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2006 Volume 24 Issue 4
2006, 24(4): 333-339
Abstract:
Anorderedladderpolyester(LPE)wasfirstsynthesizedthroughtheladdersuperstructure(LS)constructedbyconcertedinteractionsofhydroxyl-andaramide-basedH-bondingandp-terphenyl(TP)-basedp-stackingbydehydrochlorinationcondensationusingphosgene(COCl2)ascouplingagent.LPEwascharacterizedbyGPC,FTIR,NMR,XRD,DSCandAFM.Amongthem,adistinctimageofregularlylinearalignmentcorrespondingtotheladdermainchainofLPEwasfirstrevealedbyhigh-resolutionAFM.
Anorderedladderpolyester(LPE)wasfirstsynthesizedthroughtheladdersuperstructure(LS)constructedbyconcertedinteractionsofhydroxyl-andaramide-basedH-bondingandp-terphenyl(TP)-basedp-stackingbydehydrochlorinationcondensationusingphosgene(COCl2)ascouplingagent.LPEwascharacterizedbyGPC,FTIR,NMR,XRD,DSCandAFM.Amongthem,adistinctimageofregularlylinearalignmentcorrespondingtotheladdermainchainofLPEwasfirstrevealedbyhigh-resolutionAFM.
2006, 24(4): 341-344
Abstract:
Thin film morphology of a symmetric semicrystalline oxyethylene/oxybutylene diblock copolymer (E76B38) on silicon was investigated by tapping mode atomic force microscopy (AFM). It is found that the nascent thin film is composed of multiple polymer layers having mixed thicknesses of L ? L0 and L ? L0/2 (L0 is the long period of the block copolymer in bulk) besides the first layer near the substrate. This shows that the crystalline domain in the block copolymer consists of double poly(oxyethylene) layers. Annealing leads to disappearance of the polymer layers with thickness L ? L0/2, indicating that such polymer layers are metastable.
Thin film morphology of a symmetric semicrystalline oxyethylene/oxybutylene diblock copolymer (E76B38) on silicon was investigated by tapping mode atomic force microscopy (AFM). It is found that the nascent thin film is composed of multiple polymer layers having mixed thicknesses of L ? L0 and L ? L0/2 (L0 is the long period of the block copolymer in bulk) besides the first layer near the substrate. This shows that the crystalline domain in the block copolymer consists of double poly(oxyethylene) layers. Annealing leads to disappearance of the polymer layers with thickness L ? L0/2, indicating that such polymer layers are metastable.
2006, 24(4): 345-351
Abstract:
The effect of N,N,N,N-tetraalkyl terephthalamide (TATA) on the non-isothermal crystallization and melting characteristics of polypropylene (PP) was studied. The addition of TATA can lead to the formation of b-crystal PP. With the increase in TATA concentration the degree of crystallinity for b-crystal PP increased significantly, and that for a-crystal PP decreased, which indicated that TATA effectively induced the formation of b-crystal PP. WAXD also revealed the existence of b-crystal?PP after the introduction of TATA into PP. PP containing TATA crystallized at a temperature range of 5-10℃ higher than that of pure PP, and the half-crystallization time (t1/2) and Avrami exponent (n) of PP at the same cooling rate were decreased by the addition of TATA, indicating that TATA influenced the crystallization rate and crystallization growth mode of PP. The rate constant of crystallization of PP containing TATA (Zc) was larger than that of pure PP, which further indicated that the crystallization of PP was accelerated by the addition of TATA
