最新刊期
卷 ， 期 5 ， 1995
- 摘要：he copolymerization of vinyl sulphone dyes with acrylonitrile were carried out in DMF media.The effects of the increase in dye concentration on the conversion of copolymerization,molecular weight of copolymer,and the content of dye chromophores combined in the copolymer were studied.
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发布时间：2021-03-19 - 摘要：ffect of crystallization temperature on the crystalline structure of poly (vinylidene fluride)PVF2 has been investigated by TEM and FTIR. Low quenching temperatures(30℃)induce β phase formation of PVF2 directly from the melt.When the quenching temperature is in the range of 40-70℃,α and β phases coexist in the film.αphase PVF2 is normally obtained at the temperatures from 80 to 150℃, while the γ phase is produced at higher temperature(165℃).
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发布时间：2021-03-19 - 摘要：The ductile-brittle transition(DBT)of poly (phenylene ether ketone)due to long-term retaining at temperature of 200℃ has been studied by tensile experiment,scanning electron microscopy and differential scanning calorimetry measurements. The DBT can be considered as competition between fracture mechanisms of crazing and that of shear yielding.It is found that the DBT of PEK-C due to long-term retaining at 200℃ occurs at about 589 retaining hours.It is shown from tensile experiment that the deaging phenomena was observed,and it only depends on the shear deformation and has intrinsic relationship with DBT.
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发布时间：2021-03-19 - 摘要：Poly (3-hydroxyburate) (PHB) and its copolymer with 3-hydroxyvale-rate (P(HB-HV)) have attracted much attention because they are thermoplastic bio-polyesters．It has been reported that Poly (3-hydroxyburate) (PHB) and Poly (eth-ylene oxide) (PEO)，Poly (vinyl acetate) (PVAc) or Poly (vinylidene fluoride) (PVDF) are miscible in the melt，they all exhibit a single glass transition temperature．In this paper，we report the results of an investigation concerning the phase structure and miscibility of blends obtained by mixing PHB with uncrystallized com-ponent Poly (hydroxy ether of bisphenol A) (PBHE)．It is found that PHB and PBHE are partially miscible by the results obtained from DSC and FTIR measure-ments．In comparison with the samples cast from solution，the annealled samples display higher degree of crystallinity and better miscibility (Fig．1)．The results of FTIR measurements indicate that there are no hydrogen bonds between the carbonyl groups of PHB and hydroxy groups of PBHE in the cast sam-ples．But some interaction between the segments of two polymers are formed，because the wave numbers of some groups of PHB and PBHE change regularly with the inc-rease in the content of PHB in the blends (Tab．1)．The crystallite sizes of the annealled samples are listed in Table 2．Increasing the uncrystallized component in the blend from PHB／PBHE=100／0 to PHB／PBHE=50／50．it is observed that the crystallite sizes of (020) and (130) crystal faces be-come larger，and larger，which reach the largest sizes at the composition of PHB／PBHE=50／50．On the contrary，increasing the uncrystallized component from PHB／PBHE一40／60 to PHB／PBHE=20／80，the crystallite sizes get smaller．Data from SAXS experiments indicate that the thickness of the interphase of pure PHB is 1.5nm and that of the blends are about 2.0nm；the period of C axis of a PHB orthorhombic cell is 5.96A，therefore the interphase consists of three lat-tice layers．This agrees with the results predicted theoretically by Paul J．Flory and Do Y．Yoon．The lamellae of PHB／PBHE=50／50 is the largest in thickness in all blends．With the increase in uncrystallized component，the lamellae of the blends change similarly as the crystallite sizes discussed above．In all blends，the density dif-ference of PHB／PBHE=75／25 composition between crystalline and amorphous pha-ses is the biggest．This agrees with that the degree of crystallinity for PHB／PBHE=75／25 composition，obtained by DSC measurements，(Tab．3)．
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发布时间：2021-03-19 - 摘要：ffects of cooling rates on the epitaxy of high-density polyethylene(HDPE) on isotactic polypropylene(iPP)substrate film have been studied by TEM and electron diffraction. The results of electron microscopy and electron diffraction indicate that epitaxial nucleation and growth of HDPE on oriented iPP substrate take place only on the direct contact plane of HDPE with iPP.There exists a critical epitaxial thickness of HDPE on iPP film.The thickness of epitaxial interface layer is strongly affected by the cooling rate of HDPE after heat treatment. During slow cooling process,three layers of crystalline structure of HDPE are formed. The thickness of critical epitaxial layer is about 100nm. Fast cooling rate results in the formation of two layer crystalline structure. The thickness of critical epitaxial layer is about 250nm.
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发布时间：2021-03-19 - 摘要：ased on the probing technique of laser light scattering and the principle of the determination for the inhomogeneity of spatial distribution of polymer network by means of non-random index NRI(=(Rvv(0))nr/(Rvv(0))r -1),the inhomogeneity of a important functional cross-linking polymer,which is the copolymer of styrene with divinylbenzene,has been characterized successfully.Here subscripts nr,r denote nonrandom,random cross-linking network,respectively.And the former is from the experiments,the latter is from calculation. Futhermore,both have to be done in equilibrium swelling condition. Rvv(0) represents the Rayleigh ratio at zero angle under vertical both polarizer and analyser. The samller the NRI, the better the mechanical properties. As a result, a low NRI could be as a criterion for superior mechanical performance of frame of functional cross-linking copolymer.
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发布时间：2021-03-19 - 摘要：he kinetics of the polymerization of isoprene with a soluble rare earth catalyst system Nd(OPri)2Cl-AlEt3 has been examined in a specially designed dilatometer.The polymerization process was characterized by a steady-state reaction within the experimental range, and polymerization rate is first order in both the concentration of neodymium compound and monomer,that is,Rp =-d[M]/dt=Kp[Nd][M].The apparent activation energy of isoprene polmerization has been found to be 57.4KJ/mol in heptane.
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发布时间：2021-03-19 - 摘要：Hydrocarbon rubber (SBR,PB)and PDMS(silicon rubber)dispersed liquid crystal PEECB-m(α,ω-polyethylene glycol(DP=m)p-ethoxycarbonyloxy-benzoate) composite membrane PDLCM has been prepared.The membrane has a Tk-sof 25℃ and exhibits LC transition at room temperature in SBR/PEECB-4.05/PDMS (Mw = 370 ×103) system.When the content(wt%)of PEECB-4.05 exceeds a critical value (about 23.0 %),the permeation coefficient Po2 gets a mutation (increasing about 60 times)and the permselsctive coefficient αo2/N2 keeps fairly high (2.05).Various factors affecting the permselectivity of the PDLCM have been investigated.
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发布时间：2021-03-19 - 摘要：he relationship among composition,crystallinity and degradability of Polycaprolactone(PCL)-Poly(ethylene glycol)(PEG)block copolymer PCE)has been studied by means of DSC and X-ray diffraction techniques. It was found that the crystallinity of the PCE copolymer has closely depended on both the molar ratio of caprolactone(CL)unit to ethylene glycol(EG)unit(CL/EG),and the molecular weight of the PEG component,that is the crystallinity of PCE copolymer reduced with increasing either the content or molecular weight of the PEG component.Hydrophilicity of the PCE copolymer was increased with increasing the content and the molecular weight of the PEG component. Degradation rate of the PCE copoly-mer was identified by hydrolysis reaction. As a result the degradation rate of the PCE copolymer increased with introducing PEG component,that the degradation ra-te increased with reducing the crystallinity and increasing the hydrophilicity of the copolymer.
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发布时间：2021-03-19 - 摘要：ffects of maleic anhydride melt grafted polyethylene(PE-g-MA)on the morphology and dynamic mechanical behavior of nylon 6/polyethylene(PA6/PE)blends were studied by means of scanning electron micrography and Dynamic Mechanical Analysis.The results show that PE-g-MA increases the glass transition peak of PA 6 and shifts the glass transition temperature of PA 6 to lower temperature,due to the improving of the compatibility between PE and PA6 matrix by using PE-g-MA.The degree of chemical reaction between PE-g-MA and PA6 increased with the percentage of PE-g-MA in the dispersive phase including PE and PE-g-MA, resulting in an increase of the glass transition temperature of PA6.Moreover,effects of PE-g-MA on the rheological behavior of PA6/PE blends were also studied by using parallel plate rheometer. PE-g-MA increases the viscosity and dynamic storage modulus,and decreases the dynamic loss of PA6/PE blends, which is attrbuted to chemical reaction between PA6 and PE-g-MA during melt blending.
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发布时间：2021-03-19 - 摘要：ilicon-containing polyimide with biphenylene moiety in polymer backbone was prepared in our laboratory.Temperature dependence of gas pairs(H2/N2 and O2/N2)of this polymer was discussed. The permeability and diffusivity increased with the rise of temperature,whereas the solubilty and permselectivity decreased. Furthermore, the activation energy for gas permeation and diffusion and heat of sorption were also reported.
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发布时间：2021-03-19 - 摘要：The paper discussed the changes of crystal structure and mechanical properties of hot drawn and twice drawn sheets of UHMW-PE in melted state．The crvstal orientation of the drawn sheets were tested by using WAXD，the 200 and 020 pole figers were made and the orientation factors fa，fb and，fc were calcu-lated．The crystallite and amorphous region size along draw direction were obtain-ded by measuring the integral breadth of the 002 reflection profile and long period for the drawn sheets．The DSC curves for twice drawn UHMW-PE sheets showed that besides a main peak，a small melt peak was observed at 152--153℃．The dy-namic mechanical behavious for the hot drawn sheets and twice drawn sheets indica-ted that β-relaxation appears in lower draw ratio sheets and in higher draw ratio and twice drawn sheets β-relaxation degenerated greatly or disappeared．The Young’s modulus of twice drawn UHMW-PE were much higher than the first drawn one．The results showed that twice drawn UHMW-PE sheets had bi-component crystlliza-tion：most crystals were folded chain type，a few were extended chain crystals．Structures and properties of twice drawn sheets were improvement of first drawn one．
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发布时间：2021-03-19 - 摘要：Angular dependent XPS technique combined with in situ heating method was used to study the chemical and aggregational structure of polypyrrole films prepared by electrochemical polymerization. The results show that the relative concentration for various atoms within the surface region decreases in the order of C >O>S> N.There are at least two inequivalent N heteroatoms,i.e.the pyrrole N and the oxidized pyrrole N atoms. The polypyrrole chains are not degraded by heating the polypyrrole films at 200℃ in vacum. The anions,however, move to the top surface region during heating, and a decrease in the oxidized N heteroatoms is observe after heating.
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发布时间：2021-03-19 - 摘要：Studies on syneresis behavior of Xantlian/Cr(Ⅲ)hydrogels have been conducted at 70,80 and 90℃. The onset of syneresis appeared at a critical Cr(Ⅲ)density in a gel and the syneresis became serious when the Cr(Ⅲ) density increased.The process of syneresis can be described by means of apperant first-order reaction and the rate constant increased with increasing the temperature and the initial Cr(Ⅲ)concentration. The apparent activation energy was about 34.5 kcal/mol.Moreover,the syneresis did not depend on the concentration of monovalent salt (NaCl).
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发布时间：2021-03-19
Research Article
- 摘要：series of chitosan samlpes with 91% deacetylation but different molecular weight were obtained by varying the time of chitosan solution in acetic acid aqueous solution at 70℃.The viscosities and flow behavior of the concentrated solutions of chitosan were investigated in 10% (vol%) formic acid aqueous solution after the solutions were prepared for two days by using RPX-705 Rheopexy Analyzer.For each chitosan sample,at the concentration of 3.5 g/100ml,the log (ηr/η0)versus lgγη0,M curves superimpose each other within the same rheogramme. Then the relationship between log nr and lgM was studied under different shear rates.For the highest M sample, the experimental data deviate from the straight lines greatly. This was because the chitosan chain degradated in acid solution during dissolving. The molecular weights were measured in acid solution after two days of dissolving, they were right on their own straight lines. However,no obvious degradation was observed after two days in the same solution for the other lower M chitosan sam-ples. In addition, the plot of nr against M was not a straight line,probaly due to particular interaction of chitosan.
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发布时间：2021-03-19 - 摘要：According to mechanism of pore formation,micro-and ultramicro-cellular polytetraflouroethylene porous membrances were prepared with classical dispersion.gelation and pressure-induced phase separation method, and characterized by scanning electron microscope.electron spectroscopy for chemical analysis.differential scanning calorimeter and bubling method. The results show that the membranes through pressure-induced phase separation and plasma polymerization with ethylene are easy to control and have good characteristics.
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发布时间：2021-03-19 - 摘要：mall-angle X-ray scattering(SAXS)techniques were applied to measure the phase dimensions of thermoplastic IPN based on SBS and styrene-methacrylate Ionomer via statistical treatment.Correlation lengths of 1.3-3.0nm were found..Specific surface areas ranged from 145000 to 360000m2/kg.The SAXS results corresponded to the lower range of the transmission electron microscopy dimensions.The two techniques have different systematic errors and measure somewhat diffferent aspects of the morphology;therefore,comparisons are useful.
