Physical Aging of Polylactide-Based Graft Block Polymers

Ingrid N. Haugan, Bongjoon Lee, Michael J. Maher, Aristotelis Zografos, Haley J. Schibur, Seamus D. Jones, Marc A. Hillmyer, Frank S. Bates

Research output: Contribution to journalArticle

Abstract

Graft block copolymers (BCPs) with poly(4-methyl caprolactone)-block-poly(±-lactide) (P4MCL-PLA) side chains containing 80-100% PLA content were synthesized with the aim of producing tough and sustainable plastics. These graft BCPs experience physical aging and become brittle over time. For short aging times, ta, the samples are ductile and shear yielding is the primary deformation mechanism. A double-yield phenomenon emerges at intermediate ta where the materials deform by stress whitening followed by shear yielding. At long ta, the samples become brittle and fail after crazing. PLA content strongly governs the time to brittle failure, where a 100% PLA graft polymer embrittles in 1 day, an 86% PLA graft BCP embrittles in 35 days, and at 80% PLA, the material remains ductile after 210 days. Molecular architecture is also a factor in increasing the persistence of ductility with time; a linear triblock ages three times faster than a graft BCP with the same PLA content. Small-angle X-ray scattering and transmission electron microscopy analysis suggest that the rubbery P4MCL domains play a role in initiating crazing by cavitation. Prestraining the graft BCPs also significantly toughens these glassy materials. Physical aging-induced embrittlement is eliminated in all of the prestrained polymers, which remain ductile after aging 60 days. The prestrained graft BCPs also demonstrate shape memory properties. When heated above the glass-transition temperature (Tg), the stretched polymer within seconds returns to its original shape and recovers the original mechanical properties of the unstrained material. These results demonstrate that graft BCPs can be used to make tough, durable, and sustainable plastics and highlight the importance of understanding the mechanical performance of sustainable plastics over extended periods of time following processing.

Original languageEnglish (US)
Pages (from-to)8878-8894
Number of pages17
JournalMacromolecules
Volume52
Issue number22
DOIs
StatePublished - Nov 26 2019

Fingerprint

Graft copolymers
Block copolymers
Aging of materials
Crazing
Plastics
Polymers
poly(lactide)
Embrittlement
X ray scattering
Shape memory effect
Cavitation
Ductility
Transmission electron microscopy
Mechanical properties
Processing

How much support was provided by MRSEC?

  • Shared

Reporting period for MRSEC

  • Period 6

Cite this

Haugan, I. N., Lee, B., Maher, M. J., Zografos, A., Schibur, H. J., Jones, S. D., ... Bates, F. S. (2019). Physical Aging of Polylactide-Based Graft Block Polymers. Macromolecules, 52(22), 8878-8894. https://doi.org/10.1021/acs.macromol.9b01434

Physical Aging of Polylactide-Based Graft Block Polymers. / Haugan, Ingrid N.; Lee, Bongjoon; Maher, Michael J.; Zografos, Aristotelis; Schibur, Haley J.; Jones, Seamus D.; Hillmyer, Marc A.; Bates, Frank S.

In: Macromolecules, Vol. 52, No. 22, 26.11.2019, p. 8878-8894.

Research output: Contribution to journalArticle

Haugan, IN, Lee, B, Maher, MJ, Zografos, A, Schibur, HJ, Jones, SD, Hillmyer, MA & Bates, FS 2019, 'Physical Aging of Polylactide-Based Graft Block Polymers', Macromolecules, vol. 52, no. 22, pp. 8878-8894. https://doi.org/10.1021/acs.macromol.9b01434
Haugan IN, Lee B, Maher MJ, Zografos A, Schibur HJ, Jones SD et al. Physical Aging of Polylactide-Based Graft Block Polymers. Macromolecules. 2019 Nov 26;52(22):8878-8894. https://doi.org/10.1021/acs.macromol.9b01434
Haugan, Ingrid N. ; Lee, Bongjoon ; Maher, Michael J. ; Zografos, Aristotelis ; Schibur, Haley J. ; Jones, Seamus D. ; Hillmyer, Marc A. ; Bates, Frank S. / Physical Aging of Polylactide-Based Graft Block Polymers. In: Macromolecules. 2019 ; Vol. 52, No. 22. pp. 8878-8894.
@article{3fd2ca1596b244e0b915b7d9589fde84,
title = "Physical Aging of Polylactide-Based Graft Block Polymers",
abstract = "Graft block copolymers (BCPs) with poly(4-methyl caprolactone)-block-poly(±-lactide) (P4MCL-PLA) side chains containing 80-100{\%} PLA content were synthesized with the aim of producing tough and sustainable plastics. These graft BCPs experience physical aging and become brittle over time. For short aging times, ta, the samples are ductile and shear yielding is the primary deformation mechanism. A double-yield phenomenon emerges at intermediate ta where the materials deform by stress whitening followed by shear yielding. At long ta, the samples become brittle and fail after crazing. PLA content strongly governs the time to brittle failure, where a 100{\%} PLA graft polymer embrittles in 1 day, an 86{\%} PLA graft BCP embrittles in 35 days, and at 80{\%} PLA, the material remains ductile after 210 days. Molecular architecture is also a factor in increasing the persistence of ductility with time; a linear triblock ages three times faster than a graft BCP with the same PLA content. Small-angle X-ray scattering and transmission electron microscopy analysis suggest that the rubbery P4MCL domains play a role in initiating crazing by cavitation. Prestraining the graft BCPs also significantly toughens these glassy materials. Physical aging-induced embrittlement is eliminated in all of the prestrained polymers, which remain ductile after aging 60 days. The prestrained graft BCPs also demonstrate shape memory properties. When heated above the glass-transition temperature (Tg), the stretched polymer within seconds returns to its original shape and recovers the original mechanical properties of the unstrained material. These results demonstrate that graft BCPs can be used to make tough, durable, and sustainable plastics and highlight the importance of understanding the mechanical performance of sustainable plastics over extended periods of time following processing.",
author = "Haugan, {Ingrid N.} and Bongjoon Lee and Maher, {Michael J.} and Aristotelis Zografos and Schibur, {Haley J.} and Jones, {Seamus D.} and Hillmyer, {Marc A.} and Bates, {Frank S.}",
year = "2019",
month = "11",
day = "26",
doi = "10.1021/acs.macromol.9b01434",
language = "English (US)",
volume = "52",
pages = "8878--8894",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "22",

}

TY - JOUR

T1 - Physical Aging of Polylactide-Based Graft Block Polymers

AU - Haugan, Ingrid N.

AU - Lee, Bongjoon

AU - Maher, Michael J.

AU - Zografos, Aristotelis

AU - Schibur, Haley J.

AU - Jones, Seamus D.

AU - Hillmyer, Marc A.

AU - Bates, Frank S.

PY - 2019/11/26

Y1 - 2019/11/26

N2 - Graft block copolymers (BCPs) with poly(4-methyl caprolactone)-block-poly(±-lactide) (P4MCL-PLA) side chains containing 80-100% PLA content were synthesized with the aim of producing tough and sustainable plastics. These graft BCPs experience physical aging and become brittle over time. For short aging times, ta, the samples are ductile and shear yielding is the primary deformation mechanism. A double-yield phenomenon emerges at intermediate ta where the materials deform by stress whitening followed by shear yielding. At long ta, the samples become brittle and fail after crazing. PLA content strongly governs the time to brittle failure, where a 100% PLA graft polymer embrittles in 1 day, an 86% PLA graft BCP embrittles in 35 days, and at 80% PLA, the material remains ductile after 210 days. Molecular architecture is also a factor in increasing the persistence of ductility with time; a linear triblock ages three times faster than a graft BCP with the same PLA content. Small-angle X-ray scattering and transmission electron microscopy analysis suggest that the rubbery P4MCL domains play a role in initiating crazing by cavitation. Prestraining the graft BCPs also significantly toughens these glassy materials. Physical aging-induced embrittlement is eliminated in all of the prestrained polymers, which remain ductile after aging 60 days. The prestrained graft BCPs also demonstrate shape memory properties. When heated above the glass-transition temperature (Tg), the stretched polymer within seconds returns to its original shape and recovers the original mechanical properties of the unstrained material. These results demonstrate that graft BCPs can be used to make tough, durable, and sustainable plastics and highlight the importance of understanding the mechanical performance of sustainable plastics over extended periods of time following processing.

AB - Graft block copolymers (BCPs) with poly(4-methyl caprolactone)-block-poly(±-lactide) (P4MCL-PLA) side chains containing 80-100% PLA content were synthesized with the aim of producing tough and sustainable plastics. These graft BCPs experience physical aging and become brittle over time. For short aging times, ta, the samples are ductile and shear yielding is the primary deformation mechanism. A double-yield phenomenon emerges at intermediate ta where the materials deform by stress whitening followed by shear yielding. At long ta, the samples become brittle and fail after crazing. PLA content strongly governs the time to brittle failure, where a 100% PLA graft polymer embrittles in 1 day, an 86% PLA graft BCP embrittles in 35 days, and at 80% PLA, the material remains ductile after 210 days. Molecular architecture is also a factor in increasing the persistence of ductility with time; a linear triblock ages three times faster than a graft BCP with the same PLA content. Small-angle X-ray scattering and transmission electron microscopy analysis suggest that the rubbery P4MCL domains play a role in initiating crazing by cavitation. Prestraining the graft BCPs also significantly toughens these glassy materials. Physical aging-induced embrittlement is eliminated in all of the prestrained polymers, which remain ductile after aging 60 days. The prestrained graft BCPs also demonstrate shape memory properties. When heated above the glass-transition temperature (Tg), the stretched polymer within seconds returns to its original shape and recovers the original mechanical properties of the unstrained material. These results demonstrate that graft BCPs can be used to make tough, durable, and sustainable plastics and highlight the importance of understanding the mechanical performance of sustainable plastics over extended periods of time following processing.

UR - http://www.scopus.com/inward/record.url?scp=85075157083&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85075157083&partnerID=8YFLogxK

U2 - 10.1021/acs.macromol.9b01434

DO - 10.1021/acs.macromol.9b01434

M3 - Article

AN - SCOPUS:85075157083

VL - 52

SP - 8878

EP - 8894

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

IS - 22

ER -