عنوان مقاله [English]
Hypothesis: Discovering new chemical modifications for polymers is an interesting way to change the properties and final applications of the polymers. Poly(vinyl alcohol) (PVA) and ethylene-vinyl alcohol copolymer (EVA) are useful in practical investigations of functional polymers because they can be modified through their hydroxyl groups. In this study, PVA and EVA were modified to incorporate different reactive functional groups using esterification reaction. Then, substitution reaction was used to incorporate benzimidazole groups into the modified EVA. Azolated EVA can be utilized in other applications such as fuel cell as a proton exchange membrane.
Methods: Functional modification of PVA was carried out by acryloyl chloride and maleic anhydride in 1-methyl-2-pyrolydone (NMP, room temperature) and dimethyl sulfoxide (DMSO, 100°C), respectively. Similarly, EVA was modified with chloroacetyl chloride and α-bromoisobutyryl bromide via esterification reaction in NMP at room temperature. Next, benzimidazole group was incorporated into the α-bromoisobutyrylated EVA through substitution nucleation reaction with sodium-2-mercaptobenzimidazole in THF at 80°C.
Findings: Chemical structures of polymers were investigated by FTIR and
1H NMR. Functionalization of PVA with acryloyl chloride and maleic anhydride was calculated to be 9.31 and 46.28 mol% and that of EVA with chloroacetyl chloride and α-bromoisobutyryl bromide was obtained to be 71.50 and 63.46 mol%. The high yield obtained in all of the different proposed routes makes them feasible for activation of EVA copolymers. Moreover, to predict the solubility behavior of functionalized polymers, the Hansen solubility parameters of original and modified polymers were calculated via Hoftyzer-Van Krevelen's (HVK) and Hoy's group contribution methods. Calculations showed that, among studied solvents, dimethylacetamide is the best solvent for acryloylated PVA, carboxyvinylated PVA and EVA copolymer, while acetone is the best one for copolymers modified with chloroacetyl chloride and α-bromoisobutyryl bromide and azolated copolymer, which was in good agreement with the experimental results.
1.Ping ZLa F., China Daily Europe, Overcapacity Drives New Approaches to Production, http://europechinadailycomcn/epaper/2014-09/26/content_18664501htm, 2014.
2.Hikasa J., Fibers, Poly(vinyl alcohol), Kirk-Othmer Encyclopedia of Chemical Technology, John Wiley and Sons, New York, 24, 2000.
3.Moulay S., Review: Poly(vinyl alcohol) Functionalizations and Applications, Polym. Plast. Technol., 54, 1289-1319, 2015.
4.Askari F., Mortazaei M., Pourhossaini M.R., and Solimannia S., Polyvinyl Alcohol-Sulfonated Polyethersulfone Blend for Application in Proton-exchange Membranes, Iran. J. Polym. Sci. Technol. (Persian) , 29, 403-412, 2017.
5.Tang X. and Alavi S., Recent Advances in Starch, Polyvinyl Alcohol Based Polymer Blends, Nanocomposites and Their Biodegradability, Carbohyd. Polym., 85, 7-16, 2011.
6.Sánchez-Chaves M., Ruiz C., Cerrada M.L., and Fernández-García M., Novel Glycopolymers Containing Aminosaccharide Pendant Groups by Chemical Modification of Ethylene–Vinyl Alcohol Copolymers, Polymer, 49, 2801-2807, 2008.
7.Rabasco J.J., Klingenberg E.H., Dado G.P., Pinschmidt R.K., and Boylan J.R., Piperidone Functionalized Poly(vinyl alcohol), US6 096826A, 2000.
8.Rostagno M., Shen S., Ghiviriga I. and Miller S.A., Sustainable Polyvinyl Acetals from Bioaromatic Aldehydes, Polym. Chem., 8, 5049-5059, 2017.
9.Baudis S., Bomze D., Markovic M., Gruber P., Ovsianikov A., and Liska R., Modular Material System for the Microfabrication of Biocompatible Hydrogels Based on Thiol–ene-Modified Poly(vinyl alcohol), J. Polym. Sci. Polym. Chem., 54, 2060-2070, 2016.
10.Chiang W.Y. and Hu C.M., Studies of Reactions with Polymers. I. The Reaction of Maleic Anhydride with PVA and the Properties of the Resultant. J. Appl. Polym. Sci., 30, 3895-3910, 1985.
11.Tan S., Wei B., Liang T., Yang X., and Wu Y., Anhydrous Proton Conduction in Liquid Crystals Containing Benzimidazole Moieties, RSC Adv., 6, 34038-34042, 2016.
12.Tayouo R., David G., Améduri B., Rozière J., and Roualdès S., New Fluorinated Polymers Bearing Pendant Phosphonic Acid Groups. Proton Conducting Membranes for Fuel Cell, Macromolecules, 43, 5269-5276, 2010.