The effect of N,N,N,N-tetraalkyl terephthalamide (TATA) on the non-isothermal crystallization and melting characteristics of polypropylene (PP) was studied. The addition of TATA can lead to the formation of b-crystal PP. With the increase in TATA concentration the degree of crystallinity for b-crystal PP increased significantly, and that for a-crystal PP decreased, which indicated that TATA effectively induced the formation of b-crystal PP. WAXD also revealed the existence of b-crystal?PP after the introduction of TATA into PP. PP containing TATA crystallized at a temperature range of 5-10℃ higher than that of pure PP, and the half-crystallization time (t1/2) and Avrami exponent (n) of PP at the same cooling rate were decreased by the addition of TATA, indicating that TATA influenced the crystallization rate and crystallization growth mode of PP. The rate constant of crystallization of PP containing TATA (Zc) was larger than that of pure PP, which further indicated that the crystallization of PP was accelerated by the addition of TATA
2006, 24(4): 353-361
Abstract:
Novelshish-kebabtypeliquidcrystallinepoly(p-phenylenevinylene)derivativesweresynthesizedbyStillecouplingreactionfrom2,5-bis[(4-n-alkoxyl)benzoyloxy]1,4-dibromobenzene(monomer1)and1,2-bis(tributylstannyl)ethylene(monomer2).Thepolymerswithalkoxygroupsaresolubleincommonorganicsolventsandexhibitbluefluorescence.Boththecastfilmandtheannealedfilmhavelargered-shiftsinfluorescencespectraandshowyellowfluorescence.ThepolymerswithCNandNO2groupsshowpoorsolubilityandgreenfluorescence.Allthepolymerspossessliquidcrystallinesmecticphases.Themeltingpoint(Tm)ofthepolymersdecreaseswhenthelengthofthealkoxytailsofthemesogenicunitsincreases.Thepolymersareeasilyalignedunderamagneticfieldof10Tesla.ItisfoundthattheconjugatedbackboneandLCsidechainarealignedperpendicularandparalleltothemagneticfield,respectively.Thepolymersshowopticaldichroisminfluorescencespectra,suggestingthattheyareavailableforadvancematerialswithlinearopticalpolarization.
Novelshish-kebabtypeliquidcrystallinepoly(p-phenylenevinylene)derivativesweresynthesizedbyStillecouplingreactionfrom2,5-bis[(4-n-alkoxyl)benzoyloxy]1,4-dibromobenzene(monomer1)and1,2-bis(tributylstannyl)ethylene(monomer2).Thepolymerswithalkoxygroupsaresolubleincommonorganicsolventsandexhibitbluefluorescence.Boththecastfilmandtheannealedfilmhavelargered-shiftsinfluorescencespectraandshowyellowfluorescence.ThepolymerswithCNandNO2groupsshowpoorsolubilityandgreenfluorescence.Allthepolymerspossessliquidcrystallinesmecticphases.Themeltingpoint(Tm)ofthepolymersdecreaseswhenthelengthofthealkoxytailsofthemesogenicunitsincreases.Thepolymersareeasilyalignedunderamagneticfieldof10Tesla.ItisfoundthattheconjugatedbackboneandLCsidechainarealignedperpendicularandparalleltothemagneticfield,respectively.Thepolymersshowopticaldichroisminfluorescencespectra,suggestingthattheyareavailableforadvancematerialswithlinearopticalpolarization.
