最新刊期
卷 ， 期 3 ， 2003
- 摘要：The rheological behavior of HPAM solutions and Xanthan solutions,their rheological behavior in porous media and residual resistance factors were measured experimentally,and the depleted layer thickness was calculated．Displacement experiments were proceeded with various concentrations and injecting speeds．It was expounded that the increase of apparent viscosity or the decrease of depleted layer thickness generated by the entanglement of polymer molecules can increase the force parallel to oil-water interface,which can pull more residual oil out and enhance oil recovery．With the concentration increase of HPAM solutions,the apparent viscosities increase and the depleted layer thickness decrease．When the concentration of Xanthan solutions was higher than the entanglement concentration,the depleted layer thickness and the apparent viscosities varied little．The increase of injecting speed can decrease the depleted layer thickness of both polymers,with residual resistance factors varying little and viscoelasticity increasing for HPAM solutions and residual resistance factors decreasing for Xanthan solutions．The flooding results with various concentrations and injecting speeds affirm the mechanism that the entanglement effect and the depleted layer effect of polymer molecules act on the residual oil．The difference in molecular structure of the two polymers used is the essential reason that results in their different flow behavior in porous media and different mechanism of action on residual oils.
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发布时间：2021-03-19 - 摘要：Poly(N,N-diethylacrylamide)(PNDEA)-clay hydrogels were prepared and compared with pure PNDEA samples．X-ray diffraction studies showed that the PDEA-clay hydrogels were nanocomposties．These composites exhibit some unusual enhanced characteristics．For hydrogels of crosslinked PNDEA with 10％ clay their swelling ratio was as high as that of the uncrosslinked pure PNDEA samples,and their water release behavior showed an almost linear from dependence．These properties are desirable for applications in sensors,regulators and controlled release desires.
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发布时间：2021-03-19 - 摘要：Novel non-metallocene complexes are synthesized in which titanium is coordinated with acetylnaphthoxy ligand with a formula [O,O]n TiCl4-n. Their composition and structure are characterized by element analysis and IR spectroscopy．The results suggest that the ring structure is formed by the combination of two oxygen atoms in the acetylnaphthoxy ligand [O,O] and titanium atom,while n is 1 or 2．The catalysts are applied in ethylene polymerization．It is found that the catalytic activity of the catalysts for homogenous ethylene polymerization is not high with MAO as co-catalyst due to the association phenomena of the complexes．The molecular weight distribution of polyethylene obtained in homogenous polymerization is wide．The results indicate that the complexes may be “multi-site” catalysts in homogenous polymerization．The catalytic activities of the non-metallocene complex reach 106 gPE／(molTi·h),when it is supported by MgCl2．The amount of MAO can be decreased or replaced by alkyaluminum．In heterogeneous catalysis,the molecular weight of polyethylene is higher and the molecular weight distribution is narrower than those in homogenous catalysis．Through the study of XPS,the electron reduction of titanium and the draw-electron effect of magnesium are confirmed,which will favor the coordination of olefins．
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发布时间：2021-03-19 - 摘要：Polyacetylene and polyaniline usually have one-dimensional character because their interchain coupling interaction is weak．As the pressure increases,the interaction also increases and interchain energy gap reduces so that interchain distance b decreases and interchain elastic distance increases．When b approaches the lattice constant a,the polymer of one-dimensional chains becomes a two-dimensional compound lattice structure after considering their interchaln coupling action,and new physical properties may arise．In this paper,the second-nearest-neighbor interactions between lattice chains of polyacetylene and polyaniline are considered,and the two-dimensional compound lattice model is adopted．Using the method of lattice dynamics,the dispersion curves of these polymers under different mass ratio are calculated and three kinds of lattice chain interactions are also investigated．The changes of spectra in high symmetric curves under BZ are discussed．We also plot the curve under the various mass ratios．The results show that the two-dimensional compound lattice polymer has two acoustic branches and two optical branches,and the increase of interchain coupling interaction can destroy the effects of aberration of dimerization,and cause the dimensional effect．If interchain coupling interaction is weak and vibration of interchain direction can be neglected,the polymer becomes one-dimensional chain and has only an optical branch and an acoustic branch．
