最新刊期
卷 ， 期 4 ， 1993
- 摘要：By adding BF3·OEt2 (B) and its derivatives to the MoCl3 (C7H15 COO)2-(i-Bu)2 AlO- (Mo-Al) two-component catalyst system of synthesizing 1,2-polybutadi-ene with hydrogasoline as solvent, the catalytic activity was influenced remarkably. By addingthe product of HO -/BF3·OEt2 = 1. 0 to the catalyst system, the highest catalyt-ic activity of molybdenum carboxylate system was obtained for the first time. A conversion of more than 70% butadiene (Bd) was achieved with Mo/Bd = 8. 0×10-5(molar ratio) at 50℃ for 5hr. The conditions to produce the gel were preliminarily thrashed out in synthesizing 1,2-polybutadiene with molybdenum catalyst system,and the reasons of producing the gel was inferred. The influence of the polymerization conditions on catalytic activity,molecular weight and microstructure was also investigated.
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发布时间：2021-03-19 - 摘要：Carboxymethyl hydroxypropyl cellulose (CMHPC) crosslinked with a novel organic titanium exhibits good thermal stability determined by Thermogravimetry (TG) and Differential Thermogravimetry (DTG) method, and its hydrogel retains greater viscosity at high temperature. The structure of metal crosslinked CMHPC have been investigated by FTIR spectrome-try. The results show that the active crosslinking sites are not only the carboxymethyl groups, but also the hydroxypropyl groups, and the interaction model are influenced by degree of substitute of CMHPC and pH of reaction medium.
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发布时间：2021-03-19 - 摘要：The compatibility and crystallization behavior of ethylene oxide-styrene-ethylene oxide triblock copolymer (PEO-PS-PEO)/Polyphenyleneoxide (PPO) blends have been studied. The higher the PS content in PEO-PS-PEO copolymer, the better the compatibility of its mis-ture with PPO homopolymer. From the crystallization point of view, PEO-PS-PEO copolymer in the blends crystallizes in a very different way with blend composition, and the crystallization features, such as many crystallization peaks in DSC thermograms obtained during cooling,are really different from those of homopolymer blends.
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发布时间：2021-03-19 - 摘要：A new kind of alkylammonium benzoylbenzoate (BPAA)，including primary and tertiary amines with different length of hydrocarbon chain，was synthesized in this paper．The experimental results show that photophysical properties of alkylammonium benzoyl-benzoate (BPAA) are identical with simple benzophenone, these BPAA with long hydrocar-bon chain are characteristic of amphiphilic property and can aggregate into reversed micelles in non aqueous solution．The results obtained indicate that polymerization rates (Rp) of MMA initiated by BPAA/TEA are greatly faster than that initiated by simple BP/TEA at the same concentration COndition in which tertiary amiRe salts of BPAA shoW higher activities related with the corresponding primary amine salts, polymerization rates for BPAA compounds with long-chain are remarkably higher than those with short chain．By comparison of the polymer-ization rates obtained under O2 and N2 different conditions，it shows that rate enhancement by O2 for BPAA leads to increase obviously in the rate above two times higher than that for BP．The influence of concentration of each BPAA/TEA photoinitiation system is also performed．
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发布时间：2021-03-19 - 摘要：The experimental result shows that, when crystallizing temperature Tc≤196℃, the crystallinity and crystalline size perpendicular to the reflection plane (100) of isothermal crystallized nylon 1010 from melt are increased with the raising of Tc, but the relative diffraction strength of plane parallel to hydrogen-boned sheets (HB) is decreased. When Tc>196℃, the relations are turned back. The quicker rate of crystallization makes the growth of molecular chain on the plane perpendicular to HB easier, but more difficult for the plane parallel to HB.
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发布时间：2021-03-19 - 摘要：In this paper, the conformational transition of silk fibroin in different parts of silkgland was determinated by Raman spectroscopy and LAXS. It was discovered that the β-sheet conformation of fibroin came into being gradually when the stress was increased. By stretching the fresh fibroin directly with Instron, their conformational transitions were studied by Raman spectroscopy. The denaturing process of silk fibroin under stress was revealed on micro-cosmic levels, and a relevant model was made.
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发布时间：2021-03-19 - 摘要：Four porous weakly-basic resins (Ⅱ- V ) were synthesized from a highly-crosslinked polystyrene resin s-008( I ) through its chloromethylation and a successive aminoation. The structures of the resins were characterized and their properties in the adsorption of gypeno-sides were then determined. The results showed that the adsorption capacities and kinetics of these resins were influenced by both their physical and chemical structures.
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发布时间：2021-03-19 - 摘要：Three novel polybenzimidazole metal complexes, FBI H2PtCl6( I ), FBI RhC13( Ⅱ) and FBI PdCl2 (Ⅲ) were synthesized and characterized by X-ray Photoelectron Spectroscopy (XPS). The formation of the polymer metal complexes was confirmed by the disappearance of the shake-up satellites of N1sadn C1s in ( I )-(Ⅲ)and by the coalescence of the two peaks of N1s in complexes resulting in an increase of lower binding energy of N1s peak and decrease of binding energy of the metallic ion respectively. The experimental results of XPS showed that different solvent used for preparation of polymer metal complexes greatly affected the catalyt-ic activity.
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发布时间：2021-03-19 - 摘要：A smectic phase structure scheme for the thermotropic LC polyesters is explored based on the WAXD and temperature-varible FTIR analysis of Bragg spacing in LC and crystalline state and the conformational difference in crystalline, LC and isotropic state.
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发布时间：2021-03-19 - 摘要：In this paper, narrow dispersing core-shell microparticles was synthesized by composite emulsion polymerization, with particle size 70-160nm. The core/shell structure of microgel was observed and determined by TEM clearly. Main factors influencing microgel's structure were discussed by HPTLC densitometry, TEM, GPC and viscosity method etc. . Experimental results showed that when bisvinyl-A is 1-4%(wt. ) of monomer I , first-stage polymerizing time is 2h, the core-shell microparticles will be obtained which having apparent viscosity value 140-165ml/g and containing 8-16% linear PS. The shell was mainly composed of branching chain linking to core.
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发布时间：2021-03-19 - 摘要：Phenolphthalein polyether-ether ketone (PEK-C) containing 10% thermotropic liquid crystalline polymer (LCP) were prepared by melt-blending. Rheological properties of blends were studied using cone plate rheometer, the activation energy for flow process (E) was calculated from the Arrhenius equation, its value was rapidly decreased from 223. 5 KJ/mol to 102. 2 KJ/mol when the shear rate increases from 0.11 s-1 to 1.17 s-1. Glassy transition temperature of PEK-C in the blends lowered from 218℃ to 199℃ comparing with neat PEK-C.Mechanical properties,except modulus,of PEK-C did not change significantly after blending with LCP.It was shown from results of SEM that the LCP in the blends was present in a dis-crete phase,and diameter of LCP was about l μm. The droplets of LCP scattered throughout the polymer matrix.
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发布时间：2021-03-19 - 摘要：In this paper the reaction kinetics of ring-opening polymerization of propylene oxide (PO) by using a catalyst of tetraphenylporphyring AlCl complex (TPPAlCl) has been studied by NMR at various temperatures, which includes reaction order, reaction rate constants, activation energy, number of active center, average length of polymer chains and polymer tac-ticity.The NMR method, which is simple and rapid, gives a wealth of real information. It can be applied to qualitative or quantitative analysis and is one of modern measuring methods in kinetic researcn.
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发布时间：2021-03-19 - 摘要：Graft copolymerizations of methyl acrylate (MA),ethyl acrylate (EA) and butyl acrylate (BA) onto apocynum fibre using redox initiation system were carried out in heterogeneous system respectively. The structure of grafted products was characterized by means of IR, SEM, and X-ray diffraction. The grafted fibres have higher breaking elongation, higher flexibility and lower Young's modulus than those of pure apocynum fiber. The acid and base resistance of grafted fiber increases with the increasing of grafting percent,but the water absorp-tion decreases.
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发布时间：2021-03-19 - 摘要：In this paper the scaling law of linear and starlike polymer comformations in semidilute solution has been veritified by Monte Carlo simulation method. Our results indicated that the scaling law of the osmotic pressure II of polymer solution is agreement of the theory perdicat-ed by de Gennes. Forthermore, it has been obtained that the scaling behaviours of a starlike polymer are as same as a linear polymer chain.
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发布时间：2021-03-19 - 摘要：A new cationic polyelectrolyte has been synthesized by the modification of polyacrylamide (PAm) with formaldehyde (F) and dicyanodiamide (D). Methylol polyacrylamide (PAm·M) was first formed by the reaction of PAm with F in basic medium, then the cationic polyacrylamide (PAm·MG) was formed by the further reaction of PAm·M with D. Products of various content of methylol group or cationic group could be obtained by controlling the molar ratio of F. The structure and composition of both PAm·M and PAm·MG were identified by IR spec-trum and elementary analysis. The content of methylol group in PAm·M was examined by iodometry. The charge density of PAm·MG was determined by conductometric titration and turbidimetric titration,and Mw by small angle laser light scattering method.
