最新刊期
卷 ， 期 1 ， 1995
- 摘要：he pyrolytic properties of polysilazane (PSZ), synthesized from ammonolysis of mixture of halosilanes, in N2 or NH3 atmosphere have been studied.The result showed that PSZ can be convertedinto amorphous ceramics through three pyrolytic process in N2 atmosphere and a composite of a-Si3N4 crystal and β-SiC microcrystal at higher temperature. The β-SiC is formed by the pyrolysis of Si-CH3 group, therefore. the content of Si3N4 in ceramics can be increased by decreasing of Si-CH3 group in PSZ. When pyrolyzed in NH3 atmosphere,the process of carbon removal takes place, resulted in the formation of an amorphous inorganic materials which transformed into almost pure a-Si3N4 crystal at 1500℃.
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发布时间：2021-03-19 - 摘要：It is necessary that adding PAAm-CuCl2 film to Na2SO3 aqueous solution form PAAm-CuCl2 film/Na2SO3 catalytic initial system in polymerization of MMA at room temperature. Surface structure of the catalyst is examined by ESR, XPS and Electrical Conductivity methods. These results show that the copper mean content in unit area of PAAm-CuCl2 film and ligand types prominently affect the catalytic activity, namely the catalytic activity is related to the surface structure of the catalyst.
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发布时间：2021-03-19 - 摘要：new aromatic polyester-ether sulfone TLCP was prepared from 4,4 bis(4-hydroxy phenoxy) diphenyl sulfone, terephthalic acid and p-hydroxybenzoic acid. Some factors which affected melting viscosity of the polymer, such as prepolymerization reaction medium and post-polymerization reaction, etc, were discussed.The liquid crystalline properties were characterized by DSC, polarizing microscope with a hot stage and X-ray diffractometer.
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发布时间：2021-03-19 -
STUDIES ON PET/PBT BLENDⅡ.CRYSTALLINE MORPHOLOGY, MOLECULAR WEIGHT AND DYNAMIC MECHANICAL PROPERTIES
摘要：he crystalline morphology, molecular weight and dynamic mechanical properties of PET/PBT blend with polyethylene glycol [PEG] as crystalline accelerater were investigated with the aid of SEM, DMA and U-Viscosimeter. It was found that the PEG has such functions as follows: (i) PEG makes polyester molecular chain move easier and is advantageous to the directonal arrangement of molecular chain on crystallization, so crystallites grow more rapidly; (ii) PEG makes the nucleating efficiency of nucleating agent rise, the formation rate of crystal increases and the crystal number grows;(iii) A portion of PEG takes part in the exchange ester reac-tion of polyester, which either increases or decreases the molecular weight of polye-ster, depending on the PEG level. Modulus and the intensity of the γ-loss peak ha-ve the maxima when the composition of PET/PBT/PEG is 30/30/3.6(wt ratio) and the dynamic mechanical properties are the best.- 6
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发布时间：2021-03-19 - 摘要：he acrylamide microemulsion at appropriate Span 20, Tween 60 and acrylamide concentration were biscontinuous ones demonstrated by the study on the microemulsion conductance. It was proved by conductance change during polymerization that the transistion from the biscontinous microemulsion to W/O one starts at the begining of polymerization and stops at the begining of constant polymerization period.
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发布时间：2021-03-19 - 摘要：he pyrolysis of various polyphenyl-as-triazines (As-PPT) has been investigated by high resolution pyrolysis gas chromatography-mass spectrometer (HR PyGC-MS) and thermogravimetry (TG) in order to gain some insight into their degradation mechanism.The high resolution pyrograms of PPTs were obtained at the pyrolysis temperature of 650-950℃ with good reproducibility. More than 12 of the pyrolysates of AsPPTs were identified by MS. Combining with the TG data, the thermal degradation fmechanism was suggested in this paper.
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发布时间：2021-03-19 - 摘要：he radiation-induced crosslinking and oxidation reaction when the polymethylphenylene sulfide (PMPS) is irradiated by the lelectron beam at R. T. in air are investigated by XPS, IR, DSC and TG. The radiation crosslinking take place on the benzene ring. The shake-up degree of the irradiated PMPS decreases due to the crosslinking. XPS can use to determine gelation dose of the polymer. The irradiated PMPS produces ph-SO-ph, ph-SO2-ph, -CO-and C-O-C groups.
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发布时间：2021-03-19 - 摘要：Ultrafine particles were obtained by spreading dilute solution of isotactic polystyrene in benzene on a water surface, and the resulted particles were crystallized at 448.2K. Transmission electron microscopy (TEM) was used to observe both uncrystallized and crystallized particles. The molecular weight and molecular weight distribution of Ultrafine particles measured by TEM are approximately in agreement with that from GPC measurement. Therefore, the ultrafine particles are of single chain size.
