最新刊期
卷 ， 期 6 ， 1994
- 摘要：The curing mechanism of bisphenol-A diglycidyl ether type epoxy resin (DGEBA) cured with 2-ethyl-4-methylimidazole(EMI-2，4)，and the curing charac-teristics，kinetic and reactivities of DGEBA，diglyddyl ester and aliphatic cyclo type epoxy resin (TDE-85) cured with EMI-2，4 have been studied bv DSC，FTIR in this paper．The results of DGEBA cured with EMI-2，4 show that the whole curing mechanism can be separated into two stages．The first stage was addi-tion，the second stage was catalytic-polymerization．The whole curing of TDE-85 epoxy resin cured with EMI-2，4 proceed in two stages as well．The first stage mainly was addition and catalytic-polymerization of diglycidyl ester type epoxy group，the second stage mainly was addition of aliphatic cydo epoxy group．The apparent activation energy in the first stage of various epoxy resin cured system is lower than that in the second stage．It was found that in the co-curing system of reactivity of TDE-85 with DGEBA tVpe eooxy resin cured with EMI-2，4 is higher than that of TDE-85 epoxy resin．
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发布时间：2021-03-19 -
MICROSTRUCTURAL CHANGES AND MECHANISM OF POLYETHYLENE SHISH-KEBAB FILMS DURING DEFORMATION PROCESSES
摘要：he microstructural changes in highly oriented films of blends Of high densitypolyethylene(HDPE ) with ultra-high moledar weight polyethylene(UHMWPE) during deformahon process have ho investigated by TEM andSAXS methods.A sacal melt- drawn teChnique was ed to pmpare the orientedfilms with shish-kebab morphology. The films were triakially stretched alongchain direction at various temperature' It has ho found that the deformahontemperature has an impotant effeCt on the ndcrostfUCtllre changes of theshish- kebab during the stretching processes. At room temperature, the lamellae be-tween fibris undergo crystal shear and chain slip, readucing lamellae width and increasing fibrilslength between alsmella. At elevated temerature (115℃), stressed kebabs decrystallize and transform into fibrils. It results from the strain in-duced crystallization.- 53
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发布时间：2021-03-19 - 摘要：aper describes the results of the polylnerization of MMA and BMA bycoordination catalyst of Nd (P507)3 - Al(i -Bu)3.Kinetic studies in benzinum purification showed that the MMA and BMA polymerizahon rate are of first orderwith respect to both monomer concentration and catalyst concentration. The apparent activation energies of MMA and BMA polymerization reaction are 33 kJ/moland 24 kJ /mol resistively. The polymerization of MMA and BMA with Nd catalyst in benzinum purificum proceed in coordinate radical.
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发布时间：2021-03-19 - 摘要：n thes paper, the oligomers with different molecular weight of monohydroxylpolyethersulfones were synthesized in solution and the optimum condition ofpolymerization was obtained; With phase transfer catalyst method,the oligomerswas obtained and transformed to monovinylpolyethersulfones macromer. Its structure was characterized with IR and 1H-NMR.The copolymerization ofmonovinyl-macromer and styrene was studied.The monovinyl-macromer whosedegree of polymerization is 2 has the highest solubility in styrene(S>80% by weight); The copolymer is superior to the copolymer of divinyl-macromer in raising the refractive index of optical plastics. Its transmittance in vis-nir region is about 89%.
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发布时间：2021-03-19 - 摘要：series of thennotropic liquid Crystalline poly (estep-imide) s derived from1,6-hexanediamine, 1, 10-deanediamine and p-phenylenebis- (trimilitic ) dianhydidewas synthesize via a soluhon Polycondensation prare.The Poly (ester-imide)swere characterized by IR, DSC measurements, Polarizing microscopy and WAXDmeasurements.The DSC measurements revealed that the poly (ester-imide) poa sharp endothenn (Tm1) and a second endotherm (Tm2) which indicates thetransition from anisotropic to isotropic melt. Under polarizing microscope it was observed that samples, which were quenched inliquid nitrogen in the temperature range between Tm1 and Tm2, show a tipical birefringent pattern, WAXD measurements of the solid materials indicated nearly perfectly layered structure of the supermolecules.
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发布时间：2021-03-19 - 摘要：he Permeability of CO2 through Cellulose acetate membranes increases dramatically with gas pressure. This anomalous behavior is due to the membranesplasticization by CO2.The unusual pressure dependence of permeability probablymakes permeation behavior of gas mixtures containing CO2 more complex, andsuch a Pers deqendence of Permeability cannot be interpreted in terms of conventional dual-mode model.In thes paper, a new modified dual-mode model wasdeveloped,and was ed to explain the pressure.dependence of permeability. The new model proposed was verified with experimental data.
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发布时间：2021-03-19 - 摘要：The effects of propylene carbonate (PC，5％ by wt．)and γ-butylactone(γBL，10％ by wt．) upon the ionic conductivity of graft polyester network formed by PEO 800 macromer and unsaturated polyester containing LiClO4 were studied．The conductivity was found to be mainly determined by the concentration of LiClO4，with a maximum room temperature conductivity，σ298K=4.0—4.5×10-5Scm-1，at [Eo unit]／[Li+]=30．Little correlation was observed between glass transition temperature (Tg) and crossfinking degree for such polymer electrolytes，and the effect of LiClO4 concentration on Tg was also observed．The introduction of polar additives into the network increased the ionic conductivity greatly，while ex-erring little influence on Tg and degree of crosslinking．Thus，these may be con-tributed to the increase of ion mobility in the conducting pathway．The formation of graft IPN by using graft polyester and epoxy resin further improved the mechnical strength of the film sample，maintaining high conductivity at room temperature，σ298K=2.4×10-5Scm-1．
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发布时间：2021-03-19 - 摘要：Mikibility of styrene-methacrylic add copolymer P(S-MAA) with polypropylenechide PPrO were studied by means of FTIR. Some kind of carbonyl absorptivityraho in blends were given through curve-fitting technique and equilibrium constantsbetween varying carbonyls were calculated by simple way.The results show thatmiscibilty dpends on MAA content in P(S-MAA),the moledar weight andsic of polyether and compesihon of blends.
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发布时间：2021-03-19 - 摘要：Although it has ho widely accepted that both block and graft copolymerwill form microphase separation morphology, only detailed morphological knowledge of block copolymers has been reported so far. In choosing an amphiphilicgraft copolymer, namely polystyrene-g-poly(ethylene oxide)(PS-g-PEO) as amodel copolymer, the microphase morphological feature of graft copolymer wasstudied systelnatically for the first bine by means of thensmission electron microscopy.It Was discovered that PS-g-PEO may readily undergo microphase separation and the shape and size of domains depand on the composition and PEO side chain length of the graft copolymer. Both the similarity and difference of the microphase structure between block and graft copolymer were also discussed.
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发布时间：2021-03-19 - 摘要：Through the emulsion copolymerization of cydopentadienyl-ethyl acrylate,allylcyclopentadiene and ethyl acrylate, a copolymer with substituted cyclopentadiene group was prepared. The effect of polymerization conditions on yields ofcopolynmer, the solubility in solvents and the behaviour of thermal-converion ofcopolymer were also studied. The conclusion is that a novel thermoplastic elastomer with thermally reversible covalent crosslinks was obtained.
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发布时间：2021-03-19 - 摘要：Three methods for synthesis of N- aCryloyl-N'-phenylurea (APU),N- methacryloyl - N'- phenyl (or p- tolyl)urea (MPU or MTU) monomershave been inveshgated.(i) MPU and MTU were synthesized by the reaction ofmethacryloyl isocyanate with aniline and p- toluldine resghvely;(ii) MPU wassynthesized from the reaetion of methacryloyl chloride and phenylurea;(iii) APUand MPU were syntheSis via the reaction of apltalde and methacrylalinde withphenylisocyanate reSwtvely. These monomers were charactized by elemental ana-lysis,1H-NMR and FT-IR spectra. In the presence of AIBN or BPO,APU,MPU,MTU will polymerize and copolymerize with MMA and MA as well. The thermo behavior of polymers and copolymers was measured by TGA and DSC respectively.
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发布时间：2021-03-19 - 摘要：Staning from p- or m-chioroaniline, silicon-containing aromatic diamines weresynthesized through amino-proteCtion by trimethylsilyl group, Wurtz coupling reaction and deprotction with overall yield of 25%.Copolymerization ofsilicon-containing aromatic diamines, aromatic diamines and tetracarboxylic aciddianhydrides was carried out and thermal analysis of corresponding poiymidesiloxanes was determined. The effect of Para and meta regioisomers on the thermalrelaxation behaviour in Tg transition was examined,which attributed to different conformation entropy in the structure of two regiosubstituted to different conformation entropy in the structure of two regiosubstituted moieties.
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发布时间：2021-03-19 - 摘要：Two novel polyphenylquinoxalines，PPQ-I and PPQ-II，containing benzofuran ring in the main chain were prepared by the reactions of 2-P (P’-chlorophenylglyoxalyl)phenyl-5-(P-chlorophenylglyoxalyl) benzofuran or 2-(P-phenylglyoxalyl) phenyl-5-phenylglyoxalyl benzofuran，which were synthesized in our previous work，with 3，3’，4，4’-tetraaminodiphenyl ether，respectivdy．Properties of the polymers in the form of segmental film were charac-terized bv TGA，DSC，tensile strength，elemental analysis and IR spectroscopy．Experimental results showed that the polymers exhibited good thermo—oxidative stability and tensile strength at room temperature．Decomposition temperatures of the polymers were all above 500℃ according to the TGA results．The tensile strengths were higher than 1000 kg／cm2 and the Tg values were greater than that of the PPQ without any benzofuran ring in the molecular structure．It was found that the polymers can be used as membrane materials．Hence the ultrafiltration (UF) membranes prepared from the polymers by a phase inver-sion method are also reported in this paper．The retention character of PPQ—I and PPQ—II UF membrane may be quantitatively determined by ball standard matter，such as Bovine seruln albumin (BSA) and Chymotrypsinum (CMP)．Due to the fact that PPQ—I obtained by using 2-P(P’-chlorophenylglyoxalyl) Phenyl-5-(P—chlorophenylglyoxalyl) benzofuran as one of monomers contains not only benzofuran ring in the main chain but also chloro—atom in the side chain，the flux of UF membrane made from PPQ—I is higher than that of PPO—II．The morphological structures of section of PPQ—I UF membrane have been observed bv SEM．
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发布时间：2021-03-19
Research Article
- 摘要：ractal dimension of impact fracture surfaces of PVC at differenttesting temperture were investigated by means of secondary electron line scanning.Experimental results shows that the impact strenth rises linearly with the increaseof fractal dimension.The fractal dimension on crack growth region decreases butthat on final fracture region increases with the testing temperature decreasing.
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发布时间：2021-03-19 - 摘要：A new type of amphiphilic polymer with different hydrophilic degrees werefabricated. The ultrathin films including monolayer ahd mulhlayers prepared byLangmuir-Blodgett (LB) technique had ho studied. The amphiphilic polymerwhich has a grafting degrees of 30 - 50% was suitable for shaping films. Themodel Z method was the hot method for shaping polymer LB films.When theLB films were heated to 180 ℃, the Polymer were crosslinked further.
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发布时间：2021-03-19 - 摘要：thermotropic liquid Crystalline polymer(TLCP) was blended with fourthermoplastic reSins, poly (butylene terephthalate) (PBT), polycarbonate (PC),polyethersulfone (PES) and polysulfone (PSU), in ther respective " processing windows", in a wide temperature range from 270 to 360 ℃ It is shown that themicrostructure formation of their blends depends strongly on the viscosity ratioof the dispersed TLCP phase to the continuous resin phase.Viscosity ratios farbelow unity resulted in TLCP fibrillation in flexible-chain polymers. The diameter of TLCP fibrils can be as small as 0.3μm and the aspect ratio as large as 30.
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发布时间：2021-03-19 - 摘要：he introduction of hydroxymethyl groups on carbon black surface wasachieved by reaction of formaldehyde in the presence of basic catalysts. Free radical graft polymnerizahon of acrylic acid on the carbon black surface was explored,using an redox initiating system consisted of Ceric ion and hydroxymethyl groupson carbon black surface. The acidity of polymerization system, amount of cericion and reaction time have influence on the graft polymerization of acrylic acid ontocarbon black surface.The zeta electrical potential was changed for carbon black particles modified with graft polymers of acrylic acid.
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发布时间：2021-03-19 - 摘要：orphology transformation during stretching is investigated by SEM forβ-form polypropylene sheets at room temperatere and at low elongation rate.When stress whining or even yielding in specimen has occured, the β-formspherulites did not obviously change,but a lot of crazes and microcracks insidespherulites have developed Perpendicular to the stretching direction.As perfect neckis formed at 60% of drawing strain and microfibrillar structure is created. Thespherulites is broken by interlamellar sliPPage and rotation at stretching direction.
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发布时间：2021-03-19 - 摘要：new complex initiation system consists of ceric ion, Ce(IV) and potasiumPersulfate (KPS) for acrylonitrile (AN) aqueous solution polymerization has beenstudied. From Polymerization kinetic studies it showed that the rate ofpolymerization of AN using Ce (IV)/KPS, such as CS(ceric sulfate)/KPS initiation system, is either greater than CS or KPS alone. It hinted that in the complex initiation system the formation of Ce (Ⅲ) via Ce (IV) initiation reactionwould react with KPS to regenerate Ce (IV). This is also revealed by the UV investigation, which showed that at appropriate temperature (above 50℃) Ce (III) could be oxidized by KPS and a new absorption at 330-400 nm was observed by UV spectrometer. Besides, the overall activation energy of polymerization and the effects of concentrations of Ce(IV) and KPS on polymerization were also investigated.
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发布时间：2021-03-19
Research Bulletin
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