A molecular characterization of hyper-cross-linked hybrid polyPOSS-imide networks

Sylvie Neyertz, David Brown, Michiel Raaijmakers, Nieck Edwin Benes

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)

Abstract

Hybrid hyper-cross-linked membranes based on inorganic polyhedral oligomeric silsesquioxanes (POSS) covalently bonded with organic imides have been shown to maintain remarkable molecular sieving abilities and gas separation performances up to 300 C. These films are obtained through the interfacial polycondensation of POSS with a dianhydride, leading to a polyPOSS-(amic acid) network, which is then converted to a polyPOSS-imide network by thermal imidization. Using the pyromellitic (PMDA) dianhydride as a test case, the underlying molecular structures have been generated by molecular dynamics (MD) simulations and specific algorithms which closely mimicked the mixing, polycondensation and imidization steps of the experimental scheme. This allowed realistic models of the final cross-linked imide networks to be compared with their un-cross-linked monomer mixtures and their intermediate amic-acid precursors. Both the formation of the network and the subsequent imidization decreased the density as the systems became sterically more constrained. The volume shrinkage during imidization was less than expected considering the amount of water removal. This led to a larger void space and an improved gas solubility for the polyPOSS-imide films. Although the networks were constructed with the experimentally-found average of four linked arms per POSS, the distribution of the number of links per POSS were quite wide with a range from zero to the maximum possible of eight links per POSS. There was also considerable heterogeneity in the POSS imide POSS angles, which was related to the flexible aliphatic linker between the organic and inorganic moieties. Thermomechanical analyses confirmed that these cross-linked materials were well-suited for high-temperature applications. When subjected to uniaxial tension, they strain hardened at large deformations and their elastic moduli remained solid-like at high temperatures.
Original languageEnglish
Pages (from-to)338-353
JournalComputational materials science
Volume117
DOIs
Publication statusPublished - 2016

Fingerprint

Imides
imides
Interfacial polycondensation
High temperature applications
Acids
Polycondensation
Gases
Molecular structure
Molecular dynamics
Solubility
Monomers
Elastic moduli
Membranes
Computer simulation
acids
Elastic Modulus
Water
Large Deformation
Shrinkage
Voids

Keywords

  • METIS-316130
  • IR-100063

Cite this

Neyertz, Sylvie ; Brown, David ; Raaijmakers, Michiel ; Benes, Nieck Edwin. / A molecular characterization of hyper-cross-linked hybrid polyPOSS-imide networks. In: Computational materials science. 2016 ; Vol. 117. pp. 338-353.
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abstract = "Hybrid hyper-cross-linked membranes based on inorganic polyhedral oligomeric silsesquioxanes (POSS) covalently bonded with organic imides have been shown to maintain remarkable molecular sieving abilities and gas separation performances up to 300 C. These films are obtained through the interfacial polycondensation of POSS with a dianhydride, leading to a polyPOSS-(amic acid) network, which is then converted to a polyPOSS-imide network by thermal imidization. Using the pyromellitic (PMDA) dianhydride as a test case, the underlying molecular structures have been generated by molecular dynamics (MD) simulations and specific algorithms which closely mimicked the mixing, polycondensation and imidization steps of the experimental scheme. This allowed realistic models of the final cross-linked imide networks to be compared with their un-cross-linked monomer mixtures and their intermediate amic-acid precursors. Both the formation of the network and the subsequent imidization decreased the density as the systems became sterically more constrained. The volume shrinkage during imidization was less than expected considering the amount of water removal. This led to a larger void space and an improved gas solubility for the polyPOSS-imide films. Although the networks were constructed with the experimentally-found average of four linked arms per POSS, the distribution of the number of links per POSS were quite wide with a range from zero to the maximum possible of eight links per POSS. There was also considerable heterogeneity in the POSS imide POSS angles, which was related to the flexible aliphatic linker between the organic and inorganic moieties. Thermomechanical analyses confirmed that these cross-linked materials were well-suited for high-temperature applications. When subjected to uniaxial tension, they strain hardened at large deformations and their elastic moduli remained solid-like at high temperatures.",
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A molecular characterization of hyper-cross-linked hybrid polyPOSS-imide networks. / Neyertz, Sylvie; Brown, David; Raaijmakers, Michiel; Benes, Nieck Edwin.

