最新刊期
卷 ， 期 9 ， 2010
- 摘要：A kind of self-organized hybrid material—3-（ureidophenol)propyltriethoxysilane was obtained from 3-isocyanatopropyltriethoxysilane and aminophenol with chloroform as solvent.The structure and the morphology of the materials were characterized by FTIR,DSC,and XRD methods.The ion channel membrane was obtained by two ways,one of them is to prepare membranes by coating the sol onto commercial ultrafiltration planar polyacrylonitrile supports,and the second is to prepare blend membranes by casting on glass sheets the solution of the hybrid material and polyacrylonitrile (PAN).The chemical structure and surface morphology of the membranes were characterized by ATR-FTIR and SEM separately.The ion transport property of the membrane was tested by our self-made device.The results showed that the surface of ion channel membranes was dense and the dense layer was about 8~10 μm thick for membranes prepared by both methods.There is obvious difference in the transport rate of ions for the two kinds of membranes.The transport rate of the membrane made by blending method is lower than that by coating method.The transport mechanism of these ion channel membranes was explained by molecular self-organization through the hydrogen bonding action.What’s more,the ion channel membranes possess the function of recognizing and transporting sodium ions.
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发布时间：2021-03-19 - 摘要：The method of reconstruction histograms of glass transition temperature from differential scanning calorimetry (DSC) thermograms proposed by Fevotte was improved,and the temperature related with half rubbery content Tghr was defined as an new parameter for glass transition.The rubbery fraction was obtained by deduction of the heat flow caused by retardant enthalpy recovery from the recorded DSC heat flow.The revisit of the glass transition behavior of polystyrene (PS) by using the modified Fevotte method was described in this paper.It was found that Tghr of PS is about 4 K higher than that obtained by using the widely used half specific heat capacity (Cp) extrapolated method.The reproducibility of Tg acquired by the modified Fevotte method was improved compared with that using the methods provided by the general commercial software.When the effect of annealing time and cooling rate on glass-rubber transition behavior of PS was investigated,the modified Fevotte method shows its superiority.It was found that Tghr of PS increases monotonously with increasing annealing time and decreasing cooling rate.Polymer with different thermal history usually shows different Tg.Tghr of PS was predicted to be in the range of 377.5 K to 390.9 K depending on physical aging extent.Also it is indicated that the physical aging mode has little effect on polymer Tg.
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发布时间：2021-03-19 -
INFLUENCE OF SILICA NANOPARTICLES ON THE COARSENING OF CO-CONTINUOUS PMMA/PS BLENDS DURING ANNEALING
摘要：The influence of hydrophilic SiO2 nanoparticles on the stability of co-continuous structure in poly(methyl methacrylate)/polystyrene (PMMA/PS) blends under quiescent melt annealing was investigated.It was found that the filled blends displayed broader co-continuous interval and less coarsened structure than those of unfilled blends after annealing.The result indicated that the morphological stability of co-continuous blends can be improved effectively by the addition of SiO2 nanoparticles.Rheological measurements showed that the viscosity and elasticity of filled PMMA/PS blends,which were associated with the destruction process of the co-continuous structure such as breakup or retraction,were enhanced significantly.The influence of the change in the viscoelasticity and interfacial tension of blends upon the addition of SiO2 nanoparticle was analyzed qualitatively based on two available theories describing the coarsening process of the co-continuous structure of polymer blends.It was proposed that the change in the viscoelastic properties of PMMA/PS blends instead of the interfacial tension plays a dominant role in the coarsening rate of the co-continuous structure during the quiescent annealing in melt state.- 26
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发布时间：2021-03-19 - 摘要：Spinel Co0.5Zn0.5Fe2O4 ferrite was synthesized by polyacrylamide gel method with acrylamide as monomer and N,N′-methylenediacrylamide as lattice agent.Polyaniline(PANI) and PANI/Co0.5Zn0.5Fe2O4 nanocomposites were prapared by in situ polymerization in aqueous solution.The nanocomposites were characterized using Fourier transform infrared spectrometer (FIIR),Ultraviolet-Visible spectrometer (UV-Vis),X-ray diffraction (XRD) and Transmission electron microscope (TEM).The results of FIIR and XRD confirmed the formation of PANI and PANI/Co0.5Zn0.5Fe2O4 nanocomposites.The UV\|Vis spectrometer study showed that the absorption peaks of PANI/Co0.5Zn0.5Fe2O4 composite had a red shift of 23 and 5 nm,respectively,as compared with those of PANI.The average particle sizes of PANI and PAN1/Co0.5Zn0.5Fe2O4 were estimated to be about 70 and 90 nm by TEM,respectively.The complex permittivity (ε′-jε″) and the complex permeability (u′-ju″) of the nanocomposites were measured in X\|band (8.2~12.4 GHz).The results showed that PANI/Co0.5Zn0.5Fe2O4 had both electric loss (ε″) and magnetic loss (u″).The ε″ values of PANI/Co0.5Zn0.5Fe2O4 were from 9.2 to 12.3,and the u″ values of PANI/Co0.5Zn0.5Fe2O4 were from 0.15 to 0.16 within 8.2~12.4 GHz.The ε″ values of PANI/Co0.5Zn0.5Fe2O4 were lower than that of pure PANI,whereas the u″ values of PANI/Co0.5Zn0.5Fe2O4 were higher than that of pure PANI.
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发布时间：2021-03-19 - 摘要：Dynamic Monte Carlo simulations are performed for polymer chains confined between two parallel plates.The configurational entropy S of the polymer chain is calculated by using the scanning method,and the influence of the distance D between the two parallel plates and chain length n on the entropy is studied.The dependence of entropy reduction (S0-S) on D verifies the scaling results of de Gennes.Moreover,our results give the regime of the scaling results.When D is very small,the polymer chains are confined markedly,and S0-S is proportional to the polymer chain length.The latter indicates that the average repulsive force of the two plates exerting on one segment tends to be independent of the chain length.With the increase of D,the influence of the two parallel plates on the entropy becomes weaker and weaker,and the average repulsive force exerting on one segment increases with the chain length.At large D,the influence of the plates on the entropy can be ignored,and the configurational entropy becomes the same as that in the free space.
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发布时间：2021-03-19 - 摘要：Powdery coating particles mingled polymethyl methacrylate (PMMA) and calcium carbonate inorganic pigment were obtained under water-free conditions in supercritical carbon dioxide (sc-CO2).The formation was confirmed by FTIR and GPC method.The effects of monomer,initiator,stabilizer concentration and the reaction temperature and time on the polymerization conversion rate and molecular weight of the polymer were discussed and the experimental results indicated that the molecular weight and the molecular weight distribution of the PMMA could be controlled within a suitable range when the reaction pressure was 10 MPa,reaction temperature was 75℃,reaction time was 8 h,monomer concentration was 0.10 g/mL,initiator concentration was 0.10×10-2 g/mL and stabilizer concentration was 0.06×10-2 g/mL.From SEM observation,it was found that the pigment granules were able to evenly disperse and embedded in the PMMA matrix and didn’t show conglomeration.
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发布时间：2021-03-19 - 摘要：Electrospun poly(ε-caprolactone) (PCL)/polypyrrole (PPy) membranes were prepared by in situ polymerization of pyrrole (Py) via oxidization with ferric chloride from PCL/chloroform solutions containing Py.Sodium dodecyl sulfate was also added in the electrospinning solution for doping PPy.The composition of the obtained PCL/PPy membranes was verified by Fourier transform infrared spectroscopy,and the fiber morphology was observed under a scanning electron microscope and a transmission electron microscope.Tensile mechanical properties and the volume resistivity of the PCL/PPy membranes were also tested.Results exhibited that the prepared PPy nanoparticles were attached on the electrospun fiber surface.The fiber diameter decreased gradually from (730±341) nm to (325±84) nm and showed narrower distribution with increasing the Py amount (mass percentage with respect to PCL) from 0 to 20%.The tensile modulus and tensile strength gave rise to an increase tendency,and their values increased from (25.7±0.8) MPa and (2.48±0.14) MPa of the PCL membrane to (48.4±7.6) MPa and (5.05±0.59) MPa of the PCL/PPy membrane with 20% Py,respectively.The elongation at break declined from (129±27)% to (86.2±9.1)% and the volume resistivity reduced by 2~3 orders.The electrospun PCL/PPy fibrous membranes would be possibly applied as electroactive materials in biomedical or functional area.
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发布时间：2021-03-19 - 摘要：A new nematic liquid crystalline copolysiloxane (LCP-H4) was prepared by graft polymerization,and a series of PP blends containing different mass fraction of LCP-H4 with propyloxy spacers were obtained by blending PP and LCP-H4 at a proper process program.The crystallization structure,morphology and thermal properties of PP with LCP-H4 as a nucleator were characterized with wide angle X-ray diffraction (WAXD),polarizing optical microscopy (POM) and differential scanning calorimetry (DSC).The experimental results showed that LCP-H4 with mesomorphism in the PP could supply many crystal nucleuses and active spots,play a role in the heterogeneous nucleation effect,efficiently enhance the crystallization velocity,temperature and degree of crystallinity,moreover,the spherulites became smaller and more homogeneous.The nucleated PP showed different crystallization structure,morphology,and thermodynamics and kinetics.β-phase in the PP was induced,the maximal relative content of β-form (Kβ) was 54% when the mass fraction of LCP-H4 was 0.9%,and the crystalline temperature and time were 128℃ and 1 h,respectively.In addition,the birefringence of β spherulites is stronger than that of α spherulites,this difference is related to their particular growth way and lamellar morphology.The trigonal β spherulite with the sheaflike grain growth is bright and colorful compared with the black and white monoclinic α one with the cross-hatched radial grain growth.Moreover,the molecular arrangement of β crystal is looser than that of α crystal. The melting point of α- and β-crystal was about 153oC and 166oC,respectively.
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发布时间：2021-03-19 - 摘要：The compatibility between m-LLDPE and two sorts of HDPE with different molecular weights in the melt state was investigated with rheological methods,nonisothermal and isothermal crystallization dynamics.The rheological measurements suggested that HDPE and m-LLDPE blends were heterogeneous systems at 190℃ based on the relationship of lgG′ and lgω in the low ω region that deviated the linear model.The DSC results showed that with an increase in the content of m-LLDPE,the melting peak of HDPE shifted to lower temperature,suggesting that HDPE and m-LLDPE may be partially compatible.When the blends were cooled from the melt to temperatures where HDPE could crystallize,but the m-LLDPE couldn’t,the Avrami exponent n of high-Mw HDPE increased slightly compared to that of pure HDPE,and the content of m-LLDPE had little effect on the vales of n.Meanwhile,the crystallization half-time (or crystallization rate) of high-Mw HDPE was very similar to that of pure HDPE.However,the Avrami exponent and the crystallization rate of the low-Mw HDPE decreased with an increase in the content of m-LLDPE,indicating that the m-LLDPE retarded crystallization of HDPE,possibly due to the reasons including the dilution of HDPE by m-LLDPE (m-LLDPE as a solvent in molten state),hindrance of viscous m-LLDPE to the HDPE crystallization front,and decreased supercooling degree because of the compatibility between the m-LLDPE and low-Mw HDPE.This provided further evidence that the compatibility of the low-Mw HDPE with m-LLDPE was better than that with the high-Mw HDPE.
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发布时间：2021-03-19 - 摘要：A chemically modified soy protein gel was prepared by first preheating and then acylating the soy protein with ethylenediaminetetraacetic dianhydride (EDTAD),followed by crosslinking with glutaraldehyde.The variation of molecular structure of modified soy protein and the variation of swelling ratio of gels were investigated; moreover,the swelling behavior of modified soy protein gels at different mEDTAD:mSPI and different pH was analyzed by treating the swelling data with mathematical method.The results showed that the free amimo groups of soy protein side chain reacted with EDTAD,which incorporated carboxyl groups into soy protein molecule chain; the ratio of the amount of added carboxyl group and lost amino group was about 3∶1 in soy protein molecules.The swelling ratio of soy protein-based gels was 24.2,54.07,87.27 and 95.87 when mEDTAD:mSPI was 0,0.05,0.1 and 0.2,respectively,which showed that increasing the amount of EDTAD incoporating into the protein molecular chain resulted in the increasing of swelling ratio of gels.The swelling characteristic exponent (n) of the above gels was about 0.5,which meant that the protein-based gels appeared Fickian’s diffusion behavior in water,the same behavior appeared to the modified soy protein gels at pH 10.04; but at pH 4.30 and pH 6.08,the range of n was 0.5 n 1,which meant a non-Fickian’s diffusion behavior.The mechanism of swelling behavior of gels was discussed.The swelling ratio of gels appeared pH-sensitivity,the “W”— shaped curve of swelling — deswelling process appeared,which meant the function of “shape memory” of gels.
