最新刊期
卷 ， 期 4 ， 1990
- 摘要：The compatibility of poly (e-caprolactone) (PCL) with poly (styrene-co-acrylonitrile) (SAN) has been investigated using DSC and IR methods. It is shown that the mixture is compatible based on the glass transition temperature measurement. With the increasing concentration of SAN, the melting points of a semicrystalline polymer PCL depress in the PCL/SAN blends. By means of Flory-Huggins equation, the interaction parameter (x23) between these two macromolecules has been evaluated from the melting point depression. The shift and the broadening of the IR absorption hand of carbonyl group indicate that there exizts some spe-cial interaction between ester group in PCL and a-hydrogen in acrylonitrile units of SAN. This interaction results in the compatibility of PCL/SAN blends.
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发布时间：2021-03-19 - 摘要：The polymerization processes of isoprene (IP) based on (CF3CO2)2LnCl·EtOH一(i-Bu)2AlH homogeneous catalysts were traced out by 13C-NMR. First，IP coordina-ted to rare earth to become,n4-IP rare earth complexes trans and cis)．Then C-3 and C-4 of,n4-IP inserted into Ln-H bond to form n3-allyl rare earth complexes (syn and anti)．13C chemical shifts and 1JcH coupling constants of n4-IP indicated that C一1 and C-2 of n4-IP coordinated to rare earth with π coordination bond，while the double bond between C-3 and C-4 transformed to σ bond to form a metal cyclopropane structure with rare earth，i.e. a activated structure．2D 13C-NMR exchange spectra showed that the slow exchange (tautomcrism) reaction between every pair of n4-IP and,n3-allyl isomers could take place at ambient temperature．These reactions underwent the processes of bond breaking and reformi-ng,which enable insert reaction to take place at room temperature．The suggested polymerization mechanism is IP—n4-trans—IP→n4-cis-IP一n3-syn-allyl→n3一anti-allyl—trans一1，4一IP／cis—1，4一IP(C-1 insert) or 3,4-IP(C-3 insert)unit．
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发布时间：2021-03-19 - 摘要：In this paper, four new polymeric thiacrown ethers (PD1-PD4), in which some oxygen atoms of crown ring were replaced by sulfur atoms, with polythiaether backbone were synthesized via the intramolecular cyclization of poly (2'-chloroethyl-2, 3-epithiopropanyl ether) with various dimercaptans. The complexation capacities of these polymeric thiacrown ethers for Ag+, Au2+, Pd2+, Pt4+, Cu2+, Hg2+, Zn2+, Cd2+, Pb2+, Mg2+, K+ and Na+ were determined. The results showed that they possess much stronger complexation ability for the noble metal ions such as Ag+,Au2+,Pd2+ except Pt4+.
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发布时间：2021-03-19 - 摘要：An XPS study was performed on films of methacrylic acid-styrene block copolymers (PMAA-b-PS) which were cast from DMF solutions, without or with subsequent solvent treatment. The results showed that the bulk compositions of the block copolymers had little, if any, influence on the surface compositions of the films. Direct casting from DMF solutions resulted in the highest fractional area coverages of PMAA at the surfaces according to a two-phase model, reaching a value of 0.55. In the cases of solvent treatment,the surface compositions were basically dependent on the solubility parameters of the solvents used and the fractional area coverages of PMAA at surfaces decreased in the order of water>ethyl alcohol>cyclohexane>petroleum ether.
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发布时间：2021-03-19 - 摘要：Detailed carbon-13 NMR spin-lanttic relaxation (T1) measurements have been made for the protoned carbons of polyurethanes (PU) based on polybutyleneadipate diol, 4,4'-diphenyl-methane diisocyanate (MDI) and 1,4-butanediol (BDO). The solvent is DMSO-d6 and concentration is 10% (w/v). All of the data were measured on the JEOL FX-600 NMR Spectrometer. The molecular motion of the polyurethanes have been discussed with the experimental data.
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发布时间：2021-03-19 - 摘要：A series of block copolyesters based on terephthaloyl chloride, hydroquinone and hydroxy terminated telechelic polysulfone were synthesized. The copolyesters showed composition-dependent liquid crystalline properties within a wide temperature range. The mesomorphous properties were examined by visual observation of stir-opalescence, birefringence and X-ray diffraction. The minimum mole fraction of mesogenic units needed for appearance of melt anisotropy is not higher than 0.10. The glass transition temperature of the copolyesters are close to that of polymers merely of spacers.
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发布时间：2021-03-19 - 摘要：The kinetics of thermal degradation of poly (aryl ether ether ketone) and sulfonated PEEK was studied by isothermal and dynamic thermogravimetry. The results calculated from the kinetic models based on random initiation followed by rapid disproportionation and termination were in good agreement with the experimental data. The overall activation energy for the degradation was found to be 235 KJ/mol. The effect of sulfonatiorr on thermal degradation was also mentioned. It is noted there are two weight loss steps in the dynamic TG curves for S-PEEK. Compared with thetemperature programing PGC-MS data,the thermal degradation behaviour of S-PEEK was discussed here.
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发布时间：2021-03-19 - 摘要：The theoretical relationship, which correlates the glass transition temperature (Tg) with the other molecular parameters, has been proposed by taking the dynamic segment as the basic statistical unit. The dependency of Tg on the stiffness factor o2(Tg) for isolated chain at Tg and dynamic stiffness parameter (B= -d(lno2)/dT) has been discussed in detail. The theoretical prediction is compared with the experimental data for many linear polymers and the good agreement is obtained. It has been shown that Tg is essentially governed by the chain stiffness factor at Tg.
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发布时间：2021-03-19 - 摘要：Rare-earth coordination catalysts were used for the first time for the homopo-lymerization and, copolymerization of styrene (St) and divinylbenzene (DVB). Fea rtures of the polymerization of St and DVB by Nd(naph)3-Al (i-Bu)3 and Nd. (P204)3-Al(i-Bu)3 systems have been investigated. The conversion of styrene was more than 90% under the optimum conditions ([Nd] = 3 ×10-5 mol/ml; [M] = 3×10-3mol/ml, Al/Nd= 10(mole ratio), 50℃), while the catalyst system prepared by the following addition order:Nd-solvent-St-Al. With the variation of polyme-rization conditions and solvents,rere-earth polystyrene obtained was white or yellow powder showing atactic structure. Number-average molecular weight of PSt obtained ranges from 102 to 104.FeCl3 added to the polymerization system may suppress forr-ming yellow colur powder. DVB showed higher activity than styrene in copolyme-rization.
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发布时间：2021-03-19 - 摘要：Simultaneous formation and polymerization of polyphenylacetylene (PPA) films by Nd(AA)3-Fe(AA)3-Al(i-Bu)3 or Nd(BA)3-Fe(BA)3-Al(i-Bu)3 mixed, coordination catalysts was carried out in the toluene/hexane solvents at room temperature. The features and kinetic behaviour of polymerization, and properties of PPA films have been investigated. It is pointed out that neodymium-ferrum mixed catalysts show combined catalytic effects.
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发布时间：2021-03-19 - 摘要：Ethylene (E)-Propylene (P) copolymers and mixtures with long E-P sequence structures were investigated using WAXD and PLM methods. As the content of Cs reached more than 30 mol %, the (140), (130) crystal planes appear at 2θ = 20 in X-ray diffraction patterns of me-Itcrystallized samples. Planes of (140), (130) are the characteristics of γ-form, which originate from (a +γ) form in E-P copolymers.γ-form is mainly observed for long E-P sequence copolymers as slow cooling, but a-form is mainly for blocks and mixtures.
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发布时间：2021-03-19 - 摘要：In this paper the kinetic characteristics of the quaternization of poly-p-chloromethyl sty-rene (P-pCMS) are explored. It has shown that the quaternization'of P-pCMS with triethyla-mine (TEA), tributylamine (TBA), and pyridine all conform with the kinetic equation for second order reactions, i.e., they are second order reaction. The activity sequence of the ter-tiaryamines examined is as follows: triethylamine>tributylamine> pyridine >>3N N-dimethyl-aniline, p-bromo-N, N-dimethyl-aniline, ia which the activation energy of the former three is 12.92,14.57.and 19.13Kcal/mol respectively and the latter two only show negligible activity even at 80℃. This sequence of activity is consistant with the pKb values of these tertiary amine.
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发布时间：2021-03-19
Research Article
- 摘要：The solubility of BF3OEt2 in hydrogenated gasoline was improved greatly by means of premixing BF3OEt2 with C3H17OH in nickel catalyst system, so that the effeciency of fluorine in the system was increased markedly. It is confirmed that there was a intermolecular hydrogen bond between alcohol and BF3OEt2 molecules by using 1H NMR, which was a vital factor to lead the solubilization of BF3OEt2 in hydrogenated gasoline. Otherwise, the caculation formula of the chemical shift ofproton in hydroxy, 1H = xipi,was suggested in hydrogen bond system.
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发布时间：2021-03-19 - 摘要：The effects of ethylene plasma treated mica on interface structure of mica/high density polyethylene (HDPE), low density polyetylene (LDPE) or polystyrene (PS) as well as bulk structure of the matrices were studied. The experimental results of dielectric loss and moisture content of the filled polyolefines show that the uniformity and hydrophobicity of the filler/ matrix interface are enhanced by the plasma treatment. The DSC and dynamic viscoelastic spectroscopy data indicate that the plasma treatment might weaken the rigidifying effect of the filler on macromolecules of PS,and has no influence on the relaxation behavior ofHDPE and LDPE.
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发布时间：2021-03-19 - 摘要：A method i.e. analyzing the contribution to the 13C NMR spin-lattice relaxation of the quaternary carbon in macromolecular chains due to solvent molecules was reported for determining the shortest average distance between macromolecular chains and solvent molecules.
