最新刊期
卷 ， 期 4 ， 1996
- 摘要：FRS-XRSA (Full -Reciprocal Space X-Ray Scattering Analysis) is a new procedure to characterize the crystallinity and orientation of various preferred orientation polymers. FRS-XRSA overcomes the difficulty of sample orientation when the crystallinity of orientated sample is measured by the powder method (PM).FRS-XRSA can also study the crystallinity of the deformed sample in the stretching and recovery processes. In our work, we measured XRS in two directions, i. e. latitude angle β =0° (MD) and 90 ° (TD) and △α=10°.Thus MT-XRS crystallinity Xxc was obtained.Here an approximation was assumed,i.e.the distribution of XRS from M to T direction was monotonous and smooth.But usually that is impossible.Therefore,an improvement of FRS-XRSA was made as follows.First,according to the intensity distribution of FRS-XRS,the inserted XRS intensities in αi,βi=0～90° at △αi,△βi=10°,were obtained,then FRS-XRS crystallinity Xxc,which accords with the theoritical basis,can be calculated.Second,the correction factor of polar angle cosxiwas considered in FRS-XRS.Third,the strange-point at αi=0° where cosx is zero,was dealt with reasonably.The results are reasonable and satisfatory.Meanwhile,the distribution of the crystallite size in FRS was obtained.
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发布时间：2021-03-19 - 摘要：The impedance spectra of two systems of multi -phase polymeric electrolyte were studied' One system consisted of LiClO4 doping polyethylene glycol polyurethane which was characterized by bi -ionic conductor and the another system was based ona sulfonated polyurethane ionomer with single-ion transportation character. An equivalent circuit of alternating impedance measurement system for the multi-phase polymeric electrolytes was proposed. The ionic conductivity and other fundamental electricity parameters were respectively by resolving of impedance spectra with computer fitting analysis and of the dispersion relations of boundary impedance.Based on the two methods the calculated ionic conductivities came to an unanimous conclusion in spite of the difference in transport numbers of cation of the two samples.The impedance spectra of the different samples can be interoreted with the equivalent circuit suggested by the present paper.
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发布时间：2021-03-19 - 摘要：Polyepichlorohydrin - based polyurethane / poly (methyl methacrylate)interpenetrating polymer networks (PU(PECH) /PMMA IPNs) was synthesized by simultaneous method. A series of polymer alloys, such as elastomer, reinforcedelastomer, toughened plastics, brittle plastics, were easily obtained by adjusting the component ratio of the IPNs. The compatibility of the IPNs was studied by DSC,dynamic mechanical analysis (DMA) and TEM. The results show that the tWo compo-nents in the IPNs are completely compatible. Meanwhile,the stress-strain behaviour of the IPNs with different component ratio were measured and explained by compatible morphological.structure in which there are a lot of interpenetration and entanglement.SEM was used to observe the fracture surface of different samples.
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发布时间：2021-03-19 - 摘要：The problem of the dependency of the instrumental constant K of vapor pressure osmometry on the molecular weight of the sample was studied by measuringthe variation of temperature difference signals with time for four low molecular weight orgahic compounds and ten narrow MWD oligomeric polystyrene samples with known average molecular weights. A modified procedure for measuring VPO signals and data treatment which leads to more accurate number average molecular weight was proposed.
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发布时间：2021-03-19 - 摘要：There are three ldnds of unusually optical property spherulites in nylon1010: two-sectional (2), asymmetric four-sectional (A4), and six-sectional (6)spherulites' Rotating observation of the spherulites by a polarizing microscope (PLM),the morphologies and colour distribution added the first red compensating plate arevariable periodly' The two -sectional, asymmetric four-sectional and six-sectionalspherulites have 3, 1 and 2 kind changes: 2-A4-6(A), 2-A4(B), 2-2(C); A4-A4(D), and 6-A4(E), 6-6(F) respectively.So that the all radii of these spherulites may are crystallographically inequivalent.
