Modifications of Polymers through the Addition of Ultraviolet Absorbers to Reduce the Aging Effect of Accelerated and Natural Irradiation

Abstract

The photooxidative degradation process of plastics caused by ultraviolet irradiation leads to bond breaking, crosslinking, the elimination of volatiles, formation of free radicals, and decreases in weight and molecular weight. Photodegradation deteriorates both the mechanical and physical properties of plastics and affects their predicted life use, in particular for applications in harsh environments. Plastics have many benefits, while on the other hand, they have numerous disadvantages, such as photodegradation and photooxidation in harsh environments and the release of toxic substances due to the leaching of some components, which have a negative effect on living organisms. Therefore, attention is paid to the design and use of safe, plastic, ultraviolet stabilizers that do not pose a danger to the environment if released. Plastic ultraviolet photostabilizers act as efficient light screeners (absorbers or pigments), excited-state deactivators (quenchers), hydroperoxide decomposers, and radical scavengers. Ultraviolet absorbers are cheap to produce, can be used in low concentrations, mix well with polymers to produce a homogenous matrix, and do not alter the color of polymers. Recently, polyphosphates, Schiff bases, and organometallic complexes were synthesized and used as potential ultraviolet absorbers for polymeric materials. They reduced the damage caused by accelerated and natural ultraviolet aging, which was confirmed by inspecting the surface morphology of irradiated polymeric films. For example, atomic force microscopy revealed that the roughness factor of polymers’ irradiated surfaces was improved significantly in the presence of ultraviolet absorbers. In addition, the investigation of the surface of irradiated polymers using scanning electron microscopy showed a high degree of homogeneity and the appearance of pores that were different in size and shape. The current work surveys for the first time the use of newly synthesized, ultraviolet absorbers as additives to enhance the photostability of polymeric materials and, in particular, polyvinyl chloride and polystyrene, based mainly on our own recent work in the field.

Synthesis of New Norfloxacin–Tin Complexes to Mitigate the Effect of Ultraviolet-Visible Irradiation in Polyvinyl Chloride Films

“…Recently, several additives have been shown to suppress the photodegradation of PVC [ 26 ]. Examples include polybenzimidazoles [ 27 ], polyphosphates [ 28 ], Schiff bases [ 29 , 30 , 31 , 32 ], and pigments [ 33 ].…”

“…Stabilizers containing a combination of zinc and barium can be used for PVC, but co-stabilizers are needed [23][24][25]. Recently, several additives have been shown to suppress the photodegradation of PVC [26]. Examples include polybenzimidazoles [27], polyphosphates [28], Schiff bases [29][30][31][32], and pigments [33].…”

Synthesis of Methyldopa–Tin Complexes and Their Applicability as Photostabilizers for the Protection of Polyvinyl Chloride against Photolysis

“…Plastics are, therefore, efficient replacements for some common construction materials, such as steel, wood, and glass. However, a drawback is that plastics suffer from photodegradation when exposed to ultraviolet (UV) light at high temperatures in environments rich in oxygen [ 5 ]. Photodegradation leads to deterioration in their mechanical and physical properties resulting in color changes, deformation, and the appearance of cracks [ 6 ].…”

Fabrication of Highly Photostable Polystyrene Films Embedded with Organometallic Complexes

“…The roughness factor (Rq) is a measure of the smoothness of the surface of materials. The ibuprofen-metal complexes led to a reduction in the Rq of the PS and showed better performance than a range of additives used recently to stabilize polyvinyl chloride [51]. The Rq was ca.…”