Superabsorbent polymers (SAPs) were synthesized from acrylamide (AM) and itaconic acid (IA) via a crosslinking polymerization. SAP composites (SAPCs) were formed by the incorporation of silica with three particle sizes into the polymerization to increase the gel strength of SAPs. Effects of AM: IA molar ratios, silica types and concentrations on water absorbency, absorbency rate and absorbency under loadings (AUL) of the composites were investigated. The highest water absorbency of the SAP is 233 ± 8 g g−1 at an AM: IA molar ratio of 97:3 with absorbency of 149 ± 2 g g−1 within 15 min. The highest AUL of the SAPC with 0.5%–2.0% w w−1 silica is 13 g g−1 by 1.93 × 103 Pa load. A pseudo-second-order kinetics for water absorbency was found in both SAPs and in situ SAPCs. In situ SAPCs and the mechanically mixed SAPCs in vertical and horizontal direction yielded similar water absorbency values. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers