Flexible oxyethylene-ether was introduced into the aromatic copolyesters and copoly (ester-amide)s to reduce the melting point of resulting polymers. The melting point was greatly reduced to 200 degrees C or even lowe...Flexible oxyethylene-ether was introduced into the aromatic copolyesters and copoly (ester-amide)s to reduce the melting point of resulting polymers. The melting point was greatly reduced to 200 degrees C or even lower in some cases, and the molecular weight was satisfactorily high as reflected by inherent viscosity. The polymers exhibited high thermal stability and good mechanical properties as determined by TGA and mechanical tests. The copolyester showed better crystallinity and liquid crystallinity than corresponding copoly (ester-amide)s with similar monomer composition as reflected by POM observation and WAXD study. The melting points 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 value when PAB was 29 mol%.展开更多
Four novel copoly（ester-imide）s based on 3,3′,4,4′-biphenyltetracarboxylic dianhydride, bis（trimellitic acid anhydride） phenyl ester and di-p-aminophenyl ester of dicarboxylic acids were synthesized via two-step...Four novel copoly（ester-imide）s based on 3,3′,4,4′-biphenyltetracarboxylic dianhydride, bis（trimellitic acid anhydride） phenyl ester and di-p-aminophenyl ester of dicarboxylic acids were synthesized via two-step method in order to investigate whether two imide mesogenic units with different conformation and polarity could control the formation of LC-phase. Polarizes light microscopy （PLM） and differential scanning calorimetry （DSC） have shown that three polymers formed the nematic phase with ＂thread schlieren texture＂ and a polymer formed the nematic phase with ＂Inversion walls texture＂.展开更多
Various aspects of the rheological behaviour of liquid crystalline copolyesters, i.e.,samples of copoly (p-hydroxybenzoate / bisphenol A terephthalate), were explored by usingInstron capillary rheometer. The experimen...Various aspects of the rheological behaviour of liquid crystalline copolyesters, i.e.,samples of copoly (p-hydroxybenzoate / bisphenol A terephthalate), were explored by usingInstron capillary rheometer. The experimental results indicated that the apparent viscositywas affected significantly by shear rate, melt temperature and p-hydroxybenzoate unit con-tent. The flow activation energies △E_η are in the range of 205.1 to 74.5 kJ/mol, dependingon the shear rate of 10-1000 s^(-1), at temperature 568-603K. These copolyesters exhibit ayield phenomenon in the shear flow, and the values of yield stress decrease with increasingtemperature. It is quite unusual that the extrudate of the copolyester shows the smallerswelling ratio even than unity at the lower temperature and lower shear rates.展开更多
In this article,six new optically active copoly(amide-imide)s(10a-f) were synthesized through the direct polycondensation reaction of N-phthalimido-L-aspartic acid(4) with 1,5-diamino naphthalene(8),3,4-diamino benzop...In this article,six new optically active copoly(amide-imide)s(10a-f) were synthesized through the direct polycondensation reaction of N-phthalimido-L-aspartic acid(4) with 1,5-diamino naphthalene(8),3,4-diamino benzophenone(9) in the presence of therphthahc acid(7),fumaric acid(6) and adipic acid(5) as a second diacid in a medium consisting of N-methyl-2-pyrrolidone,triphenyl phosphite, calcium chloride and pyridine.The resulting copolymers were fully characterized by means of FT-IR spectroscopy,elemental a...展开更多
The permeability of copoly (1-trimethylsilyl-1-propyne-pentamethyldisilyl-1-propyne) membrane for twelve gases (0_2, N_2, CO_2, H_2, D_2, He, At, CH_4, C_2H_4, C_2H_6, C_3H_6 and C_3H_8) was examined. The basic laws o...The permeability of copoly (1-trimethylsilyl-1-propyne-pentamethyldisilyl-1-propyne) membrane for twelve gases (0_2, N_2, CO_2, H_2, D_2, He, At, CH_4, C_2H_4, C_2H_6, C_3H_6 and C_3H_8) was examined. The basic laws of solution and diffusion of the gases in the membrane were expounded preliminarily. It was found that a linear relationship between logarithm of diffusion coefficient (D) and critical molar volume (V_c) of the gases. The permeation characteristics of the gases in the copoly (1-trimethylsilyl-1-propyne-pentamethyldisilyl-1-propyne) membrane was also discussed.展开更多
