Mechanical and fracture behavior of gelatin gels

CZERNER, M; MARTUCCI, J; FASCE, L; RUSECKAITE, R; FRONTINI, P

Beijing

Congreso; 13th International Conference on Fracture; 2013

Independent tuning of elastic stiffness, large deformation capability and fracture toughness becomes essential to the development of gelatin hydrogels for applications in food, ballistic, pharmacy and tissue engineering. Large deformation and fracture behavior of hydrogels prepared from bovine and porcine gelatins were assessed by means of gel strength measurements, uniaxial compression tests and wire cutting experiments. The effect of adding glycerol and sorbitol on gel formulation was also analyzed. Scanning electron microscopy was also performed to relate the arisen ultra-structure of gelatin gels with technological, mechanical and fracture toughness parameters. All gels showed non-linear elastic deformation that could properly described by the Ogden constitutive model. Strain hardening capability was attributed to protein renaturation capability under stress. Neat porcine gelatin gels displayed higher gel strength, shear modulus, failure strain and stress, fracture toughness and water retention than bovine gelatin gels due to their different hydrophilic amino acid content. The addition of sorbitol and glycerol caused an increase in water retention capability and a marked enhancement in gels´ fracture toughness. The major content of hydrophilic amino acids in the gelatin, the stronger the effect of glycerol and sorbitol on gelatin network morphology and mechanical parameters. In modified gelatin gels a correlation between large deformation and fracture toughness parameters with gel strength (a measurement equivalent to the technological Bloom value) was not found