Study of Mechanical Properties of Poly (Vinyl Alcohol) and Collagen Hydrogels Using a Response Surface Methodology

The poly (vinyl alcohol) was modified to introduce the carboxyl groups which can be utilized to covalent bond with collagen through the cross linke, that is 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-Hydroxysuccinimide. The hydrogels were prepared with different techniques, such as the ratio of modified PVA to collagen, the cross-linker and the times of freezing and thawing. Using a response surface methodology, the mechanical properties of the hydrogels (tensile strength and elongation at break) were analyzed. The results indicated that the response surface models could significantly fit the response values. Moreover, the results shown that the interactions between factors had more obvious effects to the physical properties of PVA-COL hydrogels than the single one. After the analysis of factors' influences and deduced from the data and trends, the driving force behind these might be the re-orientation or re-crystallization structure of the hydrogels.