The shelf life of PESA (Polyepoxysuccinic acid) depends on storage conditions and formulation, but here are the general guidelines:
1. Typical Shelf Life
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Solid (Powder) PESA: 24–36 months (unopened, dry storage).
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Liquid PESA (Aqueous Solution): 12–18 months (if properly preserved).
2. Factors Affecting Shelf Life
| Factor | Impact | Recommendation |
|---|---|---|
| Moisture | Powder may clump or degrade | Store in sealed, moisture-proof containers (HDPE bags with desiccant). |
| Temperature | High temps accelerate degradation | Keep at <30°C (avoid direct sunlight). |
| pH Stability | Degrades faster in extreme pH | Liquid formulations should be pH 7–10 for stability. |
| Microbial Growth | Liquid PESA can spoil | Add biocides (e.g., sodium benzoate) if long-term storage is needed. |
3. Signs of Degradation
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Powder: Hard clumps (due to moisture absorption), color darkening.
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Liquid: Increased viscosity, foul odor (microbial growth), or precipitation.
4. Storage Recommendations
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Powder:
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Store in cool, dry conditions (humidity <60%).
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Use airtight containers (HDPE or lined steel drums).
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Liquid:
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Keep in HDPE tanks (avoid metal exposure).
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If stored >1 year, test active content before use.
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5. Extending Shelf Life
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For liquid PESA, refrigeration (4–10°C) can prolong stability.
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Rotate stock using FIFO (First In, First Out) method.
6. Post-Expiry Use
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Slightly degraded PESA may still work but at reduced efficacy—conduct a jar test to verify performance.
For precise shelf life, always refer to the manufacturer’s Technical Data Sheet (TDS). Industrial-grade PESA typically lasts longer than food/cosmetic grades due to stricter purity requirements.