Long-Term Effect of Ultraviolet Irradiation on Poly(vinyl chloride) Films Containing Naproxen Diorganotin(IV) Complexes

Abstract

As poly(vinyl chloride) (PVC) photodegrades with long-term exposure to ultraviolet radiation, it is desirable to develop methods that enhance the photostability of PVC. In this study, new aromatic-rich diorganotin(IV) complexes were tested as photostabilizers in PVC films. The diorganotin(IV) complexes were synthesized in 79–86% yields by reacting excess naproxen with tin(IV) chlorides. PVC films containing 0.5 wt % diorganotin(IV) complexes were irradiated with ultraviolet light for up to 300 h, and changes within the films were monitored using the weight loss and the formation of specific functional groups (hydroxyl, carbonyl, and polyene). In addition, changes in the surface morphologies of the films were investigated. The diorganotin(IV) complexes enhanced the photostability of PVC, as the weight loss and surface roughness were much lower in the films with additives than in the blank film. Notably, the dimethyltin(IV) complex was the most efficient photostabilizer. The polymeric film containing this complex exhibited a morphology of regularly distributed hexagonal pores, with a honeycomb-like structure—possibly due to cross-linking and interactions between the additive and the polymeric chains. Various mechanisms, including direct absorption of ultraviolet irradiation, radical or hydrogen chloride scavenging, and polymer chain coordination, could explain how the diorganotin(IV) complexes stabilize PVC against photodegradation.

Protection of Poly(Vinyl Chloride) Films against Photodegradation Using Various Valsartan Tin Complexes

“…The weight loss of the PVC films due to photodegradation was calculated from the weight of PVC before (W 0 ) and after irradiation (W t ) using Equation (2) [30].…”

“…This improvement in R q is better than that reported with many PVC additives (Table 4). Clearly, complexes 1-4 are better PVC photostabilizers compared with triazole-3-thiol Schiff bases [21], biphenyl tetraamine Schiff bases [22], naproxen tin complexes [30], melamine Schiff bases [24], 2-(4-isobutylphenyl)propanoate tin complexes [56], and furosemide tin complexes [28]. The surface morphology of the PVC film was also observed using atomic force microscopy (AFM).…”

“…The substituents on the synthesized tin complexes are varied to include aliphatic (butyl groups) or aromatic substituents (phenyl groups). Recently, various additives (Figure 1), including polyphosphates [18][19][20], Schiff bases [21][22][23][24][25], aromatic compounds [26,27], and organic-metal complexes [28][29][30][31], were investigated for use as PVC stabilizers. Some success has been achieved; however, research into the design of new and efficient PVC stabilizers for use on the commercial scale is ongoing.…”

The Effect of UV Aging on the Structure of PVC in the Presence of Organotin(IV) Compounds

“…Even though, PVC poor flexibility and durability limits its application in industry field [1]. Many new stabilizers have been synthesized to mix with PVC to achieve the excellent flexibility such as Schiff bases [2][3][4], organotin complexes [5,6] and polyphosphates [7]. However, these stabilizers have effect on the environment.…”

SEM morphological analysis of irradiated polystyrene film doped by a Schiff base containing a 1,2,4-triazole ring system

“…Heterocycles containing the 1,2,4-triazole moiety have various biological activities [18][19][20][21]. The Schiff base enhances the photostability of PS against photodegradation that is a continuation of previously reported work in the area of polymers [22][23][24][25][26][27][28][29][30][31][32][33]. The elemental composition of the PS films was measured by energy-dispersive X-ray (EDX) spectroscopy, and the surface morphology was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM).…”