) has been studied using a differential scanning calorimeter (DSC). PP samples with Mw ranging from 7×104 to 30×104 were prepared with controlled oxidative degradation. Based on the experimental data of crystallization peak time, it is obvious that the isothermal crystallization rate of PP decreases with decreasing MW. This result is consistent with the phenomena of smec-tic structure formation in fiber spinning process and injection moulding.
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发布时间：2021-03-19
Research Bulletin
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