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Crystallization of rare earth oxide‐filled polypropylene
Author(s) -
Liu Jingjiang,
Tang Gongben,
Qu Guijie,
Zhou Huarong,
Guo Qipeng
Publication year - 1993
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1993.070471204
Subject(s) - crystallization , nucleation , materials science , crystallinity , oxide , isothermal process , polypropylene , yttrium , differential scanning calorimetry , activation energy , chemical engineering , thermodynamics , composite material , chemistry , metallurgy , physics , engineering
A study has been made of the crystallization behavior of polypropylene (PP) filled with rare earth oxides under isothermal conditions. These rare earth oxides include lanthanum oxide (La 2 O 3 ), yttrium oxide (Y 2 O 3 ), and a mixture of rare earth oxides containing 70% Y 2 O 3 (Y 2 O 3 –0.70). A differential scanning calorimeter was used to monitor the energetics of the crystallization process from the melt. During isothermal crystallization, dependence of the relative degree of crystallinity on time was described by the Avrami equation. It has been shown that the addition of any of the three rare earth oxides causes a considerable increase in the overall crystallization rate of PP but does not influence the mechanism of nucleation and growth of the PP crystals. The analysis of kinetic data according to nucleation theories shows that the increase in crystallization rate of PP in the composites is due to the decrease in surface energy of the extremity surfaces. The relative contents of the β‐form in the composites are somewhat higher than that in the plain PP. However, the contents of the β‐form in the plain PP and the composites are all very low relative to those of the β‐form and the influence of the formation of the β‐form on the crystallization kinetics can be neglected. © 1993 John Wiley & Sons, Inc.