Next Article in Journal
Local and Global Order in Dense Packings of Semi-Flexible Polymers of Hard Spheres
Next Article in Special Issue
Latest Advances in Highly Efficient Dye-Based Photoinitiating Systems for Radical Polymerization
Previous Article in Journal
Case Study on Prestressed CFRP Plates Applied for Strengthening Hollow-Section Beam Removed from an Old Bridge
Previous Article in Special Issue
Modification of Covalent Triazine-Based Frameworks for Photocatalytic Hydrogen Generation
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Polymers
Volume 15
Issue 3
10.3390/polym15030550
polymers-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

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

by
Rafid R. Arraq
1,
Angham G. Hadi
1,
Dina S. Ahmed
2,
Gamal A. El-Hiti
3,*,
Benson M. Kariuki
4,
Amani A. Husain
5,
Muna Bufaroosha
6 and
Emad Yousif
7
1
Department of Chemistry, College of Science, Babylon University, Babil 51002, Iraq
2
Department of Medical Instrumentation Engineering, Al-Mansour University College, Baghdad 64201, Iraq
3
Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh 11433, Saudi Arabia
4
School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
5
Polymer Research Unit, College of Science, Al-Mustansiriyah University, Baghdad 10052, Iraq
6
Department of Chemistry, College of Science, United Arab Emirates University, P.O. Box 15551, Al-Ain 1818, United Arab Emirates
7
Department of Chemistry, College of Science, Al-Nahrain University, Baghdad 64021, Iraq
*
Author to whom correspondence should be addressed.
Polymers 2023, 15(3), 550; https://doi.org/10.3390/polym15030550
Submission received: 11 December 2022 / Revised: 18 January 2023 / Accepted: 19 January 2023 / Published: 20 January 2023
(This article belongs to the Special Issue Photosensitive Systems for Polymers Synthesis)
Browse Figures
Versions Notes

Abstract

:
Poly(vinyl chloride), PVC, has many attractive properties, including low cost of manufacture, resistance to acid and alkali corrosion, and ease of molding. However, PVC suffers from aging in harsh conditions, leading to the shortening of its useful life. Stability to irradiation, for example, can be improved through the incorporation of additives to PVC. The design, synthesis, and application of new stabilizers continue to attract attention. The current work investigates the effect of three tin–cephalexin complexes on the stability of PVC on irradiation with ultraviolet (UV) light (λ = 313 nm) at 25 °C for a long duration. The PVC was blended with tin–cephalexin complexes at low concentrations (0.5% by weight), and thin films (around 40 µm) were made from the mixed materials. Various methods, including weight loss, infrared spectroscopy, and surface inspection of irradiated films were used to investigate the role played by these additives in the inhibition of PVC photodecomposition. The results confirmed that the additives led to a significant reduction in the rate of photodecomposition of the PVC blends. Tin–cephalexin complexes can absorb harmful radiation, deactivate hydrogen chloride, and scavenge high-energy species such as peroxides, therefore acting as stabilizers for PVC.

Graphical Abstract

1. Introduction

The consumption of plastics has increased progressively due to their numerous applications [1,2]. Poly(vinyl chloride), PVC, is widely used due to its many attractive properties, including low production cost; manufacture in different shapes and forms; and resistance to flame, acid, and alkali corrosion. PVC is used in construction materials, flooring, packing, cables, wires, pipes, foams, and fibers [3,4,5]. A drawback in the use of PVC is that environmental factors, such as high temperature, light, and humidity, combined with the presence of oxygenated species, can lead to undesirable chemical and physical changes in the polymer chains [6]. This process of photodegradation results in the formation of reactive species such as hydrogen, chloride, alcohol, acid, peroxide, and hydroperoxide free radicals that initiate PVC autocatalytic degradation. The degradation initially takes place at sites of defects and abnormalities and leads to C−C bond cleavage, cross-linking, and chain scission producing unsaturated residues and PVC chains containing carbonyl groups, for example [7]. PVC photodegradation results in color change, deformation, cracking, the appearance of spots, and weight loss due to the elimination of small fragments including volatiles (e.g., hydrogen chloride, HCl) [8,9,10,11,12]. The inclusion of additives during the manufacture of PVC is one way of elongating its useful life [13,14,15].
The PVC additives should ideally be easy to synthesize, cheap to produce, highly stable, non-volatile, non-toxic, and effective in low concentrations. They should be capable of adsorbing HCl produced during PVC photodecomposition or suppressing its formation and therefore suppressing the formation of polyene residues within the chains. In addition, PVC additives should be able to absorb UV irradiation directly and resist discoloration [16,17,18,19]. Additives containing metals (e.g., zinc), nanomaterials (e.g., titanium dioxides), tetrachlorobiphenyl, tris(di-tert-butylphenyl)phosphite, and bis(2-ethylhexyl)phthalate have been shown to act as PVC plasticizers [20,21,22,23,24,25]. These additives act as common and efficient HCl plasticizers and absorbers. However, many of the additives are toxic and considered hazardous for humans, animals, and the environment and are therefore banned from use [26,27,28,29]. Attention has therefore continued to be paid to the design and synthesis of other PVC additives. Examples include highly aromatic polyphosphates, Schiff bases, and heterocycles that can act as effective PVC photostabilizers [30,31,32,33,34].
Organic compounds containing tin are involved in many applications [35,36,37,38,39]. They act as wood preservatives, disinfectants, catalysts, agrochemicals, biocides, and polymer stabilizers [40]. The design and synthesis of new organic compounds containing tin are still of interest to many researchers. In continuation of our research into alternative photostabilizers for polymers, we now report the use of three tin–cephalexin complexes for the inhibition of photodegradation in PVC. Cephalexin (a beta-lactam) is used as an antibiotic to treat skin, bone, ear, and urinary tract bacterial infections [41,42]. It is a stable molecule and contains aromatic moieties (phenyl and heterocycles) and high content of heteroatoms (39.8%; S, O, and N). Therefore, cephalexin has the qualities necessary to inhibit PVC photodecomposition in complexation with tin.

