Effect of Increasing Polyvinyl Alcohol Content on the Porous Structure and Mechanical Properties of Sol-Gel Derived Hybrids Foams
Bioactive glass/polymer hybrids are promising materials for biomedical applications because they combine the bioactivity of these bioceramics with the flexibility of polymers. In previous work hybrid foams with 80% bioactive glass and 20% polyvinyl alcohol (PVA) were prepared by the sol-gel process for application as scaffold for bone tissue engineering. In this work it was evaluated the effect of increasing the PVA content of the hybrids on structural characteristics and mechanical properties of hybrid foams produced by this method. The hybrids were prepared with inorganic phase composition of 70%SiO2-30%CaO and PVA fractions of 20 to 60% by the sol-gel method. The structural and mechanical characterization of the obtained foams was done by FTIR, SEM, Helium Picnometry, and compression tests. To reduce the acidic character of the hybrids due to the catalysts added, different neutralization solutions were tested. The immersion of hybrids in a calcium acetate solution was the most adequate neutralization method, avoiding calcium loss while maintaining pH nearly 7,0 and low PVA loss. The foams presented porosity of 60-85% and pore diameters of 100-500μm with interconnected structure. The pore structure varied with the polymer content in the hybrid. The compression tests showed that an increase of PVA fraction in the hybrids improved their mechanical properties.
Guy Daculsi and Pierre Layrolle
A. A. R. de Oliveira et al., "Effect of Increasing Polyvinyl Alcohol Content on the Porous Structure and Mechanical Properties of Sol-Gel Derived Hybrids Foams", Key Engineering Materials, Vols. 361-363, pp. 555-558, 2008