Executive Technical Summary: Procurement managers frequently make the mistake of evaluating superabsorbent polymer quality based solely on free-swelling capacity, overlooking fluid retention under physical pressure.

In raw material procurement, misunderstanding laboratory metrics can lead to devastating product failures on supermarket shelves. Free swell capacity in deionized water can exceed 300 g/g, but in realistic human physiological conditions (0.9% saline under body weight), performance is governed by two critical metrics: CRC and AUL.

Centrifuge Retention Capacity (CRC - NWSP 241.0.R2)

CRC measures the amount of 0.9% saline solution retained by 1.0g of dry SAP after 30 minutes of free swelling followed by 3 minutes of 250G centrifugal spin. This tests the polymer's permanent osmotic bonding strength.

Absorbency Under Load (AUL - NWSP 242.0.R2)

AUL measures fluid uptake against an active vertical load (typically 0.3 psi or 0.7 psi). A high CRC polymer with low AUL will expand rapidly when uncompressed, but when a baby sits or an adult shifts weight, the gel deforms, collapsing capillary channels and releasing moisture back onto the skin.

Shenghongda's in-house laboratory audits every incoming lot from Sumitomo Seika and BASF to guarantee AUL at 0.7 psi exceeds 22.0 g/g. Learn more about our Quality Control Testing Metrology.