Focus on Certificates of Analysis (COA) and Maximum Absorption Capacity
1. Introduction
Potassium polyacrylate (PAA-K), commonly referred to as a superabsorbent polymer (SAP), has become one of the most widely applied water-retention agents in modern agriculture. It plays a critical role in enhancing soil water management, improving fertilizer efficiency, and enabling sustainable agricultural practices in water-stressed environments. In the fertilizer and pesticide industry, potassium polyacrylate not only improves the water-holding capacity of soils but also enhances the controlled release of nutrients and agrochemicals.
This report provides detailed information on the Certificates of Analysis (COAs) for different commercial grades of potassium polyacrylate offered for agricultural and industrial applications. Furthermore, it outlines the maximum absorption capacities achievable under various conditions and discusses the significance of these metrics for end users in fertilizer and pesticide formulations.
2. Overview of Kaliumpolyakrylaatti
2.1 Chemical Identity
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Kemiallinen kaava: [–CH₂–CH(CO₂K)–]ₙ
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CAS-numero: 25608-12-2
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Ulkonäkö: White to off-white granular or powder form
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Solubility: Insoluble in water but capable of absorbing and retaining water up to several hundred times its own mass.
2.2 Functional Properties
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Superabsorbency: Absorbs and retains water efficiently, forming a gel-like structure.
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Release Behavior: Capable of releasing absorbed water gradually to plant roots.
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Salt Tolerance: Unlike sodium polyacrylate, potassium polyacrylate is more suitable for agricultural applications because it supplies potassium, a plant macronutrient, instead of sodium, which can be harmful.
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Durability: Stable in soil for several years, depending on soil microbial activity.
3. Applications in Fertilizer and Pesticide Industry
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Fertilizer Efficiency
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Enhances nitrogen, phosphorus, and potassium uptake by reducing leaching.
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Prolongs fertilizer residence in the rhizosphere.
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Pesticide Retention and Delivery
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Reduces pesticide runoff and volatilization losses.
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Provides a slow-release matrix for active compounds.
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Vedensäästö
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Increases water-holding capacity of sandy or arid soils.
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Reduces irrigation frequency by up to 50%.
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Crop Yield and Stress Tolerance
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Improves germination rate, root development, and drought resistance.
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4. Certificates of Analysis (COA) for Kaliumpolyakrylaatti
Below are representative COA templates for three different commercial grades. Actual values may vary by batch, but the following demonstrates typical specifications.
4.1 Agricultural Grade COA
Product: Potassium Polyacrylate – Agricultural Grade
Batch No.: AG-2025-001
Date of Issue: Sept 2025
Parameter | Specification | Tulos |
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Ulkonäkö | Valkoinen rakeinen jauhe | Complies |
Odor | Hajuton | Complies |
Potassium content (%) | ≥ 20 | 21.2 |
Moisture content (%) | ≤ 8 | 6.5 |
Residual monomer (ppm) | ≤ 500 | 320 |
Particle size (mesh) | 20–100 | 95% within |
Absorption in distilled water (g/g) | ≥ 400 | 425 |
Absorptio 0,9% NaCl:ssä (g/g) | ≥ 50 | 62 |
pH (0.5% gel) | 6.0 – 7.5 | 6.7 |
Heavy metals (Pb, Cd, Hg) | ≤ 10 ppm | < 5 ppm |
Säilyvyys | 24 months | Pass |
4.2 Industrial Grade COA
Product: Potassium Polyacrylate – Industrial Grade
**Batch No.: IND-2025-005
Date of Issue: Sept 2025
Parameter | Specification | Tulos |
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Ulkonäkö | Off-white coarse powder | Complies |
Potassium content (%) | ≥ 15 | 15.8 |
Moisture content (%) | ≤ 10 | 8.1 |
Residual monomer (ppm) | ≤ 1000 | 740 |
Particle size (mesh) | 10–80 | 88% within |
Absorption in distilled water (g/g) | ≥ 250 | 280 |
Absorptio 0,9% NaCl:ssä (g/g) | ≥ 30 | 38 |
