最新刊期
卷 ， 期 6 ， 1993
- 摘要：The Cu (Ⅱ)-ionomers based on itaconate can initiate the polymerization of MMA in the presence of CC14. Its free radical polymerization mechanism was demonstrated and the effects of various reaction conditions on the rate of polymerization, conversion and molecular weight were studied. The kinetic equation of polymerization can be expressed as Rp = Ke-67235/RT (Ionomer)0.04 (MMA)1.34(CCl4)m (in this experiment m=0. 5-3)
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发布时间：2021-03-19 - 摘要：In this paper，abstraction and gel permeation chromatography (GPC) were used to deter-mine the monomer conversion in the crosslinking copolymerization of styrene with bismethyl acrylate bisphenol-A．It is indicated that A-MA possesses high copolymerizing reactive with styrene．Affected by heat of polymerization and viscosity of the system，the crosslinking copolymerization has obvious self-acceleration．In the self-acceleration，the temperature of the system is higher than the water bath temperature (58℃)，so the crosslinking copolymer-ization will reach high monomer conversion comparing to homopolymerization of styrene．The experimental results showed that because of the high copolymerization reactivity of A-MA，gel forms as soon as the reaction starts，but sol forms very little，before the monomer conver-sion rises to 40％．When sol forms 2.4% in the system，the monomer conversion win reach 63.1％，and the sol is continuously transfer to gel in the whole polymerization．This is oppo-site to the gelation in the condensing polymerization of multi-functional groups．Gel fraction of crosslinking copolymer is affected by the heat treatment at temperature above Tg．When A-MA is up to a certain content(A-MA>5.5×10-4)，the gel fraction win increase．At the same time，the amount of styrene will decrease after heat treatment；The sol fraction will de-crease when the concentration of A-MA is high(>5.5×10-4) and increase when the concen-tration of A-MA is low (-4)，because of the reaction of the double bond suspending in the system．The initial formed sol has very high MW．Through studying the GPC curves,it is found that the higher the monomer conversion is，the lower the MW of forming sol be-comes．This lead to the widening of MW distribution and the lowering of MW of whole sol in the sample．
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发布时间：2021-03-19 - 摘要：Using the atomic scattering factors approximation expression and corrections for angle and temperature, the correct factors of three main crystal planes and amorphous state of nylon 1010 by wide angle X-ray diffraction (WAXD) have been calculated. The equation for the determination of crystallinity of nylon 1010 by WAXD is presented.
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发布时间：2021-03-19 - 摘要：The surface modification of cis-1, 4-polybutadiene membrane was studied by using CF2C12, CF2ClCF2Cl, and CF4 plasma treatments. The plasma-treated composite membrane was investigated by SEM observation, water static contact angle measurement, and XPS study. Gas permeability of the membrane was also measured.
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发布时间：2021-03-19 - 摘要：A new copolymer was synthesized by 1, 2-diethynyltetraphenyldisilane and 1, 2-di-ethynyltetramethyldisilane with a catalytic amount of a rhodium ( I ) complex. We have found that this copolymer has regular alternating arrangement in the copolymer backbone. The photochemical behavior has been examined in solid film and in solution of the copolymer. The film was treated with SbF5 vapour. And its conductivity was measured.
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发布时间：2021-03-19 - 摘要：A temperature sensitive gel as extraction agent which is a copolymer of N-isopropy-lacrylamide (NIPA) with sodium methacrylate has been synthesized. The influence of amounts of ionic agent and crosslinking agent on the swelling property of the gel have been investigated. We also inspected the swelling behaviour of the gel in different solvents and at the presentee of acid, alkali and salt. The swelling ratio of this new temperature sensitive gel at room temperature in water is obviously greater than those which are reported,and itsrecov-ery property is good.Its absorptivity of water is almost not changed even after the tenth swelling-shrink cycle.
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发布时间：2021-03-19 - 摘要：Solid-state condensation polymerization of PBT/PET blends are studied. The experimen tal results of reaction kinetics show that reaction rate of PBT/PET blends are quicker than that of the PBT or PET,and molecular weight (characterized by [η]) of reaction product of PBT/PET blends increase in ultra-addition. The ultra-additive effect has been discoursed by theory of solid-state condensation polymerization and ester interchange ,and it is show that ultra-additive effect is related to the increase of reaction rate and the formtion of block polymer.