2. Materials and Methods

2.1. General

Chemicals, solvents, and reagents were sourced from Merck (Gillingham, UK). PVC with an average molecular weight of around 180,000 g/mol was provided by Petkim Petrokimya (Istanbul, Turkey). For recording the FTIR spectra, a Shimadzu FTIR-8300 spectrophotometer (Tokyo, Japan) was used. UV light with a maximum wavelength (λmax) of 365 nm and a light intensity of 6.2 × 10–9 Einstein dm–3 s–1 was used to irradiate the samples at 25 °C using a Q-Panel tester (Homestead, FL, USA). The tester has two UV fluorescent lamps (λmax = 365 nm, 40 watts), one on each side. The films were placed vertically 10 cm away from the source of the irradiation light and parallel to the UV lamps. The films were rotated occasionally to enable even irradiation from all sides. A Meiji Techno Microscope (Tokyo, Japan), an FEI Inspect S50 microscope (Czechia, Czech Republic), and a Veeco microscope (Plainview, NY, USA) were used to inspect the surface of the PVC films.

2.2. Synthesis of Complexes 1–3

Tin–cephalexin complexes 1–3 (Scheme 1) were synthesized in high yields (78−98%) employing a reported procedure [43]. Reactions of excess cephalexin (2 mole equivalent) and disubstituted tin dichloride (diphenyltin dichloride, dibutyltin dichloride, and dimethyltin dichloride) in methanol (MeOH) under reflux for 5 h gave 1–3. The spectroscopic and analytical data of 1−3 agreed with those reported [43].

2.3. PVC Films Preparation

PVC (5 g) and 25 mg of the appropriate complex 1, 2, or 3 were mixed in tetrahydrofuran (THF; 100 mL). The mixture was stirred at 25 °C for 2 h, and the homogenous solution obtained was poured into a plate with holes (15; thickness = 40 µm). The plate was kept for 24 h at 25 °C to remove the THF. The resultant films produced were then dried in a vacuum oven (40 °C; 8 h) for complete elimination of any residual THF.

2.4. IR Spectroscopy of PVC

Photodegradation of PVC produces polymeric fragments with carbonyl (C=O) and polyene (C=C) groups due to the elimination of HCl from the polymer chains [44,45]. Thus, FTIR spectroscopy enabled the detection of the changes in the intensity of C=O (1714 cm–1) and C=C (1618 cm–1) absorption bands as photodegradation progressed. The growth in the peak intensities was compared with that for the C–H bonds (1328 cm–1), which does not change significantly during PVC irradiation. Functional group indexes (Is) for both the C=O (IC=O) and the C=C (IC=C) groups were calculated using Equation (1) from the absorbance of the functional group (As) and that of the reference band (Ar) [46].
I s = A s A r

2.5. Weight Loss of PVC

Elimination of small polymeric residues and volatiles during PVC photodegradation leads to weight loss. Equation (2) was used to calculate the PVC weight loss percentage from W0 (weight of nonirradiated film) and Wt (weight of irradiated films) [47].
W e i g h t   l o s s % = W 0 - W t W 0 × 100

3. Results and Discussion

3.1. IR Spectroscopy of PVC

The photodegradation process of PVC is initiated when the polymeric materials are exposed to UV light for an extended period in an environment containing oxygen. This process produces reactive species (free radicals) that cause cross-linking of PVC as well as small fragments. The polymeric residues most eliminated contain C=O (ketones, chloroketones, chlorocarboxylic acid, and acid chloride) and C=C (polyene) [48,49]. The mechanism of PVC photodegradation is a complex chain dehydrochlorination. The photodegradation of PVC leads to the formation of polymeric fragments that contain conjugated doubles due to the elimination of HCl. The process is a chain reaction that involves zipper elimination to form conjugated polyenes that contain up to 25 double bonds [50].
The blends of PVC and tin–cephalexin complexes 1–3 were irradiated for durations up to 300 h, followed by recording the IR spectra. The changes in the absorption bands for C=O (1732 cm–1) and C=C (1606 cm–1) were compared to that for the C–H bond (1328 cm–1). As Figure 1 shows, the signals for the C=O and C=C groups for the blank PVC film grew significantly during irradiation compared with the non-irradiated film.
The carbonyl (IC=O) and alkene (IC=C) indices for the films irradiated for different periods were calculated using Equation (1) and are represented graphically in Figure 2 and Figure 3. It is evident that tin–cephalexin complexes 1–3 stabilized the PVC substantially since both carbonyl and alkene indices were much higher for the unblended film compared with those containing additives. Tin complex 1, which contains aromatic substituents (phenyl groups), was a more efficient PVC photostabilizer compared to those with aliphatic substituents (butyl and methyl groups). At the end of the irradiation process, for example, the IC=O was 0.98 for the unblended PVC film and 0.58, 0.65, and 0.71 for the blends with complexes 1, 2, and 3, respectively. Similarly, IC=C for the irradiated materials (300 h) was 0.95 for the unblended PVC film and 0.54, 0.63, and 0.70 for the blends containing complexes 1, 2, and 3, respectively.