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发布时间：2021-03-19 - 摘要：A side chain pulled-along model of polymers is presented in this paper．It is believed that the stereo effect of side chains of polymers comes from their axis cross-area,which correlates to the number of carbon branches of side chains．The numbers of carbon branches of side chains are used directly as the descriptors of their stereo effect．Based on this assumption,quantitative structure-property relationships (QSPR) are developed to correlate the glass transition temperature (Tg) to the chemical structure of 13 polyacrylates and 9 polymethacrylates,respectively．Good three-parameter models,which consist of the number of carbon branches of side chains B,the group charge of side chains C and the topological length of side chains L,are obtained with regression coefficients R2=0.989 (s=3.8 K) and R2=0.993 (s=4.8 K) respectively．For a common three-descripter model covering both the 13 polyacrylates and the 9 polymethacrylates,the regression coefficient is R2=0.980 (s=8.3 K)．It can be seen from the statistics analysis results for all models that the descriptors B and B have positive correlation to Tg of the title compounds and the descriptor L has negative correlation．Furthermore,the descriptor B has greater influence on the models than the other two．So it is comparatively reasonable to use the number of carbon branches of side chains as the descriptor of the stereo effect for polyacrylates and polymethacrylates．All the descriptors in this paper are easy to be calculated．The models have good stability and applicability,whose standard errors are all less than or approximate to the experimental error．
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发布时间：2021-03-19 - 摘要：There are two kinds of conjugated polymers,the degenerate-ground-state (DGS) polymers and the non-degenerate (NDGS) ones．For the latter,the confinement effect induces self-trapped excitons (STE) and biexciton (STB)S,and produces photoinduced polarization reversion (PPR),when the polymer is photoexcited．Some new kinds of polymers such as PDPA have been synthesized recently．This kind of polymers has degenerate-ground-states and does not possess confinement effect and self-trapped exciton．However,the length of the real polymer chain is finite,the soliton and antisoliton in the polymer chain cannot be separated far away．It is proved that such soliton-antisoliton pair in DGS polymers can also produce negative polarization and photoinduced polarization reversion．
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发布时间：2021-03-19 - 摘要：When the degree of crystallinity (Xwc) of semicrystalline poly(ethylene terephthalate) (PET) was within a definite range,there were dual endothermic peaks appearing in the glass transition region of differential scanning calorimetry (DSC) traces of physically aged samples. By comparing the dual endothermic peaks with the single endothermic peak of physically aged wholly amorphous samples and semicrystalline samples with a fairly high Xwc,respectively,it can be concluded that there were dual amorphous regions with quite different characteristics in the semicrystalline samples：the free amorphous region and the constrained amorphous region．The dual tanδ loss peaks in dynamic mechanical thermal analysis (DMTA) curves also confirmed the existence of the dual amorphous regions．The dual amorphous regions were found to be produced due to the different constraints that the crystallites excerted on the amorphous phase．For the semicrystalline sample crystallized from glassy state,both the lower and the upper limit of the Xcw increased with increasing crystallization temperature (Tc)．With the proceeding of physical aging,some of the free amorphous regions became constrained amorphous regions,while the gross amount of the amorphous phase kept almost unchanged. The struik’s model of “extended glass transition” was proved to be the most successfulmodel for our experimental results．
