Kinetics of Phase Separation and Crystallization in Poly(Ethylene-Ran-Hexene) and Poly(Ethylene-Ran-Octene)

Published

November 1, 2003

Author(s)

G Matsuba, K Shimizu, Haonan Wang, Z G. Wang, Charles C. Han

Abstract

The kinetics of phase separation and crystallization in the blends of poly(ethylene-co-hexene) (PEH) and poly(ethylene-co-octene) (PEOC) at several compositions were studied by time-resolved phase contrast optical microscopy, differential scanning calorimetry, and simultaneous small-angle X-ray scattering and wide-angle X-ray diffraction (SAXS/WAXD) techniques. The phase contrast optical microscopy showed the interconnected bicontinuous structure during phase separation process, characteristic of a spinodal decomposition. The equilibrium melting temperature decreases with increasing PEOC concentration in the miscible region while remains about 137 C within the phase separation region. The long period increases with time for all samples but is independent of PEOC concentration. The crystallinity and crystal growth rate are dependent on PEOC concentration. The growth rates of sphelurites are similar for 50/50 PEH/PEOC blend and pure PEH. In the lower PEH concentration, PEOC chains are still mixed together with the PEH chains, and PEH becomes harder to crystallize because there are larger amorphous (non-crystallizable) region. On the other hand, at the higher PEH concentration, the crystallization processes are similar to pure PEH. The lamella thickness increases with isothermal time for all samples because of melting and recrystallization processes.

Citation

Polymer

Volume

44

Issue

No. 24

Pub Type

Journals

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Keywords

blends, crystallization, phase diagram, phase separation, polyolefins

Citation

Matsuba, G. , Shimizu, K. , Wang, H. , Wang, Z. and Han, C. (2003), Kinetics of Phase Separation and Crystallization in Poly(Ethylene-Ran-Hexene) and Poly(Ethylene-Ran-Octene), Polymer, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852106 (Accessed January 15, 2025)