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发布时间：2021-03-19 - 摘要：Sequential block copolymerization of styrene with prOPylene were carried out with TiO4-NdojOR), /MgCl2 /Ph2SiO2 / EB catalyst (called SN catalyst) which was developed in our laboratory. The influence of various polymerization conditions such as styrene prepolymerization time, monomer feed ratio, extend donor (EB),Al(iBu). concentration, catalyst concentration and temperature on the copolymerization were studied in detail' Ethyl benzoate was found to reduce the activity of the catalyst.A much higher incorporation of styrene and higher stereoregularity of each segments of copolymer,however,were observed within mole ratio EB/Ti=5;while futher addition of EB reduced incorporation of styrene and suppressed the stereospecificity of PS segment. SN catalyst was found to give higher catalytic yield (over 1000gP/gTi) and conversion yield of styrene.The styene-units of copolymer obtained were whithin 15 to 85 mile%,depending upon the polymerization conditions.
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发布时间：2021-03-19 - 摘要：Effect of heat treatment on the ndcrophase separation of a segmented poly(urethane urea) (SPUU) copolymer based on poly (propylene oalde) diol, 3, 5 dithyltoluene diandne and 4,4' -diphenylmethane diisocyanate has been studied bymeans of fourier transform infrared spectroscopy. From room temperature up to 310 t, the hydrogen bonds between urethane linkages were dissociated gradually andthe hydrogen bonds between urea linkages with the bifuracted structure were formedrapidly between 130 - 200 ℃. A part of free urethane linkages formed hydrogen bonds again when the copolymer was annealed from 310℃ down to room temperature,meanwhile urea hydrogen bonds between hard segments formed continually.The result suggests that the extent of microphase sepearation of the SPUU copolymer can be increased efficiently with the help of heat treament between 130～200℃.
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发布时间：2021-03-19 - 摘要：Temperature dependence of yield stress, Young ' s modulus and fracture toughness of phenolphthalein polyether ketone (PEK-C) were investigated. It wasconcluded that the yield stress, Young's modulus decreased with increasing temperaturefor the period from 12 ℃ to 190 ℃. The quantitative relationships between theyield stress, the Young's modulus and the fracture toughness were given' Thereexhibit good linear relationships between Log Klc, Lag GIc and yield stress forPSa - C.
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发布时间：2021-03-19 - 摘要：The phase behavior of blends of polystyrene (PS) and a random copolymercarboxylated poly (2, 6-dimethyl - 1, 4-phenylene oalde) (CPPO) with 8.0mol%carboxyl content was studied by DSC. It was found that the blends showed acoexistence of an UCST an a LCST behavior. TEM was used to study the phase morphology of blends' It was found that the phase morphology of blends at lowarmealing temperature is different from that at high annealing temperature. Themechanism of phase transformation was discussed. It was found that the phase morphology of blends at low annealing temperature is different from that at high annealing temperature.The mechanism of phase transformation was discussed.It was found that the mechanism of phase separation of blends in UCST area is different from that in LCST.
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发布时间：2021-03-19 - 摘要：Flame-retardant action of polysulfonyldiphenylene phenylphosphonate(PSPPP) on polyethylene terephthalate (PET) was investigated employing X-rayphotoelectron spectroscopy(XPS or ESCA), thermogravimetry and Fourier transform infrared spectroscopy techniques. The flame retardant PSPPP widens the temperature range of PET decomposition, and reduces the amount of combustible volatile products within the range of combustible temperature of PET. PSPPP can accelerate thedegradation of PET below and near the ignition temperature TI of PET, which is favorable for melt dripping so as to enhance the loss of heat and material from the surface of the burning PET.Some degraded products of PET/PSPPP flame retardant system are charred above TI of PET so as to limit to a certain extent heat and mass transfer across the phase boundary by creation of an insulating charred layer on the surface of the burning PET.
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发布时间：2021-03-19 - 摘要：The goal of this work was to reveal the factors which influenced the adsorption properties of hypercrosslinked polystyrene adsorbents. For this study the process of Friedel- Crafts postcrosslinking of chloro-methylated ploystyrene, and their pore structyures and adsorption properties were investigated . The results showed that their adsorption for phenol increased to the maximum and then decreased though their specific surface area and pore volume decreased with the increase fo the amount of toluene added. This suggests that the adsorption properties of hypercrosslinked polystyrene adsorbents were influenced by both pore structures and skeleton structure of them.