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发布时间：2021-03-19 - 摘要：A series of new solid polymer electrolytes (SPE) were prepared based on polyurethane／acrylate comb cross-linked polymers．The ionic conductivity of the electrolytes could reach 3.4 × 10-5 S·cm-1 at 25℃．Raman spectroscopy,DSC,SEM and conductivity measurement were used to study interrelations among salt concentration,ion states and ionic conductivity．In solid polymer electrolytes with high salt concentrations,it was considered that the ion pairs may play an important role in ion transport．When the salt content was low,the free ion was the main form of salt in the electrolytes．The content of ion pairs increased with increasing the salt content．The ion pair became an important form of salt in the electrolyte when the salt content was high,and the ionic conductivity increased greatly in a certain range．Under these conditions,the ion pairs should act as all active entity in the ionic conduction of the electrolytes．When the SPE films were in atmosphere,the ions were unstable,and they would congregate and form crystallinites．Proper conditions could keep the ion stability of the polymer electrolyte films．
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发布时间：2021-03-19 - 摘要：Amphiphilic block copolymers have many unique physical and chemical properties,especially stronger self-assembling ability,because of amphiphilic property and microphase separation of their molecules．In this investigation,the amphiphilic block copolymers of acrylamide(AM) and styrene(St) were prepared in microemulsion medium．One series of copolymers PAM-b-PSt was synthesized by changing the feed ratio under remaining other copolymerization conditions invariable．The apparent viscosity of the aqueous solutions of copolymers samples were measured using a rotational rheometer．The effects of various factors on apparent viscosity,such as concentration of polymer,composition of copolymer,shear rate,temperature and salt concentration,were investigated in detail．The studying results show that there is strong hydrophobic interaction between the block suctions of PSt in the macromolecules of PAM-b-PSt,so that stronger intermolecular hydrophobic associations are formed in aqueous solution and above a critical polymer concentration(about 0.2％,wt％)．The intermolecular association leads to network structures and the hydrodynamic size of chains is increased,so the amphiphilic block copolymer PAM-b-PSt exhibits good thickening property．The another reason leads to good thickening property of PAM-b-PSt is that introducing of phenyl groups of styrene significantly enhanced the viscosity．Besides,under increasing shear,the physical links between chains are disrupted,but recover with decreasing shear,and also the associations are enhanced by the application of shear．The reversibility of the rheological property can to avoid the irreversible mechanical degradation．Therefore,the reversible association／dissociation process gives rise to particular rheological behaviors for PAM-b-PSt．Because hydrophobic association is endothermic,the intermolecular association is favoured by increasing the temperature,and so PAM-b-PSt has the withstanding temperature property．The containing of salt in aqueous solution of polymer can increase the polarity of the solvent,and the effect favoured the intermolecular association．As a consequence,the solution of the block copolymer PAM-b-PSt has salt resistance．Above described excellent properties of amphiphilic block copolymer PAM-b-PSt will leads to its wide commercial application．
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发布时间：2021-03-19 - 摘要：As the real trans-polyacetylene molecule has finite chain length,its chain-terminal effects on various properties should be taken into account,that is to say,the aperiodic boundary condition should be employed in studying the properties of conducting polymers．However,if trans-polyacetylene chain is long enough,the chain-terminal effects can be ignored．In this paper,a one-dimensional finite compound lattice model of trans-polyacetylene chain is adopted．With considering the chain-terminal effects and the next-neighbor hopping interactions,the energy spectra and the density of states are calculated for trans-polyacetylene chains with the lattice number N from 10 to 200 under the periodic and aperiodic boundary conditions. The effects of chain length and interaction parameter on density of states and band width are also discussed．It is shown that the curves of DOS are symmetrical when the nearest-neighbor hopping is merely considered,and the valence and conduction bands are unsymmetrical when the next-neighbor term is taken into account．At the same time,some results under two kinds of boundary conditions are compared．When N＜50,the surface states appear under the aperiodic boundary condition,as well as DOS nearby the Feimi surface is larger than that under the periodic boundary condition．When N≥50,the surface states are difficult to distinguish between the valence and conduction bands,and DOS tends to be identical under two kinds of boundary conditions．Moreover,with N increasing,the difference of ionization energy under the two boundary conditions is reduced for the same parameter．In conclusion,when N＜50,there is a large difference for nearest-neighbor hopping and next-neighbor hopping due to the chain-terminal effect．This indicates that the aperiodic boundary condition plays an important role in dealing with finite systems．However,when N≥50,since the chain-terminal effect can be neglected,the periodic boundary condition is suitable for the finite trans-polyacetylene system．
