最新刊期
卷 ， 期 3 ， 1992
- 摘要：A symmetry criterion about chain folding has been proposed based on the symmetry of macromolecular chains and their space groups. It indicates that a regular adjacent re-entry fold of chains can take place, only if the symmetry of the chain remains unchanged after folding. This is a necessary condition. According to this criterion we can predict the possibility of chain folding with adjacent re-entry and possible chain folding planes. For example, it can be expected from our criterion that the folding planes must be parallel to the (010)or the (110) planes for isotactic polypropylene and the folding planes must be parallel to the (200) or the (110) planes for polyethylene.These are in agreement with reported erperimental result.
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发布时间：2021-03-19 - 摘要：The mechanical properties of ultrahigh molecular weight polypropylene films with various draw ratios have been studied bv WAXD and dynamic mechanical measurements．The“apparent”crystalline modulus(Eappc) evaluated by the X-ray di-ffraction method are about 34—38 GPa for the various samples．The Young’s mod-ulus of the samples is found to become larger gradually and to correlate with the increase in the noncrystalline orientation．For the sample with draw ratio of 69，the Young’s modulus at room temperature is about 27 GPa, which corresponds to about three fourths of the apparent crystalline modulus，and the temperature depe-ndence of the modulus is very small in the temperature region of 一150 to 160℃ These results indicate that the mechanical property and the thermal stability of su-perdrawn films are remarkably improved．Based on the parallel-series mechanical model, the fully straight crystalline fraction and the “true” crystalline modulus EtruG are evaluated and the estimated EtruG is about 47 GPa．
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发布时间：2021-03-19 - 摘要：The phase transfer reaction of 1,4-benzene-liacetonnitrile with dichloromethane in the presence of benzyltriethylammonium chloride have been studied. Poly (α, α'-dicyano-p-pheny-lene trimethylene) (1), a new polymer, was obtained with 84% yield. The hydrolyzed product (II) was given by treating (I) with 70% sulfuric acid solution. The deep-colour resin (III1), (HII2) and (III3) were resulted from p/rolysizing of (I) under the ak condition at 250, 300 and 400℃ respectively. (III1)-(III3) exhibited excellent electronic properties,thermo-stability and strong EPR signals. Their electric resistivity at room temperature,thermal dico-mposition temperature (TGA) and correpounding g-value,line-width of EPR are 1010-107 Ω.com,345-408℃ and 2.00303-2.00307,0.475-0.896 mT respectively.They are recognized as a conjugated polymer.
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发布时间：2021-03-19 - 摘要：Three kinds of diacetylenes of general structure: R1-C≡C-C≡C-R2 (a. R1= R2 = radical; b. R1≠R2 R2 R1 or R2 being radical; c. R1= R2≠ radical) polymerized in the solid state by thermal irradiation method. The magnetic properties and origin of ferromagnetism of these polymers were discussed. The two spin systems-one belonging to the fully conjugated chain and the other to the nitroxyl fragment do nor cause ferromagnetism as they are independent. The ferromagnetism of polydiacetylenes originate from the interaction of the two spin systems.
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发布时间：2021-03-19 - 摘要：The miscibility and the crystal structure of LDPE EPO blends have been investigated by DDV, DSC, WAXD, Laser Raman spectroscopy and extraction separation. It indicates that LDPE/EPO are of good cocrystallization and miscible blend system at all the compositions. The degress of crystallinity and crystallite sizes of LDPE/EPO blends decrease with increasing content of EPO and the unit cell parameters are independent of the blend compositions.
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发布时间：2021-03-19 - 摘要：Effect of β-nucleator content on the isothermal and nonisothermal crystallization of β-phase polypropylene was studied using differential scanning calorimetry. The melting curves of the foregoing samples at isothermal and non-isothermal crystallization condition were also measured in DSC-2. The results obtained indicated that the sample containing 0.005% β-nucleator have the highest β-form crystallinity as expressed by △Hmβ the highest melting temperature of β-form and lower α-form crystallinity. The WAXD measurement shows that the samples,crystallized in the presence of higher content of nucleator,have lower relative inten-sity of β(301) diffraction peak which signifies the lower order of packing of β-form crystals along the chain direction.
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发布时间：2021-03-19 - 摘要：Multiblock copolymers of butadiene and ethylene oxide prepared by coupling of telechetic hydroxyl polybutadiene and polyethylene glycol with toluene diisocyanate were purified, characterized and their emulsifying, phase transfer catalytic and mechanical properties were studied.
