Evaluation of the tensile strength properties by the difference in the degree of polymerization of PVA gels

Recently, several chemo-mechanical functions of high molecular polymers were studied for the biomimetic properties, sensor and switch function, enormous actuator and output energies as possible candidates for energy transducers etc. So, poly-vinyl alcohol (PVA) and carboxyl group containing PVA(Co-PVA) were selected as raw-materials from number of high molecules materials for making up new type gels, especially design of functional hydrogel. The reason why it is PVA gel is several kinds of properties with soft, strength, 3D meshes structure etc. and other Co-PVA gel were possessed of organic radical, ionization, polarize by electronics fields etc. For this PAV-Co-PVA hydrogel, tensile tests and swelling examination were carried out in wet condition. The stress-strain curves of the samples were obtained by tensile strength tests. In each sample, the stress increased with increasing ethanol concentration. The curve form showed concave until the ethanol concentration of about 50%. In this case, material characteristics showed the characteristics of the brittle fracture and the elastic deformation. In ethanol concentration of 50%-80%, the curve form showed the shape that elasticity and plastic deformation were mixed, and material characteristics showed plasticity fracture. Above ethanol concentration of 80%, the curve form gradually changed to convex, and elasticity area decreased, and yielding point appeared, and plasticity area clearly appeared.