In the present work, blend hydrogels from PVA and two different low PAA molecular weights, Mw 1800 g/mol and 5000 g/mol were prepared through the freezing thawing (F-T) physical crosslinking method. The obtained materials were fully characterized by means of scanning electron microscopy (SEM) in order to analyze their morphology, gel fraction (GF) to determine the crosslinking degree and Fourier transformed infrared spectroscopy (FTIR) to analyze the PVA-PAA interactions. Thermal characterizations [thermogravimetric analysis (TGA) and dynamic scanning calorimetry (DSC)] were conducted to study the relevant thermal characteristics. Sorption tests at different pH values (4 and 7) obtained from different aqueous systems were also inquired. The effects of PAA contents (between 1 and 5 wt%) and Mw of the used PAA on the hydrogel final properties were analyzed and related to the most probably PVA-PAA interactions. POLYM. ENG. SCI., 59:1479-1488 2019. (c) 2019 Society of Plastics Engineers