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发布时间：2021-03-19 - 摘要：A new crosslinker for polyurethane,DDP (N-［(1,1-dimethyl-2-acetyl)ethyl］-β-dihydroxyethylamino propanamide),was synthesized by Michael reaction between diethanolamine (DEA) and diacetone acrylamide (DAAM).Self-crosslinkable aqueous polyurethane emulsion containing active keto groups was obtained using isophorone isocyanate (IPDI),poly(tetramethylene oxide) (PTMG1000),dimethylol propionic acid (DMPA) and trimethylol propane (TMP) as main materials,both dihydroxyketon N-［(1,1-dimethyl-2-acetyl)ethyl］-β-dihydroxyethylamino propanamide (DDP) and 1,4-butanediol (BDO) as chain expanders,γ-aminopropyltriethoxysilane (KH550) as end capping agent and then adipic acid dihydrazide (ADH) was added into the emulsion.The structures of the crosslinker DDP and films were characterized by ATR-FTIR and NMR.The tests results confirm the formation and reaction of DDP.The result of ATR-FTIR also shows that the crosslinking reaction between ketone group and the hydrazine group has happened during the film curing.The effects of n(—NHNH2)/n(—CO—),n(NCO)/n(OH) and DDP content on the properties of the films were studied.The results show that,water absorption of polyurethane films without adipic dihydrazide(ADH) increases with the increase of DDP content; it is difficult to emulsify polyurethane polymer and the stability of the emulsion is deteriorated significantly in the case of n(NCO)/n(OH)﹥1.40.Under the optimal ratios (n(—NHNH2)/n(—CO—) = 1,n(NCO)/n(OH) = 1.40),when DDP content increases from 0% to 7.22%,water absorption of the films decreases from 39.36% to 18.92% also with higher performance in solvent resistance,crosslinking degree increases from 51.49% to 90.23%,tensile strength increases from 20.09 MPa to 28.26 MPa,pencil hardness is 2H.Thermogravimetic analysis (TGA) indicates that the Ketone-Hydrazide crosslinking structure can improve thermal stability of the films.
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发布时间：2021-03-19 - 摘要：A novel catalytic hydrogenation method of dechlorination for P(VDF-co-CTFE)s to convert CTFE units into TrFE units through CuCl/2,2′-bipyridine catalyzed atom transfer radical reaction and chain transfer reaction was reported in this work.In this method,the Cl atom in VDF/CTFE copolymer has been first removed by CuCl/2,2′-bipyridine complex via reductive reaction,and P(VDF-co-CTFE) macromolecule free radicals has been generated.In the presence of chain transfer agent,the free radicals would grab an H atom and the polymer radical is terminated.As a result,Cl atom has been exchanged with H atom,and P(VDF-co-CTFE) is transferred into P(VDF-co-TrFE-co-CTFE) or P(VDF-co-TrFE) as desired.The effect of solvent,reaction temperature,reaction time and catalyst dosage on the hydrogenation of P(VDF-co-CTFE) has been well discussed.It has shown that a certain reaction temperature is required to activate the reaction,and high temperature favors the reaction rate.As reaction time prolongs,the hydrogenation ratio of CTFE units increases until they are fully converted or either the catalysts or the chain transfer agents run out.The amount of TrFE units could be exactly controlled by introducing the catalyst in desired dosage since one initiator molecule is only able to hydrogenate one CTFE molecule.The rather close limiting viscosity number of P(VDF-co-CTFE) and the resultant P(VDF-co-TrFE-co-CTFE) means that no decomposition or coupling reaction happens in the process.Generally,the new method possesses advantages such as lower cost,lower toxic,higher convenience and higher controllability compared with the previous method.
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发布时间：2021-03-19 - 摘要：The effects of isothermal crystallization temperature (Tc) and crystallization time on the lamellar morphology of poly(ε-caprolactone) were investigated by using simultaneous measurement of wide-angle/small-angle X-ray scattering (SAXS/WAXS) and one-dimensional correlation function (1DCF) analysis.On the basis of the weight fraction of crystallinity obtained from WAXS result,we calculated the volume fraction crystallinity ［Vc(WAXS)］ of PCL, which was slightly larger than 50%.The 1DCF analysis of SAXS profiles gave the long period (LP) and thickness of the amorphous region (La).Comparing the data deduced from the WAXS and SAXS experimental result,we considered that the “three-phase” model is preferable to the “two-phase” model for the PCL crystal. The calculated thickness of the transition zone between the crystalline and amorphous region (E) was of 15%~18% of the LP,showing great influence to the lamellar morphology.With increasing Tc,the values of Lc increased faster than that of La and E,leading to the increase of crystallinity.During isothermal crystallization at 50℃,the Lc of PCL was increased with increasing isothermal time,whereas the La and E were decreased accordingly.After isothermal crystallization at 50℃ for 10 days,the PCL sample with Vc(WAXS) of 61% gave a SAXS profile with the multiple scattering peaks up to the fifth order,indicating that the lamellar structure was rather perfect.
