Which technique is best used to determine the modulus of elasticity of pure and filled fluoroplastic (PTFE)? The literature does not always indicate the method, and the variation of modulus values for pure material is from 400 to 1000 MPa. The problem is that the material has a low modulus of elasticity in combination with a maximum deformation of up to 400%. Measurement of the acoustic modulus of the filled material gave a value of 5 GPa