3.2. Weight Loss of PVC

The release of HCl from PVC chains at high temperatures causes discoloration. In addition, it leads to the ejection of small fragments with loss in mass [51,52]. The PVC weight loss during UV irradiation was explored. The films were irradiated (50–300 h) and the percentage loss in PVC weight was calculated using Equation (2). Figure 4 shows that the longer the irradiation time, the greater the weight loss. Additionally, the presence of tin–cephalexin complexes 1–3 reduced PVC weight loss. After 300 h of irradiation, the weight loss percentage was 0.53% for the unblended PVC film and 0.21, 0.26, and 0.31% for the blends containing complexes 1, 2, and 3, respectively. The results shown in Figure 2, Figure 3 and Figure 4 were consistent and indicated that the order of photostabilization efficiency of the metal complexes as PVC additives was 1, 2, and 3.

3.3. Surface Morphology of PVC

Inspection of the irradiated PVC film surface microscopically provides information about irregularity, roughness, and crystallinity. Another indication of damage (e.g., the appearance of spots, cracks, and darkness) to the surface of the irradiated materials is also provided [53,54,55,56]. The optical microscopy images of the PVC films indicated a tendency to form a rough, irregular, and heterogeneous surface after irradiation (Figure 5). Additionally, the presence of spots and cracks as well as dark, irregular, and rough areas was revealed. The surface damage and irregularities were more significant in the case of the unblended PVC, indicating the important role played by the tin–cephalexin complexes 1–3 in the stabilization of the polymeric materials. The least noticeable damage was observed on the surface of the PVC film blended with complex 1.
The scanning electron microscopy (SEM) technique provides high-resolution clear undistorted images of the PVC surface. The images can provide information about homogeneity and irregularity in the surface of the materials [54]. The surface damage was very significant in the case of the unblended PVC relative to those of the blends containing tin–cephalexin complexes 1–3 (Figure 6). The surface of the unblended PVC showed many holes and groves that had formed due to the high rate of HCl elimination on irradiation [57].
The atomic force microscopy (AFM) imaging was also used to record two- and three-dimensional images of the films (Figure 7). The images indicated that the surface roughness of the unblended PVC film was higher than those of the blends containing tin–cephalexin complexes 1–3. 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].

3.4. Suggested Mechanisms for PVC Photostabilization

The effectiveness of tin–cephalexin complexes 1–3 as PVC photostabilizers are in the order 1 > 2 > 3. Complexes 1–3 can reduce PVC photodegradation through different processes. Complex 1 contains extra phenyl groups (aromatic), while 2 and 3 contain butyl and methyl ligands (aliphatic) suggesting that the degree of aromaticity of additives is important in stabilizing PVC. It is possible that the aromatic residues (phenyl and heterocycles) within the complexes absorb UV irradiation directly [67,68]. The absorbed irradiation could be released as heat that does not harm the PVC chains. In addition, the polarity of the bonds linked to heteroatoms within complexes could help the coordination with the polarized C–Cl bonds in PVC. Such coordination eases the transfer of energy from the excited state complexes and PVC, enabling a slow dissipation of energy.
Complexes 1–3 contain a tin atom that is a Lewis acid and, therefore, acts as an HCl scavenger (Scheme 2). The reaction between complexes 1–3 and HCl produced from PVC during the irradiation process leads to the formation of disubstituted tin dichloride and the release of the cephalexin ligand.
Finally, tin–cephalexin complexes 1–3 can act as free radical decomposers. They deactivate the harmful and reactive species such as peroxides that are produced in the process of PVC photodegradation. For example, the complexes decompose hydroperoxides (R’O2H) produced due to the irradiation of PVC and release peroxide-containing tin and the ligand (Scheme 3). In addition, the complexes interact with peroxides and form intermediates capable of stabilization by the resonance of phenyl groups, for example [69].

4. Conclusions

Three tin complexes with the cephalexin moiety were synthesized and assessed as PVC additives. The additives were used in low proportions and were demonstrated to significantly reduce the photodegradation of PVC. The formation of residues containing functional groups, weight loss, and deformation of the surface were much lower in the presence of additives in comparison to the pure film. The tin–cephalexin complexes act as scavengers for active species such as peroxides, volatiles such as hydrogen chloride, quenchers for energy, and absorbers of harmful irradiation. The additive containing a higher proportion of aromatic substituents (phenyl groups) showed better performance than those containing aliphatic residues (butyl and methyl groups). The aromatic moieties possibly neutralize the reactive intermediates produced by irradiation through resonance stabilization acting as UV absorbers. Future research should pay attention to the hazardous effect that might be associated with the use of metal complexes as PVC additives and the possible leakage of metals into the environment.

Author Contributions

Conceptualization: D.S.A., G.A.E.-H. and E.Y.; methodology: D.S.A., G.A.E.-H. and E.Y.; software: R.R.A., A.G.H., D.S.A., G.A.E.-H., B.M.K., A.A.H., M.B. and E.Y.; validation: R.R.A., A.G.H., D.S.A., G.A.E.-H., B.M.K., A.A.H., M.B. and E.Y.; formal analysis: D.S.A., G.A.E.-H. and E.Y.; investigation: R.R.A. and A.G.H.; resources: D.S.A., G.A.E.-H. and E.Y.; data curation: R.R.A., A.G.H., D.S.A., G.A.E.-H., B.M.K., A.A.H., M.B. and E.Y.; writing—original draft preparation: D.S.A., G.A.E.-H., B.M.K., A.A.H., M.B. and E.Y.; writing—review and editing: D.S.A., G.A.E.-H., B.M.K., M.B. and E.Y.; project administration: E.Y.; funding acquisition: G.A.E.-H. All authors have read and agreed to the published version of the manuscript.

Funding

The research was supported by the Researchers Supporting Project (number RSP2023R404), King Saud University, Riyadh, Saudi Arabia.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data are contained within the article.

Acknowledgments

We thank Al-Nahrain University for technical support. We acknowledge the support received from the Researchers Supporting Project (number RSP2023R404), King Saud University, Riyadh, Saudi Arabia.