2006, 24(4): 363-368
Abstract:
A series of thermochromic polypropylene foils were prepared by embedding various leuco dye-developer-solvent systems in the polymer matrix. Bisphenol A, laurylgallate, ethylgallate and p-hydroxybenzoic acid methyl ester were used as developers, crystal violet lactone and 3,3-bis-(1-n-butyl-2-methyl-3-indolyl)-phthalide as dyes and 1-octanoic acid methyl ester as solvent. The molar ratio between the three components of the investigated leuco dye-developer-solvent systems was kept constant. All obtained polypropylene foils exhibit an excellent thermochromic behavior. The foils, prepared by extrusion technology, switch from color to colorless with increasing temperature. The influence of molecular structure of the developer on the intensity of the colored state and the influence of a developer-surfactant complex on the resulting thermochromic properties were investigated. The results are presented and discussed in detail according to a molecular model suggesting that the ring-opening process of the leuco dye is triggered by the formation of dye-developer complexes via H-bondings.A series of thermochromic polypropylene foils were prepared by embedding various leuco dye-developer-solvent systems in the polymer matrix. Bisphenol A, laurylgallate, ethylgallate and p-hydroxybenzoic acid methyl ester were used as developers, crystal violet lactone and 3,3-bis-(1-n-butyl-2-methyl-3-indolyl)-phthalide as dyes and 1-octanoic acid methyl ester as solvent. The molar ratio between the three components of the investigated leuco dye-developer-solvent systems was kept constant. All obtained polypropylene foils exhibit an excellent thermochromic behavior. The foils, prepared by extrusion technology, switch from color to colorless with increasing temperature. The influence of molecular structure of the developer on the intensity of the colored state and the influence of a developer-surfactant complex on the resulting thermochromic properties were investigated. The results are presented and discussed in detail according to a molecular model suggesting that the ring-opening process of the leuco dye is triggered by the formation of dye-developer complexes via H-bondings.
A series of thermochromic polypropylene foils were prepared by embedding various leuco dye-developer-solvent systems in the polymer matrix. Bisphenol A, laurylgallate, ethylgallate and p-hydroxybenzoic acid methyl ester were used as developers, crystal violet lactone and 3,3-bis-(1-n-butyl-2-methyl-3-indolyl)-phthalide as dyes and 1-octanoic acid methyl ester as solvent. The molar ratio between the three components of the investigated leuco dye-developer-solvent systems was kept constant. All obtained polypropylene foils exhibit an excellent thermochromic behavior. The foils, prepared by extrusion technology, switch from color to colorless with increasing temperature. The influence of molecular structure of the developer on the intensity of the colored state and the influence of a developer-surfactant complex on the resulting thermochromic properties were investigated. The results are presented and discussed in detail according to a molecular model suggesting that the ring-opening process of the leuco dye is triggered by the formation of dye-developer complexes via H-bondings.A series of thermochromic polypropylene foils were prepared by embedding various leuco dye-developer-solvent systems in the polymer matrix. Bisphenol A, laurylgallate, ethylgallate and p-hydroxybenzoic acid methyl ester were used as developers, crystal violet lactone and 3,3-bis-(1-n-butyl-2-methyl-3-indolyl)-phthalide as dyes and 1-octanoic acid methyl ester as solvent. The molar ratio between the three components of the investigated leuco dye-developer-solvent systems was kept constant. All obtained polypropylene foils exhibit an excellent thermochromic behavior. The foils, prepared by extrusion technology, switch from color to colorless with increasing temperature. The influence of molecular structure of the developer on the intensity of the colored state and the influence of a developer-surfactant complex on the resulting thermochromic properties were investigated. The results are presented and discussed in detail according to a molecular model suggesting that the ring-opening process of the leuco dye is triggered by the formation of dye-developer complexes via H-bondings.
2006, 24(4): 369-377
Abstract:
The intrinsic viscosity [h], Huggins constant (KH), [h]0, a3 and flow activation energy values of nylon 6 have been measured in water/m-cresol (0/100-20/80) systems at different temperatures (20-60℃). It has been found that the intrinsic viscosity, [h]0 and a3? increase with the increase in water contents in m-cresol up to 15% and then decrease. They increase with the increase in temperature irrespective of solvent composition. It has been noted that the percent increase of a3??is the highest at 60℃ and the lowest at 20℃ for a particular solvent system. The intrinsic viscosity data obey Arrhenius equation over the considered conditions. The activation energy and the KH values decrease very sharply with the addition of water, giving a minimum value at 15% of water and then increase slowly. The variation of all the parameters has been explained in terms of variation in thermodynamic quality of solvent with the addition of water to m-cresol and change in temperature, resulting in the change of conformational and orientational properties of polymer molecules. This change of solvent quality also results in variation of selective sorption of solvent over the polymer, such as hydrogen bonding, etc.
