最新刊期
卷 ， 期 8 ， 2010
- 摘要：Alternating ethylene-propylene copolymer (alt-EP) was synthesized by hydrogenation of polyisoprene (HCPI) having high cis-1,4 content (ca. 100%),suitable molecular weight (Mn = 41×104),and relatively narrow molecular weight distribution (Mw/Mn= 1.02).The hydrogenation of HCPI was carried out with Ni(naph)2/Al(i-Bu)3 catalyst at 60℃ and hydrogen pressure of 4.0 MPa in cyclohexane for 3 h.NMR and FTIR spectra showed that the characteristic peaks of carbon-carbon double bond disappeared in hydrogenated HCPI,indicating that the hydrogenation degree of the resulting polymer was up to 100%.GPC analysis indicated that the alt-EP maintained relatively narrow molecular weight distribution (Mw/Mn= 1.12),and degradation or crosslinking reaction did not occur during hydrogenation reaction of HCPI.NMR and FTIR spectra as well as WAXD analysis showed that the alt-EP was well-defined ethylene-propylene copolymer having high alternation,and the present completely alternating ethylene and propylene copolymer was synthesized for the first time.Further,the thermal properties of HCPI and alt-EP were examined by TGA and DSC.The glass transition temperature of alt-EP was -63.3℃,whose value is larger than that of HCPI (-66.7℃).The onset temperature of weight loss of alt-EP was 355℃ and much higher than that of HCPI (266℃),which suggesting that the thermal stability is enhanced upon hydrogenation.
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发布时间：2021-03-19
Rapid Communications
- 摘要：A series of sulfonated poly(arylene ether sulfone)/sulfonated polyimide(SPAES/SPI)blend proton exchange membranes were prepared by solution casting method.The SEM results showed that no phase separation was found in the blend membranes，which indicated good miscibility between the two polymers.With the introduction of SPI,the blend membranes showed much higher stability in pure methanol than the corresponding SPAES membrane.The much lower methanol uptake of the blend membranes compared to that of Nafion 112 suggested the lower methanol permeability in the formers.The thermal stability of the blend membranes was similar with their pristine ones,and the desulfonation temperatures were above 290℃.The blend membranes displayed much higher dimensional stability than the corresponding SPAES membrane.After aging at 130℃ for 200 h,the blend membranes maintained good mechanical properties,while the SPAES membrane was dissolved in the water.As a composite of two sulfonated polymers,the blend membranes maintained a high level of ion exchange capacity (IEC) and showed high proton conductivity.They displayed comparable proton conductivity with Nafion 112 at 80% relative humidity (RH)，and higher proton conductivity than that of Nafion 112 in water.
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发布时间：2021-03-19 - 摘要：Various polyamide1010/polypropylene (PA1010/PP) blends were prepared by melt mixing using maleic anhydride-grafted ethylene-octene copolymer (POE-g-MAH) or ethylene-butyl acrylate-glycidyl methacrylate terpolymer (PTW) as compatibilizers.The compatibilizing effects of POE-g-MAH and PTW on PA1010/PP blends obtained via dynamic packing injection molding(DPIM) were investigated by means of scaning electron microscopy (SEM),mechanical testing and differential scaning calorimetry (DSC),respectively.It was found the static specimens compatibilized with PTW had smaller domain size in the same condition,two crystallization peaks of PP appeared in DSC cooling curves,the crystallization at the lower temperature should be assigned to homogeneous nucleation,and the other one was heterogeneous nucleation.The static specimens compatibilized with PTW had better tensile and impact properties than the ones compatibilized with POE\|g\|MAH,indicating a better compatibilization effect of PTW on PA1010/PP.The tensile strength,tensile modulus and notched impact strength of all blends were found to increase largely by means of shearing.The dynamic specimens compatibilized with POE-g-MAH and PTW had almost the same impact strength.But the dynamic molded specimens compatibilized with POE-g-MAH had a remakably decrease of domain size and more uniform dispersion.Thus their impact strength increased more than that of PTW,which indicated that shear stress was more beneficial to the interactions occuring between POE-g-MAH and PA1010/PP.The differences of compatibilization effect between POE-g-MAH and PTW lay in the differences of morphology of materials caused by their chemical compositions.
