Kinetics of crystallization for polypropylene/polyethylene/halloysite nanotube nanocomposites

The aim of this study is to investigate the kinetics of non-isothermal crystallization of polypropylene/high-density polyethylene/halloysite nanotube (PP/HDPE/HNT) nanocomposites using three methods, that is, Avrami equation, combined Ozawa–Avrami method (hereafter called Mo model), and Kissinger equation. The Avrami exponent ( n) is in the range of 1–2 for all the PP/HDPE/HNT nanocomposites indicating instantaneous nucleation while the crystallization rate constant ( Zt) values of PP/HDPE increased with the addition of HNT. This proved that addition of HNT increases the crystallization rate. The reduction of half crystallization time ( t 1/2) for PP/HDPE as the increasing HNT loading indicates faster crystallization rate. In the Mo model, the cooling rate chosen at unit crystallization time F( T) values for PP/HDPE decreases with the addition of HNT. Kissinger equation showed that the activation energy ( E a) of crystallization for the PP/HDPE decreases with the addition of HNT. All the results demonstrated that HNT can accelerate the crystallization rate for the PP/polyethylene blends.

Influence of Eu3+-Doped on Phase Transition Kinetics of Pseudoboehmite

The influence of Eu3+-doped on phase transition kinetics of pseudoboehmite has not been reported in the literature. Through dropping Eu(NO3)3into pseudoboehmite colloidal solution, pseudoboehmite xerogel was produced using spray pyrolysis. The influence of Eu3+-doped on the mechanism of pseudoboehmite phase transition kinetics has been calculated and analyzed by TG/DSC, XRD, and Kissinger equation. Part of Eu3+ion formed compound EuAl12O19, which existed betweenα-Al2O3grains. Bulk diffusion of Al3+was prevented from compound EuAl12O19. Therefore, phase transition kinetics rate ofθ-Al2O3 → α-Al2O3was slowed down, causing an increase of phase transition activation energy and elevation of phase transition temperature.