Conflicts of Interest

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

References

  1. Chen, R.; Li, Q.; Xu, X.; Zhang, D. Comparative pyrolysis characteristics of representative commercial thermosetting plastic waste in inert and oxygenous atmosphere. Fuel 2019, 246, 212–221. [Google Scholar] [CrossRef]
  2. Geyer, R.; Jambeck, J.R.; Law, K.L. Production, use, and fate of all plastics ever made. Sci. Adv. 2017, 3, e1700782. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  3. Zhang, Y.; Yu, X.; Cheng, Z. Research on the application of synthetic polymer materials in contemporary public art. Polymers 2022, 14, 1208. [Google Scholar] [CrossRef] [PubMed]
  4. Young, R.J.; Lovell, P.A. Introduction to Polymers, 3rd ed.; CRC Press: Boca Raton, FL, USA, 2011; p. 76. [Google Scholar] [CrossRef]
  5. Neuba, L.D.M.; Junio, R.F.P.; Ribeiro, M.P.; Souza, A.T.; Lima, E.D.S.; Filho, F.D.C.G.; Figueiredo, A.B.-H.D.S.; Braga, F.D.O.; De Azevedo, A.R.G.; Monteiro, S.N. Promising mechanical, thermal, and ballistic properties of novel epoxy composites reinforced with Cyperus malaccensis sedge fiber. Polymers 2020, 12, 1776. [Google Scholar] [CrossRef]
  6. Chamas, A.; Moon, H.; Zheng, J.; Qiu, Y.; Tabassum, T.; Jang, J.H.; Abu-Omar, M.; Scott, S.L.; Suh, S. Degradation rates of plastics in the environment. ACS Sustain. Chem. Eng. 2020, 8, 3494–3511. [Google Scholar] [CrossRef] [Green Version]
  7. Starnes Jr, W.H. Structural defects in poly(vinyl chloride). J. Polym. Sci. A Polym. Chem. 2005, 43, 2451–2467. [Google Scholar] [CrossRef]
  8. Lu, T.; Solis-Ramos, E.; Yi, Y.; Kumosa, M. UV degradation model for polymers and polymer matrix composites. Polym. Degrad. Stab. 2018, 154, 203–210. [Google Scholar] [CrossRef]
  9. Liu, J.; Lv, Y.; Luo, Z.; Wang, H.; Wei, Z. Molecular chain model construction, thermo-stability, and thermo-oxidative degradation mechanism of poly(vinyl chloride). RSC Adv. 2016, 6, 31898–31905. [Google Scholar] [CrossRef]
  10. Folarin, O.M.; Sadiku, E.R. Thermal stabilizers for poly(vinyl chloride): A review. Int. J. Phys. Sci. 2011, 6, 4323–4330. [Google Scholar] [CrossRef]
  11. Zheng, X.G.; Tang, L.H.; Zhang, N.; Gao, Q.H.; Zhang, C.F.; Zhu, Z.B. Dehydrochlorination of PVC materials at high temperature. Energy Fuels 2003, 17, 896–900. [Google Scholar] [CrossRef]
  12. Valko, L.; Klein, E.; Kovařík, P.; Bleha, T.; Šimon, P. Kinetic study of thermal dehydrochlorination of poly(vinyl chloride) in the presence of oxygen: III. Statistical thermodynamic interpretation of the oxygen catalytic activity. Eur. Polym. J. 2001, 37, 1123–1132. [Google Scholar] [CrossRef]
  13. Yaqoob, A.A.; Noor, N.H.M.; Serrà, A.; Mohamad Ibrahim, M.N. Advances and challenges in developing efficient graphene oxide-based ZnO photocatalysts for dye photo-oxidation. Nanomaterials 2020, 10, 932. [Google Scholar] [CrossRef] [PubMed]
  14. Ma, L.J.; Lu, Y.H.; Chen, Y.; Lu, Y.W.; Yuan, G. Dehydrochlorination study of plasticized poly(vinyl chloride) containing modified titanium dioxide, cerium stearate, organotin and β-diketone complex after long-term storage. Mater. Res. Express 2022, 9, 025305. [Google Scholar] [CrossRef]
  15. Ye, X.; Pi, H.; Guo, S. A novel route for preparation of PVC sheets with high UV irradiation resistance. J. Appl. Polym. Sci. 2010, 117, 2899–2906. [Google Scholar] [CrossRef]
  16. Gao, A.X.; Bolt, J.D.; Feng, A.A. Role of titanium dioxide pigments in outdoor weathering of rigid PVC. Plast. Rubber Compos. 2008, 37, 397–402. [Google Scholar] [CrossRef]
  17. Chai, R.D.; Zhang, J. Synergistic effect of hindered amine light stabilizers/ultraviolet absorbers on the polyvinyl chloride/powder nitrile rubber blends during photodegradation. Polym. Eng. Sci. 2013, 53, 1760–1769. [Google Scholar] [CrossRef]
  18. Cadogan, D.F.; Howick, C.J. Plasticizers. In Ullmann’s Encyclopedia of Industrial Chemistry; Wiley-VCH: Weinheim, Germany, 2000. [Google Scholar]
  19. Braun, D. Recycling of PVC. Prog. Polym. Sci. 2002, 27, 2171–2195. [Google Scholar] [CrossRef]
  20. Xue, M.Y.; Lu, Y.H.; Li, K.; Wang, B.; Lu, Y.W. Thermal characterization and kinetic analysis of polyvinyl chloride containing Sn and Zn. J. Therm. Anal. Calorim. 2020, 139, 1479–1492. [Google Scholar] [CrossRef]
  21. Chrissafis, K.; Bikiaris, D. Can nanoparticles really enhance thermal stability of polymers? Part I: An overview on thermal decomposition of addition polymers. Thermochim. Acta 2011, 523, 1–24. [Google Scholar] [CrossRef]
  22. Pielichowska, K.; Nowicka, K. Analysis of nanomaterials and nanocomposites by thermo- analytical methods. Thermochim. Acta 2019, 675, 140–163. [Google Scholar] [CrossRef]