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发布时间：2021-03-19 - 摘要：Poly(styrene-co-acrylic acid) (PSA)/MgCl2 complex was coated on TiCl3 catalyst (SLC-S catalyst) supported on SiO2 using sol-gel method,and the Ziegler-Natta hybrid catalysts were prepared.The resulting catalysts were characterized by a series of techniques,namely Fourier transform infrared spectroscopy (FTIR),laser scattering particle analyzer and scanning electronic microscopy (SEM).It was found that the hybrid catalysts had a core-shell structure and the thicknesses of membrane of HC-5 (PSA/SLC-S=5 wt%) catalyst and HC-20 (PSA/SLC-S=20 wt%) catalyst were 1.5 and 3 μm,respectively.Three different kinds of catalysts were used for gas phase ethylene polymerization.The effects of thickness of the membrane in hybrid catalysts on the activity and the profile of the polymerization kinetic curves of the catalysts were investigated.The results indicated that the HC-20 catalyst had a good ethylene polymerization activity and its kinetic curve was stable with an inductive period,while HC-5 catalyst demonstrated a fast decay during polymerization and its activity and kinetic curve both resembled the traditional TiCl3 catalyst.Besides,the properties of the polyethylene made by hybrid catalysts under different hydrogen contents were obtained.It is obvious that the thickness of membranes could affect the hydrogen response of the hybrid catalysts and the molecular weight distribution of the resultant polyethylene.
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发布时间：2021-03-19 - 摘要：The crystallization behaviors of incompatible poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)/PS,PHBV/PMMA crystalline/amorphous blends with different ratios and different crystallization temperatures were investigated,with particular emphasis on the effect of amorphous components,such as PS or PMMA,on the morphology of PHBV ring-banded spherulites.PHBV ring-banded spherulites with slightly fuzzy bands were obtained when the content of PHBV in blends was 75%,which was similar to pure PHBV.Petal shaped spherulites were obtained at the crystallization temperature slightly lower than Tg of amorphous components when the content of PHBV in blends was 50%.When the content of PHBV in blends was 25%,irregular crystal morphologies were obtained in PHBV/PS blends,whereas no crystal was observed under POM in PHBV/PMMA blends.In the incompatible blends,the dispersion state and blends ratio of amorphous content had the decisive effect on the formation of PHBV ring-banded spherulites:ring-banded spherulites developed only at low crystallization temperatures when amorphous component content was high,and ring-banded spherulites generated at a wide range of crystallization temperature when amorphous component content was low,whereas the effect of amorphous content on the growth of lamellae at the front of spherulites was the main cause of the formation of petal shaped spherulites.
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发布时间：2021-03-19 - 摘要：Polyvinylidene fluoride membranes grafted with sulfonated poly(styrene-co-acrylic acid)(PVDF-g-P(SSA-co-AA))were prepared by a solution-grafting technique.In the technique,benzoylperoxide (BPO)was used as an evocating agent,and polystyrene and acrylic acid were grafted onto PVDF membranes modified with plain sodium silicate(Na4SiO4),then,the product was sulfonated to obtain PVDF-g-P(SSA-co-AA)membranes.The effects for the different ratio of styrene and acrylic acid on the grafting degree,and their humidity on the conductivity of membrane and the moisture content,were investigated.Fourier transform infrared spectroscopy (FTIR)was used to characterize the change of the membrane’s microstructures before and after the grafting and the sulphonation.The morphologies of the PVDF and the PVDF-g-P(SSA-co-AA)membranes and the distribution of silicon were studied by scanning electrolytic microscope (SEM).The results indicated that the conductivity of PVDF-g-P(SSA-co-AA)membrane doped with 10 wt% Na4SiO4 was 0.0198 S.cm-1 at a relative humidity range of 20%～80%,and the microstructures of PVDF membrane modified with plain sodium silicate (Na4SiO4)after the grafting and the sulphonation changed obviously,which indicated that the sulphonation had permeated into the membrane besides the membrane surface.
