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1.
Flexible oxyethylene-ether was introduced into the aromatic copolyesters and copoly(es-ter-amide)s to reduce the melting point of resulting polymers. The melting point was greatlyreduced to 200℃ or even lower in some cases, and the molecular weight was satisfactorilyhigh as reflected by inherent viscosity. The polymers exhibited high thermal stability and goodmechanical properties as determined by TGA and mechanical tests. The copolyester showedbetter crystallinity and liquid crystallinity than corresponding copoly(ester-amide)s with simi-lar monomer composition as reflected by POM observation and WAXD study. The meltingpoints for both copolyesters and copoly (ester-amide)s showed great dependence on the p-acetoxybenzoic acid (PAB) content in monomer composition and reached the lowest valuewhen PAB was 29 mol%.  相似文献   

2.
SYNTHESISANDPROPERTIESOFTHERMOTROPICCOPOLY(ESTERIMIDE)S¥DeWenDONG*(ChangchunInstituteofAppliedChemistry,AcademiaSinica.Changc...  相似文献   

3.
SYNTHESISANDPROPERTIESOFTHERMOTROPICLIQUIDCRYSTALLINECOPOLYESTERSCONTAININGBIS(4-HYDROXYPHENYL)METHANONE(Ⅴ)¥DeWenDONG;YuShanN...  相似文献   

4.
SYNTHESISANDPROPERTIESOFTHERMOTROPICLIQUIDCRYSTALLINECOPOLYESTERSCONTAININGBIS(4-HYDROXYPHENYL)METHANONE(Ⅵ)SYNTHESISANDPROPER...  相似文献   

5.
A series of copolyesters were prepared from chloro-hydroquinone or methyl-hydroquinone,terephthalic acid, and two kinds of comonomers, such as oxy-4,4'-diphenol and isophthalic acid.which could provide kinking and bending in chain. The four-components copolyesters in certain range of compositions have low melting point,ssteady mesophase in a broad temperature range and fiber-forming tendency. This report focuses on the relations of their molecular composition-transitions-liquid crystallinityand fiber-forming tendency and the morphologic characterizations of mesophase.  相似文献   

6.
A series of main chain liquid crystal aromatic copolyesters with X-shapedand rod-shaped mesogenic units were synthesized via solution condensation polymerizationsof 4, 4'-(α,ω-octanedioyloxy)-dibenzoyl dichlorides with 2,5-bis(p-octanoxy benzoyloxy)-hydroquinone and diphenol. All of the copolyesters showed thermotropic liquid crystallinebehaviors through observations using DSC, polarized microscopy and X-ray diffraction.The melting point (T_m) and the isotropization temperature (T) change regularly withvarying the content of diphenol unit in the copolymers.  相似文献   

7.
Several novel aromatic liquid crystalline copolyesters with regular sequence structure were prepared by melt Sehotten-Baumann polycondensation via complex monomer. Polarizing microscope with hot stage, thermal analysis and X-ray diffraction were used to investigate the structure and properties of the copolyesters. The effects of structural units, such as flexible spacer, noncolinear meta-linked phenylene unit, crankshaft unit, kink with flexible bridging unit and various substituted benzene rings on melting temperature of aromatic copolyesters were studied and discussed on the basis of crystalline structure of the polymers.  相似文献   

8.
The direct polymerization of an unsymmetrical kink non-coplanar heterocyclic diamine (1) with various aromatic bis(trimellitimide)s (2a-e) using triphenyl phosphite and pyridine as condensing agents could generate a series of new aromatic poly(amide imide)s (3a-e) containing the kink non-coplanar phthalazinone heterocyclic units in the polymer main chains with inherent viscosities of 0.58-0.66 dL/g. The polymers are readily soluble in a variety of solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidinone, pyridine and m-cresol and can be cast to form flexible and tough films. The glass transition temperatures of polymers (T8) are in the range of 301-327℃, and the temperatures for 5% weight loss in nitrogen are in the range of 498-521℃.  相似文献   

