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

Abstract

Polyvinyl chloride is used in the manufacturing of a wide range of products, but it is susceptible to degradation if exposed to high temperatures and sunlight. There is therefore a need to continuously explore the design, synthesis, and application of new and improved additives to reduce the photodegradation of polyvinyl chloride in harsh environments and for outdoor applications. This research investigates the use of new norfloxacin–tin complexes as additives to inhibit the photodegradation of polyvinyl chloride to make it last longer. Reactions between norfloxacin and substituted tin chlorides, in different molar ratios and in methanol under reflux conditions, gave the corresponding organotin complexes in high yields. The chemical structures of the synthesized complexes were established, and their effect on the photodegradation of polyvinyl chloride due to ultraviolet-visible irradiation was investigated. Norfloxacin–tin complexes were added to polyvinyl chloride at very low concentrations and homogenous thin films were made. The films were irradiated for a period of up to 300 h, and the damage that occurred was assessed using infrared spectroscopy, polymeric materials weight loss, depression in molecular weight, and surface inspection. The degree of photodegradation in the polymeric materials was much less in the blends containing norfloxacin–tin complexes compared to the case where no additives were used. The use of the additives leads to a reduction in photodegradation (e.g., a reduction in the formation of short-chain polymeric fragments, weight loss, average molecular weight depletion, and roughness factor) of irradiated polyvinyl chloride. The norfloxacin–tin complexes contain aromatic moieties (aryl and heterocycle), heteroatoms (nitrogen, oxygen, and fluorine), and an acidic center (tin atom). Therefore, they act as efficient photostabilizers by absorbing the ultraviolet radiation and scavenging hydrogen chloride, peroxides, and radical species, thereby slowing the photodegradation of polyvinyl chloride.

Metal Oxide Nanoparticles Containing Clotrimazole to Suppress Photodegradation of Poly(Vinyl Chloride) Thin Films

“…The C–H bond (1328 cm −1 ) of CH 2 groups in the polymeric chain was used for comparison since irradiation has minimal effect on its intensity. The frequency corresponding to the C=O and C=C absorption bands is consistent with those reported [ 47 , 48 , 49 , 50 ]. However, the position of the C=O absorption band may vary depending on the type of carbonyl-containing fragments produced (aliphatic ketone, acid chloride, or chloroketone).…”

“…Recently, several groups of organometallics have been synthesized and used as PVC photostabilizers [ 47 , 48 , 49 , 50 ]. The current research involves the assessment of a combination of several metal oxide NPs and clotrimazole as PVC photostabilizers with the advantage that no additional synthetic procedures are involved to produce the additives.…”

Enhancement of Photostabilization of Poly(Vinyl Chloride) in the Presence of Tin–Cephalexin Complexes

“…At the end of the irradiation process, the roughness factors (Rq) were 516.2 for the unblended film and 38.2, 41.2, and 46.3 for the PVC film blends containing tin–cephalexin complexes 1 , 2 , and 3 , respectively. Notably, the use of complex 1 led to a 13.5-fold reduction in the Rq, which is higher than observed (reduction in the Rq by fold = 5.2–12.9) for other tin complexes comprising different aromatic moieties [ 58 , 59 , 60 , 61 ]. However, additives containing high contents of heteroatoms and aromatic residues were more efficient (reduction in the Rq by fold = 15.4–21.2) in reducing the PVC surface roughness than the current ones [ 62 , 63 , 64 , 65 , 66 ].…”

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

“…The use of methyldopa–tin complexes led to a significant improvement in the Rq and showed great efficiency in stabilizing PVC compared to many other PVC additives that have recently been reported [ 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ]. For example, organotin complexes containing naproxen [ 62 ], carvedilol [ 63 ], furosemide [ 64 ], valsartan [ 65 ], telmisartan [ 66 ], trimethoprim [ 67 ], norfloxacin [ 68 ], and levofloxacin [ 69 ] led to a reduction in the Rq by 5.2–15.4 fold.…”

“…The use of methyldopa–tin complexes led to a significant improvement in the Rq and showed great efficiency in stabilizing PVC compared to many other PVC additives that have recently been reported [ 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ]. For example, organotin complexes containing naproxen [ 62 ], carvedilol [ 63 ], furosemide [ 64 ], valsartan [ 65 ], telmisartan [ 66 ], trimethoprim [ 67 ], norfloxacin [ 68 ], and levofloxacin [ 69 ] led to a reduction in the Rq by 5.2–15.4 fold. On the other hand, organotin complexes with a high level of heteroatoms and aromaticity (e.g., ciprofloxacin, 4-(benzylideneamino)benzenesulfonamide, and 4-methoxybenzoic acid) resulted in greater improvement in the Rq (16.6–21.2 fold) [ 70 , 71 , 72 ].…”