The intrinsic viscosity [h], Huggins constant (KH), [h]0, a3 and flow activation energy values of nylon 6 have been measured in water/m-cresol (0/100-20/80) systems at different temperatures (20-60℃). It has been found that the intrinsic viscosity, [h]0 and a3? increase with the increase in water contents in m-cresol up to 15% and then decrease. They increase with the increase in temperature irrespective of solvent composition. It has been noted that the percent increase of a3??is the highest at 60℃ and the lowest at 20℃ for a particular solvent system. The intrinsic viscosity data obey Arrhenius equation over the considered conditions. The activation energy and the KH values decrease very sharply with the addition of water, giving a minimum value at 15% of water and then increase slowly. The variation of all the parameters has been explained in terms of variation in thermodynamic quality of solvent with the addition of water to m-cresol and change in temperature, resulting in the change of conformational and orientational properties of polymer molecules. This change of solvent quality also results in variation of selective sorption of solvent over the polymer, such as hydrogen bonding, etc.
2006, 24(4): 379-387
Abstract:
The effect of compatibility on phase morphology and orientation of isotactic polypropylene (iPP) blends under shear stress was investigated via dynamic packing injection molding (DPIM). The compatibility of iPP blended with other polymers, namely, atactic polypropylene (aPP), octane-ethylene copolymer (POE), ethylene-propylene-diene rubber (EPDM) and poly(ethylene-co-vinyl acetate) (EVA), have first been studied using dynamic mechanical analysis (DMA). These blends were subjected to DPIM, which relies on the application of shear stress fields to the melt/solid interfaces during the packing stage by means of hydraulically actuated pistons. The phase morphology, orientation and mechanical properties of the injection-molded samples were characterized by SEM, 2D WAXS and Instron. For incompatible iPP/EVA blends, a much elongated and deformed EVA particles and a higher degree of iPP chain orientation were observed under the effect of shear. However, for compatible iPP/aPP blends, a less deformed and elongated aPP particles and less oriented iPP chains were deduced. It can be concluded that the compatibility between the components decreases the deformation and orientation in the polymer blends. This is most likely due to the hindering effect, resulting from the molecular entanglement and interaction in the compatible system.
The effect of compatibility on phase morphology and orientation of isotactic polypropylene (iPP) blends under shear stress was investigated via dynamic packing injection molding (DPIM). The compatibility of iPP blended with other polymers, namely, atactic polypropylene (aPP), octane-ethylene copolymer (POE), ethylene-propylene-diene rubber (EPDM) and poly(ethylene-co-vinyl acetate) (EVA), have first been studied using dynamic mechanical analysis (DMA). These blends were subjected to DPIM, which relies on the application of shear stress fields to the melt/solid interfaces during the packing stage by means of hydraulically actuated pistons. The phase morphology, orientation and mechanical properties of the injection-molded samples were characterized by SEM, 2D WAXS and Instron. For incompatible iPP/EVA blends, a much elongated and deformed EVA particles and a higher degree of iPP chain orientation were observed under the effect of shear. However, for compatible iPP/aPP blends, a less deformed and elongated aPP particles and less oriented iPP chains were deduced. It can be concluded that the compatibility between the components decreases the deformation and orientation in the polymer blends. This is most likely due to the hindering effect, resulting from the molecular entanglement and interaction in the compatible system.
2006, 24(4): 389-394
Abstract:
Thebrittle-ductiletransitionisaveryimportantphenomenonforpolymertoughening.Polypropylene(PP)isoftentoughenedbyusingrubbers,e.g.,ethylene-propylenedienemonomer(EPDM)hasoftenbeenusedasamodifier.Inthisarticle,thetougheningofPPbyusinganewkindofrubber,knownaselastomericnano-particle(ENP),andthebrittle-ductiletransitionofPP/EPDM/ENPwasstudied.ComparedtoPP/EPDMbinaryblends,thebrittle-ductiletransitionofPP/EPDM/ENPternaryblendsoccurredatlowerEPDMcontents.SEMexperimentwascarriedouttoinvestigatetheetchedandimpact-fracturedsurfaces.ENPalonehadnoeffectontheimpactstrengthofPP,however,withthesameEPDMcontent,PP/EPDM/ENPternaryblendshadsmallerparticlesize,betterdispersionandsmallerinterparticledistanceincontrarytoPP/EPDMbinaryblends,whichpromotedthebrittle-ductiletransitiontooccurearlier.