9.
Side chain liquid crystalline polysiloxanes containing benzyl ether linkingunits were synthesized by the hydrosilylation of poly (methylhydrosiloxane) with a series of4-(4-alkoxybenzyloxy)-4'-allyloxybiphenyl monomers [4-(4-methoxybenzyloxy )-4'-allyloxy-biphenyl(M_1), 4-(4-ethoxybenzyloxy)-4'-allyloxybiphenyl (M_2), 4-(4-propoxybenzyloxy)-4'-allyloxybiphenyl (M_3), 4-(4-butoxybenzyloxy)-4'-allylox(M_4), 4-(4-pentoxy-benzyloxy)-4'-allyloxybiphenyl (M_5), 4-benzyloxy-4'-allyloxybiphenyl (M_6)]. The phasebehavior of monomeric and polymeric liquid crystals was characterized by differential scan-ning calorimetry and optical polarization microscopy where the groups are ranged frommethoxy to pentoxy Both the monomeric and polymeric liquid crystals exhibit 1iquidcrystal behaviors.  相似文献   

10.
A new series of thermotropic liquid crystalline poly(ester-imide)s were synthesized via a solution polycondensation process.Thepolymers were also characterized by IR,DSC,polarizing microscopy and WAXDmeasurements.  相似文献   

11.
A series of new optically active aromatic poly(ester arnide)s containing a chiral group in the side chain prepared from the p-toluenesulfonic acid salt of o,o‘-bis(leucyl)-hexanediol (TS^- LHD^ TS^-) and p-phthaloyl chloride and styrene-2,5-dicarbonyl chloride styrene have been synthesized by interfacial polymerization. The structure of the monomer is elucidated by FT-IR and elemental analysis. The thermal properties of the polymers were studied by DSC and TGA. The chiroptical properties of the above polymer have also been studied by circular dichroism (CD) spectroscopy. Results indicated that these polymers form helical structures.  相似文献   

12.
A novel series of main chain liquid crystalline copolyesters with X-shaped two-dimensional mesogenic unit and crown ether cycle of cis-4,4′-bis(4-hydroxyphenylazo) dibenzo-18-crown-6 was prepared via solution condensation polymerization from 4,4′-(α,ω-hexanedioyloxy) dibenzoyl dichloride (M1), 2,5-bis(p-octyloxybenzoyloxy) hydro-quinone (M2) and cis-4,4′-bis(4-hydroxyphenylazo) dibenzo-18-crown-6 (M3). Monomer M1 was synthesized by esterification and substitution of adipoyl chloride with p-hydroxybenzoic acid, monomer M2 was synthesized by esterfication and reduction reaction of 2,5-dihydroxybenzoquinone and p-octanoxybenzoyl chloride and monomer M3 was synthesized by diazotization and coupling reaction of cis-diaminodibenzo-18-crown-6 with phenol. The molecular weights of copolyesters are not high,and the intrinsic viscosity [η] of copolyesters ranges from 0.25-0.35. The monomers' structures were identified by using elemental analysis, IR, UV, 1H-NMR, MS, etc. All the copolyesters are yellowish powders and insoluble in THF and CHCl3 at room temperature except CP9. The properties of copolyesters were investigated by using GPC, [η] , DSC, TG,WAXD and POM. It was found that all the copolyesters entered into liquid crystal phase when they were heated to above their melting temperature (Tm). The typical smectic and nematic phase texture can be observed on POM. Their mesophase transition temperature and thermal stability change regularly with varying the content of cis-4,4′-bis(4-hydroxyphenylazo)dibenzo-18-crown-6 unit in the copolyesters.  相似文献   

13.
14.
The segmented block copoly(ether ester)s were swollen by tetrahydrofuran (THF) at 60℃and formedfibers by gel-drawing. The morphology and properties of these fibers were investigated by optical and electron microscopes, X-ray diffraction, DSC and an Instron test machine. The band structure morphology was observed in the gel-drawing fibers. The molecular chains were highly oriented as proved by X-ray diffraction data. The results indicated that the gel-drawing fibers have much better mechanical properties than those obtained otherwise. The tensile strength and elastic modulus were found to be 280 MPa and 802 MPa, repsectively. The mechanism of the gel-drawlng process was also discussed.  相似文献   

15.
郑世军  Kazuo  Akagi  Qun  Xua  Zi-fa  Li  Shao-kui  Cao  Qi-feng  Zhou 《高分子科学》2006,(3):265-271
Abstract The novel shish-kebab-type liquid crystalline poly(p-phenylene)s were synthesized through Suzuki coupling reaction from 2,5-bis[(4-n-alkoxyl)benzoyloxy]1,4-dibromobenzene (monomer 1) and 1,4-benzenediboronic acid bistrimethylene cyclic ester (monomer 2). Their structure and properties were characterized by GPC, DSC, X-ray diffraction and polarizing optical microscope (POM). It was found that the polymers turned to liquid crystalline phase above their melting point. The melting point (Tm) of the polymers decreases when the length of the alkoxy tails of the mesogenic units increases. The mesophase was identified by X-ray diffraction method. The polymers could dissolve in common organic solvents and show strong blue fluorescence. The maximum absorption bands of polymers prepared from annealed films have large red-shift due to the spontaneous orientation of the liquid crystalline side chains. The same phenomena were also observed in the fluorescence spectra.  相似文献   

16.
NMRSTUDYONTHECONFORMATIONCHANGEINTHEAGGREGATIONPROCESSESOF1,3-DI(α-NAPHTHYL)PROPANEANDDI(α-NAPHTHYLMETHYL)ETHER¥RuiQsingXIE;Z...  相似文献   

17.
SYNTHESIS,COMPLEXATIONPROPERTIESANDCRYSTALSTRUCTUREOFNEWDIOXOCYCLAMBEARING8-METHYLQUINOLINEASFUNCTIONALPENDANT(S)¥DaoLiAN;Xia...  相似文献   

18.
This paper deals with the transport properties of oligomer of polythioether PSA used as moble carrier in bulk liquid membrane for gold(Ⅲ).It was found that Au(Ⅲ) can be transported by PSA from source phase to receiving phase completely under appropriate conditions and only Au(Ⅲ) can be transferred through the liquid membrane to receiving phase from a mixture of Na(I)-Cu(Ⅱ)-Au(Ⅲ)-Fe(Ⅲ)-Pt(Ⅳ) in the following system:HAuCl4-HCl(aq.)/PSA-ClCH2-CH2Cl/(NH2)2CS-HCl(aq.).The transport rate of Au(Ⅲ) depended on the concentration of carrier,the thickness of liquid membrane,the concentration of Au(Ⅲ) in source phase and the acidity of the media.  相似文献   

19.
20.
A novel sulfonated poly(arylene ether) containing triphenylmethane moieties was synthesized by the sulfonation of a designed parent polymer using chlorosulfonic acid as sulfonation agent. The sulfonation took place at the para position of the pendant phenyl rings because of the specially designed parent polymer. The position and degree of sulfonation were characterized by ^1H-NMR and elemental analysis. The sulfonated polymers are highly soluble in common organic solvents, such as dimethylsulfoxide, N,N'-dimethylacetamide, dimethylformamide, ethylene glycol monomethyl ether, and can be readily cast into tough and smooth films from solutions. The films showed good thermal and hydrolysis stabilities. Moreover, Fenton's reagent test revealed that the films exhibited superior stability to oxidation. The proton conductivities of the films were comparable with Nation 117 under same conditions. The membrane electrode assembly (MEA) prepared with the asmade film (706 EW, 100 μm dry thickness) shows better cell performance than Nation 115-MEA in the whole current density range.  相似文献   

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