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1997 Volume 15 Issue 1
1997, 15(1): 1-7
Abstract:
Polymer-metal oxane bonds (M-O-Si) can be created in the form of tight networks bysilane plasma polymerization directly on the metal (e.g. copper) substrates. In this paperthe structure and properties of the plasma-deposited organosilane polymers, the corrosionperformance of such coating system on copper substrates were investigated.
Polymer-metal oxane bonds (M-O-Si) can be created in the form of tight networks bysilane plasma polymerization directly on the metal (e.g. copper) substrates. In this paperthe structure and properties of the plasma-deposited organosilane polymers, the corrosionperformance of such coating system on copper substrates were investigated.
1997, 15(1): 8-14
Abstract:
The relation between the rheological behavior and various interfacial properties ofKaolin rigid particle toughened polypropylene (PP / Kaolin) composites were studied bymeans of parallel-plate rheometer, melt flow rate apparatus, scanning electron microscopy(SEM) and other testing methods. The results show that addition of interfacial modffier toPP/Kaolin composites is advantageous to homogeneous dispersion of filler in PP matrix,formation of flexible interlayer between Kaolin particles and PP matrix and improvement of the melt processibility of the composites.
The relation between the rheological behavior and various interfacial properties ofKaolin rigid particle toughened polypropylene (PP / Kaolin) composites were studied bymeans of parallel-plate rheometer, melt flow rate apparatus, scanning electron microscopy(SEM) and other testing methods. The results show that addition of interfacial modffier toPP/Kaolin composites is advantageous to homogeneous dispersion of filler in PP matrix,formation of flexible interlayer between Kaolin particles and PP matrix and improvement of the melt processibility of the composites.
1997, 15(1): 15-23
Abstract:
Three series of polythiophenes containing fluoroalkoxy and fluoroether substituentswere prepared by electrochemical polymerization. The effect of substituents with fluoro-alkoxy or ether functional groups on the electrochemical polymerization of thiophene mono-mers and properties of the obtained polymers were analyzed. The introduction of a flu-oroether functional group at the 3-position of the thiophene ring leads to an increase ofthe oxidation potential of the monomer and to a decrease of the conductivity of the resulting polymers,even with the use of a CH2 group as spacer.Conversely,the presence of an oxygen atom directly at the 3-position of the thiophene ring,which offsets the negative withdrawing effect of fluoroalkyl groups,facilitates the synthesis of highly conducting polythiophenes.
Three series of polythiophenes containing fluoroalkoxy and fluoroether substituentswere prepared by electrochemical polymerization. The effect of substituents with fluoro-alkoxy or ether functional groups on the electrochemical polymerization of thiophene mono-mers and properties of the obtained polymers were analyzed. The introduction of a flu-oroether functional group at the 3-position of the thiophene ring leads to an increase ofthe oxidation potential of the monomer and to a decrease of the conductivity of the resulting polymers,even with the use of a CH2 group as spacer.Conversely,the presence of an oxygen atom directly at the 3-position of the thiophene ring,which offsets the negative withdrawing effect of fluoroalkyl groups,facilitates the synthesis of highly conducting polythiophenes.
1997, 15(1): 24-33
Abstract:
Ionic, electronic and mixed (ionic-electronic) conductivities of blends of poly(2-vinylpyridine) (P2VP) and poly(ethylene oxide) (PEO) with high molecular weight after dopedwith LiClO4, TCNQ or LiClO4 and TCNQ were investigated. Effects of LiClO4 and TCNQconcentrations on the conductivity of PEO/P2VP/LiClO4 or TCNQ blend were studied.The ionic conductivity of PEO/P2VP/LiClO4 blend increases with increasing PEO content.At a Li/ethylene oxide molar ratio of 0.10 and a TCNQ/2-vinyl pyridine molar ratio of 0.5,the mixed conductivity of PEO/P2VP/LiClO4/TCNQ is higher than the total of ionic conductivity of PEO/P2VP/LiClO4 and electronic conductivity of PEO/P2VP/TCNQ when the weight ratio of PEO and P2VP is 6/4 or 5/5.Scanning electron microscopy (SEM)on the broken cross-section of the PEO/P2VP/LiClO4 blend and differential scanning calorimetry(DSC) results show that LiClO4 could act as a compatibilizer in the blend.
Ionic, electronic and mixed (ionic-electronic) conductivities of blends of poly(2-vinylpyridine) (P2VP) and poly(ethylene oxide) (PEO) with high molecular weight after dopedwith LiClO4, TCNQ or LiClO4 and TCNQ were investigated. Effects of LiClO4 and TCNQconcentrations on the conductivity of PEO/P2VP/LiClO4 or TCNQ blend were studied.The ionic conductivity of PEO/P2VP/LiClO4 blend increases with increasing PEO content.At a Li/ethylene oxide molar ratio of 0.10 and a TCNQ/2-vinyl pyridine molar ratio of 0.5,the mixed conductivity of PEO/P2VP/LiClO4/TCNQ is higher than the total of ionic conductivity of PEO/P2VP/LiClO4 and electronic conductivity of PEO/P2VP/TCNQ when the weight ratio of PEO and P2VP is 6/4 or 5/5.Scanning electron microscopy (SEM)on the broken cross-section of the PEO/P2VP/LiClO4 blend and differential scanning calorimetry(DSC) results show that LiClO4 could act as a compatibilizer in the blend.
