PMMA for anti-counterfeit application

Abstract

Shape memory materials are known for the ability to recover to their original shape by using the right kind of stimulus such as heat (thermal responsive), light (photo responsive) and chemical (chemo-responsive), after undergoing severe distortion.

In this report, the shape memory effect of Polymethyl methacrylate (PMMA) is investigated and tested under controlled environment. PMMA is a clear plastic that is often used as shatterproof replacement for glass. The emphasis on this project is to fabricate samples of PMMA by making indentation of coin image onto PMMA at certain temperatures. PMMA underwent thermal analysis such as thermo-gravimetric analysis (TGA) differential scanning calorimetry (DSC) to determine their glass transition temperature and melting temperature. Two types of specimens are generated under constant displacement compression. One of them is compressed below its melting point (Temporary indentation) and another one above its melting point (Permanent indentation). The indentation on both types of sample is subjected to thermal recovery at different temperature below the temperature that they were compressed. Lastly, the levels of recovery under those temperatures are recorded and analyzed.