The isomerization kinetics of a spiropyran(1)and a spirooxazine(2)embedded in bilayer membranes of sodium 1-pentadecylhexadecyl sulfate(3)and sodium 1-undecyl dodecyl sulfate(4),respeatively,were investigated.The ther...The isomerization kinetics of a spiropyran(1)and a spirooxazine(2)embedded in bilayer membranes of sodium 1-pentadecylhexadecyl sulfate(3)and sodium 1-undecyl dodecyl sulfate(4),respeatively,were investigated.The thermal decay of 2 obeyed first-order kinetics, whereas that of 1 consisted of two simultaneous first-order processes.Kinetic parameters were obtained from Arrhenius plots.展开更多
The non-isothermal crystallization kinetics, isothermal crystallization and the morphology of crystals of the copolymer poly (ethylene terephthalate/ isophthalate )(IPET) were studied by DSC and polarized-light micros...The non-isothermal crystallization kinetics, isothermal crystallization and the morphology of crystals of the copolymer poly (ethylene terephthalate/ isophthalate )(IPET) were studied by DSC and polarized-light microscopy in this paper. DSC results indicate that the glass transition temperature Tg of IPET is slightly lower than that of poly(ethylene terephthalate) (PET), but the melting temperature Tm and the crystallization temperature Tc of PET and IPET have much difference.The difference of Tc between PET and IPET2 is about 7℃, and the difference of Tm between PET and IPET2 is about 16℃. From the kinetics analysis of the crystallization, the crystallization mechanism of all samples is of three-dimension spherulitic growth from instantaneous nuclei and the incorporation of isophthalate (IPA) decreases the crystallization rate of IPET greatly. The isothermal results indicate that the morphologies of PET and IPET crystals are all spherulite, which is in conformity to the results of nonisothermal dynamic crystallization. At the same time,the spherulite of IPET grows slower and has longer incubation time than the spherulite of PET under the same crystallization condition.展开更多
基金project supported by the National Natural Science Foundation of China.
文摘The isomerization kinetics of a spiropyran(1)and a spirooxazine(2)embedded in bilayer membranes of sodium 1-pentadecylhexadecyl sulfate(3)and sodium 1-undecyl dodecyl sulfate(4),respeatively,were investigated.The thermal decay of 2 obeyed first-order kinetics, whereas that of 1 consisted of two simultaneous first-order processes.Kinetic parameters were obtained from Arrhenius plots.
文摘The non-isothermal crystallization kinetics, isothermal crystallization and the morphology of crystals of the copolymer poly (ethylene terephthalate/ isophthalate )(IPET) were studied by DSC and polarized-light microscopy in this paper. DSC results indicate that the glass transition temperature Tg of IPET is slightly lower than that of poly(ethylene terephthalate) (PET), but the melting temperature Tm and the crystallization temperature Tc of PET and IPET have much difference.The difference of Tc between PET and IPET2 is about 7℃, and the difference of Tm between PET and IPET2 is about 16℃. From the kinetics analysis of the crystallization, the crystallization mechanism of all samples is of three-dimension spherulitic growth from instantaneous nuclei and the incorporation of isophthalate (IPA) decreases the crystallization rate of IPET greatly. The isothermal results indicate that the morphologies of PET and IPET crystals are all spherulite, which is in conformity to the results of nonisothermal dynamic crystallization. At the same time,the spherulite of IPET grows slower and has longer incubation time than the spherulite of PET under the same crystallization condition.
