A Novel Acid‐Based Strategy for PET Surface Modification: Hydrophilization via Chromic Acid and Aqua Regia

ABSTRACT

Chemical modification of the PET polymer surface with acid solutions through oxidation is carried out to increase surface properties so that it is more resistant to non‐polar compounds. PET has a hydrophobic surface, so this research is expected to make it more hydrophilic. Modification is carried out in one stage using various acid solutions, namely chromic acid and aqua regia. This treatment is expected to break the polymer chains, form free radicals, and replace them with polar functional groups on the surface. Thus, the hydrophobic properties of the polymer surface are chemically changed to be more hydrophilic through the addition of polar functional groups. The success of the modification was analyzed through FTIR (Fourier Transform Infrared Spectroscopy) measurements, contact angle measurements to observe changes in surface properties, and tensile strength tests to assess mechanical strength. Observations were made using different acid solutions, as well as varying treatment times and temperatures. The FTIR test results showed that the polymer surface after chemical treatment became more hydrophilic with the appearance of polar functional groups. Furthermore, the PET contact angle decreased to 54.2°, and the tensile strength decreased by 42%.