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发布时间：2021-03-19
Research Article
- 摘要：A transition metal acetylacetone was studied as latent accelerator in the curing of anhydride cured epoxy resin by DSC, TEA, and rotation viscometer technique. The results reveal that the metal acetylacetone serves as an latent accelerator for anhydride curable epoxy resin system, and the rate of curing is found to increase with enhanced concentrations of the metal chelate. The system provides very fast gel time at 160-180℃ and combined with very good storage stability (> two months). Curing kinetic studies reveal that the overall suring process follows first order kinetics. The electrical,mechanical and thermal properties of cured com-pound of epoxy resin system catalyzed by the MT(acac)n and BDMA accelerator and cured by anhydride was also studied and compared in this paper.
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发布时间：2021-03-19 - 摘要：The effect of inorganic salts on the cloud point temperature of aqueous PEG was measured by laser method. It was found that there is a linear relationship between the cloud point temperature and salt concentrations while the concentration of salt is low Tc = T0 + Km The experimental results indicate that the lower critical solution temperature (LCST) of PEG 10000 is 115±0. 5℃, and the critical composition is 11. 5 wt% PEG.
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发布时间：2021-03-19 - 摘要：The prepolymer of hydroxyl terminated polyepichlorohydrin (PPEPCH) was synthesized by ionic ring-opening polymerization of epichlorohydrin in solution and a series of polyurethane damping materials with the prepolymer as soft segment, including the change of the molecular weight of soft segment ,the content of hard segment and chain extender, were synthesized. The results of dynamic mechanical spectrometry (DMS) show that the compatibility between the soft and hard segments can be modulated by these changes and the materi-als with various compositions have excellent damping property in a wide range of tempera-ture. Because the content of chlorine in these materials is very high,they are expected to have excellent fire-resistant and oil resistant properties.
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发布时间：2021-03-19 - 摘要：Both super-cooling(△Tsc) and super-heating (△Tsh) temperatures of polyethylene tereph-thalate (PET) containing 0,5,10 and 15 weight percent flame retardants have been determined by DSC curves. PET with 5 wt% flame retardant has the smallest △Tsc and △Tsh, which means that it has stronger crystallizability than the others. Avrami equation for the isothermal crystallization has been extended to the non-isothermal process of the constant heating rates so that the parameters characterizing crystallization kinetcs,such as Avrami exponent n, the half life of crystallization t1/2and the crystallization rate constant K, which are usually obtained from Avrami equation,can be calculated from the extended equation for non-isother-mal crystallization. This method has been applied into the investigation of crystallization ki-netics of PET and PET with 5 wt% of flame retardant. The results show that the value of t1/2 fo PET with 5 wt% of flame retardant is smaller than that of pure PET,and that the value of n of the former is about l less than that of the latter.
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发布时间：2021-03-19 - 摘要：The polymerization of ortho-、 meta- and para-phenylenediamine was investigated using ammonium persulfate and acetic acid as catalyst, The conductivity, magnetic property and thermal stability of the polymers were studied . The conductivity of the doped polymers is more than 10-9 Scm-1 and displays semiconductivity. The rusult of TG analysis indicates that these polymers possess same stability and the stability of the polymers is infected by the catalyst for the polymerization
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发布时间：2021-03-19 - 摘要：Thin films of Poly(methyl methacrylate) (PMMA) were prepared by casting from dilute solutions. Methylene chloride, chloroform and benzene were used as solvent respectively. These films were annealed at 40 ℃ or 70 ℃. When rectangular specimens were drawn at a slow strain rate, the tensile strain for crazing εc and for specimen breakdown e?was recorded. The results show that for these films their εc , εb and the craze fibril stability which was defined as εb- εc , depends strongly on the kind of solvent and annealing temperature.
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发布时间：2021-03-19 - 摘要：This article reports the polymerization kinetics of methyl methacrylate initiated by copper chloride-sodium sulfite redox system at higher copper ( I ) concentration. The equation of polymerization kinetics may be expressed as:Rp = 1.35×109e-46.000/RT[MMA]2.0 [Na2SO3]1.0 [Cu2+]0The kinetics and mechanism are discussed, the growing chains are terminated by trans-fering to copper ( I ) ions.
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发布时间：2021-03-19
Research Bulletin
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