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发布时间：2021-03-19 - 摘要：Mechanical properties of polymers can be improved by incorporating nanoparticles,however,there are few works about the influence of nanoparticles on the crystallization mechanism of polymers．To develop an understanding of the important role of nanoparticles in polymer crystallization,the current paper introduced different surface modifications for calcium carbonate nanoparticles,and studied their effects on the crystallization behavior of isotactic polypropylene (iPP) by DSC measurement．The CaCO3 particles used are 40 nm in diameter,and their surfaces were treated by stearic-coating,PS-grafting,and PBA-grafting methods,respectively．The isothermal crystallization results show that the addition of both neat and modified nono-CaCO3 into PP has an obvious nucleating effect on the crystallization of iPP,resulting in lower supercooling degree,higher rate of nucleation and overall rate of crystallization,and higher crystallinity．Even through grafted PBA and PS belong to amorphous polymers,their evident nucleating effects indicate some regular structure forming on the particles surface．However,the grafted PBA exhibits different effect from PS because of its distinct molecular polarity and stiffness．On the other hand,the non-isothermaI crystallization results show that the addition of these nano-CaCO3 reduced the rate of nucleation and overall rate of crystallization of iPP,which is related with the slower formation procedure of β-form crystallites of iPP．The melting behavior and WAXD results revealed that all of these nano-CaCO3 have a strong promoting effect on the nucleation and crystallization of β-form crystallites of iPP,especially for the systems containing modified fillers,implying that this promoting effect was strongly dependent on the surface modifications of the nano-CaCO3 particles．
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发布时间：2021-03-19 - 摘要：The method of substitution reaction followed by modification was used to synthesize a novel polyphosphazene containing amino acethydroxamic acid benzyl esters．By changing the feed ratio of reactants during the polymer modification,two resultant polymers with different contents of amino acethydroxamic acid benzyl ester were obtained．IR,1H-NMR and elemental analysis were applied to characterize these polymers．The degradation test in vitro was carried out in phosphorous-free buffer solutions in the pH range of 5.0～8.0．The result revealed that the polymer with certain amount of amino acethydroxamic acid side groups (80％) exhibited strong pH-responsive degradation property．After 1.5 d,the sample dissolved completely in the solution of pH7.4,but lost only about 8％ and 4％ in solutions of pH6.0 and pH5.0,respectively．The degradation rate of polymer accelerated suddenly in the pH range 6.0～7.4．These features are feasible for polymers to act as carriers of oral enteric drug controlled delivery systems．
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发布时间：2021-03-19 - 摘要：A novel approach to synthesize core-shell nanoparticles with Fe3O4 as the magnetic core and PPY as the conducting shell was investigated．The Fe3O4 nanoparticles primarily prepared by precipitation-oxidation method,and the Fe3O4-PPY nanoparticles with core-shell structure was synthesized via all in-situ polymerization of pyrrole monomer in an aqueous solution containing well-dispersed Fe3O4 nanoparticles and surfactant NaBS．The particles are almost spherical with diameters ranging from 20～30 nm．These particles are polydisperse and some of them agglomerated due to magneto-dipole interactions between particles．70％ to 80％ of the Fe3O4-PPY particles are ranged from 30～40 nm in diameter．The core-shell structure of nanoparticles was evidenced by TEM observations. The Fe3O4 content was found to affect significantly both the conductivity and the magnetization of the resulting PPY composites．When 9％ Fe3O4 was incorporated into PPY,the conductivity of PPY composite was gready reduced from 6.52 × 10-3 to 1.94 × 10-4 S／cm．Further increasing of Fe3O4 content from 8.2％ to 28.2 wt％,resulted in slight reduction of the conductivity at room temperature．The decrease in conductivity of Fe3O4-PPY composites with increasing Fe3O4 content was due to a decrease in the doping degree,assigned as S/N ratio．The S/N ratios decrease from 0.34 to 0.19 with increasing Fe3O4 content from 0 to 28.2％．The magnetic properties of the Fe3O4-PPY nanocomposites depend on the Fe3O4 content too．Increasing Fe3O4 content from 0 to 28.2％ considerably increased both the saturated magnetization (Ms) and the coercive force (Hc) from 0 to 23.42 emu／g and 0 to 45.2 Oe, respectively．Since PPY powder is not magnetic,the ferromagnetic properties of the composites are attributed to the magnetic Fe3O4 nanoparticles．The magnetic Fe3O4 nanoparticles can improve the thermal stability of Fe3O4-polypyrrole nanocomposites due to interaction between Fe3O4 particles and PPY chains．