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发布时间：2021-03-19 - 摘要：hrough analyzying photocarrier mobilities in stationary and transient photocurrent decay in polydiacetylene-(bis-p-toluene sulfonate), PDA-TS, a new photocarrier transport model is presented. The fast (picosecond) initial component of photocurrent decay is due to hot carriers in extended band states, and the longertime (nanosecond) component of photocurrent decay is defects (chain end) dominated transport and due to its one-D character.
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发布时间：2021-03-19 - 摘要：he morphology of solution-cast films of the blends of isotactic polypropylene (iPP) with chlorinated polyethylene (CPE) has been investigated in this work by transmission electron microscopy. When the content of CPE in the blends is below 70% the presence of CPE does not prevent the iPP from the formation of two kinds of textures, i.e. cross-hatched structure and lathlike structure. While the content of CPE is over 80gb the discrete iPP phase forms loose lamellar network with the intercrossing angle of 80°.In the whole range of composition of the blends the CPE crystals grow epitaxially on iPP lamellae with their c axes about 50°apart.
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发布时间：2021-03-19 - 摘要：he influences of different level of ionization on the morphology of the ionic aggregates in the block polyurethane anionomer were studedby the small angle X-ray scattering in this paper. The results indicated that it would mainly exist in the form of nonclustered ions or multiplets at lesser ion contents while in the form of clusters at higher ion contents. The ionization of the polyurethane is in favor of the microphase separation of the soft and hard segments.
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发布时间：2021-03-19 - 摘要：Linear copolymers of methylacrylate and styrene were prepared in ben.zene using AIBN as initiator. The linear copolymers were mercuriated by mercury (Ⅱ) trifluoroacetate in THF solution and purified by reprecipitating in distilled water from the THF solution. The mercuriated soluble copolymers loading mercury (Ⅱ) were charaterized by IR, NMR and atomic absorption analysis and the result indicated that the mercury reagent substituted the protons of the phenyl residues and had no reaction with the esther residues under the condition of mercuriation.
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发布时间：2021-03-19 - 摘要：The copolymerization of CO2, propylene oxide (PO) and isocyanates was studied. In this paper, the dependence of the yields, intrinsic viscosity and their distribution as well as thermal stability of the terpolymers on the reaction conditions and isocyanate content were described. The addition of isocyanates resulted in chain extending, branching and crosslinking. The experimental results showed that the copolymerization produced polyimidocarbonates instead of the polyurethanes. The terpolymlers were thermally more stable than the copolymer of CO2 and propyleneoxide.
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发布时间：2021-03-19 - 摘要：he oligomerlzatlon of α-Pinene initiated by Protonic acids,Lewis acids and compound catalysts of vrotonic acids/Lewis acids underlvarlous conditions were discussed in terms of polymerlzation kinetics, isomerization andproduct's components.The results show that these three types of catalysts with active suedes vroton(H+)produced mainly dimer,trimer and tetramer. The compound catalysts of protonic acids/Lewis acids are more active than either one, and the isomerization ofα-pinene decreased significantly. It is discovered that a dimer could be synthesized selective-ly by the compound catalysts with isomerization ratio only 0.5%. Polymer yield and dimer content 99.5% and 83.4% respectively were obtained by the AlCl3/CF3CO-OH.
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发布时间：2021-03-19 - 摘要：new class of materials featuring PP/HDPE composite matrix modified by SBS toughening agent are explored. Excellent mechanical properties are offered by the present three component blending materials. Furthermore, a systematic discussion on the toughening mechanisms of the said material system is conducted from three different but mutually connected viewpoints, namely the morphology structures, the macroscopic mechanics response and the evolution of the crack tip profile. The investigation indicates that toughening can be achieved by the super-blunted crack tip in the plane strain portion of the crack profile, and the deve-lopment of crack tip superblunting is resulted by controlling the material morphology and the suppressing on the early evolution of the dilatational defor-mation.
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发布时间：2021-03-19 - 摘要：he microscopic molecular structure of a poly (methylmethacrylate)(PMMA) Langmuir-Blodgett (LB) monolayer was studied by Atomic Force Microscopy (AFM). An AFM image of a PMMA monolayer on highly oriented pyrolytic graphite (HOPG) indicating that the alignment direction of the backbone of PMMA is parallel to the barrier surface and vertical to the deposition direction of the LB films was observed for the first time. The area per PMMA unit obtained from AFM images fits well with that from -A curves of PMMA Langmuir films. Then the description of PMMA LB films performed process was given and reasons of PMMA backbone alignment were discussed. By means of AFM images, another case of PMMA monolayer which is on silic (Si) substrate was shown to have the helical coiling of PMMA chains. Reasons for this phenomenon are suggested.