  23. Wang, B.; Lu, Y.H.; Lu, Y.W. Organic tin, calcium-zinc and titanium composites as reinforcing agents and its effects on the thermal stability of polyvinyl chloride. J. Therm. Anal. Calorim. 2020, 142, 671–683. [Google Scholar] [CrossRef]
  24. Porta, M.; Zumeta, E. Implementing the Stockholm treaty on persistent organic pollutants. Occup. Environ. Med. 2002, 59, 651–652. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  25. Grossman, R.F. Mixed metal vinyl stabilizer synergism. II: Reactions with zinc replacing cadmium. J. Vinyl Technol. 1990, 12, 142–145. [Google Scholar] [CrossRef]
  26. Fu, M.; Li, D.; Liu, H.; Ai, H.; Zhang, Y.; Zhang, L. Synergistic effects of zinc-mannitol alkoxide with calcium/zinc stearates and with β-diketone on thermal stability of rigid poly(vinyl chloride). J. Polym. Res. 2016, 23, 13. [Google Scholar] [CrossRef]
  27. Li, D.; Xie, L.; Fu, M.; Zhang, J.; Indrawirawan, S.; Zhang, Y.; Tang, S. Synergistic effects of lanthanum-pentaerythritol alkoxide with zinc stearates and with beta-diketone on the thermal stability of poly(vinyl chloride). Polym. Degrad. Stab. 2015, 114, 52–59. [Google Scholar] [CrossRef]
  28. Meng, J.; Xu, B.; Liu, F.; Li, W.; Sy, N.; Zhou, X.; Yan, B. Effects of chemical and natural ageing on the release of potentially toxic metal additives in commercial PVC microplastics. Chemosphere 2021, 283, 131274. [Google Scholar] [CrossRef]
  29. Barrick, A.; Champeau, O.; Chatel, A.; Manier, N.; Northcott, G.; Tremblay, L.A. Plastic additives: Challenges in ecotox hazard assessment. PeerJ. 2021, 9, e11300. [Google Scholar] [CrossRef]
  30. Sabaa, M.W.; Oraby, E.H.; Naby, A.S.A.; Mohammed, R.R. Anthraquinone derivatives as organic stabilizers for rigid poly(vinyl chloride) against photo-degradation. Eur. Polym. J. 2005, 41, 2530–2543. [Google Scholar] [CrossRef]
  31. Yang, T.C.; Noguchi, T.; Isshiki, M.; Wu, J.H. Effect of titanium dioxide on chemical and molecular changes in PVC sidings during QUV accelerated weathering. Polym. Degrad. Stab. 2014, 104, 33–39. [Google Scholar] [CrossRef]
  32. Schiller, M. PVC Additives: Performance, Chemistry, Developments, and Sustainability; Carl Hanser Verlag: Munich, Germany, 2015. [Google Scholar]
  33. Yang, T.C.; Noguchi, T.; Isshiki, M.; Wu, J.H. Effect of titanium dioxide particles on the surface morphology and the mechanical properties of PVC composites during QUV accelerated weathering. Polym. Compos. 2016, 37, 3391–3397. [Google Scholar] [CrossRef]
  34. El-Hiti, G.A.; Ahmed, D.S.; Yousif, E.; Alotaibi, M.H.; Star, H.A.; Ahmed, A.A. Influence of polyphosphates on the physicochemical properties of poly(vinyl chloride) after irradiation with ultraviolet light. Polymers 2020, 12, 193. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  35. Annuar, S.N.S.; Kamaludin, N.F.; Awang, N.; Chan, K.M. Cellular basis of organotin(IV) derivatives as anticancer metallodrugs: A review. Front. Chem. 2021, 9, 657599. [Google Scholar] [CrossRef] [PubMed]
  36. Niu, L.; Li, Y.; Li, Q. Medicinal properties of organotin compounds and their limitations caused by toxicity. Inorg. Chim. Acta 2014, 423, 2–13. [Google Scholar] [CrossRef]
  37. Pellerito, C.; Nagy, L.; Pellerito, L.; Szorcsik, A. Biological activity studies on organotin(IV)n+ complexes and parent compounds. J. Organomet. Chem. 2006, 691, 1733–1747. [Google Scholar] [CrossRef]
  38. Davies, A.G. Organotin Chemistry, 2nd ed.; Wiley-VCH: Weinheim, Germany; John Wiley: Chichester, UK, 2004. [Google Scholar]
  39. Arkış, E.; Balköse, D. Thermal stabilisation of poly(vinyl chloride) by organotin compounds. Polym. Degrad. Stab. 2005, 88, 46–51. [Google Scholar] [CrossRef] [Green Version]
  40. Schibli, R.; Schubiger, P.A. Current use and future potential of organometallic radiopharmaceuticals. Eur. J. Nucl. Med. Mol Imaging 2002, 29, 1529–1542. [Google Scholar] [CrossRef] [PubMed]
  41. Nguyen, H.M.; Graber, C.J. A critical review of cephalexin and cefadroxil for the treatment of acute uncomplicated lower urinary tract infection in the era of “bad bugs, few drugs”. Int. J. Antimicrob. Agents 2020, 56, 106085. [Google Scholar] [CrossRef] [PubMed]
  42. Derrick, C.W.; Reilly, K. The role of cephalexin in the treatment of skin and soft-tissue infections. Postgrad. Med. J. 1983, 59, 43–46. [Google Scholar]
  43. Arraq, R.R.; Hadi, A.G. Synthesis, identification, and anti-oxidant activity of di-organotin(IV)-cephalexin complexes. J. Med. Chem. Sci. 2023, 6, 392–401. [Google Scholar] [CrossRef]
  44. Karayıldırım, T.; Yanık, J.; Yüksel, M.; Saglam, M.; Haussmann, M. Degradation of PVC containing mixtures in the presence of HCl fixators. J. Polym. Environ. 2005, 13, 365–379. [Google Scholar] [CrossRef]