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发布时间：2021-03-19 - 摘要：Multiwalled carbon nanotubes (MWCNTs)/carbon black (CB) mixed filler filled polyoxymethylene (POM) composites were prepared by melt mixing in a rotational rheometer.The relationship between electrical resistivity of the composites and the filler concentration was investigated.The electrical percolation threshold of MWCNTs/CB mixed filler-filled POM is much lower than that of CB-filled POM but higher than MWCNTs-filled POM,because MWCNTs and CB build up the conductive path together.The experimental data were used to examine the existing equation derived from the model of mixed filler systems which was published previously,and the comparison showed that deviation existed for some data points.It is speculated that the conditions for using the model are too ideal,not suitable to practical cases,so deviation is inevitable.In order to facilitate the practical application,the equation was further developed,and a new equation describing the relationship between percolation threshold and the ratio of the two fillers was obtained.A working curve was drawn on the basis of the newly developed equation and examined by the experimented data.The results demonstrate that the working curve can provide a general guidance for practice.This work shows that the existing model of mixed carbon filler systems is useful for predicting the conductive behavior of the composite materials.
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发布时间：2021-03-19
Research Article
- 摘要：Modified PVA films were prepared by casting method using urea/ethanolamine as a mixed plasticizer.The interactions between urea/ethanolamine and PVA molecules were investigated by FTIR spectra.The crystallinity of plasticized PVA film was measured by X-ray diffraction(XRD) method.Tm of modified PVA films was studied by differential scanning calorimetry(DSC).The mechanical properties of modified PVA films were studied by tensile testing.It was found that ethanolamine could prevent urea separating out from PVA and urea/ethanolamine mixture was a good plasticizer for PVA.FTIR spectra show that no significant structure difference between PVA and modified PVA,indicating that no chemical reaction happened between PVA and urea/ethanolamine.The shift of wavenumber shows that urea/ethanolamine can decrease the extent of inter- or intramolecular hydrogen bonds in PVA molecules.The XRD investigations show that the crystalline fraction significantly reduces with the addition of urea/ethanolamine.DSC shows that addition of urea/ethanolamine can reduce the Tm of PVA film.Tm of PVA film with 30 phr urea/ethanolamine can reduce to 199.3℃.Modified PVA films show lower degree of swelling but higher solubility than that of pure PVA film.Urea/ethanolamine mixture can soften the PVA film,resulting in lower tensile strength and higher elongation at break.The tensile strength and elongation at break for PVA film modified with 30 phr urea/ethanolamine were 23.89 MPa and 542.88%,respectively.
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发布时间：2021-03-19 - 摘要：Poly(propylene carbonate) (PPC) with high molecular was synthesized by copolymerization of carbon dioxide (CO2) with propylene oxide (PO) using a supported muti-components zinc glutarate catalyst.The resulting polymers synthesized under different reaction conditions were characterized by 1H-NMR,GPC,DSC and TGA.The effects of reaction time and reaction pressure on the yields and the properties of the polymers were investigated.With reaction time increasing from 20 h to 40 h,the yield of polymer increased from 59.9 to 98.0 g polymer/g catalyst.However,reaction time had little influence on thermal and mechanical properties,as well as molecular weight of the polymers.With the reaction pressure decreasing from 5.2 to 2.6 MPa,the thermal and mechanical properties of the polymer decreased significantly.According to the GPC and NMR results,this phenomenon can be explained by the fact that the molecular weight of polymer decreased,and the content of polyether (PE) unit in the backbone and cycle propylene carbonate (CPC) increased with the reaction pressure decreasing.Polymer with high molecular weight of 237×103,a glass transition temperature of 38℃ and a tensile strength of 31.17 MPa was obtained at the optimal reaction conditions with 5.2 MPa,40 h.
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发布时间：2021-03-19
Research Bulletin
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