Swelling property of PVA hydrogels with different concentration and specifications and its influencing factors

Aim: This study aimed to prepare polyvinyl alcohol (PVA) hydrogel with the physical cross linking and then explore the water-swelling property of PVA hydrogels with different concentration and specifications. Methods: The cryodesiccated PVA hydrogels were swelled again using simulated body fluid (SBF) to observe the time-varying swelling law of PVA hydrogels with different concentration. Besides, PVA xerogel with different specifications were soaked in SBF to compare the effects of their size and shape on the water absorption rate of PVA hydrogels. Results: The volume of PVA gels was significantly different at the time of pre-drying, post-drying and reswelling. The swelling degree of PVA hydrogels with different concentration was also different. 25% PVA hydrogel swelled the fasted at the beginning of swelling, while 15% PVA hydrogel had a significantly high swelling rate than the other two types at last. All the PVA hydrogels soaked in 37 degrees C SBF swelled fast that the volume swelling rate of them could be up to 5 times within 10 days. In addition, the lamelliform PVA hydrogel had the largest water absorption rate, indicating that the bigger specific surface area and smaller size of PVA hydrogels matched with faster equilibrium rate. Conclusion: in the study, the maximum volume swelling rates of PVA hydrogels in SBF were all larger than 5, indicating that they could use for the increment of oral soft tissues.