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发布时间：2021-03-19 - 摘要：According to mastication degradation mechanism and long-chain molecular model, the equation of TQ= TQ0(t+1)-n was introduced to reveal the rheological behavior of HDPE/NR blends.DSC results showed that partial NR chains rheowere clamped by HDPE crystals and thus act as the tie molecules in the blend.Small amount of NR can improve HDPE's tensile elongation and environmental stress cracking resistance dramatically,while the melt flow property maintained because of the degradation of NR.
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发布时间：2021-03-19 - 摘要：Reaction of C60 with poly (styrene-co-allylamine)was studied by GPC, FT-IR and TGA methods.GPC traces demonstrated that the M.of reaction product increased and exhibited a broader molecular weight distribution.The strong new bands at 1200cm-1 appeared in FT-IR spectrum of the product indicated that the covalently C60--bound copolymer was formed. TGA analysis showed that fullerene-functionalized polymer was a homogeneous system which increased the thermosteadiness of copolymer.
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发布时间：2021-03-19 - 摘要：ffects of the chain orientation in the global sense on the solvent induced crystallization (SINC),diffusion velocity of toluol into poly(ethylene terephtlialate)(PET)and crystallization morphology were:studied by using density measurement and SEM.It has been shown that the SINC and diffusion velocity of toluol into PET increase with increasing degree of chain orientation in global sense,and the chain orientatioll can be essentially remained during SINC.
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发布时间：2021-03-19 - 摘要：he rheological properties of glass beads suspensions in three difference matrices,i.e.Newtonian fluid, Boger fluid and concentrated polymer solution,were investigated.In this paper it analyzed the influence of the shear rate γ on viscosities and first normal stress differences N1 of these [suspensions with the different volume fraction φ of glass beads in the different matrices. There was not any first normal stress difference N1 for the suspension based on Newtonian fluid at all.For suspension in the concentrated polymer solution the linear relationship of logarith-mic values of N1 and γ was found. The slope of lgN1～lgγ was decreased with increasing φ. Although this linearity exacts for Boger fluid itself,the nonlinearity relationof lgN1～lgtγ is obvious for its suspensions. With increasing γ the ratio N1r between first normal stress differences for the suspension and their matrix of Boger fluid was increasing at the low range of γ,through a maximum, then dec-reasing at the high range of γIn addition,the higher the value φ,the larger the value of N1r and the smaller the value of γ corresponding to the maximal N1r.
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发布时间：2021-03-19 - 摘要：Both polycaprolactone macromer and polypropylene oxide macromer were prepared from the ring opening polymerization of caplorolactone and propylene oxide respectively through the tetrapkenyl porphyrin aluminium chloride/hydroxypropyl methacrylate catalytic system.Both the polycaprolactone macromer and polypropylene oxide macromer possess narrow molecular weight distributions around 1.20.The butyl methacrylate copolymers with polycaprolactone macromer or polypropylene oxide as the side chains were prepared from the copolymerization of butyl me-thacrylate with polycaprolactone macromer or polypropylene oxide macromer respec-tively.
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发布时间：2021-03-19 - 摘要：nickel complex of linear 2-vinylpyridine-Methyl Acrylate copolymers has been found to be able to catalyze the carbonylation of methanol to produce acetic acid in a mild conditions. Experimental results show that the polymer-nickel complex contains two kinds of coordination bonds, N→Ni and O→Ni.Catalytic activity of the complex is increasing with the augmentation of O→Ni bond.And it also shows that the complex has a resistant effect on poisoning of suphur compounds.
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发布时间：2021-03-19 - 摘要：ased on the diameter and the diameter distribution of fibers,spun in their optimized spinning temperature ranges,six TLCPs were classified into two groups with good and poor spinnability,respectively.Under the same conditions TLCPs with good spinnability generate fibrils of smaller diameters,narrower diameter distributions and larger intrinsic aspect ratios in blend extrudates.This correlation between the TLCP spinnability in air medium and TLCP fibrillation in resin melt could be taken as a prerequisite coondition for the achievement of sub-micron reinforcing with TLCP fibrils.
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发布时间：2021-03-19
Research Bulletin
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