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发布时间：2021-03-19 - 摘要：olarized IR has been used to follow the changes in the size, conformation and orientation of oriented amorphous poly (ethylene terephthalate) films during increasing temperature. The results showed that relaxation of the oriented segments took place in lower temperature as compared with the relaxation of the on'ented molecular chains in global sense. The considerable thermal contraction of the oriented PET films is due to the relaxation of global molecular chains. Spontaneous extension is related to crystallization of oriented PET films. The degree of orienta-tion of chains has an important effect on magnitude of spontaneous extension of film.
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发布时间：2021-03-19
Research Article
- 摘要：igh molecular weight polyaromatic ether ketone ketones (PEKK) were prepared by low emperature solution polycondensation of diphenyl ether (DPE) and terephthaloyl chloride (TPC), isophthaloyl chloride (IPC) in presence of aluminum chloride, 1,2-dichloroethane and N,N-dimethylformamide (DMF). The effects of some factors on polycondensation were investigated. The copolymers were characterized by IR, X-ray diffraction DSC, TG, etc. It is shown that melting temperatures,glass transition temperatures, crystalline temperatures of PEKK products decrease with increasing of mole ratios of IPC to TPC. The pekk prepared have good heat-resis-tance and excellent chemical-resistance.
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发布时间：2021-03-19 - 摘要：new series of sulfur-contalning side chain liquid crystalline polymers were described. Mesomorphic side chains with methylene spacer in different length have been synthesized and their structures were identified by NMR, IR and MS.The liquid crystalline nature of the polymers was characterlzed by microscopy.The Polymers have liquid crystalline nature.
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发布时间：2021-03-19 - 摘要：n the basis of the steady state flow model in the capillary, the viscosity of the blends of the thermotropic liquid crystalline polymer (TLCP) and the thermoplastics (TP) were studied. In this paper, several assumptions were brought up to derive a function of viscosity as a function of the volume percent of the TLCP. By compared with the experimental results, this formula was confirmed to be useful to express the viscosity of TP/TLCP blends.
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发布时间：2021-03-19 - 摘要：wo aα,w-dipolar amphiphiles, 10, 12-docosadiyne-1, 22-dicarboxylicacid (DDCA) and 10, 12-docosadiyne-1, 22-diol(DDOL)were synthesized by coupling the corresponding 10-undecylcarboxylic acid and 10-undecynol, respectively. They could form hybrid liposomes when ultrasonically dispersed with dimyristoylphosphatidylcholine (DMPC) at equal molar ratio. Liposome formation was confirmed by electron microscopy, UV measurement as well as encapsulation of fluorescent probes. UV irradiation of the mixed liposomes induced the polymerization of DDCA and DDOL on the liposomes, which could be followed by UV-Vis measurement.
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发布时间：2021-03-19 - 摘要：Chiral polyacrylates liquid crystalline polymers have been prepared by free radical polymerization The structure ofthese polymers was confirmed by analysis of1H-NMR. They were examlnedbypolarlzing optlcalmlcroscopy,DSC and X-ray dlffractlon.The experlmentalresults showedthat these polymers exhibit liquid crystal phase The transition temperature range of liquid crystal phase and isotropic temperature denpend on mesogenic unit and connection group.On coolingfrom the isotropic liquid Smectic A or Smectic Sc has been evidenced.
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发布时间：2021-03-19 - 摘要：The chiral liquid crystalline monomer(Ⅰ) 4-acryloxyundecanloxy-4'-(S(-)-2-methylbutyloxy)-biphenyl, the achiral monommer(Ⅱ) 4-acryloxyundecanloxy-blphe-nyl and the copolyacrylates of(Ⅰ) and(Ⅱ) with different composition of chiral units have been synthesized in the present work.The structures of the monomers and the copolyacrylates were identlfledby Elemental Analysis, FTIRand 1H-NMR.The liquid crystalline behavior ofcopolyacrylates hasbeen studledby DSC, POM,and X-Ray diffraction.The results of DSC and POM demonstrate that the liquid crystalline phase texture and phase transition temperature of the copolyacrylates are affected by the composition of chiral units in copolyacrylates. The copolyacrylates with chiral moiety exceeding 58.0% show SA and Sc phase, whereas the copolyacry-lates with chiral moiety below 58.0% only exhibit SA phase probably due to the mo-lecular polarizability.
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发布时间：2021-03-19
Research Bulletin
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