Thin crystal melting produces the low-temperature endotherm in ethylene/methacrylic acid ionomers

Yueh Lin Loo; Katsuyuki Wakabayashi; Y. Evelyn Huang; Richard Alan Register; Benjamin S. Hsiao

doi:10.1016/j.polymer.2005.04.043

Thin crystal melting produces the low-temperature endotherm in ethylene/methacrylic acid ionomers

Yueh Lin Loo, Katsuyuki Wakabayashi, Y. Evelyn Huang, Richard Alan Register, Benjamin S. Hsiao

Research output: Contribution to journal › Article › peer-review

52 Scopus citations

Abstract

Upon extended aging at room temperature, ethylene/methacrylic acid (E/MAA) ionomers develop an endotherm near 50 °C in their differential scanning calorimetry traces. The origin of this low-temperature endotherm has been the subject of considerable debate, in part because direct structural probes have been little applied to its study. Here, we use in situ small-angle X-ray scattering and wide-angle X-ray diffraction to show that this endotherm reflects the melting of thin polyethylene crystals, which gradually develop following primary crystallization. These secondary crystals form within the amorphous layers separating primary crystals. When the framework of primary crystals is oriented by crystallization during flow, the secondary crystals follow this orientation, indicating that the secondary crystals are not isometric fringed micelles but instead have a substantial lateral extent.

Original language	English (US)
Pages (from-to)	5118-5124
Number of pages	7
Journal	Polymer
Volume	46
Issue number	14
DOIs	https://doi.org/10.1016/j.polymer.2005.04.043
State	Published - Jun 27 2005

All Science Journal Classification (ASJC) codes

Organic Chemistry
Polymers and Plastics
Materials Chemistry

Keywords

Ionomer
Secondary crystals
Small-angle X-ray scattering

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10.1016/j.polymer.2005.04.043

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title = "Thin crystal melting produces the low-temperature endotherm in ethylene/methacrylic acid ionomers",

abstract = "Upon extended aging at room temperature, ethylene/methacrylic acid (E/MAA) ionomers develop an endotherm near 50 °C in their differential scanning calorimetry traces. The origin of this low-temperature endotherm has been the subject of considerable debate, in part because direct structural probes have been little applied to its study. Here, we use in situ small-angle X-ray scattering and wide-angle X-ray diffraction to show that this endotherm reflects the melting of thin polyethylene crystals, which gradually develop following primary crystallization. These secondary crystals form within the amorphous layers separating primary crystals. When the framework of primary crystals is oriented by crystallization during flow, the secondary crystals follow this orientation, indicating that the secondary crystals are not isometric fringed micelles but instead have a substantial lateral extent.",

keywords = "Ionomer, Secondary crystals, Small-angle X-ray scattering",

author = "Loo, {Yueh Lin} and Katsuyuki Wakabayashi and Huang, {Y. Evelyn} and Register, {Richard Alan} and Hsiao, {Benjamin S.}",

note = "Funding Information: Financial support for this work came from DuPont Packaging and Industrial Polymers and from the National Science Foundation, Polymers Program (DMR-9711436 and DMR-0220236). We thank Dr John W. Paul (DuPont) for providing Zn80-11 and the corresponding E/MAA copolymer; Dr David M. Dean (DuPont) for the blown film of Zn46-12; and Dr Stephanie T. Lopina (Princeton) for the neutralization of Na16-11. We are also grateful to Dr Fengji Yeh for his assistance with the synchrotron experiments, and to Professor Anthony J. Ryan for the use of his Linkam DSC600. ",

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doi = "10.1016/j.polymer.2005.04.043",

language = "English (US)",

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T1 - Thin crystal melting produces the low-temperature endotherm in ethylene/methacrylic acid ionomers

AU - Loo, Yueh Lin

AU - Wakabayashi, Katsuyuki

AU - Huang, Y. Evelyn

AU - Register, Richard Alan

AU - Hsiao, Benjamin S.

N1 - Funding Information: Financial support for this work came from DuPont Packaging and Industrial Polymers and from the National Science Foundation, Polymers Program (DMR-9711436 and DMR-0220236). We thank Dr John W. Paul (DuPont) for providing Zn80-11 and the corresponding E/MAA copolymer; Dr David M. Dean (DuPont) for the blown film of Zn46-12; and Dr Stephanie T. Lopina (Princeton) for the neutralization of Na16-11. We are also grateful to Dr Fengji Yeh for his assistance with the synchrotron experiments, and to Professor Anthony J. Ryan for the use of his Linkam DSC600.

PY - 2005/6/27

Y1 - 2005/6/27

N2 - Upon extended aging at room temperature, ethylene/methacrylic acid (E/MAA) ionomers develop an endotherm near 50 °C in their differential scanning calorimetry traces. The origin of this low-temperature endotherm has been the subject of considerable debate, in part because direct structural probes have been little applied to its study. Here, we use in situ small-angle X-ray scattering and wide-angle X-ray diffraction to show that this endotherm reflects the melting of thin polyethylene crystals, which gradually develop following primary crystallization. These secondary crystals form within the amorphous layers separating primary crystals. When the framework of primary crystals is oriented by crystallization during flow, the secondary crystals follow this orientation, indicating that the secondary crystals are not isometric fringed micelles but instead have a substantial lateral extent.

AB - Upon extended aging at room temperature, ethylene/methacrylic acid (E/MAA) ionomers develop an endotherm near 50 °C in their differential scanning calorimetry traces. The origin of this low-temperature endotherm has been the subject of considerable debate, in part because direct structural probes have been little applied to its study. Here, we use in situ small-angle X-ray scattering and wide-angle X-ray diffraction to show that this endotherm reflects the melting of thin polyethylene crystals, which gradually develop following primary crystallization. These secondary crystals form within the amorphous layers separating primary crystals. When the framework of primary crystals is oriented by crystallization during flow, the secondary crystals follow this orientation, indicating that the secondary crystals are not isometric fringed micelles but instead have a substantial lateral extent.

KW - Ionomer

KW - Secondary crystals

KW - Small-angle X-ray scattering

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Thin crystal melting produces the low-temperature endotherm in ethylene/methacrylic acid ionomers

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