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
Covalent organic skeletons(COFs)have been widely used in gas separation due to their excellent pore structure,high crystallinity,and high specific surface area.In this work,Dha Tab-COF was synthesized by solvothermal ...Covalent organic skeletons(COFs)have been widely used in gas separation due to their excellent pore structure,high crystallinity,and high specific surface area.In this work,Dha Tab-COF was synthesized by solvothermal method and filled in polyether block polyamide(PEBAX)to form mixed matrix membranes(MMMs).Various characterization methods such as Fourier transform infrared spectroscopy(FT-IR),Xray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)and X-ray diffractometry(XRD)were used to characterize the structure of Dha Tab-COF as well as the MMMs.The effects of operating pressure,operating temperature and the content of Dha Tab-COF particles on the CO_(2)/CH_(4)separation performance of the membranes were investigated.The best separation performance with a CO_(2)permeability of 295.8 barrer(1 barrer=7.52×10^(-18)m^(3)·(STP)·m^(-2)·m·s^(-1)·Pa^(-1))and a CO_(2)/CH_(4)selectivity of 21.6 was achieved when the Dha Tab-COF content is 2%(mass),which were 45.7%and 108.1%higher than that of the pure PEBAX membrane,respectively.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.
基金supported by the National Natural Science Foundation of China(No.22271022,No 22378327).
文摘Covalent organic skeletons(COFs)have been widely used in gas separation due to their excellent pore structure,high crystallinity,and high specific surface area.In this work,Dha Tab-COF was synthesized by solvothermal method and filled in polyether block polyamide(PEBAX)to form mixed matrix membranes(MMMs).Various characterization methods such as Fourier transform infrared spectroscopy(FT-IR),Xray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)and X-ray diffractometry(XRD)were used to characterize the structure of Dha Tab-COF as well as the MMMs.The effects of operating pressure,operating temperature and the content of Dha Tab-COF particles on the CO_(2)/CH_(4)separation performance of the membranes were investigated.The best separation performance with a CO_(2)permeability of 295.8 barrer(1 barrer=7.52×10^(-18)m^(3)·(STP)·m^(-2)·m·s^(-1)·Pa^(-1))and a CO_(2)/CH_(4)selectivity of 21.6 was achieved when the Dha Tab-COF content is 2%(mass),which were 45.7%and 108.1%higher than that of the pure PEBAX membrane,respectively.