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发布时间：2021-03-19 - 摘要：A gelatin hydrogel crosslinked with glutaraldehyde has been prepared,and its swelling ratio at equlibium,mechanical properties and stimuli-response behavior were studied．The results indicated that the water take-up of the gelatin hydrogel decreased as the concentration of NaCl solutions increased,and the mechanical properties of gelatin hydrogel films swollen in O.01 mol／L NaCl solution are shown as follows：4.29 kPa of Young’s modulus,5.11 kPa of tensile strength and 110％ of elongation at break．The hydrogel sheets bended toward the cathode under a non-contact D．C．electric field in NaCl aqueous solutions．The bending speed and deflection of the hydrogel sheets increased with increasing of the applied voltage．The electroresponsive behavior of the hydrogel was also affected by the electrolyte concentration of the external NaCl solution,and there is a critical ionic strength of O.03．Under a cyclically varying electric field,the hydrogel sheets exhibited a good reversible bending behavior．The bending of gelatin hydrogels was initially explained by a bending theory of polyelectrolyte hydrogels based on the change of osmotic pressure due to the ion concentration difference between the inside and the outside of the hydrogel．
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发布时间：2021-03-19 - 摘要：The novel catalysts of TiCl4-CH3COCH2COCH3-Co(acac)2 supported on SiO2-MgCl2 carrier (Ti-Co complex catalyst) were prepared by reaction procedure．The polyethylene with various branching chains was synthesized by using these Ti-Co complex catalysts．The effects of the kinds of AlR3,polymerization temperation and the constituent of catalysts on the polymerization activity and the product properties were investigated．The polymerized products have analyzed by using IR and 13C-NMR spectroscopies．The results of 13C-NMR studies suggested that the polyethylene products contained n-butyl branches,pentyl branches and long branching chains(n≥6)．The polymerization mechanism was discussed also．Experimental results showed that the Ti-Co complex catalyst with Et2AlCl as cocatalyst exhibited high catalytic activity and excellent properties of oligomerization and in situ copolymerization for ethylene．
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发布时间：2021-03-19 - 摘要：An interpenetrating polymer networks is a polymeric alloy in which the thermodynamics characteristics of the components comprised the SIN dominates miscibility between the components,microphase structures and therefore the damping behaviors of the SIN materials．In this paper,based on polyphenylsiloxane (PMPS) and polymethacrylate (PMAc),a series of novel simultaneous full-interpenetrating polymer networks (SIN) materials have been synthesized,and simultaneously the relationship between a compatibility of the components consisted of the SIN and the damping properties of the SIN has been investigated from solubility parameters,DMA,and AMF etc． The results show that the SIN materials derived from the components with better compatibility have the maximum damping value of tanδmax=1.4,the sample only appearing one glass temperature peak and showing dual phase continue structures. On the contrast the sample has the widest effective damping function area whose range of temperature with tanδ ≥ O.3 can arrive to 170℃,when the components of the SIN possesses a medium compatibility,the materials displaying monophase continue structures．And moreover the SIN sample made by the components with the worst compatibility split the loss peak into two．Therefore,the damping characteristics of the PMPS/PMAc SIN materials can be tailored through regulating the compatibility of the corresponding components．
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发布时间：2021-03-19 - 摘要：A new simple nonlinear viscoelastic constitutive model under uniaxial tension is proposed by means of experimental method and internal-variable theory．The tension tests of two viscoelastic materials,i．e．,polypropylene (PP) and high-density polyethylene (HDPE),are carried out at different strain rate．The experimental date shows that the relation between stress and strain depends distinctly on strain rate．The result of curve fitting for experiment data indicates that the relaxation time of the materials is rate sensitive．When strain rate changes in orders of magnitude,the value of relaxation time varies in the same order．Under the condition of uniaxial stress,a new nonlinear viscoelastic constitutive relation with iteration form is studied by adopting internal-variable theory,and the convergence condition is derived．If the degree of iteration is taken to be one,then the corresponding constitutive relation reduces to Maxwell model with rate related relaxation time．Such a nonlinear viscoelastic model can be used to fit and predict the constitutive relation of PP and HDPE perfectly．
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发布时间：2021-03-19 -
STUDIES ON SYNTHESIS OF NOVEL TYPE POLYMERIC BISAZACROWN PSEUDO ETHER PACE AND ADSORPTION PROPERTIES
摘要：Using 2-phenoxyethanol as initial material,a novel phenolic type polymeric bisazacrown pseudo ether PACE were synthesized by methods of first polymerization then functionalization and Na+ template-guided．Series synthetic reactions were studied using FTIR spectra method for tracking monitor．A best experimental formula of phend-aldehyde crosslinking reaction using monomer phenoxyethanol and a better conditions of series substitution reactions on the phenolic aldehyde parent polymer were achieved．FTIR spectra data of polymers of a series were achieved also．Polymeric static adsorption properties for normal metallic ions were tested．The results showed that the polymer has good adsorption properties for K+,Na+,Hg2+,Cd2+,Fe3+,Pb2+,Cu2+ and the capacities of adsorption were 1.43,0.98,1.84,0.68,0.79,0.61 and 0.57 mmol／g-r,respectively．By FTIR spectra method,a preliminary discussion on adsorption mechanism was given in this paper．The results showed not only —CH2OCH22—and PhOCH2—and —CH2NCH2—,could chelate metalion,but also —CH2OH did to a certain extent in the above mentioned complexes．There is slow oxidation-reduction in the adsorption of Hg2+ on PACE and the —CH2OH in the polymer PACE was oxidized to —COOH and Hg2+ were reduced to Hg2+2．- 2
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发布时间：2021-03-19
Research Article
- 摘要：New pH and temperature-sensitive hydrogels have been synthesized though copolymerization of anionic acrylate polyurethane prepolymer (P(U)) and N-isopropyl acrylamide (NIPAAm) under various feed ratios．Single glass transition temperature was noticed from the DSC curves of the dried hydrogels,indicating of good miscibility between the two components．The pH sensitivity was much affected by the composition of the hydrogels and a lowest swelling degree was shown in hydrogel H4 with P(U)／NIPAAm feed ratio of 1／1．Hydrogel H4 also possessed lower critical solution temperature (LCST) of about 27℃ at both pH=11 and pH=7 solutions．In the equilibrium hydrogel,most of the absorbed water was fzeezable water with its content little affected by the hydrogel composition．Furthermore,the gel strength was improved with incorporating more P(U) chains into the hydrogel．
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发布时间：2021-03-19 - 摘要：A mesogen-jacketed liquid crystal polymer,poly{2,5-bis [(4′-hexyloxyphenyl) oxycarbonyl] styrene} (PHPCS),with number-averaged molecular weight of 1.28×105 and polydispersity of 1.48 was prepared via 2,2,6,6-tetramethyl-piperidinyloxy mediated free radical polymerization．The thermotropic behavior was studied by a combination of differential scanning calorimetry,thermogravimetry,polarized optical microscope and wide-angle X-ray diffraction．PHPCS was not crystalline over the entire temperature region studied．On heating,PHPCS first became an isotropic melt at glass transition temperature (Tg) and then a mesophase at temperatures much higher than Tg．On subsequent cooling,the formed ordered phase disappeared above Tg．Contrary to theoretical predictions and previous experimental observations,the transition from isotropic melt to liquid crystalline phase was an endothermic process and the order-disorder transition took place with concurrence of heat release．
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发布时间：2021-03-19 - 摘要：Poly(vinyl chloride)-g-poly(2-hydroxyethyl methacrylate) (PVC-g-PHEMA) copolymers were prepared by the aqueous suspension-swelling graft copolymerization process．The grafting of HEMA On PVC was confirmed by the infrared spectrum．The grafting degree increased with the increase of feeding mass fraction of HEMA,and a maximum grafting efficiency appeared at 10％ mass fraction of HEMA in feed．The grafting degree and efficiency increased as partially dehydrochlorinated PVC was used．The intrinsic viscosity of graft copolymers increased slowly with the increase of the grafting degree of HEMA,and decreased at high grafting degrees．PVC-g-PHEMA copolymers exhibited a higher glass transition temperature (Tg) in the first DSC run than that in the second run,and Tg of graft copolymers increased as the grafting degree increased．