1997, 15(1): 34-39
Abstract:
The compatibility of mixtures of polymeric pour point depressants, i.e. poly(ethylene-co-vinylacetate) (EVA), poly (EVA-graft-octadecylacrylate) (EVA-g-POA ), poly (ethylene-co-octadecylacrylate) (EOA) and poly(ethylene oxide-co-propylene oxide) (EO-co-PO) withwax or resin-asphaltene from crude oil have been studied by means of dilute-solution vis-cometry. It was found that each mixture pair is incompatible, but the degrees of incompati-bility are quite different, which are in good agreement with the results from photomicrography.
The compatibility of mixtures of polymeric pour point depressants, i.e. poly(ethylene-co-vinylacetate) (EVA), poly (EVA-graft-octadecylacrylate) (EVA-g-POA ), poly (ethylene-co-octadecylacrylate) (EOA) and poly(ethylene oxide-co-propylene oxide) (EO-co-PO) withwax or resin-asphaltene from crude oil have been studied by means of dilute-solution vis-cometry. It was found that each mixture pair is incompatible, but the degrees of incompati-bility are quite different, which are in good agreement with the results from photomicrography.
1997, 15(1): 40-49
Abstract:
The polycrystalline powder of para- and meta-dimethyl ester of pyromellitic acid (PMDE)have been prepared by fractional crystallization, and their crystal structures have been de-termined by Wide-Angle X-ray Diffraction (WAXD). Both p-PMDE and m-PMDE wasfound to be orthorhombic crystal system, and their unit cell parameters a = 0.840nm,b = 0.707 nm, c = 1.136 nm and a = 1.032 nm, b = 0.835 nm, c = 0.714 nm, respectively.Space group all belongs to Pmmm. p-PMDE has two molecules per unit cell with crystal density 1.388g·cm-3,while m-PMDE has two molecules per unit cell with crystal density 1.522g·cm-3.Indices of crystal diffraction peaks are also detailed in the present work.The difference in crystal structures between p-PMDE and m-PMDE has thus been used to explain the curing behavior of isomerically pyromellitic dianhydride-based poly(amic ester)s.
The polycrystalline powder of para- and meta-dimethyl ester of pyromellitic acid (PMDE)have been prepared by fractional crystallization, and their crystal structures have been de-termined by Wide-Angle X-ray Diffraction (WAXD). Both p-PMDE and m-PMDE wasfound to be orthorhombic crystal system, and their unit cell parameters a = 0.840nm,b = 0.707 nm, c = 1.136 nm and a = 1.032 nm, b = 0.835 nm, c = 0.714 nm, respectively.Space group all belongs to Pmmm. p-PMDE has two molecules per unit cell with crystal density 1.388g·cm-3,while m-PMDE has two molecules per unit cell with crystal density 1.522g·cm-3.Indices of crystal diffraction peaks are also detailed in the present work.The difference in crystal structures between p-PMDE and m-PMDE has thus been used to explain the curing behavior of isomerically pyromellitic dianhydride-based poly(amic ester)s.
1997, 15(1): 50-56
Abstract:
The homopolymerization of 5-methyl-5-hexen-2, 4-dione (methacryloylacetone, MAA),a vinyl monomer having β-diketone group, was carried out in the presence of benzophe-none (BP)/N N-dimenthyl-4-toluidine (DMT) system. Graft polymerization of acrylamideinitiated by ceric ion onto the homopolymer film was investigated and the mechanism ofthe grafting reaction was proposed on the basis of ESR study. The grafted copolymer wascharacterized by means of grafting percentage, water absorption, XPS spectra and scanning electron photomicrographs.
The homopolymerization of 5-methyl-5-hexen-2, 4-dione (methacryloylacetone, MAA),a vinyl monomer having β-diketone group, was carried out in the presence of benzophe-none (BP)/N N-dimenthyl-4-toluidine (DMT) system. Graft polymerization of acrylamideinitiated by ceric ion onto the homopolymer film was investigated and the mechanism ofthe grafting reaction was proposed on the basis of ESR study. The grafted copolymer wascharacterized by means of grafting percentage, water absorption, XPS spectra and scanning electron photomicrographs.
1997, 15(1): 57-64
Abstract:
The thermal behavior of thermotropic hydroxythyl cellulose acetate (HECA)/polyethy-lene (PE) blends has been studied by DSC. It is found that the blends of HECA and PEare immiscible but the crystallization of PE is affected by HECA chains in the blends withmore than 50% HECA, which results in the subordinate crystallization of PE and the for-mation of imperfect structures in the PE crystals. The imperfection of PE crystals in theblends can be eliminated after annealing at 393K.