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发布时间：2021-03-19 - 摘要：Polyamide 6(PA6)powder with high relative viscosity of 22.47 was prepared via anionic slurry polymerization,and then different PA6 gels were gained by dissolving PA6 powder in formic acid using calcium chloride (CaCl2)as complex agent.X-ray photoelectron spectroscopy(XPS)was used to characterize the bonding energy of inside electrons of pure PA6,CaCl2 and PA6/CaCl2 complexes,and Fourier transform infrared spectroscopy (FTIR)was performed to analyze the changes of the wave number of NH,amide Ⅰ and amide Ⅱ related to hydrogen bond in PA6/CaCl2 complexes.Based on the experiment results,a complexation mechanism was proposed to explain the reaction between amide group and CaCl2.Calcium cations coordinated with the oxygen atom of carbonyl group,which weakened the hydrogen bonding between the molecular chains of PA6 and released the free N—H group,so the N—H group coordinated with chloride anions to form the hydrogen bonding.There was no complexation between calcium cations and the nitrogen atom as the mole ratio of calcium chloride to the unit of amide group in PA6 was 0.2.The coordination number between CaCl2 and the amide groups was predicted to be four or six by conductivity measurements.
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发布时间：2021-03-19 - 摘要：Sodium sulfonate terminated polystyrene(PS-SO3Na) was synthesized by atom transfer radical polymerization of styrene with 2′-(p-sulfophenyl)ethyl 2-bromoisobutyrate ao initiator, and the resulting polymer reacted with NaOH. The initiator was lyntheaized from 2-phenylethanol and 2-bromoisobutyryl bromide. Polymer brushes constructed on the surface of cationically functionalized SiO2(SiO2-CBAFS) were prepared via electrostatic-assembly between PS-SO3Na and SiO2-CBAFS.IR,1H-NMR,TG,TEM,AFM,GPC and water contact angle were used to characterize the structure,the assembly amount and the regularity of the assembly system.The results show that PS-SO3Na can be synthesized with 2′-(p-sulfophenyl)ethyl 2-bromoisobutyrate successfully,the assembly efficiency is increased in some extent with the polymer terminated 100% sodium sulfonate,and the amount of polymer brushes assembled on the surface of SiO2 is as high as 34.4%;white layers can be observed at the surface of SiO2 colloid particles with TEM,and the dispersion of SiO2 is modified obviously; the descent of water contact angles of the samples below 4° when the rinsed solvents altered from THF to H2O; the decorate effect of SiO2 is preferable when the molecular weight of PS-SO3Na range from 1.5×104 to 3.6×104 and the molar concentration of polymer solutions range from 2.5×10-5 mol/L to 5×10-5 mol/L with the analysis of the results of TG,AFM and water contact angles.
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发布时间：2021-03-19 - 摘要：The curing processes of bisphenol A epoxy resin E51/4,4′-diaminodiphenyl sulfone (DDS) and multi-functional epoxy resin AG80/DDS were studied using dynamic and isothermal model free kinetics (MFK) of Vyazovkin integral method based on DSC measurements.The MFK method from dynamic DSC data and the advanced MFK (AMFK) from isothermal DSC data were adopted to predict the evolution of curing degree and the relationship between activation energy and curing degree.Moreover,the curing reactions under dynamic and isothermal conditions were compared by the change of glass transition temperature and the experimental results of in situ infrared measuring method.The results show that comparing to traditional fitting model method,MFK is more suitable to predict quantitatively the curing process of epoxy resin and can provide important evidences for the study on the change of curing mechanism during curing reaction.Moreover,AMFK based on isothermal condition can predict the isothermal curing courses of two resin systems with higher accuracy.The relationships between reaction activation energy and the extent of cure obtained from dynamic and isothermal MFK are different,demonstrating that the curing mechanisms of two epoxy systems under different temperature conditions distinct.These results agree well with the vitrification effect and the evolution of epoxy group conversion under dynamic and isothermal conditions.
