最新刊期
卷 ， 期 5 ， 1992
- 摘要：The compatibility of poly (ε-caprolactone) (PCL) and poly (ethylene oxide) (PEO) as well as the crystallization behavior and morphology of their blends have been studied. These two polymers with their melting temperature close to each other can be compatible within a given range of composition.In blends with minor PCL, it was found from small angle X-ray scattering experiment that not only a scattering peak from PCL lamellar stacks but also another peak located at an scattering angle lower than that from PCL lamellar stacks were observed. This peak should be corresponding to the scattering by a kind of sandwitch lamellar ones from alternative stack-ing of PCL and PEO lamellar systems. In addition,in blend with minor PEO, it is shown that PEO could not crystallize during the crystallization of PCL.
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发布时间：2021-03-19 - 摘要：The literature swelling ratio data of anionic styrene-divinylbenzene block copolymers in good solvent were reanalyzed theoretically. It was pointed out first that such networks are typical two phase model networks. The retreated data are in accord with the demands of the theory of swelling based on statistical thermodynamics only for networks with high crosslin-king density of Mc≤3×104, while for networks with Mc≥3×104 the data conform to the scaling law of swelling.
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发布时间：2021-03-19 - 摘要：In this paper, we described the synthesis, structure, catalytic behavior of a new type of polymer-bound coordinate catalyst, silica-bound poly 4, 7-dithianonylsilsesquioxane rhodium complex. The complex exhibited good catalytic activity for the hydrosilylation reaction of olefins with trie-thoxysilane at 110 to 130℃. Even if the amount of complex used was lowered to the molar ratio of 10-5(rhodium to olefin), the hydrosilylation reaction took place smoothly and the turnover number of olefin was more than 80,000 in such a case. The structure of the polymer ligand was discussed in detail,and the possible structure of coordinate center was sugested.
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发布时间：2021-03-19 - 摘要：PBZT is a rigid rod polymer, Its molecula chain is consisted by benzene ring and hybrid benzene ring. PBZT film is extruded from PBZT/MSA anisotropic solution. The delocalizing π electrons in molecular chain result in electrical conductivity. Its energy gap is 1.69ev. The electrical conductivity σ11 measured by the alternating current complex resistance spectra in the direction parallel to the molecular chain in PBZT film is 10-56 scm-1 and ratio perpendicular to the molecular chain in PBZT film σ is 10-10scm-1. The anisotropy σ11/σ is 104 It can be raised by ten fold when the film was heat-treatmented above 460℃.
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发布时间：2021-03-19 - 摘要：High resolution 1H and 13C-NMR spectra for PET/30PHB and PET/6 PHB copolyes-ters in solution have been measured. The 13C absorptions were assigned by the help of the determination of quaternary carbon absorption with INEPT and partially relaxed FT techniques. Our method previously proposed was applied to characterize the sequence distribution of the copolyesters. The degree of randomness Bq for PET/30PHB and PET/60PHB were found to be 0.87 and 0.81 respectively, the values which are both less than unity for the com-pletely random copolyester. In addition, lt has been pointed out to be improper to judge whe-ther the chain structure of PET/PHB copolyesters is random by comparing their melting po-ints with that predicted by Flory's equation,as some researchers have done.
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发布时间：2021-03-19 - 摘要：Polyazoester(PAE) was obtained by the reaction of AIBN and PEG400. The kinetics of thermal decomposition by DSC gave Ea = 146.6 KJ/mol and A = 5.2×1017s-1.The PAE was used to indicate radical polymerization of methacrylic acid limiting the decomposition of initiator to 37%. This azo group-containing polymethacrylic acid(prepoly-mer) was neutralized by NaOH, thus, a macroinitiator-emulsifier was obtained. It had critical micelle concentration of 0.05 to 0,15 and surface tension of 58 to 68 mN/m.The results show that the kinetics of emulsion polymerization usingthis macroinitiator-emulsifier possesses similiar characteristics of he norral emulsion polmerization.
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发布时间：2021-03-19 - 摘要：Ultrasonic attenuation and velocities have been measured in three kinds of copolymers: Methyl methacrylate-Butyl methacrylate (MMA-BMA), Methyl methacrylate-Methyl acrylic acid (MMA-MAA) containing different kinds of crosslinkers and Styrene-Methyl acrylic acid (ST-MAA) containing crosslinker EGD and BA respectively.Experimental results indicate that ultraconic attenuation increases and velocity decreases in MMA-BMA as increasing BMA content. Adding crosslinkers EGD or BA in MMA-MAA and in ST-MAA, ultrasonic attenuation inbcreases,velocity decreases evidently. The glass transition temperature Tg in MMA-BMA shifts towards lower temperature as BMA content. increasing.
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发布时间：2021-03-19 - 摘要：The relationships between maximum crystallization temperature (Tcsmax) and the other parameters were investigated by using the classical temperature dependence of polymer crystallization rate. The results show that the ratio of Tcsmax/Tm is dependent on the ratio of the nucleation parameter to the activation energy for transport. The crystallization of polymers can be assumed to be the process of the secondary nucleation. In case the temperature dependence of the crystallization rate of polymers is adopted as.
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发布时间：2021-03-19 - 摘要：A new visible-light sensitive photoinitiator, bis (diphenyl-iodonium) salt of eosin, is reported. This system has good thermal stabi ity in ground state. When excited, it can undergo intra-ion-pair electron transfer, leading to the bleaching of the dye and the decomposition of the onium salt. The later results in the formation of initiating radical species. This system can be used as a photoinitiator in radical polymerization of conventional vinyl monomers, especially for acrylates. When methyl methacrylate (MMA) is chosen as the monomer,the polymeri-zation satisfeis the following kinetic equation. The activation energy of polymerization was obtained to be Ea=7.00kcal/mol. In the poly-merization system,oxygen acted not only as the inhibitor of polymerization,but also as the quencher of the triplet of the initiator.
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发布时间：2021-03-19 - 摘要：The bimetal complexes supported on styrene-acrylic acid copolymer (SAAC.Nd.Na. and SAAC.Nd.Fe) have been presence of a new type catalyst system composed of these complexes has been studied. We have found that the system activity is optimum when Nd and free function group -COOH molar ratio in the bimetal complexes is lower. For SAAC.Nd.Fe the system activity decreases gradually with increasing the Fe content. For SAAC.Nd.Na metal Na can promote the system activity, no matter whether the content of Na in the bimetal com-plexes is much or little. Only when the molar ratio of Nd to -COOH is lower,the activity increase is greater. In addition,the activity of the putadiene polymerization catalyzed by SAAC.Nd.Fe-AlEt Cl-Al(i-Bu) in the presence of phenanthroline and the relationship bet-ween the polybutadiene microstructure obtained with the content of Fe in SAAC.Nd.Fe were studied.
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发布时间：2021-03-19 - 摘要：The bimodal molecular weight distribution (MWD) of polyoctene-1 synthesized with TiCl3-Al(C2H5)3 are fitted with the Schulz-Flory "most probable" distribution and seperated into two peaks. It was found that the peak with higher molecular weight is formed on one kind of active center, while the peak with lower molecular weight is produced by at least two kinds of active center, Combining the results of MWD fitting with data of the polymerization rate and the number of active centers, a series of kinetic paraMeters (proparation rate constant,number of active centers,chain transfer constants,etc.) of different kinds of active centers are deter-mined. The results highlighted the plurality of active centers,the differences in catalytical characteristics between these centers and the origin of the broadened bimodal MWD.
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发布时间：2021-03-19 - 摘要：Graft copolymer(PAEPS) of polysiloxanes and polyethers were synthesized by hydrosily-lation from poly(hydrogenmethyl/dimethyl)-siloxanes and allyl ethers of Poly(ethylene/propy-lene)oxides. Polymer electrolyte complexes were made from the crosslinked PAEPS and alkali salts by solvent-casting from acetone. The influences of the copolymer composition, the species and concentration of the salts on the ionic conductivity were discussed. It is shown that the room temperature coductivities of crosslinked PAEPS with alkali salts were two or three or-der of magnitude higher than those of linear FEO.
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发布时间：2021-03-19 - 摘要：A study is presented concerning the three different structural levels of isotactic polypropylene (iPP). Involved wkhin, is the coordinated application of optical and electron microscopy on both α-form and β-form iPP, crystallized from melt. For TEM in particular, the RuO4 staning technique has been used to reveal the lamellar morphology in both spherulites of iPP. The investigation itself has centred on the different spherulite types, as identified optically, which were correlated with the details of their particular lamellar morphology, The lamellar morphology of both iPP crystallized from melt drawing has also been studied.
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发布时间：2021-03-19 - 摘要：By means of differential scanning calorimetry(DSC) and depolarized light intensity me-thod(DLI), isothermal and non-isothermal crystallization of polyblends containing a thermo-tropic liquid crystalline copolyester and polypropylene has been investigated. It is shown that the crystallization of polypropylene is induced, nucleated and accelerated by this copolyester. The fastest crystallization rate is reached in the range of copolyester concentration between 2% and 5%. Polypropylene transcrystallines nucleate at the surface of liquid crystalline fibrils for-med in-situ in polypropylene melt.