Thebrittle-ductiletransitionisaveryimportantphenomenonforpolymertoughening.Polypropylene(PP)isoftentoughenedbyusingrubbers,e.g.,ethylene-propylenedienemonomer(EPDM)hasoftenbeenusedasamodifier.Inthisarticle,thetougheningofPPbyusinganewkindofrubber,knownaselastomericnano-particle(ENP),andthebrittle-ductiletransitionofPP/EPDM/ENPwasstudied.ComparedtoPP/EPDMbinaryblends,thebrittle-ductiletransitionofPP/EPDM/ENPternaryblendsoccurredatlowerEPDMcontents.SEMexperimentwascarriedouttoinvestigatetheetchedandimpact-fracturedsurfaces.ENPalonehadnoeffectontheimpactstrengthofPP,however,withthesameEPDMcontent,PP/EPDM/ENPternaryblendshadsmallerparticlesize,betterdispersionandsmallerinterparticledistanceincontrarytoPP/EPDMbinaryblends,whichpromotedthebrittle-ductiletransitiontooccurearlier.
2006, 24(4): 395-401
Abstract:
The new chelate resins, abbreviated as PNBMZs and PBBMZs based on epoxide polymer, were synthesized by polycondensation of N,N-diglycidyl-4-glycidyloxyaniline or 1,4-bis(2,3-epoxypropyl)benzene with the primary amine group of 1,3-bis(benzimidazol-2yl)propylamine (BBPAH). The ion exchangers contain 2.71?3.23 mmol of the ligand contents per gram of the resin. Batch extraction capacities were determined for the metal chloride salts in buffer solutions in the pH range from ?1 to 6.0. The chelate resins were very selective for Cu2+, Zn2+, Cd2+ in the presence of other divalent transition metal ions. The maximum uptake capacities of PNBMZ (synthetic molar ratio = 1:1.5) under non-competitive condition were found to be 0.94 mmol/g for Cu2+ at pH = 2, 1.3 mmol/g for Cd2+ at pH = 1 and 1.75 mmol/g for Zn2+ at pH = ?1 respectively. While in the case of PBBMZ, it was 1.39 mmol/g for Cd2+ at pH = 1. The metal-uptake behaviors for both of them showed strong pH dependence, and their extraction capacities increase with decreasing pH. The uptake of Cu2+ by the resin PNBMZs at pH = 1 was found to be rather fast with t1/2 = 18 min. Metal-uptake experiments under competitive conditions also confirm that the chelate resins have a high selectivity for Cu2+, Zn2+, Cd2+ and the contrary pH dependence.
The new chelate resins, abbreviated as PNBMZs and PBBMZs based on epoxide polymer, were synthesized by polycondensation of N,N-diglycidyl-4-glycidyloxyaniline or 1,4-bis(2,3-epoxypropyl)benzene with the primary amine group of 1,3-bis(benzimidazol-2yl)propylamine (BBPAH). The ion exchangers contain 2.71?3.23 mmol of the ligand contents per gram of the resin. Batch extraction capacities were determined for the metal chloride salts in buffer solutions in the pH range from ?1 to 6.0. The chelate resins were very selective for Cu2+, Zn2+, Cd2+ in the presence of other divalent transition metal ions. The maximum uptake capacities of PNBMZ (synthetic molar ratio = 1:1.5) under non-competitive condition were found to be 0.94 mmol/g for Cu2+ at pH = 2, 1.3 mmol/g for Cd2+ at pH = 1 and 1.75 mmol/g for Zn2+ at pH = ?1 respectively. While in the case of PBBMZ, it was 1.39 mmol/g for Cd2+ at pH = 1. The metal-uptake behaviors for both of them showed strong pH dependence, and their extraction capacities increase with decreasing pH. The uptake of Cu2+ by the resin PNBMZs at pH = 1 was found to be rather fast with t1/2 = 18 min. Metal-uptake experiments under competitive conditions also confirm that the chelate resins have a high selectivity for Cu2+, Zn2+, Cd2+ and the contrary pH dependence.
2006, 24(4): 403-411
Abstract:
The orientation and crystallinity evolution of isotactic polypropylene (iPP) induced by rolling were studied using wide angle X-ray scattering with an area detector. The tensile mechanical properties of rolled isotactic polypropylene sheets were also measured in this work. The texture component method was used to analyze the rolling texture. The rolling texture consists mainly of (010)[001], (130)[001] and [001]∥RD fiber components in the sample with a rolling true strain of 1.5. The results reveal that crystallinity drastically decreases during rolling. It is suggested that amorphization is a deformation mechanism which takes place as an alternative to crystallographic intralamellar slip depending on the orientation of the lamellae. Both the orientation and crystallinity affect the tensile mechanical properties of rolled polypropylene. Crystallinity influences the elastic modulus on both directions and yield strength on transverse direction at the first stage of deformation. Orientation is the main reason for the changes of mechanical properties, especially at the latter part of deformation. The changes of both tensile strength and elongation percentage on rolling direction are larger than those on transverse direction, which results from the orientation. At last, the anisotropic mechanical properties occur on the rolling and transverse direction: high tensile strength with low elongation percentage on rolling direction and low tensile strength with high elongation percentage on transverse direction.
The orientation and crystallinity evolution of isotactic polypropylene (iPP) induced by rolling were studied using wide angle X-ray scattering with an area detector. The tensile mechanical properties of rolled isotactic polypropylene sheets were also measured in this work. The texture component method was used to analyze the rolling texture. The rolling texture consists mainly of (010)[001], (130)[001] and [001]∥RD fiber components in the sample with a rolling true strain of 1.5. The results reveal that crystallinity drastically decreases during rolling. It is suggested that amorphization is a deformation mechanism which takes place as an alternative to crystallographic intralamellar slip depending on the orientation of the lamellae. Both the orientation and crystallinity affect the tensile mechanical properties of rolled polypropylene. Crystallinity influences the elastic modulus on both directions and yield strength on transverse direction at the first stage of deformation. Orientation is the main reason for the changes of mechanical properties, especially at the latter part of deformation. The changes of both tensile strength and elongation percentage on rolling direction are larger than those on transverse direction, which results from the orientation. At last, the anisotropic mechanical properties occur on the rolling and transverse direction: high tensile strength with low elongation percentage on rolling direction and low tensile strength with high elongation percentage on transverse direction.
2006, 24(4): 413-419
Abstract:
Anovelhyperbranchedpoly(phenyleneoxide)(HPPO)withphenolicterminalgroupswaspreparedfrom4-bromo-4′,4″-dihydroxytriphenylmethaneasAB2monomerindimethylsulfoxide(DMSO)viaamodifiedUllmannreaction.Themolecularweightandpolydispersity(PD)oftheresultingpolymersincreasedwithincreasingreactiontime.Inthepresenceofcoremolecules(bisphenolAand1,3,5-trihydroxybenzene),whichhavethesimilarmolecularbackbonestothereactivemonomer,themolecularweightcouldbecontrolledbyvaryingthecore-to-monomerratio.Incorporationofaverysmallamountofcoremoleculescouldleadtoahighermolecularweightascomparedwiththatwithouttheadditionofcoremolecules.However,whenthecorecontentreachedcertainextent,themolecularweightwoulddecreasewiththefurtherincreaseinthecorecontent.AnewsimilarbehaviorofcontroloverthePDwasalsoobtained.Theresultingpolymerswerecharacterizedby1H-NMR,13C-NMR,FT-IR,andGPC.
