Poly[nitrilo(diphenoxyphosphoranylidyne)]

• CAS: 28212-48-8
• Catalog Number: ACM28212488
• Category: Main Products
• Molecular Formula: (C12H10NPO2)n
• Synonyms: SP 100 (phosphazene);Phenoxyphosphazene Oligomer
• Appearance: White crystalline

Case Study

Poly(bis(phenoxy)phosphazene) as Flame-Retardant Additive for Polymers

Gutru, Rambabu, et al. Solid State Ionics 296 (2016): 127-136.

Proton exchange membrane fuel cells (PEMFCs) represent a promising clean energy technology, but the high cost and durability limitations of current membrane materials hinder widespread commercialization. acid-base blend membranes by combining sulfonated poly(bis(phenoxy)phosphazene) (sPOP) with sulfonated poly(ether ether ketone) (sPEEK) as alternative electrolytes for PEMFCs. The polyphosphazene backbone provides inherent chemical and mechanical stability due to its inorganic P=N character, while sulfonation imparts the necessary proton conductivity.
Experimental Protocol: Poly(bis(phenoxy)phosphazene) (POP) was sulfonated using sulfuric acid to produce sPOP. Blend membranes were fabricated by varying the sPOP content from 2 to 4 weight percent relative to sPEEK. The membranes were characterized by FTIR spectroscopy, TGA, SEM with elemental mapping, and AFM in tapping mode. SAXS was employed to analyze ionic cluster dimensions. Proton conductivity was measured by electrochemical impedance spectroscopy. Membrane electrode assemblies were fabricated and tested in H2/O2 fuel cells with polarization measurements.
Performance Evaluation: SAXS analysis revealed enhanced dimensions of ionic clusters in the sPOP-sPEEK blend membranes compared to pristine sPEEK, indicating improved ion channel connectivity. AFM phase imaging confirmed clear hydrophobic-hydrophilic phase separation. The blend membranes exhibited higher ionic conductivity than pristine sPEEK due to acid-base interactions between the sulfonic acid groups of sPEEK and the basic nitrogen atoms of sPOP. In fuel cell polarization tests, the sPOP (3 wt%)-sPEEK blend membrane achieved a peak power density of 935 mW/cm2, comparable to the commercial perfluorosulfonic acid benchmark membrane. The blend also demonstrated low fuel crossover and comparable operational stability, making it a cost-effective alternative for PEMFC applications.

Poly(bis(phenoxy)phosphazene) for High-Temperature Elastomer Applications

Orme, Christopher J., et al. Journal of Applied Polymer Science 138.15 (2021): 50207.

This work developed blended membranes composed of poly(bis(2-(2-methoxyethoxy)ethoxy)phosphazene) (MEEP-80), which exhibits high CO2 permeability and selectivity, and poly(bis-phenoxyphosphazene) (PPOP), which provides mechanical durability and non-adhesive surface properties. The blend approach aimed to overcome the principal shortcomings of MEEP-80, namely poor mechanical integrity and surface tackiness, while preserving its favorable gas transport characteristics.
Experimental Protocol: MEEP-80 and PPOP were synthesized and characterized individually. Blend membranes were prepared by solution casting at various MEEP-80 to PPOP ratios. Pure gas permeation measurements for CO2 and N2 were conducted using a constant-volume variable-pressure method at 30 degrees Celsius. Gas permeability coefficients and ideal selectivities were calculated.
Performance Evaluation: The blended membranes demonstrated increased CO2 permeability with higher selectivity over N2 compared to pristine PPOP. Thermal analysis and transport modeling supported a structural model in which crystalline PPOP domains are dispersed within an amorphous MEEP-80 continuous phase, rather than an intimate molecular blend or bulk phase-separated structure. The PPOP domains retained their crystallinity while the MEEP-80 phase provided the primary gas transport pathways. This morphology enabled the blend to combine the high CO2/N2 selectivity of MEEP-80 with the mechanical durability and processability of PPOP. The non-adhesive surface characteristics of the blends facilitated handling and module fabrication, addressing a key practical limitation of pure MEEP-80 membranes for industrial gas separation applications.

Poly(bis(phenoxy)phosphazene) as Polymer Electrolyte for Solid-State Batteries

Mu, Xiaowei, et al. RSC advances 5.93 (2015): 76068-76078.

This work reported a halogen-free flame retardant system for PLA by combining poly(bis(phenoxy)phosphazene) (POP) with expandable graphite (EG) through melt blending. The phosphazene-based flame retardant was designed to act in both condensed and gas phases, while EG provides an intumescent char layer. The study systematically investigated the flame retardant properties, thermal stability, synergistic effects, and anti-dripping performance of PLA/POP/EG composites, with particular attention to the underlying flame retardant mechanism.
Experimental Protocol: PLA composites with varying ratios of POP and EG were prepared by melt blending. Limiting oxygen index (LOI) and UL-94 vertical burning test evaluated flammability. Cone calorimetry measured heat release rate, total heat release, and smoke production. Thermogravimetric analysis (TGA) assessed thermal stability. Residual char was characterized by Raman spectroscopy, XPS, and FTIR. Gas-phase flame retardant action was investigated using TG-FTIR and TG-MS to detect radical species in gaseous decomposition products.
Performance Evaluation: The PLA/POP/EG composites exhibited significantly improved thermal stability, flame retardancy, and anti-dripping performance compared to neat PLA. The combination of POP and EG produced a notable synergistic effect, with LOI values increasing substantially and UL-94 rating improving from no rating to V-0 without dripping. Cone calorimetry confirmed reduced heat release rates. Residual char analysis revealed a composite structure of graphite and phosphorus-containing materials forming an effective protective barrier. Gas-phase analysis detected radical species including C6H5OP, C6H5O2, and PO, confirming that POP also exerts flame retardant action in the gas phase by scavenging reactive radicals. This dual-phase mechanism explains the synergistic flame retardant and anti-dripping performance.