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Title: Melt and Solid-State Structures of Polydisperse Polyolefin Multiblock Copolymers

Abstract

Crystallization in polydisperse ethylene-octene multiblock copolymers, polymerized via chain shuttling chemistry, is examined using two-dimensional synchrotron small- and wide-angle X-ray scattering on flow-aligned specimens. The multiblocks are composed of alternating crystalline (hard) blocks of low 1-octene content and amorphous (soft) blocks of high 1-octene content; the block lengths and the number of blocks per chain are characterized by most-probable distributions. These polymers self-assemble into lamellar domain morphologies in the melt, and the melt morphology is retained in the solid state. Despite extensive mixing between hard and soft blocks, the high crystallinity (>50%) of the hard blocks leads to an alignment of the crystallites within the domain structure, with the orthorhombic polyethylene c-axis generally perpendicular to the lamellar domain normal. The interlamellar domain spacings exhibited by the multiblocks, which exceed 100 nm, are estimated to be 5 times larger than those in near-monodisperse block copolymers having a similar chemical composition and a number-average molecular weight equivalent to the multiblock's 'constituent diblock' repeating unit. This swelling factor exceeds the value of 3 previously reported for analogous polydisperse olefin diblock copolymers, due to the lower segregation strength and enhanced phase mixing of the multiblocks studied here.

Authors:
; ; ;  [1];  [2]
  1. (Dow)
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
NSFINDUSTRY
OSTI Identifier:
1047918
Resource Type:
Journal Article
Journal Name:
Macromolecules
Additional Journal Information:
Journal Volume: 45; Journal Issue: (14) ; 07, 2012
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; ALIGNMENT; ALKENES; CHAINS; CHEMICAL COMPOSITION; CHEMISTRY; COPOLYMERS; CRYSTALLIZATION; DOMAIN STRUCTURE; MOLECULAR WEIGHT; MORPHOLOGY; POLYETHYLENES; POLYMERS; POLYOLEFINS; SCATTERING; SEGREGATION; SWELLING; SYNCHROTRONS

Citation Formats

Li, Sheng, Register, Richard A., Weinhold, Jeffrey D., Landes, Brian G., and Princeton). Melt and Solid-State Structures of Polydisperse Polyolefin Multiblock Copolymers. United States: N. p., 2012. Web. doi:10.1021/ma300910m.
Li, Sheng, Register, Richard A., Weinhold, Jeffrey D., Landes, Brian G., & Princeton). Melt and Solid-State Structures of Polydisperse Polyolefin Multiblock Copolymers. United States. doi:10.1021/ma300910m.
Li, Sheng, Register, Richard A., Weinhold, Jeffrey D., Landes, Brian G., and Princeton). Tue . "Melt and Solid-State Structures of Polydisperse Polyolefin Multiblock Copolymers". United States. doi:10.1021/ma300910m.
@article{osti_1047918,
title = {Melt and Solid-State Structures of Polydisperse Polyolefin Multiblock Copolymers},
author = {Li, Sheng and Register, Richard A. and Weinhold, Jeffrey D. and Landes, Brian G. and Princeton)},
abstractNote = {Crystallization in polydisperse ethylene-octene multiblock copolymers, polymerized via chain shuttling chemistry, is examined using two-dimensional synchrotron small- and wide-angle X-ray scattering on flow-aligned specimens. The multiblocks are composed of alternating crystalline (hard) blocks of low 1-octene content and amorphous (soft) blocks of high 1-octene content; the block lengths and the number of blocks per chain are characterized by most-probable distributions. These polymers self-assemble into lamellar domain morphologies in the melt, and the melt morphology is retained in the solid state. Despite extensive mixing between hard and soft blocks, the high crystallinity (>50%) of the hard blocks leads to an alignment of the crystallites within the domain structure, with the orthorhombic polyethylene c-axis generally perpendicular to the lamellar domain normal. The interlamellar domain spacings exhibited by the multiblocks, which exceed 100 nm, are estimated to be 5 times larger than those in near-monodisperse block copolymers having a similar chemical composition and a number-average molecular weight equivalent to the multiblock's 'constituent diblock' repeating unit. This swelling factor exceeds the value of 3 previously reported for analogous polydisperse olefin diblock copolymers, due to the lower segregation strength and enhanced phase mixing of the multiblocks studied here.},
doi = {10.1021/ma300910m},
journal = {Macromolecules},
number = (14) ; 07, 2012,
volume = 45,
place = {United States},
year = {2012},
month = {10}
}