  45. Nief, O.A. Photostabilization of polyvinyl chloride by some new thiadiazole derivatives. Eur. J. Chem. 2015, 6, 242–247. [Google Scholar] [CrossRef] [Green Version]
  46. Gaumet, S.; Gardette, J.-L. Photo-oxidation of poly(vinyl chloride): Part 2—A comparative study of the carbonylated products in photo-chemical and thermal oxidations. Polym. Degrad. Stab. 1991, 33, 17–34. [Google Scholar] [CrossRef]
  47. Pospíšil, J.; Nešpurek, S. Photostabilization of coatings. Mechanisms and performance. Prog. Polym. Sci. 2000, 25, 1261–1335. [Google Scholar] [CrossRef]
  48. Gardette, J.L.; Gaumet, S.; Lemaire, J. Photooxidation of poly(viny1 chloride). 1. A reexamination of the mechanism. Macromolecules 1989, 22, 2576–2581. [Google Scholar] [CrossRef]
  49. Khalil, A.M.; Rabie, S.T.; Kapralkova, L.; Abd El Ghaffar, M.A. Itaconamide derivatives as organic stabilizers for poly(vinyl chloride) against photodegradation. J. Macromol. Sci. A 2016, 53, 96–103. [Google Scholar] [CrossRef]
  50. Ivan, B.; Kelen, T.; Tudos, F. Degradation and Stabilization of Poly(vinyl chloride). In Degradation and Stabilization of Polymers; Jellinek, H.H.G., Kachi, H., Eds.; Elsevier: Amsterdam, The Netherlands, 1989; Volume 2, pp. 483–714. [Google Scholar]
  51. Sabaa, M.W.; Oraby, E.H.; Naby, A.S.A.; Mohamed, R.R. N-Phenyl-3-substituted-5-pyrazolone derivatives as organic stabilizer for rigid PVC against photodegradation. J. Appl. Polym. Sci. 2005, 101, 1543–1555. [Google Scholar] [CrossRef]
  52. Chaochanchaikul, K.; Rosarpitak, V.; Sombatsompop, N. Photodegradation profiles of PVC compound and wood/PVC composites under UV weathering. Express Polym. Lett. 2013, 7, 146–160. [Google Scholar] [CrossRef] [Green Version]
  53. Venkateshaiah, A.; Padil, V.V.T.; Nagalakshmaiah, M.; Waclawek, S.; Černík, M.; Varma, R.S. Microscopic techniques for the analysis of micro and nanostructures of biopolymers and their derivatives. Polymers 2020, 12, 512. [Google Scholar] [CrossRef] [Green Version]
  54. Nikafshar, S.; Zabihi, O.; Ahmadi, M.; Mirmohseni, A.; Taseidifar, M.; Naebe, M. The effects of UV light on the chemical and mechanical properties of a transparent epoxy-diamine system in the presence of an organic UV absorber. Materials 2017, 10, 180. [Google Scholar] [CrossRef] [PubMed]
  55. Mehmood, N.; Andreasson, E.; Kao-Walter, S. SEM observations of a metal foil laminated with a polymer film. Procedia Mater. Sci. 2014, 3, 1435–1440. [Google Scholar] [CrossRef]
  56. See, C.H.; O’Haver, J. Atomic force microscopy characterization of ultrathin polystyrene films formed by admicellar polymerization on silica disks. J. Appl. Polym. Sci. 2003, 89, 36–46. [Google Scholar] [CrossRef]
  57. Shi, W.; Zhang, J.; Shi, X.M.; Jiang, G.D. Different photo-degradation processes of PVC with different average degrees of polymerization. J. Appl. Polym. Sci. 2008, 107, 528–540. [Google Scholar] [CrossRef]
  58. Hadi, A.G.; Yousif, E.; El-Hiti, G.A.; Ahmed, D.S.; Jawad, K.; Alotaibi, M.H.; Hashim, H. Long-term effect of ultraviolet irradiation on poly(vinyl chloride) films containing naproxen diorganotin(IV) complexes. Molecules 2019, 24, 2396. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  59. Ali, M.M.; El-Hiti, G.A.; Yousif, E. Photostabilizing efficiency of poly(vinyl chloride) in the presence of organotin(IV) complexes as photostabilizers. Molecules 2016, 21, 1151. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  60. Yaseen, A.A.; Yousif, E.; Al-Tikrity, E.T.B.; El-Hiti, G.A.; Kariuki, B.M.; Ahmed, D.S.; Bufaroosha, M. FTIR, weight, and surface morphology of poly(vinyl chloride) doped with tin complexes containing aromatic and heterocyclic moieties. Polymers 2021, 13, 3264. [Google Scholar] [CrossRef] [PubMed]
  61. Fadhil, M.; Yousif, E.; Ahmed, D.S.; Mohammed, A.; Hashim, H.; Ahmed, A.; Kariuki, B.M.; El-Hiti, G.A. Synthesis of new norfloxacin–tin complexes to mitigate the effect of ultraviolet-visible irradiation in polyvinyl chloride films. Polymers 2022, 14, 2812. [Google Scholar] [CrossRef] [PubMed]
  62. Fadhil, M.; Yousif, E.; Ahmed, D.S.; Kariuki, B.M.; El-Hiti, G.A. Synthesis and application of levofloxacin–tin complexes as new photostabilizers for polyvinyl chloride. Polymers 2022, 14, 3720. [Google Scholar] [CrossRef]
  63. Naoom, N.; Yousif, E.; Ahmed, D.S.; Kariuki, B.M.; El-Hiti, G.A. Synthesis of methyldopa–tin complexes and their applicability as photostabilizers for the protection of polyvinyl chloride against photolysis. Polymers 2022, 14, 4590. [Google Scholar] [CrossRef]