Anovelhyperbranchedpoly(phenyleneoxide)(HPPO)withphenolicterminalgroupswaspreparedfrom4-bromo-4′,4″-dihydroxytriphenylmethaneasAB2monomerindimethylsulfoxide(DMSO)viaamodifiedUllmannreaction.Themolecularweightandpolydispersity(PD)oftheresultingpolymersincreasedwithincreasingreactiontime.Inthepresenceofcoremolecules(bisphenolAand1,3,5-trihydroxybenzene),whichhavethesimilarmolecularbackbonestothereactivemonomer,themolecularweightcouldbecontrolledbyvaryingthecore-to-monomerratio.Incorporationofaverysmallamountofcoremoleculescouldleadtoahighermolecularweightascomparedwiththatwithouttheadditionofcoremolecules.However,whenthecorecontentreachedcertainextent,themolecularweightwoulddecreasewiththefurtherincreaseinthecorecontent.AnewsimilarbehaviorofcontroloverthePDwasalsoobtained.Theresultingpolymerswerecharacterizedby1H-NMR,13C-NMR,FT-IR,andGPC.
2006, 24(4): 421-429
Abstract:
Surfacemodificationbyphysicaladsorptionofaseriesofnon-ionicsurfactantsincludingTween20,Tween40,Tween60,Tween80andTween85,wasaccomplishedonpolypropylenemicroporoushollowfiberandflatmembranes.Theadsorptioncurveofthemembranesurfacewasanalyzedbyweightmeasurementsandthetypicalresultsshowedatwo-platformcharactersimilarly.Differencesinthedegreeandcurveshapeofadsorptionresultingfromsuchfactorsasconcentration,temperature,aswellaswatercleaningtimewereobservedforTween85amongotherTweens.Attenuatedtotalreflection—FouriertransforminfraredspectroscopyanalysisandfieldemissionscanningelectronmicroscopyobservationshowedthattheadsorptionofTweenonpolypropylenemicroporousmembrane(PPMM)iseffectiveandoccursmainlyintheporesofPPMMsatlowadsorptionamount,andonthemembranesurfacealsoathighadsorptionvalue.
Surfacemodificationbyphysicaladsorptionofaseriesofnon-ionicsurfactantsincludingTween20,Tween40,Tween60,Tween80andTween85,wasaccomplishedonpolypropylenemicroporoushollowfiberandflatmembranes.Theadsorptioncurveofthemembranesurfacewasanalyzedbyweightmeasurementsandthetypicalresultsshowedatwo-platformcharactersimilarly.Differencesinthedegreeandcurveshapeofadsorptionresultingfromsuchfactorsasconcentration,temperature,aswellaswatercleaningtimewereobservedforTween85amongotherTweens.Attenuatedtotalreflection—FouriertransforminfraredspectroscopyanalysisandfieldemissionscanningelectronmicroscopyobservationshowedthattheadsorptionofTweenonpolypropylenemicroporousmembrane(PPMM)iseffectiveandoccursmainlyintheporesofPPMMsatlowadsorptionamount,andonthemembranesurfacealsoathighadsorptionvalue.