In: Computational materials science, Vol. 117, 2016, p. 338-353.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - A molecular characterization of hyper-cross-linked hybrid polyPOSS-imide networks

AU - Neyertz, Sylvie

AU - Brown, David

AU - Raaijmakers, Michiel

AU - Benes, Nieck Edwin

PY - 2016

Y1 - 2016

N2 - Hybrid hyper-cross-linked membranes based on inorganic polyhedral oligomeric silsesquioxanes (POSS) covalently bonded with organic imides have been shown to maintain remarkable molecular sieving abilities and gas separation performances up to 300 C. These films are obtained through the interfacial polycondensation of POSS with a dianhydride, leading to a polyPOSS-(amic acid) network, which is then converted to a polyPOSS-imide network by thermal imidization. Using the pyromellitic (PMDA) dianhydride as a test case, the underlying molecular structures have been generated by molecular dynamics (MD) simulations and specific algorithms which closely mimicked the mixing, polycondensation and imidization steps of the experimental scheme. This allowed realistic models of the final cross-linked imide networks to be compared with their un-cross-linked monomer mixtures and their intermediate amic-acid precursors. Both the formation of the network and the subsequent imidization decreased the density as the systems became sterically more constrained. The volume shrinkage during imidization was less than expected considering the amount of water removal. This led to a larger void space and an improved gas solubility for the polyPOSS-imide films. Although the networks were constructed with the experimentally-found average of four linked arms per POSS, the distribution of the number of links per POSS were quite wide with a range from zero to the maximum possible of eight links per POSS. There was also considerable heterogeneity in the POSS imide POSS angles, which was related to the flexible aliphatic linker between the organic and inorganic moieties. Thermomechanical analyses confirmed that these cross-linked materials were well-suited for high-temperature applications. When subjected to uniaxial tension, they strain hardened at large deformations and their elastic moduli remained solid-like at high temperatures.

AB - Hybrid hyper-cross-linked membranes based on inorganic polyhedral oligomeric silsesquioxanes (POSS) covalently bonded with organic imides have been shown to maintain remarkable molecular sieving abilities and gas separation performances up to 300 C. These films are obtained through the interfacial polycondensation of POSS with a dianhydride, leading to a polyPOSS-(amic acid) network, which is then converted to a polyPOSS-imide network by thermal imidization. Using the pyromellitic (PMDA) dianhydride as a test case, the underlying molecular structures have been generated by molecular dynamics (MD) simulations and specific algorithms which closely mimicked the mixing, polycondensation and imidization steps of the experimental scheme. This allowed realistic models of the final cross-linked imide networks to be compared with their un-cross-linked monomer mixtures and their intermediate amic-acid precursors. Both the formation of the network and the subsequent imidization decreased the density as the systems became sterically more constrained. The volume shrinkage during imidization was less than expected considering the amount of water removal. This led to a larger void space and an improved gas solubility for the polyPOSS-imide films. Although the networks were constructed with the experimentally-found average of four linked arms per POSS, the distribution of the number of links per POSS were quite wide with a range from zero to the maximum possible of eight links per POSS. There was also considerable heterogeneity in the POSS imide POSS angles, which was related to the flexible aliphatic linker between the organic and inorganic moieties. Thermomechanical analyses confirmed that these cross-linked materials were well-suited for high-temperature applications. When subjected to uniaxial tension, they strain hardened at large deformations and their elastic moduli remained solid-like at high temperatures.

KW - METIS-316130

KW - IR-100063

U2 - 10.1016/j.commatsci.2016.02.015

DO - 10.1016/j.commatsci.2016.02.015

M3 - Article

VL - 117

SP - 338

EP - 353

JO - Computational materials science

JF - Computational materials science

SN - 0927-0256

ER -