SYNOPSISGraft copolymerization of vinyl compounds onto chitin was studied, and an efficient and reproducible procedure has been established, cerium ( I V ) being used as the initiator. The reactions with acrylamide and acrylic acid onto powdery chitin were carried out under various conditions to elucidate the polymerization behavior in terms of grafting percentage.The amount of cerium (IV) affected the polymerization most strikingly, and grafting percentages showed maxima with suitable amounts of initiator for both the monomers. As a solvent water proved to be superior to aqueous nitric acid except the reaction with a small amount of initiator. Under appropriate conditions, around 240 and 200% grafting percentages were achieved for acrylamide and acrylic acid, respectively. The resulting graft copolymers showed much improved affinity for solvents and hygroscopicity compared to the original chitin.
ABSTRACT:Tri-0-acetyl-, tri-0-benzyl-, tri-0-methyl-o-glucal were copolymerized with maleic anhydride (MAnh) to afford novel vinyl copolymers containing sugar residues in the main chain. Tri-0-benzyl-o-glucal (TBG) showed higher copolymerization reactivity with MAnh than the other glucal derivatives. The copolymerization of TBG and MAnh was carried out at various monomer feed ratios to give the copolymers always rich in MAnh units. Both the complex and penultimate models could explain the compositional data, but the analysis of the copolymerization rate suggested the participation of the CT complex in the propagation.
ABSTRACT:A stable furanoid glucal, 3-O-benzyl-l ,2-dideoxy-5,6-O-isopropylidene-Darabino-hex-l-enofuranose (BIF) was synthesized, and the equilibrium association constant K for the charge-transfer complex formation with maleic anhydride in CDCl3 at 25°C was 0.131 mol-1 as determined by 13 C NMR. BIF copolymerized with maleic anhydride almost alternatingly, AIBN being used as the initiator. Other electron accepting monomers such as N-phenylmaleimide and acrylonitrile also copolymerized with BIF. Terpolymerization of BIF-maleic anhydrideacrylonitrile gave the copolymer containing BIF residues.KEY WORDS Radical Copolymerization / Alternating Copolymerization / Unsaturated Sugar/ Furanoid Glucal / Maleic Anhydride/ Charge-Transfer Complex/ Many kinds of carbohydrate-containing polymers have been extensively studied, 1 • 2 and reported to exhibit various interesting properties characteristic of natural polysaccharides, including high degrees of water absorption,3·4 rapid water flux through their membranes,4 and the interaction with lectins. 5·6 In the previous paper 7 we described the radical copolymerization of pyranoid glucal derivatives with maleic anhydride, affording novel vinyl copolymers containing sugar residues in the main chain. However, the resulting copolymers had only low molecular weights presumably owing to steric hindrance at the propagation transition step. Furanoid glucals seem to be more appropriate to synthesize high molecular weight copolymers because of smaller steric hindrance of their five-membered ring structures.In the present paper, we describe the preparation of a stable furanoid glucal, 3-0-benzyl-l ,2-dideoxy-5,6-0-isopropylidene-oarabino-hex-1-enofuranose (BIF), and the charge-transfer complex polymerization with maleic anhydride and other electron acceptor monomers. Terpolymerization of BIF with maleic anhydride and acrylonitrile was also attempted. l-Chloro-l-deoxy-2,3 : 5,6-di-O-isopropylidene-cx-o-mannose8 (37.5 g, 0.135 mol) was reduced with sodium naphthalide in dry tetrahydrofuran as reported by Eitelman and coworkers 9 to give l ,2-dideoxy-5,6-0-isopropylidene-o-arabino-hex-1-enofuranose as an oily product. After purification by column chromatography, it was dissolved in 326 ml of dimethylformamide and treated 695 EXPERIMENTAL 3
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.