In this paper the change of segment ratio, segmental sequence distribution and randonmess B of PET-PTMG block copolymer have been investigated by IR and ^(13)C-NMR spectra during the polycondensation reaction.
The compositional homogeneity of a poly (ethylene terephthalate)-poly (tetramethylene ether) multiblock copolymer sample with low content of hard segment was examined by GPC, TLC, and solubility method. The copolymer ...The compositional homogeneity of a poly (ethylene terephthalate)-poly (tetramethylene ether) multiblock copolymer sample with low content of hard segment was examined by GPC, TLC, and solubility method. The copolymer sample was found to have a uniform composition as a function of elution volume over the major portion of sample from GPC method. However within one elution fraction, the copolymer chains, although having the same hydrodynamic volume, may have some difference in composition. Two fractions with different composition were obtained by precipitation in ethanol. Some low molar mass copolymers were also separated by a TLC technique from the copolymer sample.展开更多
The molar segment mass, weight-average molar mass, and molar mass distribution of a poly-(ethylene terephthalate)-poly (tetramethylene ether) multiblock copolymer sample were determined by the methods of proton nuclea...The molar segment mass, weight-average molar mass, and molar mass distribution of a poly-(ethylene terephthalate)-poly (tetramethylene ether) multiblock copolymer sample were determined by the methods of proton nuclear magnetic resonance, low angle laser light scattering, and gel permeation chromatography.展开更多
A liquid crystalline block copolymer (BCPE) was synthesized from bis phenol A epoxy oligomer and liquid crystalline polyester (PBHT) which was prepared from polyhexamethylene bis (4 oxybenzoates) and terephthaloyl dic...A liquid crystalline block copolymer (BCPE) was synthesized from bis phenol A epoxy oligomer and liquid crystalline polyester (PBHT) which was prepared from polyhexamethylene bis (4 oxybenzoates) and terephthaloyl dichloride by solution polymerization.The intrinsic viscosity ( η inh ) of the polymers was determined using an ubbelohde viscometer in phenyl hydroxide/1,1,2,2 tetrachloroethane mix solvent (1:1) at 30℃, and the results showed that the η inh values of PBHT and BCPE are 0.16 dL/g and 0.46 dL/g respectively. FTIR analysis identified the reaction between bis phenol A epoxy oligomer and PBHT. The crystalline properties of polymers were investigated with DSC and WAXD, and the results found that the crystallinity of BCPE is inferior to that of PBHT due to addition of amorphous epoxy. Thermotropic liquid crystalline nematic phase textures of polymers were observed under a polarizing microscope with hot stage.展开更多
文摘In this paper the change of segment ratio, segmental sequence distribution and randonmess B of PET-PTMG block copolymer have been investigated by IR and ^(13)C-NMR spectra during the polycondensation reaction.
文摘The compositional homogeneity of a poly (ethylene terephthalate)-poly (tetramethylene ether) multiblock copolymer sample with low content of hard segment was examined by GPC, TLC, and solubility method. The copolymer sample was found to have a uniform composition as a function of elution volume over the major portion of sample from GPC method. However within one elution fraction, the copolymer chains, although having the same hydrodynamic volume, may have some difference in composition. Two fractions with different composition were obtained by precipitation in ethanol. Some low molar mass copolymers were also separated by a TLC technique from the copolymer sample.
文摘The molar segment mass, weight-average molar mass, and molar mass distribution of a poly-(ethylene terephthalate)-poly (tetramethylene ether) multiblock copolymer sample were determined by the methods of proton nuclear magnetic resonance, low angle laser light scattering, and gel permeation chromatography.
文摘A liquid crystalline block copolymer (BCPE) was synthesized from bis phenol A epoxy oligomer and liquid crystalline polyester (PBHT) which was prepared from polyhexamethylene bis (4 oxybenzoates) and terephthaloyl dichloride by solution polymerization.The intrinsic viscosity ( η inh ) of the polymers was determined using an ubbelohde viscometer in phenyl hydroxide/1,1,2,2 tetrachloroethane mix solvent (1:1) at 30℃, and the results showed that the η inh values of PBHT and BCPE are 0.16 dL/g and 0.46 dL/g respectively. FTIR analysis identified the reaction between bis phenol A epoxy oligomer and PBHT. The crystalline properties of polymers were investigated with DSC and WAXD, and the results found that the crystallinity of BCPE is inferior to that of PBHT due to addition of amorphous epoxy. Thermotropic liquid crystalline nematic phase textures of polymers were observed under a polarizing microscope with hot stage.