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发布时间：2021-03-19 -
STUDY ON BULK COPOLYMERIZATION OF BUTADIENE AND ISOPRENE WITH HOMOGENEOUS RARE EARTH CATALYST SYSTEM
摘要：Bulk copolymerization of butadiene and isoprene was studied with homogeneous catalyst system: Nd(naph)3-Al(i-Bu)2H-CH3SiHCl3. It was shown that the polymerization conversion and [η] of the polymers obtained depended on the catalyst level and the molar ratio of AlH/ Nd. The catalyst system had high activity when the molar ratio of Cl/Nd was in the range of 1-4. The polymerization activity decreased with the increasing of butadiene ratio in the monomers. DSC showed that these polymers obtained had only one glass transition temperature. It was indicated that the product were true copolymers and not the mixture of the homopoly-mers, The structure and composition of the copolymers were determined with IR and 1H-NMR.The cis-1,4 content of the two monomer units in the copolymers was higher than 96%,and the molar ratio of the two monomer units was similar to the monomer feed ratio.The performance test of the raw and vulcanizated rubber were carried out.- 36
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发布时间：2021-03-19 - 摘要：In this paper, two types of mesogenic units, two-dimensional X-shaped and rod-shaped, were copolymerized into the polymer chains. A series of aromatic copolyesters were synthesized by solution polycondensation at the refluxing temperature. The copolymers were all thermotro-pic liquid crystalline. The transition temperatures of the copolymers regularly changed with the substituents in the X-shaped mesogens and with the length of flexible spacers between two mesogens in the chain.
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发布时间：2021-03-19
Research Article
- 摘要：Phase separation of quenched critical and off-critical polymer blends of poly (methyl methacrylate) and poly(vinyl acetate) was studied by using light scattering technique. The results show I(q, t) - qm-3-s(q/qm);s(X) -X2/(3 + X8) and X2/(2 + X6) for critical off-critical mixtures, respectively. In the late stage of phase separation, the self-similarity of the structure is preserved and the coarsening processes are one that the domains increase with self-similar.
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发布时间：2021-03-19 - 摘要：Surlyn is the sodium salt of ethylene/methacrylic acid copolymer. The phase separation behavior of blend of Surlyn and Poly(ethylene terephthalate)(PET) has been studied by Scanning Electron Microscope and IR. It is shown that particles of Surlyn are dispersed in PET matrix, and this phase separation is controlled by heat-treated condition of blend. When the thermal treatment temperature is higher, more reaction is occurred between Surlyn and PET, thus the compatibility of Surlyn with PET' enhances and less particles of Surlyn are found.
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发布时间：2021-03-19 - 摘要：The photopolymerization of acrylonitrile (AN) sensitized by N-methacrylyl-N'-pyrimidi-nopiperazine (MPMP) and its polymer, P(MPMP) was studied kinetically. It was found that the photopolymerization rate of AN sensitized by monomeric MPMP is proportional to 0.35th power of MPMP concentration and 0.85th power of AN concentration, respectively. In the case sensitized by Polymeric MPMP, P(MPMP) is proportional to 0.30th power of P(MP-MP) concentration and 1.0 power of AN concentration, respectively. The overall activation energies for photopolymerization sensitized with MPMP and P(MPMP) were determined to be 4.71Kcal/mol and 4.58Kcal/mol,respectively.From the fluorescence analysis for P(AN) senstitized by either MPMP or P(MPMP),it was confirmed that MPMP and P(MPMP) not only sensitized the photopolymerization of AN but also entered into the P(AN) chains.
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发布时间：2021-03-19 - 摘要：The concepts of polymeric segmental relaxation were employed to interprete phenomeno-logically the negative temperature-dependence of salt dissociation behavior in polymer media. The result predicts that the anomalous characteristic might be universal in all media of high viscosity.
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发布时间：2021-03-19 - 摘要：It has been investigated that the role of donor such as tributyl phosphate (TBP) and ethyl benzoate (EB) in preparing of NdCl3 supported catalyst for olefins polymerization. The surface complexes were produced when the NdCU reacted with TBP and EB. There is a TiCl4/ TBP complex occurred in NdCl3/TBP/TiCl4 catalyst, whereas only the complex of EB with NdCl3 was discovered in NdCl3/EB/TiCl4 catalyst. The polymerization activity of above mentioned two kinds of catalysts for ethylene is much higher than that for propylene. The kinetic curve of polymerization for ethylene is of the decay-type with NdCl3/TBP/TiCl4 catalyst. The interaction between NdCl3 and MgCl2 supports occurred when the NdCl3 and MgCl2 were grounded together,which accelerates the breaking of supports.A higher activity of co-support NdCl3-MgCl2 catalyst for olefins polymerization was obtained.
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发布时间：2021-03-19
Research Bulletin
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