13.Xue J., Wang T., Nie J., and Yang D., Preparation and Characterization of a Bioadhesive with Poly(vinyl alcohol) Crosslinking Agent, J. Appl. Polym. Sci., 12, 75051-5058, 2013.
14.Giménez V., Reina J.A., Mantecón A., and Cádiz V., Unsaturated Modified Poly(vinyl alcohol), Crosslinking Through Double Bonds, Polymer, 40, 2759-2767,1999.
15.Giménez V., Mantecón A., Ronda J.C., and Cádiz V., Poly(vinyl alcohol) Modified with Carboxylic Acid Anhydrides: Crosslinking Through Carboxylic Groups, J. Appl. Polym. Sci., 65,1643-1651, 1997.
16.Roman Jantas Z.D., Lucyna Herczyńska., and Dawid Stawski., Poly(vinyl alcohol)-Salicylic Acid Conjugate: Synthesis and Characterization, Am. J. Polym. Sci., 2, 79-84, 2012.
17.Jin B., Shen J., Peng R., Shu Y., Tan B., Chu S., and Dong H., Synthesis, Characterization, Thermal Stability and Sensitivity Properties of the New Energetic Polymer Through the Azidoacetylation of Poly(vinyl alcohol), Polym. Degrad. Stabil., 97, 473-480, 2012.
18.Bu F., Zhang Y., Hong L., Zhao W., Li D., Li J., Na H., and Zhao C., 1,2,4-Triazole Functionalized Poly(arylene ether ketone) for High Temperature Proton Exchange Membrane with Enhanced Oxidative Stability, J. Membr. Sci., 545, 167-175, 2018.
19.Campagne B., David G., Améduri B., Jones D.J., Rozière J., and Roche I., Novel Blend Membranes of Partially Fluorinated Copolymers Bearing Azole Functions with Sulfonated PEEK for PEMFC Operating at Low Relative Humidity: Influence of the Nature of the N-Heterocycle, Macromolecules, 46, 3046-3057, 2013.
20.Begtrup M. and Larsen P., Alkylation, Acylation and Silylation of Azoles, Acta Chem. Scand., 44, 1050-1057, 1990.
21.Ketels H., Beulen J., and Van der Velden G., Tacticity, Sequence Distribution, Anomalous Linkages, and Alkyl Chain Branching in Ethylene-Vinyl Alcohol Copolymers as Studied by Proton and Carbon-13 NMR. Macromolecules, 21, 2032-2037, 1988.
22.Tang Z., Wei J., Yung L., Ji B., Ma H., Qiu C., Yoon K., Wan F., Fang D., and Hsiao BS., UV-cured Poly(vinyl alcohol) Ultrafiltration Nanofibrous Membrane Based on Electrospun Nanofiber Scaffolds, J. Membr. Sci., 328, 1-5, 2009.
23.Ruiz J., Mantecón A., and Cádiz V., Synthesis and Swelling Characteristics of Acid-Containing Poly(vinyl alcohol) Hydrogels, J. Appl. Polym. Sci., 81, 1444-1450, 2001.
24.Wang X., Fu Q., Wang X., Si Y., Yu J., Wang X., and Ding B., In Situ Cross-linked and Highly Carboxylated Poly(vinyl alcohol) Nanofibrous Membranes for Efficient Adsorption of Proteins, J. Mater. Chem., 3, 7281-7290, 2015.
25.Kenawy E.R., El-Newehy M.H., Abdel-Hay F.I. and El-Shanshoury AE-RR., Synthesis and Biocidal activity of Modified Poly(vinyl alcohol), Arab. J. Chem., 7, 355-361, 2014.
26.Mohan S., Sundaraganesan N., and Mink J., FT-IR and Raman Studies on Benzimidazole, Spectrochim. Acta. A, 47, 1111-1115, 1991.
27.Persson J.C. and Jannasch P., Intrinsically Proton-Conducting Comb-Like Copolymers with Benzimidazole Tethered to the Side Chains, Solid State Ionics, 177, 653-658, 2006.
28.Brandrup J., Immergut E.H. and Grulke E.A., Polymer Handbook, 4th ed., Wiley, New York, 4th ed.,Chapt. VII, 1999.
29.Hansen C.M., Hansen Solubility Parameters: A User’s Handbook, 2nd ed. CRC, 2007.
30.Van Krevelen D.W. and Te Nijenhuis K., Properties of Polymers: Their Correlation with Chemical Structure; Their Numerical Estimation and Prediction from Additive Group Contributions, 4th ed., Elsevier, Netherlands, Chapt. 7, 2009.
31.Ho B.C., Chin W.K., and Lee Y.D, Solubility Parameters of Polymethacrylonitrile, Poly(methacrylic acid) and Methacrylonitrile/methacrylic Acid Copolymer. J. Appl. Polym. Sci., 42, 99-106, 1991.