Superabsorbent Polymer (SAP) Testing Methods
Independent SAP testing to support confident material decisions.
Whether you're qualifying a new supplier, comparing SAP materials, or investigating a performance difference, you need reliable data to understand how your materials perform.
Absorbent Product Services (APS) provides independent superabsorbent polymer testing using established NWSP methods and project-specific procedures. We help manufacturers, material suppliers, and product developers obtain the performance data they need to evaluate materials and make informed decisions.
Included Tests
Controlled comparison of raw and recovered SAP across key performance properties:
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Free Swell Capacity (FSC) -- Raw & Recovered
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Centrifuge Retention Capacity (CRC) -- Raw & Recovered
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Absorption Against Pressure (AAP, 0.3 & 0.7 psi) -- Raw & Recovered
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Moisture Content -- Raw only
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pH -- Raw only
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Polymer Vortex Speed -- Raw only
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Controlled recovery of SAP from finished product
SAP Test Methods
Absorption & Retention
NWSP 240.0 — Free Swell Capacity (FSC)
Determines the amount of saline solution absorbed by a superabsorbent polymer under free-swelling conditions, without an applied load.
NWSP 241.0 — Centrifuge Retention Capacity (CRC)
Determines the amount of saline solution retained by a superabsorbent polymer following centrifugation.
NWSP 242.0 — Absorption Against Pressure (AAP)
Determines the amount of saline solution absorbed by a superabsorbent polymer under a specified applied pressure.
Available applied loads:
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0.7 psi: Standard applied pressure per NWSP 242.0.
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0.3 psi: Modified applied pressure available upon request.
NWSP 243.0 — Permeability Dependent Absorption Under Pressure (PDAUP)
Determines the absorption capacity of a superabsorbent polymer under applied pressure, where permeability is a significant controlling factor.
Absorption Time
APS-108 — Polymer Vortex Speed (PVS)
Determines the time required for superabsorbent polymer to absorb saline solution and form a gel, as indicated by the disappearance of the vortex.
Physical Characterization
NWSP 220.0 — Particle Size Distribution (PSD)
Determines the particle size distribution of superabsorbent polymer using sieve shaking.
NWSP 230.0 — Moisture Content
Determines the moisture content of superabsorbent polymer by measuring mass loss upon heating.
NWSP 200.0 — pH
Determines the pH of a saline solution containing superabsorbent polymer.
NWSP 251.0 — Bulk Density & Flow Rate
Determines the bulk density and mass flow rate of superabsorbent polymers.
Testing requirements and applicable method references are confirmed during project review.
When Standard Testing Isn't Enough
Not every material or development question fits neatly into a standard test procedure.
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APS accommodates alternative test fluids, modified testing conditions, method optimization, and project-specific procedures to address different polymer technologies, material characteristics, and client requirements.
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Testing capabilities extend to conventional, bio-based, and emerging superabsorbent polymer materials.
A Straightforward Approach to Independent Testing
1. Tell us what you need to evaluate.
Share your required methods, materials, or performance questions.
2. Receive a testing proposal.
APS reviews your requirements and provides a project-specific scope of work.
3. Get the data you need.
Receive clear technical results to support your material evaluations and next decisions.
Deliverables
Comparative report with side-by-side raw and recovered SAP results and performance assessment notes highlighting notable observations
