Measuring method and system for elasticity modulus of polymer

Abstract

The invention discloses a measuring method and system for elasticity modulus of a polymer. The method comprises the steps that a load-displacement curve is acquired; the load-displacement curve is a change curve of load applied to a probe of an atomic force microscope with displacement of a piezoelectric ceramics scanning pipe when the atomic force microscope is used for conducting a nanoindentation experiment on a polymer sample; the load-displacement curve is converted into a force curve; the force curve comprises a loading curve and an unloading curve; a first turning point of the loading curve is determined; data points behind the first turning point of the loading curve are deleted, and data points before the first turning point of the loading curve are reserved; the data points before the first turning point are subjected to fitting through a hertz model to obtain fitting data; according to the fitting data and a hertz model calculating formula, the elasticity modulus of the polymer sample is calculated. According to the method, the fitting range can be definitely selected, therefore the Hertz model can be conveniently and accurately utilized for conducting fitting on the loading curve, and the obtained elasticity modulus of the polymer can be more accurate after calculation.

Description

technical field [0001] The invention relates to the field of ultra-precision machining, in particular to a method and system for measuring elastic modulus of polymers. Background technique [0002] With people's continuous exploration in the micro / nano field, higher requirements are put forward for detection equipment, and atomic force microscopes (AFM for short) stand out for their excellent performance. As a practical ultra-precision detection equipment, the atomic force microscope can not only obtain the real three-dimensional shape information of the sample, but also can freely select the indentation area and image the indentation area in time in AFM nanoindentation. field has been increasingly applied. AFM nanoindentation can be used to measure the elastic modulus of materials. Currently, the commonly used calculation models are Oliver&Pharr model and Hertz model. When using AFM nanoindentation to measure the elastic modulus of polymer materials (such as PC, PMMA), du...

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Problems solved by technology

However, since there is no clear curve fitting range, the polymer elastic modulus value obtained by this method will change with the fitting range, making the obtained elastic modulus value inaccurate

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