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发布时间：2021-03-19 - 摘要：Three styrene-butyl acrylate-acrylic acid random copolymers with different proportions of acrylic acid were synthesized by emulsion polymerization. By neutralization, a series of ionomers with different proportions of ions and different metal counterions were prepared. The dielectric properties of the sample so obtained were investigated with a DP- I dielectric spectra detector. It was found that the α and β peaks of the dielectric loss tangent (tg δ) coincided like a single peak and with higher permittivities (εr),if the unneutralized copolymers were used as the parent materials.As ionization was increasing,the permittivities (εr) decreased and the a,βpeaks shifted toward the higher temperature.
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发布时间：2021-03-19 - 摘要：The number of active centers of 1-octene polymerization systems catalyzed by TiCl4/Mg-Cl2-AlR3 was determined by quenching with acetyl chloride,and the effects of cocatalyst and organic electron donors on the polymerization rate,the number of active centers and the propagation rate constant were studied. Combining with the study of the polymer molecular weight distribution by a multi-peak fitting method,the presence of 3 or 4 kinds of active center with different properties was evidenced. It is found that electron donors can selectively change the properties of certain kinds of active center.
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发布时间：2021-03-19 - 摘要：The double lamellae morphology of poly (ethylene oxide) was investigated by using transmission electron microscopy (TEM) and differential scanning calorimetry(DSC). The double lamellae were observed in the crystallization temperature region 54-56℃,above 56℃ both double lamellae and single layer lamellae were formed, but below 54 ℃ only single layer lamellae could be found. The melting point of double lamellae crystals was found to be slightly higher than single layer lamellae. On the basis of the transformation of nonintegral folede-chain (NIF) crystals into integral folded-chain(IF) crystals,the growth processes of double lamellae and single layer lamellae is discussed.H bonds on facing folded chain crystal surfaces leda to a decrease of surface free energy and this fact is a main reason for the formation of double lamellae.
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发布时间：2021-03-19 - 摘要：The kinetics and mechanism of copolymerization of methyl acrylate (MA) and isobuty-lene (IB) in the presence of AlEtCl2 and benzoyl peroxide (BPO) has been examined. It is suggested that when [IB]≥[MA], the copolymerization proceeds via a homopolymerization of a three-component complexed monomer (T) to form the alternating MA-IB copolymer. When [MA]>[IB], the formation of a MA-IB copolymer rich in MA and containing MA blocks may occur through the copolymerization of a three-component complexed monomer (T) and a two-component complexed monomer (B),or simply MA.
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发布时间：2021-03-19 - 摘要：A new kind of catalyst, WOBr4, which can be used in the polymerization of pheny-lacetylene (PhA), has been synthesized. The polyphenylacetylene (PPhA) obtained using WOBr4as catalyst is soluble and fusible and brown-red and has 1830 (Mn). The structure analysis of PPhA shows that the polymer has cis-transoidal structure and the reaction mechanism is via complex catalysis.
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发布时间：2021-03-19
Research Article
- 摘要：The miscibility of polyimide (PBPI-E)/polyimide (PTI-E) blends prepared by solution blending was studied by DSC and DMA techniques. The results obtained indicate that the blends are miscible for all compositions. Meanwhile, the unusual glass transition behaviour of the blends is discussed in terms of the changes of inter- and intramolecular charge-transfer interaction in the blends.
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发布时间：2021-03-19 - 摘要：Based on Hermans and Weidinger postulate that the crystalline fraction is proportional to crystalline intensity Ic and that the amorphous fraction is proportional to amorphous intensity Ia, it is. Suggseteet that for PBT/PET blends we assume that the intensity at 18. 2° is completely originated from amorphous scattering. The separation between the peaks at 17. 2° and 20. 8° is 3. 6°m, which is regarded as large enough to justify this assumption. Thus , it is possible to draw an acceptable demaraction line between the crystalline and amorphous scattering. The degree of crystallinity Xc is given by Xc-Ic/(Ic+KIa),coefficient K is available by the values of Ic plotted against the values of Ia.For PBT/PET blends,we obtain that K is 0.95 and that correlation coefficient is 0.92 According to the method revieved above,we investi-gated the crystallinity of PBT/PET blends prepared by different ways.
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发布时间：2021-03-19 - 摘要：N-(p-Ethenyloxyphenyl) carbazole (NEOPC) has been synthesized by etherification of p-bromophenol with vinyl acetate, then p-bromophenyl vinyl ether reacting with carbaxole in the presence of brass power and potassium carbonate at 200℃. The product was identified by elemental analysis, 1H NMR, 13C NMR and IR spectra. NEOPC is readily polymerized by conventional catalysts of cationic polymerization, such as BF3OEt2, I2, TiCl4, AlCl3, etc. But no polymer was obtained when free radical initiators were used. The rearrangement products and/or the solvent-insoluble products in cationic polymerization of NEOPC. which may be produced by the crosslinking have been discussed.
