The Design Of The Polymer Scratch Machine And Its Experimental Application

The scratch process is defined as a mechanical deformation process where a prescribed force or displacement allows a hard tip indenting into a substrate and then moving across the surface at certain velocity. Thanks for the research efforts during last several decades, the equipment and experimental method of scratch have achieved an extreme improvement, which has led to the establishment of ASTM/ISO polymer scratch test standards. Due to the lack of the scratch machine and the overseas technical monopoly, there is little domestic research of polymer scratch. In consideration of the complexity of mechanical properties of polymer materials and surface scratch damage process, how to effectively perform polymer scratch test, objectively evaluate the scratch resistance properties and reasonably analyze the scratch damage mechanism is one of the important issues for the researchers from the areas of mechanics, polymer material science.With the established ASTM/ISO polymer scratch standards, this paper conducted the following work:(1) Referencing to the features of the existing scratch machines, we designed and manufactured a polymer scratch machine with the flexible and controllable loading mode and the capability of real-time data acquisition. This effort not only promotes the technique of polymer scratch experiment, but also provides a reliable tool for the systematic experiment research on the scratch damage mechanism.(2) With the developed polymer scratch machine, we performed scratch tests for various polymer materials (such as PMMA, PC, PP and HNBR) under different loading modes. The effectiveness of the scratch machine has been validated. With the real-time acquired data and the microscopy observation after the scratch test, the typical polymer scratch damage modes and their evolution were analyzed and summarized.(3) With the help of the developed scratch test platform, the effect of physical aging on the scratch behaviors of PMMA and HNBR was investigated. The correlation between the long-term service mechanical properties and the scratch properties, as well as their influence on the scratch properties, has been discussed.