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发布时间：2021-03-19 - 摘要：A novel series of organic-inorganic hybrid hydrogels based on (N-isopropylacrylamide) (NIPAM) and octavinyl polyhedral oligomeric silsesquioxane (OVPOSS) (P(OVPOSS-co-NIPAM)) were synthesized by solution free radical polymerization.The products were characterized by FTIR,SEM,XRD,DSC,TGA and DMA methods.The results showed that OVPOSS could be introduced into PNIPAM matrix successfully by free radical polymerization.The actual POSS content in the hybrid hydrogel could be controlled by changing the feed ratio and increased from 2.3 wt% to 12.0 wt% with increasing the feed ratio from 5.0 wt% to 16.0 wt%.Typical hole structures of hydrogels were also observed in P(OVPOSS-co-NIPAM) hybrid hydrogels and the size of the holes decreased with increasing POSS content.Aggregation phenomenon of OVPOSS was observed in 12-P(OVPOSS-co-NIPAM) and 16-P(OVPOSS-co-NIPAM) hybrid hydrogels.All the synthesized hybrid hydrogels showed thermosensitive property.The lower critical solution temperatures (LCST) of P(OVPOSS-co-NIPAM) hybrid hydrogels were lower than those of the conventional PNIPAM hydrogel and decreased gradually from 33.0℃ to 30.0℃ with the increase of POSS content.The introduction of the OVPOSS increased the glass transition temperature (Tg) of PNIPAM from 142.0℃ to 148.0℃.The thermal stability of PNIPAM was improved and the thermal decomposition temperatures (Tdec) of PNIPAM increased from 385.0℃ to 391.3℃,which are higher than that of the conventional hydrogel.The mechanical property of PNIPAM was also improved and the strain of P(OVPOSS-co-NIPAM) hybrid hydrogels under the same stress decreased with increasing POSS content.
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发布时间：2021-03-19 - 摘要：The in situ crystallization kinetics of syndiotactic 1,2-polybutadiene (s-PB) from melt has been investigated by synchrotron radiation small-angle X-ray scattering (SR-SAXS) and wide-angle X-ray diffraction(WAXD).The structure evolutions during the isothermal crystallization of s-PB crystallized at different temperatures have been observed.The results obtained from the scattering peaks in the SR-SAXS curves indicated the development of crystalline structure parameters including long period and lamellar thickness in the isothermal process.The calculated detail information about structure parameters according to the one dimensional electron intensity correction function showed that the long period decreased gradually along with time because the thickness of amorphous layers reduced significantly as the lamellar thickness remained unchanged.The final structures of s-PB about the lamellar thickness and the crystallite size were obtained from SAXS and WAXD,respectively.The line widths were measured for s-PB by WAXD for the selected L110 refection to determine the crystallite size according to Scherrer equation.The lamellar thickness and semi-crystallite size were directly proportional to 1/T∞c-T,which can be explained by the mesomorphic phase theory on polymer crystallization.
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发布时间：2021-03-19 - 摘要：A new monomer 2-β-pinenyloxy-5-vinylbenzaldehyde (POVB) containing both formyl and β-Pinene functional groups,was designed and prepared readily by the reaction of β-pinenyl-4-methylbenzensulfonate with 2-hydroxy-5-vinylbenzaldehyde,and its structure was confirmed via elemental analysis,MS and NMR spectroscopy.The conventional radical polymerization of the new monomer POVB was investigated with AIBN in THF at 60℃,and the polymer with high molecular weight (Mn = 132100,Mw/Mn = 2.20,measured by GPC) was obtained at 68% conversion in 24 h,indicating the new monomer exhibited good polymerization activity.The thermal properties of the polymer were studied using TGA and DSC.The polymer exhibited good thermal stability until 320℃,and had a relatively high glass transition temperature (Tg) at 130.6℃ due to its bulky substituents.Furthermore,the “living”/controlled radical polymerization of POVB was successfully achieved using 2,2′-azobis(isobutyronitrile) as the initiator and 1-phenylethyl phenyldithioacetate (PEPDA) as the reversible addition-fragmentation chain transfer (RAFT) agent at 60℃ in tetrahydrofuran.Compared with 1-phenylethyl dithiobenzoate (PEDB),a much smaller retardation was observed using PEPDA as a RAFT agent.The polymerization followed first-order kinetics,the number-average molecular weight of the obtained polymers increased in direct proportion to the monomer conversion,and the molecular weight distribution was narrow (polydispersity index 1.2).The chain and terminal structures of the obtained poly(POVB) were confirmed with the 1H-NMR analysis.Moreover,the circular dichroism (CD) spectra of the resulting polymers in THF solutions confirmed that poly(POVB)s were optically active.