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发布时间：2021-03-19 - 摘要：The effect CMMS (cyclohexylmethyl dimethoxysilane/DPCS (diphenyl dichloridesilane) as electron donor on the polymerization of propene was discussed. The solvent polymerization of propene was carried out in 60 ℃ at 1. 04×105 Pa. It was found that the catalyst activity has gone up by 20 per cent when CMMS/DPCS=1/3 under the given condition . The concentration of active titanium center (C) was determined with kinetic-molecular weight method. It turns out that the active titanium centers do not increase by using mixedelectron donor CMMS/DPCS as compare with CMMS as electron donor but can increase Kp by 20% In addition,average-chain length can be achieved in five minutes with CMMS/DPCS.So polymer isotacticity index does not change with the time of polymerization.
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发布时间：2021-03-19 - 摘要：Fractionation of isotactic polystyrene based on phase equilibrium was preformed by using o-dimethylphthalate (DMP) as a solvent and cyclohexanol (CHA) as a nonsolvent. Fractionation with semi-preparative GPC was also preformed. The effect of fractionation based on phase equilibrium is limited, but the result obtained from semi-preparative GPC is quite well.
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发布时间：2021-03-19 - 摘要：In the present work, the crystalline morphology of polypropylene/high density polyethylene (PP/HDPE) was observed by the method of polarized light micrography(PLM),and the melting behaviour was in vestigated by differential scanning calorimetry. It has been shown that the incorporation of HOPE resulted in decreasing the regularity degree of PP spherulites and forming some defection in the crystalline region. It was also found that Y-irradiation strongly affected the crystallinity of PP/HDPE blends. The melting point and crystallinity of PP and/or HDPE in the blends decreased with radiation dose. The crystallinity of pure PP wasn't noticeable changed and that of pure HDPE increased with radiation dose. The more the blends contained HDPE,the faster the melting point and crystallinity of PP decreased,but pure PP showed a relatively faster decreased in themelting point than in the PP/HDPE blends. The results mighat radiation induced chain scission mainly took place in PP crystalline regions,especially in the imperfect regions.
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发布时间：2021-03-19 - 摘要：The cis-1,4 random copolymers of butadiene and isoprene obtained by using a rare earth catalyst are cyclized in the presence of AlEt2Cl-PhCH2Cl system. The cyclized products are characterized by IR > 1H-NMR and pyrolysis gas chromatography. It was proved that the both units of butadiene and isoprene also take part in the cyclization, but the degree of cyclization of isoprene unit is more than that of butadiene unit.
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发布时间：2021-03-19 - 摘要：The relationship between processing condition, microscopic morphology and mechanical properties of in-situ composite or blend of a thermotropic liquid crystalline polymer (TLCP) with polycarbonate (PC) was investigated. The processing condition, such as melt temperature , has a striking influence on the mechanical properties. The tensile strength of the blend is slightly higher than that of PC because the TLCP phase assumes a spherical shape in the center region of the specimen at low melt temperature of 270℃.At meilt temperature of 310℃,the blend exhibits great strength due to in-situ formed fibers of the disperse TLCP phase in PC matrix,and reinforced effect isenhanced appreciably. The tensile strength and modulus of the TLCP contribution in composite are much higher than those of the pure TLCP.
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发布时间：2021-03-19 - 摘要：The mechanical behavior of polyionic complex (PIC)membranes derived from polyvinyl alcohol(PVA) or ethylene-vinyl alcohol copolymer (EVA) have been investigated. The presence of ethylene block segment in the backbone of polyions can endow PIC membranes with more toughness. Increasing the degree of substitution of the polyions, the formed PIC becomes harder and more brittle. Under the environment of relative humidity (R. H. ) of 40%, the tensile strength, relative elongation and modulus of PICs are at about 300kg/cm2,10% and 8×103kg/cm2,respectively,whereas inthe environment of 90% R.H.M these of PICs derived from EVA are at about 90 kg/cm2,150% and 13kg/cm2,respectively,better than that of PVA derived polyionic membrane and ordinary PIC such as Ioplex 101. The permeabil-ity of PIC membranes derived from EVA have also been studied.
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发布时间：2021-03-19
Research Bulletin
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