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发布时间：2021-03-19 - 摘要：A new route for synthesis of amphiphilic graft copolymer PE-gPEO containing hydrophobic polyethylene as the backbone and hydrophilic poly(ethylene oxide) as the side chain has been discussed in this paper．The structure of the copolymer(such as graft density and graft length),the molecular weights of both polyethylene and poly(ethylene oxide) side chain,as well as the molecular weight distribution of the copolymer can be designed and controlled easily by this route．The molecular weight of poly(ethylene oxide) side chain is proportional to the polymerization reaction time and the ethylene oxide monomer concentration,which indicates the “living”characterization of the anonic polymerization of ethylene oxide．The graft copolymers PE-g-PEO synthesized have been characterized by 1H-NMR and DSC tests．And the SEM result shows that after adding the amphiphilic graft copolymer PE-g-PEO as the compatibilizer for the PE/PC polymeric blend,the compatibility of the blend improved greatly．Therefore,this kind of amphiphilic graft copolymers can be used as the efficient surfactant for the polyolefin blend and composite materials．
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发布时间：2021-03-19 - 摘要：The self-assembly between poly(4-diazonium styrene)(PDS) and poly(sodiumsulfonate styrene)(PSS) was investigated．The mutilayer ultra thin films were fabricated layer-by-layer successfully from PDS and PSS．After heating for 10 min at 70℃ the multilayer film became very stable towards polar solvents．No considerable changes were observed for the heated film soaked in DMF (20℃) for 48 h,while the unheated film almost destroyed at same condition．The dramatic improvement in stability of the film towards polar solvents should be attributed to the conversion of bonds between the layers of the film from ionic bond to covalent bond under heating．
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发布时间：2021-03-19 - 摘要：A series of self-yellowished polymer latexes were prepared from styrene (St),butyl acrylate (BA) and 2-[4-(4′-nitrophenylazo) phenoxyl] ethyl acrylate (NAPEA) via semi-continuous emulsion polymerization．The influence of NAPEA on the polymerization,the latex properties and molecule weight of copolymer were investigated．The copolymerization of NAPEA with St and BA was preliminary confirmed using thin layer chromatography analysis．Experiments showed that the monomer conversion and the molecular weight of polymer decreased obviously with the increase of the amount of NAPEA,and the electrolyte resistance and mechanical stability of latexes were improved by incorporating NAPEA into polymer chains．
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发布时间：2021-03-19 - 摘要：A novel room-temperature ionic liquid (RTIL),1-allyl,3-methylimidazolium chloride ([AMIM]Cl),was synthesized,characterized and used for dissolving cellulose．The solubility of cellulose in [AMIM] Cl was better than in 1-butyl,3-methylimidazolium ([BMIM]Cl)．The pristine cellulose and two cellulose samples regenerated from [AMIM]Cl and [BMIM] Cl solutions were compared by FTIR,WAXD and TGA measurements．Results show that these two RTILs are non-derivatizing solvents for cellulose．After regeneration from RTIL solutions．the crystalline form of cellulose films is completely transformed from cellulose Ⅰ to cellulose Ⅱ．Compared to pristine cellulose,the regenerated cellulose exhibits a lower onset temperature of thermal decomposition,with a higher char yield．
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发布时间：2021-03-19 - 摘要：Sulfonated polyether ether ketone (SPEEK) with various degree of sulfonation (DS) were synthesized by reaction of PEEK with sulfonic acid as sulfonating agent and solvent．Their proton conductivity and methanol permeability as a function of the degree of sulfonation were investigated．For 46.71％ DS,proton conductivity was 1.68×10-2S／cm at 80℃ and 4.25×10-2S／cm at 100℃,which is closed to or superior to that of NafionοR 115 membrane at the same conditions．Methanol permeability of SPEEK was considerable srualler than that of NafionοR 115 membrane．Because of their high conductivity and low methanol permeability,SPEEK membranes appear to be excellent candidate for use in DMFC applications．
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发布时间：2021-03-19
Research Bulletin
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