Yumei Zhang

Synthesis and Non-isothermal Crystallization Behavior of PET/Surface-treated TiO 2 Nanocomposites

Poly(ethylene terephthalate) (PET)/TiO 2 nanocomposites were prepared by melt-blending PET and surface-treated TiO 2 . The crystallization behavior and the non-isothermal crystallization kinetics of these composites were investigated by differential scanning calorimetry (DSC). Jeziorny and Mos methods were applied to describe the kinetics of the non-isothermal crystallization process. It was found that the PET matrix with incorporated surface-treated TiO 2 particles has lower crystallization temperature and melting point than that with incorporated pure nano-TiO 2 particles. Unlike plain TiO 2 , surface-treated TiO 2 particles showed less effect on the degree of crystallization of the PET matrix.

Unstable Supramolecular Structure of [Bmim][BF4] in Aqueous Solution

To unravel the exact composition and structure of aggregates in an aqueous solution of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4 ]), we performed static and dynamic light-scattering measurements, as well as transmission electron microscopy (TEM). Results from this work show that the aggregates are vesicles and unstable; herein, we discuss the driving force behind the self-assembly. Apart from the van der Waals forces and repulsive electrostatic interactions between adjacent cation clusters, the hydrogen-bonding forces as well as counterion effects might also contribute to this driving force. The information obtained here is useful for a better understanding of the vital role that aggregation behavior plays in the field of ionic liquid recovery, and its potential use in controlled release, drug delivery, and petroleum recovery.

Establishment of the Melt Spinning Dynamics Model for Polymeric Nanocomposites

A model suitable to polymeric nanocomposites was developed for the simulation of both low‐ and high‐speed melt spinning. Considering the different content of nanoparticles, different TiO2 modifications, and different take‐up speeds, various spinning parameters along the spinline, such as velocity gradient, tension, relative crystallinity, etc., were predicted. Calculations based on the model indicated that the addition of nanoparticles has a large effect on the spinning parameters, especially relative crystallinity, apparent elongational viscosity, and tensile force