Tin-Naphthalene Sulfonic Acid Complexes as Photostabilizers for Poly(vinyl chloride).

Hadeer Jasem,Angham G Hadi,Dina S Ahmed,Ahmed A Ahmed,Hassan Hashim,Mohammed A Baashen,Gamal A El-Hiti,Emad Yousif

doi:10.3390/molecules26123629

Hadeer Jasem, Angham G Hadi + Show 6 more

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https://doi.org/10.3390/molecules26123629

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Abstract

Poly(vinyl chloride) degrades when exposed to ultraviolet light for long durations; therefore, the photostability of polymeric materials should be enhanced through the application of additives. New organotin complexes containing 4-aminonaphthalene-1-sulfonic acid were synthesized and their role as poly(vinyl chloride) photostabilizers were evaluated. The reaction of 4-amino-3-hydroxynaphthalene-1-sulfonic acid and appropriate di- or trisubstituted tin chloride (triphenyltin chloride, tributyltin chloride, dibutyltin dichloride, and dimethyltin dichloride) in methanol under reflux gave the corresponding tin-naphthalene complexes with yields of 75%–95%. Elemental analyses and spectroscopic techniques including infrared and nuclear magnetic resonance (proton and tin) were used to confirm their structures. The tin complexes were added to poly(vinyl chloride) to produce thin films that irradiated with ultraviolet light. Various parameters were assessed, such as the weight loss, formation of specific functional groups, changes in the surface due to photoirradiation, and rate constant of photodegradation, to test the role played by the organotin complexes to reduce photodegradation in polymeric films. The results proved that organotin complexes acted as photostabilizers in these circumstances. The weight loss, formation of fragments containing specific functional groups, and undesirable changes in the surface of polymeric films were limited in the presence of organotin complexes. Organotin complexes containing three phenyl groups showed the most desirable stabilization effect. These act as efficient primary and secondary photostabilizers, and as decomposers for peroxides. In addition, such an additive inhibits the dehydrochlorination process, which is the main cause of poly(vinyl chloride) photodegradation.

Highlights

Plastics are large molecular mass polymers that have very useful properties that enable their adaptation to various applications
Four substituted tin-naphthalene sulfonic acid complexes were synthesized in high yields using a simple procedure
The reaction of the ligand and dibutyl- and dimethyltin dichlorides resulted in disubstituted tin complexes 3 and 4 with 95% and 89% yields, respectively (Scheme 2)

Summary

Introduction

Plastics are large molecular mass polymers that have very useful properties that enable their adaptation to various applications. PVC is produced in various forms mainly as a flexible (plasticized with a low degree of crystallinity) or rigid (non-plasticized with a high degree of crystallinity) material [5]. It has unique properties; it suffers from weathering due to long term exposure to ultraviolet (UV) light, humidity, and high temperatures (above 100 ◦ C) [6,7]. Suitable photostabilizers should be mixed with PVC to prevent its decomposition and photooxidation Such additives can preserve the mechanical and physical properties of PVC for a long time.

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