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发布时间：2021-03-19 - 摘要：In this paper, the relationship between Tm and composition of PEO/PVAc blend were studied and the Flory-Huggins parameter of the blend system were calculated. The experimental results show that this blend system is compatible and have only one glass transition temperature (Tg), so we can extend the relationship between sol fraction (S) and radiation dose (R) of linear polymer to the PEO/PVAc system. The Bb value of PEO/PVAc system were calculated, which is in good agreement with the experimental value.
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发布时间：2021-03-19 - 摘要：Extrusion of rubber compounds were made on a Monsanto Processability Tester (MPT) to examine the relationship between the instable flow and the parameter variables in extrusion process. An empirical equation distinquishing the critical extrusion rate for instable flow was presentee! as follows:where L/D is the ratio of length-to-diameter of capillary die; a, is apparent shear viscosity of the melts, yw, the shear rate at wall; r is the melt characteristic relaxation time and tR, the resident time of the melts in die;△P is pressure drop. The re-sultsof regression analysis and experiment verification showed that the calculation values using equation (5) were better correspondent with the data measured.
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发布时间：2021-03-19 - 摘要：This paper reports the results on group transfer polymerization (GTP) of methyl metha-crylate in THF with dimethylketene ethyl trimethylsilyl acetal (ETS) as initiator and Et4NHF2 as catalyst. The dependence of the polymerization rates, molecular weights and polydispersity on the catalyst concentration has been studied. The living character of GTP is presented.
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发布时间：2021-03-19 - 摘要：Activity coefficients of hexane, heptane, methyl cyclo-hexane, benzene, toluene, ethyl benzene, o-, m-, p-xylene at infinite dilution in polystyrene-volatile component systems are determined by GLPC method. The relation may be expressed as following equation:with an error less than 5 % to the experimental data.
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发布时间：2021-03-19 - 摘要：Fumed silica-bound poly-4-oxa-6,7-epithioheptylsiloxane platinum complex was synthesized from γ-(2,3-epithiopropoxy) propyltrimethoxysilane via immobilization on fumed silica, followed by reacting with potassium chloroplatinite in acetone. It was found that the title complex exhibits high catalytic activity for the hydrosilylation of olefins by triethoxysilane and excellent recovery and reuse properties. The yield of decyltriethoxysilane was unchanged from the second run to fifteenth run.
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发布时间：2021-03-19 - 摘要：This paper was concerned with synthesis of poly-y-(L-tryptophan) propylsiloxane palladium complex catalysts in different -COOH/Pd ratio. The data indicated that the hydrogenation activity of the title catalyst was very high. Initial rate of styrene hydrogenation was 4972 mlH2/min. mmol Pd when the -COOH/Pd, mol ratio 4.5:1. Besides, the hydrogenation activity increased with the increasing of the -COOH/Pd mol ratio. The influence of polar solvent was higher than nonpolar solvent.
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发布时间：2021-03-19 - 摘要：Ceric ion (Ceric ammonium nitrate)/ethyl acetylacetate (EACAC) system can be used as an initiator for acrylamide (AAM), acrylonitrile (AN) radical polymerization. The presence of EACAC will promote the polymerization of AAM and pronouncedly enhance the rate of polymerization. The low value of overall activation enrgy of AAM polymerization (Ea=19.8 KJ/mol) shows that it belongs to redox polymerization. The primary radicals formed from the reaction of eerie ion and EACAC were detected by sping trapping technique and ESR spectrum. The FR-IR spectrum is used for the end group analysis method.
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发布时间：2021-03-19 - 摘要：The fluorescence spectra of an acrylic monomer having electron-donating chromophore moiety, N-(2-methacryloyloxyethyl)-N-methylaniline (MEMA) and its polymer in solution are recorded. It is observed that the fluorescence intensity of MEMA monomer is dramatically weaker than that of its polymer in the same chromophore concentration. Due to the coexistence of both electron-donating chromophore moiety and electron-accepting carbon-carbon double bond in the same molecule, the exciplex formation would be suggested. The phenomena of fluorescence quenching of such monomers are termed"Structureal Self-quenching Effect" dif-fering from the concentration self-quenching effect which is caused by concentration factor. The Stern-Volmer constants of fluorescene-quenching of MEMA polymer by methacrylonitrile,acrylonitrile,fumaronitrile,tetracyanoethylene,methyl methacrylate and methyl acrylate are obtained. The correlation between "e" values of above acrylic monomers and Stern-Volmer constants are discussed.
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发布时间：2021-03-19 - 摘要：The effects of drawing temperature and draw ratio on the contraction and extension of oriented amorphous PET film during thermal treatment has been studied. It has been shown that considerable thermal contraction of the oriented PET film before crystallization is due to relaxation of molecular chains in global sense while the spontaneous extension is related to crystallization of the oriented PET film. The maximum amount of contraction of the oriented PET film during thermal treatment increased with increasing λfor λ>2.3,owing to faster crystallization rate of PET film in highly oriented state. The maximum extension exibits similar behavior as that of maximum contraction with increasing λ and showed a peak at λ≌ 3.3,which isalmost the same draw ratio above which the densityof PET film began to increase during drawing.
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发布时间：2021-03-19
Research Bulletin
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