The effect of heating modes in drawing process on the structure and properties of PET fibers was investigated. Sample B was prepared by drawing amorphous as\|spun PET filaments under laser radiation. A CO\-2 laser (λ...The effect of heating modes in drawing process on the structure and properties of PET fibers was investigated. Sample B was prepared by drawing amorphous as\|spun PET filaments under laser radiation. A CO\-2 laser (λ=10.6?μm, 30 W) was used for this purpose, and the diameter of its radiation area was about 3 mm. The feeding speed of the filaments was 50 m/min, and the draw ratio was 5\^0. Sample A was prepared under the same conditions except the heating mode, the filaments were heated by hot rolls. Some difference in structure and mechanical properties were found for the two samples.Sample B exhibited high tenacity (0\^8 GPa),elongation(9\^2%) and toughness (0\^047 GPa).The latter was about 1\^8 times as high as that of sample A.Both of the samples were obviously oriented.WAXD and density measurements showed the crystallinity and the crystallite size of sample B were larger than those of the sample A.展开更多
The photoluminescence spectrum of poly(ethylene terephthalate) (PET) excited by light with wavelength in the reign from 260 to 360?nm was investigated.When the excitation wavelength was shorter than 300?nm,it was obse...The photoluminescence spectrum of poly(ethylene terephthalate) (PET) excited by light with wavelength in the reign from 260 to 360?nm was investigated.When the excitation wavelength was shorter than 300?nm,it was observed that the profile and structure of the photoluminescence spectrum of PET did not change with the increase of the excitation wavelength. When the excitation wavelength was longer than 300 nm,the wavelength dependence of the spectrum was observed. Excited in the reign from 300 nm to the value that was a little larger than the maximum excitation wavelength, there was only one main peak at 367 nm in the photoluminescence spectrum. However, with the continued increasing of the excitation wavelength, another peak appeared at 387 nm and its intensity increased accompanying with the decrease of the intensity of the peak at 367 nm. At last, the peak at 387 nm became the main peak and the peak at 367 nm changed to the second main peak. It was suggested that the photoluminescence of 367 nm and 387 nm would rather come from the excimeric emission and the ground state dimmer, respectively, than origin from the same emitting center.展开更多
文摘The effect of heating modes in drawing process on the structure and properties of PET fibers was investigated. Sample B was prepared by drawing amorphous as\|spun PET filaments under laser radiation. A CO\-2 laser (λ=10.6?μm, 30 W) was used for this purpose, and the diameter of its radiation area was about 3 mm. The feeding speed of the filaments was 50 m/min, and the draw ratio was 5\^0. Sample A was prepared under the same conditions except the heating mode, the filaments were heated by hot rolls. Some difference in structure and mechanical properties were found for the two samples.Sample B exhibited high tenacity (0\^8 GPa),elongation(9\^2%) and toughness (0\^047 GPa).The latter was about 1\^8 times as high as that of sample A.Both of the samples were obviously oriented.WAXD and density measurements showed the crystallinity and the crystallite size of sample B were larger than those of the sample A.
文摘The photoluminescence spectrum of poly(ethylene terephthalate) (PET) excited by light with wavelength in the reign from 260 to 360?nm was investigated.When the excitation wavelength was shorter than 300?nm,it was observed that the profile and structure of the photoluminescence spectrum of PET did not change with the increase of the excitation wavelength. When the excitation wavelength was longer than 300 nm,the wavelength dependence of the spectrum was observed. Excited in the reign from 300 nm to the value that was a little larger than the maximum excitation wavelength, there was only one main peak at 367 nm in the photoluminescence spectrum. However, with the continued increasing of the excitation wavelength, another peak appeared at 387 nm and its intensity increased accompanying with the decrease of the intensity of the peak at 367 nm. At last, the peak at 387 nm became the main peak and the peak at 367 nm changed to the second main peak. It was suggested that the photoluminescence of 367 nm and 387 nm would rather come from the excimeric emission and the ground state dimmer, respectively, than origin from the same emitting center.
