【摘要】 使用扫描电镜、X射线粉末衍射、傅里叶红外光谱和差热分析等方法,对不同温度超临界CO₂流体中PBT纤维表面形态结构、聚集态结构、化学结构及耐热性能的变化情况进行了研究。扫描电镜观察结果显示,由于CO₂流体的增塑膨化作用,在不同温度的流体介质中处理时,纤维中各类低聚物、歧聚物不断向表面迁移,并随流体温度升高而变得更明显;而当流体温度高于100℃时,在CO₂流体的溶解作用下,纤维表面的各类低聚物、歧聚物开始减少。纤维的X射线粉末衍射分析表明,随流体温度升高,PPT纤维的结晶度总体呈现不同程度的降低。红外光谱分析显示,不同温度条件下的流体处理对PBT纤维的化学结构没有显著影响,但使得纤维链段及其主要官能团所处化学环境,以及其排列、超分子结构受到一定影响。不同温度的流体介质可对PBT纤维的宏观热稳定性产生一定影响,其中流体温度为80℃时影响较明显。更多还原

【Abstract】 SEM, X-ray powder diffraction, Fourier transform infrared spectroscopy and differential thermal analysis were used to study the surface morphology, aggregation structure, chemical structure and heat resistance of PBT fibers in supercritical CO₂ fluid at different temperatures. The SEM investigation showed that due to plasticization and swelling actions, the oligomers remained in the inner phase of PBT fiber migrated to the surfaces of the fiber during the fluid treatment from supercritical CO₂ fluid; the higher fluid temperature is, the more obvious the phenomenon is. However, when the fluid temperature is higher than 100 ℃, oligomers reduced under enhanced dissolution in the supercritical fluid medium. XRD analysis revealed that with the increased fluid temperature, the crystallinity of PBT fiber was decreased in a general tendency. FTIR investigation indicated that the treatment of supercritical CO₂ fluid under different temperature didn’t affect the chemical structure of the fiber evidently, but could bring some effects on the chemical environments of chain segment and functional groups, as well as their arrangements and the supramolecular structure. Fluid media with different temperatures can affect the macroscopic thermal stability of PBT fibers, and the effect is obvious when the fluid temperature is 80 ℃.更多还原