Investigation of the Impact of Chemical Modifications on the Photostability of Polymethyl Methacrylate

Abstract

For practical application, it is crucial to ensure that polymeric materials are protected against degradation due to aging and ultraviolet (UV) irradiation. A range of advancements in developing novel photostabilizers has been made in the last few years. Another approach is the alteration of polymer structures to enhance their ability to resist photodegradation and photooxidation on exposure to UV light for extended periods in harsh conditions. Polymeric chain modifications have proved to be efficient in increasing the photostability of materials. The current work deals with the surface functionalization of polymethyl methacrylate (PMMA) by incorporating organotin moieties on the polymer backbone. PMMA reacts with ethylenediamine to attach amino groups to the polymer chains. The amino group reacts with 2-hydroxynaphthaldehyde to produce the corresponding Schiff base. Adding trisubstituted (methyl, butyl, and phenyl) tin chloride led to the addition of organometallic residence to the polymeric chains. Thin films of the modified PMMA were made and irradiated with ultraviolet light for long durations to test the effect of chain modification on the photostability of polymeric materials. The effect of the substituent on the tin atom on the photostability of PMMA has been analyzed. Various methods were used for assessment, including infrared spectroscopy, weight loss, surface morphology, and roughness factor. The modified polymers showed increased resistance to photodegradation and had lower roughness factor, weight reduction, surface damages, and small fragments generated compared to the blank PMMA. The polymer containing phenyl substituents showed the most apparent photostabilization effect and the least destructive changes in the PMMA surface on photoirradiation.