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发布时间：2021-03-19 - 摘要：Five members of a novel family of silane coupling agents containing amine-lig-ands, X-CH,--CH2CH2 Si(OCH3)3 [X=-NH2, -NH(CH2)2CH3) -NH(CH2)3CH3, -N(C2H5)2, and -NH(CH2)2NH2], were synthesized by the amination reaction of β-(p-chloromethylphenyl) ethyltrimethoxysilane with corresponding ami. nes. The structure of the coupling agents was characterized and confirmed by FT-IR, 'H-NMR spectrometry and elementary analysis. The organosilanes could be easily immobilized onto the surface of silica fume and due to thepresence of the anchored amine-ligands the silanized silica fume showed in varying degrees the abi-lity to catch Cu2+ from its aqueous solution.
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发布时间：2021-03-19 - 摘要：Four new acrylate terpolymer supported sulfide platinum complexes were synthesized by copolymerization of 1,4-butanediol diaorylate, methyl acrylate, β-chloroethyl acrylate of ω-chlorohexyl acrylate in various molar ratio, followed by mercaptoethylation with sodium ethyl mercaptide, and by reaction with K2PtCl4. Decene-1, dodecene-1, allyl phenyl ether and sty-rene were used as probe to explore their catalytic characteristics in the hydrosilylation reaction. The influences of temperature, the amount of complex used on the catalytic activity and reused properties were also investigated.
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发布时间：2021-03-19 - 摘要：Cryo-hydrogel-rubbery elastomer, containing above 85% water was prepared by freezing aqueous solution of poly (vinyl alcohol) (PVA). Structure of cryo-PVA-hydrogel was studied by TEM. Experimental results showed that the cryo-hydrogel was a non-covalent bonded gel formed due to linking of polymer "clusters".Electron microscopy demonstrates the heterogeneous porous structure of the cryogel. It was found that the porous structure become more and more perfect with increasing the freezing time and polymer concentration.It is considered that phase separation plays an important role in gelation.The freezing is to encourage the phase separation and reinforce the mechanical strength.
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发布时间：2021-03-19 - 摘要：In this article the chain structure of PEMA was studied by 1H-NMR, 13C-NMR and COSY spectroscopy. Some difficulties in recognition of the spectra of PEMA come from the overlap of proton peaks. The assignment of the peaks in spectra of PEMA was discussed deeply with information provided from H-H COSY and C-H COSY spectra. But there are still some problems about the assignment of 13C peaks of β-CH2 in tetrad level. Finally the pentad sequences of atactic PEMA were calculated based on the discussion mentioned above.
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发布时间：2021-03-19 - 摘要：The morphology of copolymers of acrylamide and ammonium-2-acrylamidohexadecane (AM/AMCi16SNH4) has been studied by TEM. The copolymer molecule in water is extended to form filamentous structure. Aqueous solutions of the copolymers showed much better viscosity retention in salt solutions, temperature and aging stability than those of partially hydrolyzed polyacrylamides.
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发布时间：2021-03-19 - 摘要：A new initiator for group transfer polyme ization-1-(N, N-dimethylamino-)-1-trime-thylsiloxy butene-1 has been synthesized, The initiation activity of the new initiator, the effect of the catalyst/initiator ratio and monomer/initiator ratio on the rate of reaction and molecular weight distribution have been investigated. PMMA with narrow molecular weight distribution and predetermined molecular weight were obtained.
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发布时间：2021-03-19 - 摘要：This paper is concerned with synthesis of poly-γ-(L-glycyltrytophane) propylsiloxane palladium catalysts in different N/Pd ratioes and study on its hydrogenation activity for olefins and nitrobenzene. The structural characterization of the title catalysts indicates that the activity center may be complex compound composed of the -COOH of amino acid ligand and PdCl3 The hydrogenation activity of the title catalysts is very high for acrylonitrile and styrene, but inactive for nitrobenzene. Besides, the hydrogenation activity was influenced by solvent and reaction temperature.
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发布时间：2021-03-19 - 摘要：In the present paper the effects of the fiber content and the interfaee On the linear thermal expansion coefficient of the uniaxial glass fiber and the carbon fiber reinforced epoxy composites have been studied in the temperature range from 123 to 415K．The results show that the transverse thermal expansioncoefficient of the composites are greater than that of the matrix itself when the fiber conten t V，=0.2 to 0.4 and the surface treatment seems to have no effect on the axial thermal expansion coefficient of the composites．The relation-ships between the fiber content and the axial thermal expansion coefficient can be described by Shapery’s equation．When the temperature is higher than the glass transition temperature of the epoxy matrix，the two transverse di,rection(X-and Y-axis) thermal expansion coefficients are quite different from those expected by Shapery's equation．The morphology shows that an epoxy resin layer existed between the laminas．The thickness of the resin layer depends on the surface treatment of the fibers，hence it make the difference between the two thermal expansion coeffi-cients in the two transverse direction．
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发布时间：2021-03-19
Research Article
- 摘要：Fourier transform infrared spectroscopy (FTIR) has been used to study the effect of tacticity of PMMA on β-phase formation of poly (vinylidene fluoride) (PVF2) during quenching process. For pure PVF2, quenching at lower temperature results in formation of β-phase crystallites. The critical quenching temperature for 3-phase formation is about 30℃. Adding a given amount of PMMA (30%), especially syndiotactic PMMA (s-PMMA), into PVF2 results in increase of the critical quenching temperature upto 70℃. This is due to the interac-tion of hydrogen bonding between the molecules of PVF2 and PMMA,which stablizes the TTT conformation of PVF2 and forms the nuchleation sites of the β-phase at higher temperature.
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发布时间：2021-03-19 - 摘要：Under UV-irradiation, Acrylamide (AAM) and N, N-dimethyl acrylamide (DMAA) were grafted onto segmented polyether-urethane (SPEC) films without any sensittizer. The formation of grafted polymer was verified by its solubility, water sorption and the scanning electron microscopy photograp. The effect of the reaction conditions and the structure of monomers on the grafting yield was investigated.Some model compounds of soft and hard segment of SPEU were used to clarify the graft site. The experimental results showed that the grafting polymerization could be initiated by SPEU soft segment containing ether linkages and hard segment containig amino groups.
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发布时间：2021-03-19 - 摘要：Phase transition processes of benzoylated poly (phenylene oxide) with styrene-butadiene-styrene copolymer blends were studied by using light scattering. The results show that the phase separation at early stage follows the Cahn's theory. In later stage, the phase separation processes were found to give the scaling law on the wave number of the dominant Fourier component of the fluctuation qm(t) and on the maximum scattered intensity Im as given by qm - t-a and Im -tβ. But β<3a
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发布时间：2021-03-19 - 摘要：Crosslinked functional microspheres with Carboxylic group have been synthesized by the method of Phaseseparated polymerization from monomers of methacrylic acid and other vinyl-type monomers. The effects of reaction condition such as comonomer, crosslinking agent, initiator and polymerization temperature, as well as polymerization time on the morphological structure of microspheres formed have been studied. The functional polymeric microspheres with good spherical form, diameter near 5 micrometers, narrow dispersion in diameter and contained carboxylic group can be synthesized stably.
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发布时间：2021-03-19 - 摘要：The melting behavior of Nylon-6,6 ( PA6.6) and its blend with polyethersulfone (PES) were studied by differential scanning calorimetry. The Avrami equation was used to analyse the kinetics of isothermal crystallization of the samples. It was showed that crystallization temperature of the blend increased 15℃ than that of pure PA6,6 and the Avrami exponent of the sample containing 20% PES was 2.1 while 1.4 for pure PA6,6 The activation energies were 739.6 KJ/mol and 646.1 KJ/mol for the PA6.6 and the blend witj 20% PES, respectively. It was attributed to the nucleation of the PES during the crystallization of PA6.6.
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发布时间：2021-03-19 - 摘要：Radical copolymerization of di-iso-propyl fumarate (DiPF), di-t-butyl fumarate (DtBF) with di-n-propyl fumarate (DnPF), di-n-butyl fumarate (DnYE) (DnBF), di-2-ethylhexyl fumarate (DnHF). di-2-ethyl-hexyl fumarate (DeHF) were studied, The relative reactivities of copolymerization of the following monomer pairs such as DiPF-DnDF. DiPF-DHF, DiFP-Dn AF, DiPF-DeHF were determined.
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发布时间：2021-03-19 - 摘要：Photopolymerization of acrylonitrile (AN) initiated by polymerizable photo-redox initiation system consisting of 4-methacryloxy benzophenone (MABP) and N,N-dimethylaminoethyl methacrylate (DMAEMA) has been studied kinetically. The rate equation of this polymerization system is:Rp∝[AN]0.95[MABP]0.28[DMAEMA]0.25The overall activition energy of this system is 30.43KJ/mol. From the UV analysis, it is confirmed that both MABP and DMAEMA not only act as photoinitiators, but also incorporate into the P (AN) chains. The comparisons of initiation ability,of P(MABP) and P(DMAEMA) with their monomeric forms are also studied.The result indicate that P(MABP) has much greater initiation ability in comparison with monomeric MABP,but P(DMAEMA) does not.it has almost the same ability in comparison with monomeric DMAEMA.
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发布时间：2021-03-19
Research Bulletin
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