ICCAS OpenIR
Liquid-liquid phase separation in a polyethylene blend monitored by crystallization kinetics and crystal-decorated phase morphologies
Wang, Shujun3; Wu, Changjiang1; Ren, Min-Qiao1; Van Horn, Ryan M.3; Graham, Matthew J.3; Han, Charles C.2; Chen, Erqiang1; Cheng, Stephen Z. D.3
2009-02-09
Source PublicationPOLYMER
ISSN0032-3861
Volume50Issue:4Pages:1025-1033
AbstractA series of polyethylene (PE) blends consisting of a linear high density polyethylene (HDPE) and a linear low density polyethylene (LLDPE) with an octane-chain branch density of 120/1000 carbon was prepared at different concentrations. The two components of this set of blends possessed isorefractive indices, thus, making it difficult to detect their liquid-liquid phase separation via scattering techniques. Above the experimentally observed melting temperature of HDPE, T(m) = 133 degrees C, this series of blends can be considered to be in the liquid state. The LLDPE crystallization temperature was below 50 degrees C; therefore, above 80 degrees C and below the melting temperature of HDPE, a series of crystalline-amorphous PE blends could be created. A specifically designed two-step isothermal experimental procedure was utilized to monitor the liquid-liquid phase separation of this set of blends. The first step was to quench the system from temperatures of known miscibility and isothermally anneal them at a temperature higher than the equilibrium melting temperature of the HDPE for the purpose of allowing the phase morphology to develop from liquid-liquid phase separation. The second step was to quench the system to a temperature at which the HDPE could rapidly crystallize. The time for developing 50% of the total crystallinity (t(1/2)) was used to monitor the crystallization kinetics. Because phase separation results in HDPE-rich domains where the crystallization rates are increased, this technique provided an experimental measure to identify the binodal curve of the liquid-liquid phase separation for the system indicated by faster t(1/2). The annealing temperature in the first step that exhibits an onset of the decrease in t(1/2) is the temperature of the binodal point for that blend composition. In addition, the HDPE-rich domains crystallized to form spherulites which decorate the phase-separated morphology. Therefore, the crystal dispersion indicates whether the phase separation followed a nucleation-and-growth process or a spinodal decomposition process. These crystal-decorated morphologies enabled the spinodal curve to be experimentally determined for the first time in this set of blends. (C) 2008 Elsevier Ltd. All rights reserved.
KeywordPolyolefin Blends Liquid-liquid Phase Separation Crystallization
DOI10.1016/j.polymer.2008.12.028
Indexed BySCI
Language英语
WOS IDWOS:000263344200009
PublisherELSEVIER SCI LTD
Citation statistics
Cited Times:17[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.iccas.ac.cn/handle/121111/66652
Collection中国科学院化学研究所
Corresponding AuthorChen, Erqiang
Affiliation1.Peking Univ, Dept Polymer Sci & Engn, Beijing 100871, Peoples R China
2.Chinese Acad Sci, Inst Chem, Beijing 100080, Peoples R China
3.Univ Akron, Coll Polymer Sci & Polymer Engn, Dept Polymer Sci, Akron, OH 44325 USA
Recommended Citation
GB/T 7714
Wang, Shujun,Wu, Changjiang,Ren, Min-Qiao,et al. Liquid-liquid phase separation in a polyethylene blend monitored by crystallization kinetics and crystal-decorated phase morphologies[J]. POLYMER,2009,50(4):1025-1033.
APA Wang, Shujun.,Wu, Changjiang.,Ren, Min-Qiao.,Van Horn, Ryan M..,Graham, Matthew J..,...&Cheng, Stephen Z. D..(2009).Liquid-liquid phase separation in a polyethylene blend monitored by crystallization kinetics and crystal-decorated phase morphologies.POLYMER,50(4),1025-1033.
MLA Wang, Shujun,et al."Liquid-liquid phase separation in a polyethylene blend monitored by crystallization kinetics and crystal-decorated phase morphologies".POLYMER 50.4(2009):1025-1033.
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