The thermal behavior of thermotropic hydroxythyl cellulose acetate (HECA)/polyethy-lene (PE) blends has been studied by DSC. It is found that the blends of HECA and PEare immiscible but the crystallization of PE is affected by HECA chains in the blends withmore than 50% HECA, which results in the subordinate crystallization of PE and the for-mation of imperfect structures in the PE crystals. The imperfection of PE crystals in theblends can be eliminated after annealing at 393K.
1997, 15(1): 65-73
Abstract:
A series of liquid crystalline polymers with T-shaped two-dimensional mesogenic unitswere synthesized via low temperature solution polycondensation of 2-(4'-alkoxy-phenyl)hydroquinone with various diacyl dichlorides. The polymers were found to be nematic andshown thermotropic liquid crystalline behaviors through observations using DSC, polarizedmicroscopy and X-ray diffraction. The melting temperature Tm and the isotropizationtemperature Ti of the polymers change regularly with varying of the monomer structures.
A series of liquid crystalline polymers with T-shaped two-dimensional mesogenic unitswere synthesized via low temperature solution polycondensation of 2-(4'-alkoxy-phenyl)hydroquinone with various diacyl dichlorides. The polymers were found to be nematic andshown thermotropic liquid crystalline behaviors through observations using DSC, polarizedmicroscopy and X-ray diffraction. The melting temperature Tm and the isotropizationtemperature Ti of the polymers change regularly with varying of the monomer structures.
1997, 15(1): 74-83
Abstract:
Three kinds of polypyrrolones (PMDA-DAB, PMDA-TADPE and DEDA-DAB) werepyrolyzed at high temperature in order to study the effect of the chain structure of polypyrro-lones on the electrical properties of the pyrolyzed polymers. Results show that the num-ber of fusing rings in the main chain of polymers has a little effect on the pyrolysis pro-cess, whereas, the ether bond in the main chain plays an important role during pyrolysis.Structure characterizations by elemental analyis, XPS spectra, X-ray diffraction and SEM images indicate that because the ether bond is easy to break,it is difficult to form large area planar network.This hampers the formation of the graphite-like structure in the polypyrrolones containing ether bond even after being pyrolyzed at 1200℃.
Three kinds of polypyrrolones (PMDA-DAB, PMDA-TADPE and DEDA-DAB) werepyrolyzed at high temperature in order to study the effect of the chain structure of polypyrro-lones on the electrical properties of the pyrolyzed polymers. Results show that the num-ber of fusing rings in the main chain of polymers has a little effect on the pyrolysis pro-cess, whereas, the ether bond in the main chain plays an important role during pyrolysis.Structure characterizations by elemental analyis, XPS spectra, X-ray diffraction and SEM images indicate that because the ether bond is easy to break,it is difficult to form large area planar network.This hampers the formation of the graphite-like structure in the polypyrrolones containing ether bond even after being pyrolyzed at 1200℃.
1997, 15(1): 84-91
Abstract:
Poly(butylene terephthalate )-b-poly (tetramethylene glycol) (PBT-b-PTMG) was usedas rheology modifier for the epoxy resin. The segmental copolymer formed spherulites inthe epoxy medium. This copolymer was very effective in endowing yield stresses to theliquid resin. The PTMG segment brought in a lowering of the dissolution temperature ofthe spherulites in the epoxy gel. The cured resin with PBT-b-PTMG as modifier was two-phase materials. The rheology modifier improved the mechanical properties of the cured resin as well.The flexible PTMG segments,however,were not in favour of the toughening effect of the modifier.This was attributed to the large domain size of the dispersed phase.
Poly(butylene terephthalate )-b-poly (tetramethylene glycol) (PBT-b-PTMG) was usedas rheology modifier for the epoxy resin. The segmental copolymer formed spherulites inthe epoxy medium. This copolymer was very effective in endowing yield stresses to theliquid resin. The PTMG segment brought in a lowering of the dissolution temperature ofthe spherulites in the epoxy gel. The cured resin with PBT-b-PTMG as modifier was two-phase materials. The rheology modifier improved the mechanical properties of the cured resin as well.The flexible PTMG segments,however,were not in favour of the toughening effect of the modifier.This was attributed to the large domain size of the dispersed phase.
1997, 15(1): 92-96
Abstract:
Werborne ultrafine particles of epoxy resin were prepared by phase inversion tech-nique. The results of SEM revealed that the particles diameter was in the range of 50 to 100 nm and the effects on amount of water required at phase inversion point were also discussed.
Werborne ultrafine particles of epoxy resin were prepared by phase inversion tech-nique. The results of SEM revealed that the particles diameter was in the range of 50 to 100 nm and the effects on amount of water required at phase inversion point were also discussed.
