Polyvinyl alcohol and polyvinyl alcohol/ polyvinyl pyrrolidone biomedical foams crosslinked by gamma irradiation

Foams for biomedical applications were made from polyvinyl alcohol, polyvinyl alcohol / polyvinyl pyrrolidone blend and their nanocomposites with nanoclay by clean processes. Air was entrapped into the aqueous polymer solutions during vigorous mixing and then the solutions were freeze-dried. The foams structure was stabilized by crosslinking via gamma irradiation without using any harmful chemicals. The hydrophilic biocompatible foams possessed interconnected open cell structure with remarkable capacity to absorb and retain water. The foams in wet state were soft and flexible. Desirable pore structure and higher water absorption was obtained at a solution concentration of 5 wt% for both polyvinyl alcohol and polyvinyl alcohol / polyvinyl pyrrolidone foams and also for the nanocomposite foams. The polyvinyl alcohol / polyvinyl pyrrolidone foams at a composition of 80/20 had a uniform porous structure. Addition of 20 wt% polyvinyl pyrrolidone increased the size and interconnectivity of the cell structure and rendered more flexible foams than the neat polyvinyl alcohol. Also the nanoclay, in the nanocomposite foams, elevated pore population through generation of more air bubbles during aqueous polymer solution mixing.