Abstract
Polystyrene (PS) was modified by covalently binding P-, P-N- and/or N- containing fireretardant moieties through co- or ter-polymerization reactions of styrene with
diethyl(acryloyloxymethyl)phosphonate (DEAMP), diethyl-p-vinylbenzyl phosphonate (DEpVBP),
acrylic acid-2-[(diethoxyphosphoryl)methylamino]ethyl ester (ADEPMAE) and maleimide (MI). In
the present study, the condensed-phase and the gaseous-phase activities of the abovementioned fire
retardants within the prepared co- and ter-polymers were evaluated for the first time. Pyrolysis–Gas
Chromatography/Mass Spectrometry was employed to identify the volatile products formed during
the thermal decomposition of the modified polymers. Benzaldehyde, α-methylstyrene, acetophenone,
triethyl phosphate and styrene (monomer, dimer and trimer) were detected in the gaseous phase
following the thermal cracking of fire-retardant groups and through main chain scissions. In the
case of PS modified with ADEPMAE, the evolution of pyrolysis gases was suppressed by possible
inhibitory actions of triethyl phosphate in the gaseous phase. The reactive modification of PS by
simultaneously incorporating P- (DEAMP or DEpVBP) and N- (MI) monomeric units, in the chains
of ter-polymers, resulted in a predominantly condensed-phase mode of action owing to synergistic P
and N interactions. The solid-state 31P NMR spectroscopy, Scanning Electron Microscopy/Energy
Dispersive Spectroscopy, Inductively-Coupled Plasma/Optical Emission Spectroscopy and X-ray
Photoelectron Spectroscopy of char residues, obtained from ter-polymers, confirmed the retention of
the phosphorus species in their structures
diethyl(acryloyloxymethyl)phosphonate (DEAMP), diethyl-p-vinylbenzyl phosphonate (DEpVBP),
acrylic acid-2-[(diethoxyphosphoryl)methylamino]ethyl ester (ADEPMAE) and maleimide (MI). In
the present study, the condensed-phase and the gaseous-phase activities of the abovementioned fire
retardants within the prepared co- and ter-polymers were evaluated for the first time. Pyrolysis–Gas
Chromatography/Mass Spectrometry was employed to identify the volatile products formed during
the thermal decomposition of the modified polymers. Benzaldehyde, α-methylstyrene, acetophenone,
triethyl phosphate and styrene (monomer, dimer and trimer) were detected in the gaseous phase
following the thermal cracking of fire-retardant groups and through main chain scissions. In the
case of PS modified with ADEPMAE, the evolution of pyrolysis gases was suppressed by possible
inhibitory actions of triethyl phosphate in the gaseous phase. The reactive modification of PS by
simultaneously incorporating P- (DEAMP or DEpVBP) and N- (MI) monomeric units, in the chains
of ter-polymers, resulted in a predominantly condensed-phase mode of action owing to synergistic P
and N interactions. The solid-state 31P NMR spectroscopy, Scanning Electron Microscopy/Energy
Dispersive Spectroscopy, Inductively-Coupled Plasma/Optical Emission Spectroscopy and X-ray
Photoelectron Spectroscopy of char residues, obtained from ter-polymers, confirmed the retention of
the phosphorus species in their structures
| Original language | English |
|---|---|
| Article number | 278 |
| Pages (from-to) | 1-18 |
| Number of pages | 18 |
| Journal | Molecules |
| Volume | 28 |
| Issue number | 1 |
| Early online date | 29 Dec 2022 |
| DOIs | |
| Publication status | Published (in print/issue) - 29 Dec 2022 |
Bibliographical note
Funding Information:This research was funded by the Royal Society of Chemistry, grant number R19-3521.
Publisher Copyright:
© 2022 by the authors.
Keywords
- polystyrene
- thermal decomposition
- reactive modification
- P- and N-containing fire retardants;
- mode of action of fire retardance
- gaseous-phase inhibition
- char formation
- P- and N-containing fire retardants
