Phosphite Nanoparticle Antioxidants: Hydroperoxide Scavenging Simulator (2D)

Stabilizer Formulation

Phosphite scavenger loading 60

Scavenging rate constant k 1.0×

Thermal / UV stress (ROOH generation) 1.0×

Oxidation State

[ROOH]

0.00

[Phosphite]

0.00

Degradation index

0.0%

Scavenger left

100%

Elapsed exposure time

0.0 h

How it works

Phosphite (P(III)) nanoparticles are secondary antioxidants: each scavenges a hydroperoxide (ROOH) molecule non-radically, being stoichiometrically oxidized to phosphate (P(V)) in the process. ROOH is meanwhile continuously generated by thermal/UV stress on the polymer. This is a genuine coupled second-order kinetic system:

d[ROOH]/dt      = G − k·[ROOH]·[Phosphite]
d[Phosphite]/dt = −k·[ROOH]·[Phosphite]

G = generation rate (thermal/UV stress)
k = second-order scavenging rate constant

While phosphite remains, it consumes ROOH almost as fast as it forms — the protection window. Because phosphite is consumed stoichiometrically (one molecule per ROOH scavenged, never regenerated), it eventually runs out. Once [Phosphite] → 0, the sink term vanishes and d[ROOH]/dt = G: hydroperoxide accumulates unchecked and the degradation index — the running integral of ROOH exposure — accelerates.

Loading — initial phosphite scavenger concentration dispersed in the matrix.
Rate constant k — how fast a phosphite site reacts with a ROOH molecule it meets.
Thermal / UV stress — the generation rate G that continuously seeds new hydroperoxide.

The strip chart at the bottom of the stage plots real [ROOH] (orange) and [Phosphite] (teal) trajectories over simulated exposure time — watch the flat protection window, then the crossover where ROOH breaks away as phosphite hits zero.

Protection window

Phosphite scavenger (active) Phosphite (spent, P(V)) Hydroperoxide ROOH