Electrospun polybutylene terephthalate nanofibers and its effect on the transcrystallization of isotactic polypropylene

• Main Authors: Chih-YungFang, 方志勇
• Other Authors: Chi Wang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/56641313614078839504

碩士 === 國立成功大學 === 化學工程學系碩博士班 === 101 === Electrospun polybutylene terephthalate (PBT) nanofibers were prepared from a trifluoroacetic acid (TFA)-based solvent. The effects of solution viscosity (ηo) on Taylor cone, jet length, jet diameter (dj) and fiber diameter (df) were investigated. The double-logarithmic plots of jet and fiber diameters versus the zero-shear viscosity (ηo) revealed that two scaling laws existed for the present solution, i.e., dj~ηo0.06 and df~ηo0.73. We compared the electrospinning of PBT/TFA solutions with that of PET/TFA solutions under the same conditions. It showed that under the same solution viscosity, the jet diameter of PBT/TFA solution is larger than that of PET solution. However, the diameter of electrospun PBT fibers is smaller. Transcrystallization of isotactic polypropylene (iPP) on as-apun PTT and PBT fibers was investigated by polarized optical microscopy. By measuring the transmitted light intensity under cross-polarized configuration, the induction temperature (Ti) for iPP transcrystallization was determined. We compared the nucleating ability of electrospun PET、PTT and PBT fibers that induced the transcrystallization of iPP. The nucleating ability of PBT fibers was much better than the others. The nucleating ability of fibers could be ranked as follows：PBT 〉 PET 〉 PTT. The electric field distribution of ball/plate electrode configuration was calculated by finite element analysis. Decreasing the diameters of ball electrode led to an increasing in the electric field at the top surface of ball electrode. The double-logarithmic plots of electric field at ball top versus the ball diameter (d) revealed that two scaling laws, i.e., 3D axisymmetric：E/Eo~d-1.00 and 2D plane：E/Eo~d-0.78. It was found that the electric field intensity of ball/plate electrode configuration was stronger than cylinder/plate electrode configuration, but the decay of electric field intensity became larger. As the numbers of ball electrode increased from one to three, the electric field intensity at both side balls were stronger than that of the middle one. As the separation of ball electrode was increased, the electric field decay between the middle ball and collecting plate became smaller. A similar tendency was found for the cylinder/plate electrode configuration.