Kinetics of crystallization for polypropylenepolyethylenehalloysite nanotube nanocomposites

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Date
2018-06
Authors
Ong, Mun Yee
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Polypropylene (PP) is commonly used due to its affordable price and high performance but its low impact strength limits its applications which can be improved by blending with high density polyethylene (HDPE). Crystallization rate of PP/HDPE is lower compared to pure PP. Therefore, provides the need to use nanofiller as nucleating agent such as HNT. The aim of this thesis is to investigate the effects of HNT on the thermal properties of PP/HDPE blends and the kinetics of non-isothermal crystallization of PP/HDPE/HNT nanocomposites by using Avrami, Kissinger and Mo model. In this study, the incorporation of HNT nanoparticles decreases the crystallization temperature (𝑇𝑐) and increases the degree of crystallinity (𝜒𝑐 ). From the Avrami model, the Avrami exponent (n) is in the range of 1 to 2 for all PP/HDPE/HNT nanocomposites indicating instantaneous nucleation while the crystallization rate constant (𝑍𝑡) values of PP/HDPE increased with the addition of HNT. This indicates that addition of HNT increases crystallization rate. The reduction of half crystallization time (𝑡1/2) for PP/HDPE as the increasing HNT loading indicates faster crystallization rate. Kissinger model showed that the activation energy (𝐸𝑎) of crystallization for the PP/HDPE decreases with the addition of HNT. In Mo model, the cooling rate chosen at unit crystallization time F(T) values for PP/HDPE decreases with the addition of HNT. In summary, the most suitable HNT loading for PP/HDPE blend is 8 wt% HNT as it increases the overall crystallization rate of PP/HDPE blend.
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