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Title: Microphase separated structures in the solid and molten states of double-crystal graft copolymers of polyethylene and poly(ethylene oxide)

Abstract

Transitions from one microphase separated structure in the solid state to a different one in the molten state in polyethylene-graft-poly(ethylene oxide) copolymers, PE-g-PEO, were investigated by variable temperature X-ray scattering measurements and thermal analyses. Small-angle X-ray scattering patterns from polymers with PEO grafts with 25, 50 and 100 ethylene oxide (EO) units show that the polymer passes through three distinct structures at {approx}10 nm length scales with increase in temperature (T): lamellar structures of PE and PEO at T < T{sub m}{sup PEO}, PE lamellae surrounded by molten PEO at T{sub m}{sup PEO} < T < T{sub m}{sup PE}, and microphase separated structures at T > T{sub m}{sup PE} when both PE and PEO are molten (T{sub m} refers to the melting temperature). These phase transformations also occur during cooling but with hysteresis. Crystalline phases of PEO side chains and PE main chains could be identified in the wide-angle X-ray diffraction profiles indicating that the PE backbone and PEO grafts crystallize into separate domains, especially with longer grafted chains (50 and 100 units). At EO segment lengths >50, PEO shows the expected increase in melting and crystallization temperatures with the increase in the grafted chain length. PE does not affectmore » T{sub m}{sup PEO} but does decrease the onset of crystallization upon cooling. PEO grafts result in fractionation of PE, decrease the melting point of PE and increase the undercooling for the onset of crystallization of PE.« less

Authors:
; ; ; ; ;  [1]
  1. Vermont
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE
OSTI Identifier:
1006694
Resource Type:
Journal Article
Journal Name:
Polymer
Additional Journal Information:
Journal Volume: 49; Journal Issue: (13-14) ; 06, 2008; Journal ID: ISSN 0032-3861
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; COOLING; COPOLYMERS; CRYSTALLIZATION; ETHYLENE; FRACTIONATION; GRAFT POLYMERS; HYSTERESIS; LAMELLAE; LENGTH; MELTING; MELTING POINTS; OXIDES; PHASE TRANSFORMATIONS; PLASMA SWITCHES; POLYETHYLENES; POLYMERS; SCATTERING; SOLIDS; UNITS; X-RAY DIFFRACTION

Citation Formats

Mark, P R, Murthy, N S, Weigand, S, Breitenkamp, K, Kade, M, Emrick, T, NWU), and UMASS, Amherst). Microphase separated structures in the solid and molten states of double-crystal graft copolymers of polyethylene and poly(ethylene oxide). United States: N. p., 2008. Web. doi:10.1016/j.polymer.2008.05.012.
Mark, P R, Murthy, N S, Weigand, S, Breitenkamp, K, Kade, M, Emrick, T, NWU), & UMASS, Amherst). Microphase separated structures in the solid and molten states of double-crystal graft copolymers of polyethylene and poly(ethylene oxide). United States. https://doi.org/10.1016/j.polymer.2008.05.012
Mark, P R, Murthy, N S, Weigand, S, Breitenkamp, K, Kade, M, Emrick, T, NWU), and UMASS, Amherst). Tue . "Microphase separated structures in the solid and molten states of double-crystal graft copolymers of polyethylene and poly(ethylene oxide)". United States. https://doi.org/10.1016/j.polymer.2008.05.012.
@article{osti_1006694,
title = {Microphase separated structures in the solid and molten states of double-crystal graft copolymers of polyethylene and poly(ethylene oxide)},
author = {Mark, P R and Murthy, N S and Weigand, S and Breitenkamp, K and Kade, M and Emrick, T and NWU) and UMASS, Amherst)},
abstractNote = {Transitions from one microphase separated structure in the solid state to a different one in the molten state in polyethylene-graft-poly(ethylene oxide) copolymers, PE-g-PEO, were investigated by variable temperature X-ray scattering measurements and thermal analyses. Small-angle X-ray scattering patterns from polymers with PEO grafts with 25, 50 and 100 ethylene oxide (EO) units show that the polymer passes through three distinct structures at {approx}10 nm length scales with increase in temperature (T): lamellar structures of PE and PEO at T < T{sub m}{sup PEO}, PE lamellae surrounded by molten PEO at T{sub m}{sup PEO} < T < T{sub m}{sup PE}, and microphase separated structures at T > T{sub m}{sup PE} when both PE and PEO are molten (T{sub m} refers to the melting temperature). These phase transformations also occur during cooling but with hysteresis. Crystalline phases of PEO side chains and PE main chains could be identified in the wide-angle X-ray diffraction profiles indicating that the PE backbone and PEO grafts crystallize into separate domains, especially with longer grafted chains (50 and 100 units). At EO segment lengths >50, PEO shows the expected increase in melting and crystallization temperatures with the increase in the grafted chain length. PE does not affect T{sub m}{sup PEO} but does decrease the onset of crystallization upon cooling. PEO grafts result in fractionation of PE, decrease the melting point of PE and increase the undercooling for the onset of crystallization of PE.},
doi = {10.1016/j.polymer.2008.05.012},
url = {https://www.osti.gov/biblio/1006694}, journal = {Polymer},
issn = {0032-3861},
number = (13-14) ; 06, 2008,
volume = 49,
place = {United States},
year = {2008},
month = {8}
}