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

Abstract

Polyvinyl chloride (PVC) is a ubiquitous thermoplastic that is produced on an enormous industrial scale to meet growing global demand. PVC has many favorable properties and is used in various applications. However, photodecomposition occurs when harsh conditions, such as high temperatures in the presence of oxygen and moisture, are encountered. Thus, PVC is blended with additives to increase its resistance to deterioration caused by exposure to ultraviolet light. In the current research, five methyldopa–tin complexes were synthesized and characterized. The methyldopa–tin complexes were mixed with PVC at a concentration of 0.5% by weight, and thin films were produced. The capability of the complexes to protect PVC from irradiation was shown by a reduction in the formation of small residues containing alcohols, ketones, and alkenes, as well as in weight loss and in the molecular weight of irradiated polymeric blends. In addition, the use of the new additives significantly reduced the roughness factor of the irradiated films. The additives containing aromatic substituents (phenyl rings) were more effective compared to those comprising aliphatic substituents (butyl and methyl groups). Methyldopa–tin complexes have the ability to absorb radiation, coordinate with polymeric chains, and act as radical, peroxide, and hydrogen chloride scavengers.

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).…”

“…The use of synthesized organotin complexes led to significant improvements in the Rq. The level of improvement in the Rq was found to be highly dependent on the type of organic moiety in the tin complexes [ 47 , 48 , 49 , 50 ].…”

“…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

“…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 ].…”

Effect of ecofriendly grapefruit peel extract on PVC thin films photostabilizing tested under harmful weathering conditions

“…17 In order to assess the rise in the intensity of these functional groups, the study utilized a reference peak (C H bond at 1328 cm À1 ) that remained unchanged throughout the exam. 12 The FTIR spectra of the plain polymeric sheet, shown in Figure 1 that the photoirradiation of PVC caused the generation of unsaturated tiny fragments, a reduction in molecular weight, and weight loss. The purpose of the study was to investigate the effectiveness of adding 0.025, 0.05, and 0.075 wt% of naringin and 0.075% of TINUVIN 622 on stabilizing the PVC chains.…”