Effects of Alkyl Substitution on the Physical Properties and Gas Transport Behavior in Selected Poly(R-phenoxyphosphazenes)
A systematic preparation of alkyl substituted phenoxy-phosphazene polymers was performed. In this study, phosphazenes substituted with 4-methylphenol, 4-ethylphenol, and 4-isopropylphenol are reported. An additional polymer substituted with 4-tert-butylphenoxy-1-ethanol also was synthesized in this work. Data derived for these materials, including chemical, thermal and gas transport characterization, were compared to previous reports discussing poly[bis-phenoxyphosphazene] and its analog with tert-butyl substitution: poly[bis-(4-tert-butylphenoxy)phosphazene]. The tert-butyl moiety influences orderly chain packing, presumably through steric hindrance that can influence aromatic p-stacking. For the new poly[(alkylphenoxy)phosphazenes], semi-crystallinity is maintained and the added steric bulk serves to decrease the Tg and increase both permeability and selectivity for the gas pairs: O2/N2 and CO2/CH4. Removal of the tert-butyl moiety from the immediate vicinity of the backbone through a flexible spacer serves to depress the Tg as compared to poly[bis-(4-tert-butylphenoxy)phosphazene], but provides no performance enhancement for gas transport.
- Research Organization:
- Idaho National Laboratory (INL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC07-05ID14517
- OSTI ID:
- 1028228
- Report Number(s):
- INL/JOU-11-22071
- Journal Information:
- Polymer, Journal Name: Polymer Journal Issue: 18 Vol. 52; ISSN 0032-3861; ISSN POLMAG
- Country of Publication:
- United States
- Language:
- English
Similar Records
Gas Permeability in Rubbery Polyphosphazene Membranes
Aqueous solubilities of alkylphenols and methoxyphenols at 25 C