2006, 24(4): 431-436
Abstract:
Asurfactant-assistedmethodforpreparingcolloidalsphereswithnarrowsizedistributionfromapolydispersedazopolymerhasbeendevelopedinthiswork.ThecolloidalsphereswereformedthroughgradualhydrophobicaggregationofthepolymericchainsinTHF-H2Odispersionmedia,whichwasinducedbyasteadyincreaseinthewatercontent.Resultsshowedthattheadditionofasmallamountofsurfactant(SDBS)couldsignificantlynarrowthesizedistributionofthecolloidalspheres.Thesizedistributionofthecolloidalsphereswasdeterminedbytheconcentrationsofazopolymerandtheamountofsurfactantinthesystems.Whentheconcentrationsofpolymerandsurfactantamountwereinaproperrange,colloidalsphereswithnarrowsizedistributioncouldbeobtained.ThecolloidalspheresformedbythismethodcouldbeelongatedalongthepolarizationdirectionofthelaserbeamsuponAr+laserirradiation.Thecolloidalspheresareconsideredtobeanewtypeofthecolloid-basedfunctionalmaterials.
Asurfactant-assistedmethodforpreparingcolloidalsphereswithnarrowsizedistributionfromapolydispersedazopolymerhasbeendevelopedinthiswork.ThecolloidalsphereswereformedthroughgradualhydrophobicaggregationofthepolymericchainsinTHF-H2Odispersionmedia,whichwasinducedbyasteadyincreaseinthewatercontent.Resultsshowedthattheadditionofasmallamountofsurfactant(SDBS)couldsignificantlynarrowthesizedistributionofthecolloidalspheres.Thesizedistributionofthecolloidalsphereswasdeterminedbytheconcentrationsofazopolymerandtheamountofsurfactantinthesystems.Whentheconcentrationsofpolymerandsurfactantamountwereinaproperrange,colloidalsphereswithnarrowsizedistributioncouldbeobtained.ThecolloidalspheresformedbythismethodcouldbeelongatedalongthepolarizationdirectionofthelaserbeamsuponAr+laserirradiation.Thecolloidalspheresareconsideredtobeanewtypeofthecolloid-basedfunctionalmaterials.
2006, 24(4): 437-440
Abstract:
Thereducedviscosityofpolymerguargumsolutionscontainingacertainconcentrationofsodiumdodecylbenzenesulfonate(SDBS)wasmeasured.IthasbeenfoundthattheHugginscoefficientkHofpolymersolutionsisverysensitivetotheconcentrationofthesurfactant,cSDBS,insolutions.IfcSDBSislowerthanCMC,thecriticalmicelleconcentrationofSDBS,kHincreasesrapidlywithcSDBS.Ontheotherhand,ifcSDBSislargerthanCMC,kHdecreasesrapidlywithcSDBS.Comparatively,theintrinsicviscosityofpolymersolutiondoesnotshowanotablechangewithcSDBS.TheexperimentalresultsindicatethattheinterchainassociationofpolymerguarguminsolutionisgreatlyassociatedwithSDBSinteractedwithpolymerchainsthroughhydrogenbonds.However,theeffectofSDBSupontheintrachainassociationofpolymerguargumsolutionisnegligible,presumablyduetothefactthatguargumisaslightlystiffenedrandom-coilchainpolymer.
Thereducedviscosityofpolymerguargumsolutionscontainingacertainconcentrationofsodiumdodecylbenzenesulfonate(SDBS)wasmeasured.IthasbeenfoundthattheHugginscoefficientkHofpolymersolutionsisverysensitivetotheconcentrationofthesurfactant,cSDBS,insolutions.IfcSDBSislowerthanCMC,thecriticalmicelleconcentrationofSDBS,kHincreasesrapidlywithcSDBS.Ontheotherhand,ifcSDBSislargerthanCMC,kHdecreasesrapidlywithcSDBS.Comparatively,theintrinsicviscosityofpolymersolutiondoesnotshowanotablechangewithcSDBS.TheexperimentalresultsindicatethattheinterchainassociationofpolymerguarguminsolutionisgreatlyassociatedwithSDBSinteractedwithpolymerchainsthroughhydrogenbonds.However,theeffectofSDBSupontheintrachainassociationofpolymerguargumsolutionisnegligible,presumablyduetothefactthatguargumisaslightlystiffenedrandom-coilchainpolymer.