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发布时间：2021-03-19 - 摘要：Six macromolecular polyester ligands were synthesized by copolymerization of diethylenetrithenepentaacetic dianhydride with N -butyl, octyl, benzyl, p -toluenesulfonyl, phenyl and p-bromophenyl diethanolamine, respectively. Their Gd(Ⅲ)complexes were also prepared' The structures of these macromolecular polyester ligandsand their Gd(Ⅲ) complexes were characterized by 'H-NMR, IR, Elemental analysis and DSC. The molecular weight of these polyseter ligands were determined by VPO method. Average degree of polymerization of these copolymers were found to be around 4.Two of these macromolecular Gd(Ⅲ) complexes were chosen for the relaxation measurement.Preliminary results showed that the relaxivity (R1) of macromolecular GD(Ⅲ) Complex 3b and 3c han an enhancement of 40% and 36% in comparison with that of Gd-DTPA.
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发布时间：2021-03-19 - 摘要：Polyether dendritic polymers of three generations with branch ends mobified by allyl groups were synthesized by convergent approaches. 3,5 -dihydroxybenzyl alco hol was used as branching monomer while tris (4' -hydroxyphenyl) methane as core of the polymers. Allyl group was introduced from the beginning of the procedures,i.e., 3, 5-diallyloxybenzyl bromide was used as starting materials. There were six,twelve and twenty-four allyl groups in the three polymers respectively. Dendrimers,were characterized by 1H-NMR,13C-NMR and MS.
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发布时间：2021-03-19 - 摘要：A series of PCL /TDI / BDO polyurethanes with different compositions was synthesized by solution copolymerization. DSC, WAXD and DMTA were used to study the crystallization of PCL soft segment and mincrophase separation of the polyurethanes. It was showed that the crystallizability of PCL soft segment was depressed by the introduction of hard segment in the polyurethanes, and the soft segment was not able to crystallize until its average molecular weight was above 3000.The hard segment was able to form sufficient domains if its content was relatively high.The polyurethanes with proper compositions show good thermally stimulated shape memory effect.In addition,the influence of draw ratio,times of cyclic deformation on the shape memory behavior was also investigated.
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发布时间：2021-03-19 - 摘要：The effects of morphological parameters, including the polydispersity of the particle size (o), on the brittle-ductile transition of amorphous polyvinyl chloride (PVC) /nitrile rubber (NBR) blends have been studied. The brittle-ductile transitions of PVC /NBR blends occur when the particle size (d) is smaller than a critical value dc or the particle volume fraction (φ ) is larger than a critical value c. The higher the value of a, the lower the value of dc, and the higher the value of c. Thereforea high o value is unfavorable for attaining high impact toughness in polymer blends.We have developed an expression relating the matrix ligament thickness T to d,φ and σ.The impact strength of PVC/NBR blends is found to depend on the single parameter T,and the blend becomes very tough when T is smaller than a critical value Tc,So the Tc criterion,which is valid for blends with a pseudo-ductile matrix, is also applicable to OVC/NBR blends whose matrix has the chain parameters intermediate between those of brittle and pseudo-ductile polymers.
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发布时间：2021-03-19 - 摘要：Effects of physical ageing on the yield behavior during uni-axial stretching of amorphous PET film were studied by differential scanning calorimetry and stress-strain measurements. It was shown that the endothermic peak at Tg, the yield stress, and the stress yield peak in the stress-strain curve all increased as physical ageing progressed. On passing through the yield point, DSC indicated that theendothechc peak disappeared. Post-yield amorphous film followed by further heat treatngllt below Tg, a yield stress peak in the stress-strain curve was shown again during re-stretching.The nature of the physical ageing and stress yield were explained on the basis of cohesional entanglements.
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发布时间：2021-03-19 - 摘要：The molecular composites of a rigid polymer polyindde (PI) with a flexible matrix polymer polyvinylpyrrolidone (PVP) were successfully synthesized by in-situ polycondensation. A strong specific interaction of acid-base between the polyamic acid (the precursor of PI) and the PVP was confirmed experimentally. By this specific interaction the ndscibility of PI with PVP was substantially improved.The PI dispersed in the PVP matrix polymer on a molecular level or nearly molecular level.The films of the molecular composites of PI/PVP are transparent.Only one Tgexhibited over the whole composition range suggesting a homogeneous phase.No phase separation was observed by SEM for the sample with PI content 40% the finely dispersed rod-like PI micro-crystals can be found by SEM. Due to the molecular composite formation of PVP with PI,the PVP become insoluble in ethanol even with only 10% PI.
