AFM nanoindentation to determine Young's modulus for different EPDM elastomers

作者：Ferencz R^*; Sanchez J; Bluemich B; Herrmann W

来源：Polymer Testing, 2012, 31(3): 425-432.

DOI：10.1016/j.polymertesting.2012.01.003

• Atomic force microscopy (AFM)
• Young's modulus
• Indentation
• EPDM

AFM nanoindentation was investigated as a method for determining the micromechanical properties of polymer materials. It is generally accepted that the shape of the tip of the cantilever undergoes a change in a standard AFM setup. The shape defines the projected contact area, so it is a parameter directly proportional to the elastic modulus; any change in the shape thus affects the accuracy of the results. The method suggested in this paper relies on the introduction of an experimentally determined tip-area function. Values for Young's modulus were calculated for EPDM samples with different degrees of cure and crystallinity. The degree of crystallinity has a greater impact on the mechanical properties of the material than the degree of cure. Depending on the amplitude of the indentation, the E-moduli determined by AFM are systematically higher. When studying different regions of polymer materials, the values of the E-modulus determined by AFM become identical to those measured by means of DMA on extrapolation of the modulus at zero indentation.

• 出版日期2012-5