pH (0.5% gel) | 6.0 – 8.0 | 7.2 |
Heavy metals (Pb, Cd, Hg) | ≤ 20 ppm | < 12 ppm |
Säilyvyys | 18 months | Pass |
4.3 Premium High-Absorption Grade COA
Product: Potassium Polyacrylate – Premium Grade (High Absorption)
**Batch No.: PRM-2025-009
Date of Issue: Sept 2025
Parameter | Specification | Tulos |
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Ulkonäkö | White fine powder | Complies |
Potassium content (%) | ≥ 22 | 22.5 |
Moisture content (%) | ≤ 5 | 3.8 |
Residual monomer (ppm) | ≤ 300 | 180 |
Particle size (mesh) | 30–120 | 96% within |
Absorption in distilled water (g/g) | ≥ 600 | 630 |
Absorptio 0,9% NaCl:ssä (g/g) | ≥ 70 | 78 |
Absorption under pressure (g/g) | ≥ 40 | 45 |
pH (0.5% gel) | 6.0 – 7.0 | 6.5 |
Heavy metals (Pb, Cd, Hg) | ≤ 5 ppm | < 3 ppm |
Säilyvyys | 36 months | Pass |
5. Maximum Absorption Capacities
Potassium polyacrylate’s performance is heavily dependent on environmental conditions, water quality, and ionic strength. The following summarizes absorption capacities across conditions.
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In Distilled Water
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Agricultural Grade: 400–450 g/g
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Industrial Grade: 250–300 g/g
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Premium Grade: 600–650 g/g
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In Saline Solution (0.9% NaCl)
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Agricultural Grade: 60–70 g/g
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Industrial Grade: 30–40 g/g
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Premium Grade: 70–80 g/g
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Under Soil Pressure
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Absorption capacity decreases due to compression.
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Premium grade retains 40–50 g/g under pressure, suitable for root zone applications.
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Cycle Stability
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Potassium polyacrylate can undergo multiple swelling/drying cycles.
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After 5 cycles, average absorption retention is:
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Agricultural Grade: ~70%
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Premium Grade: ~85%
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6. Comparative Advantage Over Alternatives
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Versus Sodium Polyacrylate: Potassium is plant-friendly, improves soil fertility, and avoids sodium toxicity.
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Versus Natural Polymers (e.g., starch, cellulose): Higher durability and absorption capacity.
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Versus Traditional Soil Amendments (e.g., clay, peat): Far superior in water retention efficiency.
7. Regulatory and Quality Assurance
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Compliance with REACH and RoHS for safe use in agricultural settings.
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ISO 9001 Certified production ensures batch-to-batch consistency.
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Ympäristöturvallisuus: Biodegrades over years, leaving potassium ions as beneficial residues.
8. Practical Recommendations for Fertilizer and Pesticide Integration
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Application Dosage: 20–40 kg/ha depending on soil type.
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Mixing with Fertilizers: Blend with NPK formulations to extend nutrient release.
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Pesticide Delivery: Incorporate into formulations to reduce evaporation and increase soil residence.
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Target Crops: Particularly useful for dryland crops such as maize, sorghum, cotton, vegetables, and fruit trees.
9. Conclusion
Potassium polyacrylate represents a powerful tool for the fertilizer and pesticide industry, enabling better water management, improved nutrient uptake, and reduced chemical losses. The COAs provided for different grades highlight product reliability and adaptability across diverse agricultural and industrial needs. The maximum absorption capacity data demonstrates clear advantages for premium-grade materials where superior water retention and durability are required.
For companies involved in fertilizer and pesticide production, the integration of potassium polyacrylate ensures not only better crop yield and resource efficiency but also supports the broader movement toward sustainable and climate-resilient agriculture.