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发布时间：2021-03-19
Research Article
- 摘要：Poly(sebacic anhydride) (PSA) was prepared from the mixed anhydride of diacid. PSA was blended with polylactone (PLA) and polycaprolactone (PCL) respectively. The blends were fabricated into film by solvent casting. Hydrolytic degradation and drug release experiments were carried out in 0.1 mol /1 phosphate buffer PH 7.4 at 37℃ by examining the changes in weight, molecular weight, DSCcurve. Indomethacinum and p-nitroauiline were used as model drugs. Samples with a higher portion of PSA showed higher degradation rate.Rate of release depended on the content of PSA and the properties of drug.All systems demonstrated burst release during the first few days.
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发布时间：2021-03-19 - 摘要：Two synthetic methods of polyvinyl alcohol with high absorbency for saltliquor were described: (1) Make partially phosphorylated polyvinyl alcohol crosslinking using Zr(IV) salt as crosslinking agents. (2) Make polyvinyl alcohol, free phosphoricacid and ZI(IV) salt forming crosslinking complex resin. The absorbency of synthesizedcomplex resin for 1% NaCl liquors is above 100 times by both (1) and (2). It is fairly stable in water, salt solutions, great major dilute solutions of acid, and non-aqueous solvents.A structure of this complex resin was proposed on the basis of chemical analysis,IR spectra and the theory of zirconium chemistry and making it compare with those of model reaction.
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发布时间：2021-03-19 - 摘要：Compatibilzing effeCts of diglycidyle ether of bisphenol-A (DGEBA) epoxy resins and Phenoxy resin on the blends of Nylon-6 and core-shell type MBS impact mwhfier, based on polybutadiene core and on PMMA shell, was studied interms of morphology, mechanical, rheological and thermal properties. Compatibilizers have proved useful for the purpose that MBS impact mwhfier must be appropriately dispersed in and coupled to Nylon-6 in order to toughen the Nylon-6 effectively'Scanning and transaction electron micrographs show that impact modifier exhibits a more regular and finer dispersion when DEGBA epoxy and Phenoxy resins were added. The blends also exhibit supper toughness with the addition of compatibilizers,which seems to be attributable to both reduce impact modifier pasticle size and improve interfacial adhesion.
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发布时间：2021-03-19 - 摘要：As a rule, crystalline and flexble polymers can gain higher mechanical properties through extra-drawing' In the paper, the effect of drawing conditions on structures and properties of ultra-high molecular weight polyethylene (UHMWPE)'during two-stage drawing was studied' Results showed that during super-drawing,elastic modulus (E) and break strength (o) increased with drawing ratio (a) Attemperature Td= 150 ℃; when a=60, the perfect mechanical state was abtained, and at this time, E and a were in the highest(E=130.44GPa,σ=3.86Gpa),34 and 29 times of those by onestage (cold) drawing respectively.
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发布时间：2021-03-19 - 摘要：The copolymerization of propene and octene- I using rac-Et(Ind)2ZrCl2 /MAO catalyst has been investigated. Results show that with increasing theconcentration of octene-l in the system, the catalytic activity increased first and then decreased, the incorporation rate of octene- I increased, and in consequence, M,Tm, crystallinity of copolymer decreased. The monomer composition and sequencedistribution of the copolymers were determined by IR and 13C-NMR.
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发布时间：2021-03-19 - 摘要：Zinc salt of lightly sulfonated polystyrene ionomer (Zn-SPS) was used as a compatibilizer in blends of polysulfone (PSF) and a liquid crystalline polymer (LCP).DSC results showed that PSF and LCP were almost completely immiscible, but with addition of Zn-SPS, Tg's of PSF in blends had sighficant shifts. In SEM pictures the size of dispersed phase decreased dramatically with increasing amount of Zn-SPS. With improvement of the adhesion between two phases, partially compatibilized blends had significantly higher tensile strengths and modulus than blends of PSF/LCP without Zn-SPS.
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发布时间：2021-03-19 - 摘要：A main-chain liquid crystalline polyurethane elastomer (LCPUE) based on biphenyl mesogenic diol(HB6), poly(tetramethylene oxide)(PTMO), and hexamethylene diisocyanate (HDI) was studied by solid-state high-resolution variable-temperature 13C-NMR spectroscopy from room-temperature to 130℃. It was revealed that in the heating process, even when temperature exceeds the melting-point of the sample, there still. exist hard-segment micelles with ordered packing structure.The finding is applicable to explain the phenomenon that the liquid-crystalline phase does not aooear in the heating process of LCPUE.
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发布时间：2021-03-19
Research Bulletin
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