Phosphonium-containing ABA triblock copolymers

Controlled free radical polymerization of phosphonium ionic liquids

Shijing Cheng, Frederick L. Beyer, Brian D. Mather, Robert B. Moore, Timothy Edward Long

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

Phosphonium ion-containing acrylate triblock (ABA) copolymers were synthesized using nitroxide mediated radical polymerization. The polymerization of styrenic phosphonium-containing ionic liquid monomers using a difunctional alkoxyamine initiator, DEPN2, afforded an ABA triblock copolymer with an n-butyl acrylate soft center block (DP ∼ 400) and symmetric phosphonium-containing external reinforcing blocks (DP < 30). Two phosphonium monomers with different alkyl substituent lengths enabled an investigation of the effects of ionic aggregation of phosphonium cations on the physical properties of ABA block copolymer ionomers. Subsequently, the thermomechanical properties and morphologies of these materials were compared to a noncharged triblock copolymer analogue with neutral polystyrene external blocks. Shortening the alkyl substituents on the phosphonium cation enhanced the hydrophilicity of tributyl-4-vinylbenzyl phosphonium chloride (BPCl) relative to trioctyl-4-vinylbenzyl phosphonium chloride (OPCl). In both cases, phosphonium cations promoted microphase-separation and thermoplastic elastomer performance for the OPCl- and BPCl-containing triblock copolymers compared to a less well-defined, microphase segregated morphology for the styrene analogue. Dynamic mechanical analysis (DMA) of phosphonium-containing triblock copolymers exhibited well-defined rubbery plateau regions, whereas the plateau was shortened for the nonionic analogue. The solid state morphologies of the block copolymers were studied using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), and both techniques revealed phase separation at the nanoscale. DMA studies indicated that phosphonium aggregation governed flow activation energies.

Original languageEnglish
Pages (from-to)6509-6517
Number of pages9
JournalMacromolecules
Volume44
Issue number16
DOIs
Publication statusPublished - 2011 Aug 23
Externally publishedYes

Fingerprint

Ionic Liquids
Free radical polymerization
Ionic liquids
Block copolymers
Cations
Positive ions
Dynamic mechanical analysis
Agglomeration
Monomers
Microphase separation
Thermoplastic elastomers
Styrene
Ionomers
Polystyrenes
Hydrophilicity
X ray scattering
Phase separation
Activation energy
Physical properties
Polymerization

ASJC Scopus subject areas

  • Organic Chemistry
  • Materials Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry

Cite this

Phosphonium-containing ABA triblock copolymers : Controlled free radical polymerization of phosphonium ionic liquids. / Cheng, Shijing; Beyer, Frederick L.; Mather, Brian D.; Moore, Robert B.; Long, Timothy Edward.

In: Macromolecules, Vol. 44, No. 16, 23.08.2011, p. 6509-6517.

Research output: Contribution to journalArticle

Cheng, Shijing ; Beyer, Frederick L. ; Mather, Brian D. ; Moore, Robert B. ; Long, Timothy Edward. / Phosphonium-containing ABA triblock copolymers : Controlled free radical polymerization of phosphonium ionic liquids. In: Macromolecules. 2011 ; Vol. 44, No. 16. pp. 6509-6517.
@article{164fb503dbb845a6af1f85a3585b3a52,
title = "Phosphonium-containing ABA triblock copolymers: Controlled free radical polymerization of phosphonium ionic liquids",
abstract = "Phosphonium ion-containing acrylate triblock (ABA) copolymers were synthesized using nitroxide mediated radical polymerization. The polymerization of styrenic phosphonium-containing ionic liquid monomers using a difunctional alkoxyamine initiator, DEPN2, afforded an ABA triblock copolymer with an n-butyl acrylate soft center block (DP ∼ 400) and symmetric phosphonium-containing external reinforcing blocks (DP < 30). Two phosphonium monomers with different alkyl substituent lengths enabled an investigation of the effects of ionic aggregation of phosphonium cations on the physical properties of ABA block copolymer ionomers. Subsequently, the thermomechanical properties and morphologies of these materials were compared to a noncharged triblock copolymer analogue with neutral polystyrene external blocks. Shortening the alkyl substituents on the phosphonium cation enhanced the hydrophilicity of tributyl-4-vinylbenzyl phosphonium chloride (BPCl) relative to trioctyl-4-vinylbenzyl phosphonium chloride (OPCl). In both cases, phosphonium cations promoted microphase-separation and thermoplastic elastomer performance for the OPCl- and BPCl-containing triblock copolymers compared to a less well-defined, microphase segregated morphology for the styrene analogue. Dynamic mechanical analysis (DMA) of phosphonium-containing triblock copolymers exhibited well-defined rubbery plateau regions, whereas the plateau was shortened for the nonionic analogue. The solid state morphologies of the block copolymers were studied using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), and both techniques revealed phase separation at the nanoscale. DMA studies indicated that phosphonium aggregation governed flow activation energies.",
author = "Shijing Cheng and Beyer, {Frederick L.} and Mather, {Brian D.} and Moore, {Robert B.} and Long, {Timothy Edward}",
year = "2011",
month = "8",
day = "23",
doi = "10.1021/ma200829h",
language = "English",
volume = "44",
pages = "6509--6517",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "16",

}

TY - JOUR

T1 - Phosphonium-containing ABA triblock copolymers

T2 - Controlled free radical polymerization of phosphonium ionic liquids

AU - Cheng, Shijing

AU - Beyer, Frederick L.

AU - Mather, Brian D.

AU - Moore, Robert B.

AU - Long, Timothy Edward

PY - 2011/8/23

Y1 - 2011/8/23

N2 - Phosphonium ion-containing acrylate triblock (ABA) copolymers were synthesized using nitroxide mediated radical polymerization. The polymerization of styrenic phosphonium-containing ionic liquid monomers using a difunctional alkoxyamine initiator, DEPN2, afforded an ABA triblock copolymer with an n-butyl acrylate soft center block (DP ∼ 400) and symmetric phosphonium-containing external reinforcing blocks (DP < 30). Two phosphonium monomers with different alkyl substituent lengths enabled an investigation of the effects of ionic aggregation of phosphonium cations on the physical properties of ABA block copolymer ionomers. Subsequently, the thermomechanical properties and morphologies of these materials were compared to a noncharged triblock copolymer analogue with neutral polystyrene external blocks. Shortening the alkyl substituents on the phosphonium cation enhanced the hydrophilicity of tributyl-4-vinylbenzyl phosphonium chloride (BPCl) relative to trioctyl-4-vinylbenzyl phosphonium chloride (OPCl). In both cases, phosphonium cations promoted microphase-separation and thermoplastic elastomer performance for the OPCl- and BPCl-containing triblock copolymers compared to a less well-defined, microphase segregated morphology for the styrene analogue. Dynamic mechanical analysis (DMA) of phosphonium-containing triblock copolymers exhibited well-defined rubbery plateau regions, whereas the plateau was shortened for the nonionic analogue. The solid state morphologies of the block copolymers were studied using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), and both techniques revealed phase separation at the nanoscale. DMA studies indicated that phosphonium aggregation governed flow activation energies.

AB - Phosphonium ion-containing acrylate triblock (ABA) copolymers were synthesized using nitroxide mediated radical polymerization. The polymerization of styrenic phosphonium-containing ionic liquid monomers using a difunctional alkoxyamine initiator, DEPN2, afforded an ABA triblock copolymer with an n-butyl acrylate soft center block (DP ∼ 400) and symmetric phosphonium-containing external reinforcing blocks (DP < 30). Two phosphonium monomers with different alkyl substituent lengths enabled an investigation of the effects of ionic aggregation of phosphonium cations on the physical properties of ABA block copolymer ionomers. Subsequently, the thermomechanical properties and morphologies of these materials were compared to a noncharged triblock copolymer analogue with neutral polystyrene external blocks. Shortening the alkyl substituents on the phosphonium cation enhanced the hydrophilicity of tributyl-4-vinylbenzyl phosphonium chloride (BPCl) relative to trioctyl-4-vinylbenzyl phosphonium chloride (OPCl). In both cases, phosphonium cations promoted microphase-separation and thermoplastic elastomer performance for the OPCl- and BPCl-containing triblock copolymers compared to a less well-defined, microphase segregated morphology for the styrene analogue. Dynamic mechanical analysis (DMA) of phosphonium-containing triblock copolymers exhibited well-defined rubbery plateau regions, whereas the plateau was shortened for the nonionic analogue. The solid state morphologies of the block copolymers were studied using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), and both techniques revealed phase separation at the nanoscale. DMA studies indicated that phosphonium aggregation governed flow activation energies.

UR - http://www.scopus.com/inward/record.url?scp=80051768526&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80051768526&partnerID=8YFLogxK

U2 - 10.1021/ma200829h

DO - 10.1021/ma200829h

M3 - Article

VL - 44

SP - 6509

EP - 6517

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

IS - 16

ER -