A new series of copoly(ester-thioester)s had been synthesized using direct polycondensation technique. These copolythioesters were synthesized by direct polycondensation of 4,4'-(tereph-thaloyIdithio) diacetic aci...A new series of copoly(ester-thioester)s had been synthesized using direct polycondensation technique. These copolythioesters were synthesized by direct polycondensation of 4,4'-(tereph-thaloyIdithio) diacetic acid I, 3,3'(isophthaloyl-dithio) diacetic acid II, or 1,8 (sebacoyldithio) diacetic acid III, with 2,6-bis(p-hydroxybenzylidene) tert. butyl cyclohexanone IV and 2,6-divanyli-dene tert. butyl cyclohexanone V, using a condensing agent consisting of pyridine-thionyl clhloride complex. The resulting copolymers were characterized by elemental and spectral analyses, solubility, viscometery, electronic spectra and thermogravimietric analyses. The crystallinity of some copolymers was examined by X-ray diffraction analyses. Furthermore, the morphology of selec ted examples of the copolymers was examined by scanning electron microscopy.展开更多
: Copolymers used for transparent fibre glass-reinforced thermoplastic composite -were prepared from methyl methacrylate (.MMA) and styrene (St). Composites containing 20~25 ivt% glass fibre and 0. 7 mm in thickness h...: Copolymers used for transparent fibre glass-reinforced thermoplastic composite -were prepared from methyl methacrylate (.MMA) and styrene (St). Composites containing 20~25 ivt% glass fibre and 0. 7 mm in thickness had an overall optical transmission of 88 ~90%. The gel time and cure time of the prepolymers from MM A and St decreased markedly ivith addition of tiie two linear unsaturated polyesters (.LUPE) and curing process of composite laminate became controlling easily-The effect of the concentration of LUPE on thermal stability of copolymers 晅he optical properties and the hydrothermal sta-bility of composites was investigated by comparing with those of trans-parent unsaturated composites .展开更多
Block copolymers are a class of soft matter that self-assemble to form ordered morphologies on the scale of nanome- ters, making them ideal materials for various applications. These applications directly depend on the...Block copolymers are a class of soft matter that self-assemble to form ordered morphologies on the scale of nanome- ters, making them ideal materials for various applications. These applications directly depend on the shape and size of the self-assembled morphologies, and hence, a high degree of control over the self-assembly is desired. Grafting block copolymer chains onto a substrate to form copolymer brushes is a versatile method to fabricate functional surfaces. Such surfaces demonstrate a response to their environment, i.e., they change their surface topography in response to different external conditions. Furthermore, such surfaces may possess nanoscale patterns, which are important for some applica- tions; however, such patterns may not form with spun-cast films under the same condition. In this review, we summarize the recent progress of the self-assembly of block copolymers grafted onto a flat substrate. We mainly concentrate on the self-assembled morphologies of end-grafted AB dibloek eopolymers, junction p0int-grafted AB diblock copolymers （i.e., Y-shaped brushes）, and end-grafted ABA triblock copolymers. Special emphasis is placed on theoretical and simulation progress.展开更多
基金This work was supported by the National Natural Science Foundation of China and the National Key Projects for Fundamental Research"Macromolecular Condensed State",The State Science and Technology Commission of China.
文摘Flexible oxyethylene-ether was introduced into the aromatic copolyesters and copoly (ester-amide)s to reduce the melting point of resulting polymers. The melting point was greatly reduced to 200 degrees C or even lower in some cases, and the molecular weight was satisfactorily high as reflected by inherent viscosity. The polymers exhibited high thermal stability and good mechanical properties as determined by TGA and mechanical tests. The copolyester showed better crystallinity and liquid crystallinity than corresponding copoly (ester-amide)s with similar monomer composition as reflected by POM observation and WAXD study. The melting points 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 value when PAB was 29 mol%.
基金supported by the National Science Foundation of China(No.50433010).
文摘Four novel copoly（ester-imide）s based on 3,3′,4,4′-biphenyltetracarboxylic dianhydride, bis（trimellitic acid anhydride） phenyl ester and di-p-aminophenyl ester of dicarboxylic acids were synthesized via two-step method in order to investigate whether two imide mesogenic units with different conformation and polarity could control the formation of LC-phase. Polarizes light microscopy （PLM） and differential scanning calorimetry （DSC） have shown that three polymers formed the nematic phase with ＂thread schlieren texture＂ and a polymer formed the nematic phase with ＂Inversion walls texture＂.
文摘Various aspects of the rheological behaviour of liquid crystalline copolyesters, i.e.,samples of copoly (p-hydroxybenzoate / bisphenol A terephthalate), were explored by usingInstron capillary rheometer. The experimental results indicated that the apparent viscositywas affected significantly by shear rate, melt temperature and p-hydroxybenzoate unit con-tent. The flow activation energies △E_η are in the range of 205.1 to 74.5 kJ/mol, dependingon the shear rate of 10-1000 s^(-1), at temperature 568-603K. These copolyesters exhibit ayield phenomenon in the shear flow, and the values of yield stress decrease with increasingtemperature. It is quite unusual that the extrudate of the copolyester shows the smallerswelling ratio even than unity at the lower temperature and lower shear rates.
文摘In this article,six new optically active copoly(amide-imide)s(10a-f) were synthesized through the direct polycondensation reaction of N-phthalimido-L-aspartic acid(4) with 1,5-diamino naphthalene(8),3,4-diamino benzophenone(9) in the presence of therphthahc acid(7),fumaric acid(6) and adipic acid(5) as a second diacid in a medium consisting of N-methyl-2-pyrrolidone,triphenyl phosphite, calcium chloride and pyridine.The resulting copolymers were fully characterized by means of FT-IR spectroscopy,elemental a...
文摘The permeability of copoly (1-trimethylsilyl-1-propyne-pentamethyldisilyl-1-propyne) membrane for twelve gases (0_2, N_2, CO_2, H_2, D_2, He, At, CH_4, C_2H_4, C_2H_6, C_3H_6 and C_3H_8) was examined. The basic laws of solution and diffusion of the gases in the membrane were expounded preliminarily. It was found that a linear relationship between logarithm of diffusion coefficient (D) and critical molar volume (V_c) of the gases. The permeation characteristics of the gases in the copoly (1-trimethylsilyl-1-propyne-pentamethyldisilyl-1-propyne) membrane was also discussed.
文摘A new series of copoly(ester-thioester)s had been synthesized using direct polycondensation technique. These copolythioesters were synthesized by direct polycondensation of 4,4'-(tereph-thaloyIdithio) diacetic acid I, 3,3'(isophthaloyl-dithio) diacetic acid II, or 1,8 (sebacoyldithio) diacetic acid III, with 2,6-bis(p-hydroxybenzylidene) tert. butyl cyclohexanone IV and 2,6-divanyli-dene tert. butyl cyclohexanone V, using a condensing agent consisting of pyridine-thionyl clhloride complex. The resulting copolymers were characterized by elemental and spectral analyses, solubility, viscometery, electronic spectra and thermogravimietric analyses. The crystallinity of some copolymers was examined by X-ray diffraction analyses. Furthermore, the morphology of selec ted examples of the copolymers was examined by scanning electron microscopy.
文摘: Copolymers used for transparent fibre glass-reinforced thermoplastic composite -were prepared from methyl methacrylate (.MMA) and styrene (St). Composites containing 20~25 ivt% glass fibre and 0. 7 mm in thickness had an overall optical transmission of 88 ~90%. The gel time and cure time of the prepolymers from MM A and St decreased markedly ivith addition of tiie two linear unsaturated polyesters (.LUPE) and curing process of composite laminate became controlling easily-The effect of the concentration of LUPE on thermal stability of copolymers 晅he optical properties and the hydrothermal sta-bility of composites was investigated by comparing with those of trans-parent unsaturated composites .
基金supported by the National Natural Science Foundation of China(Grant Nos.20990234,20925414,and 91227121)the Program for Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT1257)+1 种基金the Programme of Introducing Talents of Discipline to Universities,Chinaby the Tianhe No.1,China
文摘Block copolymers are a class of soft matter that self-assemble to form ordered morphologies on the scale of nanome- ters, making them ideal materials for various applications. These applications directly depend on the shape and size of the self-assembled morphologies, and hence, a high degree of control over the self-assembly is desired. Grafting block copolymer chains onto a substrate to form copolymer brushes is a versatile method to fabricate functional surfaces. Such surfaces demonstrate a response to their environment, i.e., they change their surface topography in response to different external conditions. Furthermore, such surfaces may possess nanoscale patterns, which are important for some applica- tions; however, such patterns may not form with spun-cast films under the same condition. In this review, we summarize the recent progress of the self-assembly of block copolymers grafted onto a flat substrate. We mainly concentrate on the self-assembled morphologies of end-grafted AB dibloek eopolymers, junction p0int-grafted AB diblock copolymers （i.e., Y-shaped brushes）, and end-grafted ABA triblock copolymers. Special emphasis is placed on theoretical and simulation progress.