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发布时间：2021-03-19 - 摘要：Arachidic acid/poly(3,4-ethylenedioxythiophene) (AA/PEDOT) multilayer films were prepared by modification of AA multilayer Langmuir-Blodget (LB) films.3,4-Ethylenedioxythiophene (EDOT) monomers were introduced into the AA multilayer films and polymerized to form PEDOT layers between the AA layers.Ultraviolet visible spectroscopy (UV-Vis),Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses evidenced the EDOT polymerization in the AA film templates.Analyses of X-ray diffraction and secondary-ion mass-spectroscopy indicated that the final films had a well-arranged lamella structure,and obvious interfaces between the AA and PEDOT layers were detected.Further research showed that the polymerization of EDOT destroyed the orderliness of the original AA multilayer LB film.The four-point probe method and semiconductor testing instruments were used to study the conductivity of the films.It was found that in the process of EDOT polymerization the conductivity of the films exhibited a sudden increase.It was explained as a percolation phenomenon,the sudden increase of conductivity should be related with the formation of an effective conductive network within the AA/PEDOT multilayer films.
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发布时间：2021-03-19
Research Article
- 摘要：Atomic force microscopy (AFM) was chosen to investigate the electrostatic adsorption of PS nanospheres on carboxymethylated chitosan (CM-CHI) self assembled monolayer,and the effect of the morphology of CM\|CHI self assembled monolayer on the adsorption of PS nanospheres.The concentration of electrolyte,adsorption time and temperature of the process of PS adsorption were especially concerned in the adsorption kinetics study.For the CM-CMI self assembled monolayer prepared under the same condition,the respective electrolyte concentration for maximal coverage rate (Rc),48.0% at 20℃ is 0.5 mol/L,and the time for equilibrium adsorption is 20 min.The effect of the morphology of CM-CHI self assembled monolayers on the Rc was represented by the rapid increase of Rc with the rise of adsorption temperature.The reason of this phenomenon was discussed thoroughly in this paper.The drying process of carboxymethylated chitosan self assembled monolayer and the washing process of PS nanosphere adsorption were also discussed to investigate their contribution to the Rc.
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发布时间：2021-03-19 - 摘要：A novel method for grafting polymer onto the surface of nano-SiO2 particles via the esterification reaction at room temperature,atmosphere,etc.was developed and organic/inorganic composite nano-particles were prepared.The method was carried out via two steps.First,the nano-SiO2 was modified with 3-glycidoxypropyl trimethoxysilane,and then the introduced epoxy groups at the surface of the nano-SiO2 particles were converted into alkyl-hydroxyl groups.Secondly,the polymer was grafted onto the nano-SiO2 surface via the esterification reaction between the alkyl-hydroxyl groups and the carboxyl groups at the polymer terminal at room temperature.The modification of the nano-SiO2 and the resulting composite particles were characterized by XPS,FTIR,TEM and TGA.Results showed that the method has higher grafting efficiency,and the grafted polymer accounted for 55 wt%~70 wt% of the total composite particles.As a result,the particle size increased from 40 nm to 64~75 nm upon the polymer grafting.Consequently,the core-shell composite particles with polymer chains on the outside and SiO2 in the core were obtained.
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发布时间：2021-03-19
Research Bulletin
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