  64. Ghazi, D.; El-Hiti, G.A.; Yousif, E.; Ahmed, D.S.; Alotaibi, M.H. The effect of ultraviolet irradiation on the physicochemical properties of poly(vinyl chloride) films containing organotin(IV) complexes as photostabilizers. Molecules 2018, 23, 254. [Google Scholar] [CrossRef] [Green Version]
  65. Ghani, H.; Yousif, E.; Ahmed, D.S.; Kariuki, B.M.; El-Hiti, G.A. Tin complexes of 4-(benzylideneamino)benzenesulfonamide: Synthesis, structure elucidation and their efficiency as PVC photostabilizers. Polymers 2021, 13, 2434. [Google Scholar] [CrossRef]
  66. Hadi, A.G.; Baqir, S.J.; Ahmed, D.S.; El-Hiti, G.A.; Hashim, H.; Ahmed, A.; Kariuki, B.M.; Yousif, E. Substituted organotin complexes of 4-methoxybenzoic acid for reduction of poly(vinyl chloride) photodegradation. Polymers 2021, 13, 3946. [Google Scholar] [CrossRef] [PubMed]
  67. Larché, J.F.; Bussière, P.O.; Therias, S.; Gardette, J.L. Photooxidation of polymers: Relating material properties to chemical changes. Polym. Degrad. Stab. 2012, 97, 25–34. [Google Scholar] [CrossRef]
  68. Scott, G. Mechanism of Polymer Degradation and Stabilization; Elsevier: New York, NY, USA, 1990. [Google Scholar]
  69. Pospíšil, J.; Klemchuk, P.P. Oxidation Inhibition in Organic Materials; CRC Press: Boca Raton, FL, USA, 1989; Volume 1, pp. 48–49. [Google Scholar]
Polymers 15 00550 sch001 550
Scheme 1. Synthesis of tin–cephalexin complexes 1–3.
Scheme 1. Synthesis of tin–cephalexin complexes 1–3.
Polymers 15 00550 sch001
Polymers 15 00550 g001 550
Figure 1. FTIR spectra of the unblended PVC film (a) before irradiation and (b) after 300 h of irradiation.
Figure 1. FTIR spectra of the unblended PVC film (a) before irradiation and (b) after 300 h of irradiation.
Polymers 15 00550 g001
Polymers 15 00550 g002 550
Figure 2. Effect of the time of irradiation on the IC=O of PVC films.
Figure 2. Effect of the time of irradiation on the IC=O of PVC films.
Polymers 15 00550 g002
Polymers 15 00550 g003 550
Figure 3. Effect of the time of irradiation on the IC=C of PVC films.
Figure 3. Effect of the time of irradiation on the IC=C of PVC films.
Polymers 15 00550 g003
Polymers 15 00550 g004 550
Figure 4. Effect of the time of irradiation on the weight of PVC films.
Figure 4. Effect of the time of irradiation on the weight of PVC films.
Polymers 15 00550 g004
Polymers 15 00550 g005 550
Figure 5. Microscope images (400× magnifications) of irradiated (a) pure PVC, (b) PVC + 1, (c) PVC + 2, and (d) PVC + 3.
Figure 5. Microscope images (400× magnifications) of irradiated (a) pure PVC, (b) PVC + 1, (c) PVC + 2, and (d) PVC + 3.
Polymers 15 00550 g005
Polymers 15 00550 g006 550
Figure 6. SEM images of irradiated (a) pure PVC, (b) PVC + 1, (c) PVC + 2, and (d) PVC + 3.
Figure 6. SEM images of irradiated (a) pure PVC, (b) PVC + 1, (c) PVC + 2, and (d) PVC + 3.
Polymers 15 00550 g006
Polymers 15 00550 g007 550
Figure 7. AFM images of irradiated (a) pure PVC, (b) PVC + 1, (c) PVC + 2, and (d) PVC + 3.
Figure 7. AFM images of irradiated (a) pure PVC, (b) PVC + 1, (c) PVC + 2, and (d) PVC + 3.
Polymers 15 00550 g007
Polymers 15 00550 sch002 550
Scheme 2. Cephalexin–tin complexes act as HCl scavengers.
Scheme 2. Cephalexin–tin complexes act as HCl scavengers.
Polymers 15 00550 sch002
Polymers 15 00550 sch003 550
Scheme 3. Cephalexin–tin complexes act as peroxide decomposers.
Scheme 3. Cephalexin–tin complexes act as peroxide decomposers.
Polymers 15 00550 sch003
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Arraq, R.R.; Hadi, A.G.; Ahmed, D.S.; El-Hiti, G.A.; Kariuki, B.M.; Husain, A.A.; Bufaroosha, M.; Yousif, E. Enhancement of Photostabilization of Poly(Vinyl Chloride) in the Presence of Tin–Cephalexin Complexes. Polymers 2023, 15, 550. https://doi.org/10.3390/polym15030550

AMA Style

Arraq RR, Hadi AG, Ahmed DS, El-Hiti GA, Kariuki BM, Husain AA, Bufaroosha M, Yousif E. Enhancement of Photostabilization of Poly(Vinyl Chloride) in the Presence of Tin–Cephalexin Complexes. Polymers. 2023; 15(3):550. https://doi.org/10.3390/polym15030550

Chicago/Turabian Style

Arraq, Rafid R., Angham G. Hadi, Dina S. Ahmed, Gamal A. El-Hiti, Benson M. Kariuki, Amani A. Husain, Muna Bufaroosha, and Emad Yousif. 2023. "Enhancement of Photostabilization of Poly(Vinyl Chloride) in the Presence of Tin–Cephalexin Complexes" Polymers 15, no. 3: 550. https://doi.org/10.3390/polym15030550

APA Style

Arraq, R. R., Hadi, A. G., Ahmed, D. S., El-Hiti, G. A., Kariuki, B. M., Husain, A. A., Bufaroosha, M., & Yousif, E. (2023). Enhancement of Photostabilization of Poly(Vinyl Chloride) in the Presence of Tin–Cephalexin Complexes. Polymers, 15(3), 550. https://doi.org/10.3390/polym15030550

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop