Effects of different temperatures and freezing/freezing-thawing cycles on the water absorption and holding properties of superabsorbent polymers

Superabsorbent polymers (SAPs) can significantly improve the water retention properties of the soil for plant growth in drought and harsh environments. Therefore, the SAPs have been widely used in agricultural production and ecological restoration projects, in order to rehabilitate the degraded land and vegetation growth in the areas with scarce water resources. This study focuses on the water absorption and retention properties of SAPs under different temperatures and freezing/freezing-thawing cycles. A systematic investigation was also made to clarify the effects of different temperatures, freezing cycles, compositions, and particle sizes on the water absorption and water retention properties of SAP. One-way and multi-factor ANOVA was employed to determine the water absorption and water retention properties of 10 SAPs. The order of preference was ranked from the similarity to the ideal solution. The results showed that a great difference was found in the water absorption ratio of 10 SAPs, ranging from 167.99 to 527.5 g/g. The property was closely related to the main composition of SAPs. The higher water absorption of SAP was observed in the main composition of the polymer ratio. The main composition of SAPs also shared a significant effect on their water retention. Most of the polymer SAPs were superior in water retention. The water absorption rate of SAPs depended greatly on the particle size, indicating a decreasing trend with the increase of particle size. The low temperature was limited to the water absorption rate and retention performance of SAP. At the same time, the water retention rate of SAPs shared an increasing trend with the increase in ambient temperature. Multifactorial ANOVA showed that the particle size of SAPs had a highly significant effect on the attenuation rate of the repeated water absorption multiplicity and the water absorption ratio after freezing and freezing/thawing cycles (P < 0.001) while the freezing and freezing/thawing likewise significantly dominated the water absorption and the retention ratio of SAP (P < 0.001). The relatively high comprehensive performance was ranked in the SAP with the potassium polyacrylate as the main component, in terms of water absorption, water retention, and cold resistance. This finding can provide the theoretical basis and reference for the application and development of SAPs in cold regions.