Synthesis of Biohybrid Particles by Modification of Chitosan Beads via RAFT Polymerization in Dispersed Media

Abstract

in various fields including, water and wastewater treatment as adsorbents or coagulation-flocculation agents, medical applications as drug delivery systems, and the cosmetic or agriculture sectors. [2,4,8] However, the properties of unmodified CTS limit its use for some applications. Consequently, researchers have focused on the modification of CTS to improve and tune its properties, such as improved solubility in organic solvents, compatibility with various polymers, or affinity for molecules of interest. Possible chemical modifications of CTS include acylation, alkylation, quaternization, azidation, and phosphonation, [9-19] as well as the grafting of polymers. [20,21] One of the incentives for modifying CTS is to enhance its solubility in organic solvents for the preparation of advanced materials requiring chemical modification in specific solvents. For this purpose, N-phthaloylation was described by Kurita et al. using a method that involved the presence of small amounts of hydroxy-containing compounds for selective N-phthaloylation while avoiding O-6 phthaloylation. [22-24] N-phthaloylation with a high degree of substitution was prepared in acidic aqueous media by Ifuku et al. [25] The same group also successfully prepared N-(4-bromophthaloyl) chitosan exhibiting high solubility in common solvents, such as dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide, and N-methylpyrrolidone (NMP). [9] The alkylation of CTS was reported in heterogeneous and homogeneous conditions for the introduction of specific chemical groups, such as aromatic structures, imidazole, sulfonate, or carboxylation. [26-31] Complexation of CTS with surfactants, such as sodium dodecylsulfate or sodium dodecylbenzenesulfonate was also described as a method for improving its solubility in organic solvents. [32-35] The grafting of synthetic polymers on CTS is a powerful and flexible tool among the strategies for preparing innovative materials. [20] Most reports on CTS modification by grafting have examined the use of free radical polymerization, [36-39] ring-opening polymerization, [40,41] γ-radiation, [38,40] or cationic polymerization [37,42] via both "grafting from" and "grafting to" approaches. Controlled radical polymerization, now more commonly known as reversible deactivation radical polymerization (RDRP), has provided a versatile tool for designing new CTSbased materials grafted with well-defined and functional (co) polymers. Atom transfer radical polymerization (ATRP) [43-51] Spherical macroscopic particles (beads) made from chitosan (CTS), a polysaccharide derived from the valorization of food waste, are converted into a biohybrid material by grafting poly(4-vinylpyridine) (P4VP) using a "grafting from" approach via reversible addition-fragmentation chain-transfer (RAFT) polymerization. Varying the time of reaction, and therefore the conversion, allows to readily tune the composition (CTS vs synthetic polymer content) and consequently the bead properties. P4VP has specific affinity for certain compounds. Th...

Perspective on the controlled polymer‐modification of chitosan and cellulose nanocrystals: Towards the design of functional materials

“…XCTS-CPS-g-P4VP maintained its ability after being cycled 7 times with 61%-62% of the initial adsorption retained after the seventh cycle. [42] Modified chitosan with phosphorous groups also may be a promising candidate for applications in wastewater treatment, anticorrosion of coatings, or as flame retardancy material. [41] Our research group has also investigated applications for the modified CNC.…”

“…CNC is currently a material of significant interest to the scientific community due to the all the properties that a single material can present. [8,29,43,44] The primary S C H E M E 1 0 Synthesis scheme to obtain functionalized chitosan (CTS-CPA), grafting from polymerization reactions of 4VP (CTS-CPAg-P4VP), and crosslinking of the beads (XCTS-CPA-g-P4VP) [42] objective of our research was to modify the surface properties of CNC to make it compatible with more hydrophobic systems and/or stimuli-responsive. We explored the modification of CNC (made by acid hydrolysis) with grafted polymers via RDRP both via grafting from and grafting to approaches.…”

“…Synthesis scheme to obtain functionalized chitosan (CTS‐CPA), grafting from polymerization reactions of 4VP (CTS‐CPA‐g‐P4VP), and crosslinking of the beads (XCTS‐CPA‐g‐P4VP) [ 42 ] …”

Anaerobic mono-digestion of wastewater from the main slaughterhouse in Yamoussoukro (Côte d’Ivoire): Evaluation of biogas potential and removal of organic pollution

“…Finally, after yielding the macroparticles modified with P4VP, these were cross-linked with dialdehyde (producing XCTS-CPS-g-P4VP) in order to improve chemical and mechanical resistance for further applications. [42]…”

“…In this case, the adsorption of bisphenol (BPA) from water was studied. [42] BPA presents significant hazards to human health and it has been used in the plastic industry and had been found in water for food for human consumption; therefore, its removal from water can be of significant importance. By adsorption kinetics studies, it was observed that modified XCTS-CPS-g-P4VP performed considerably better than native chitosan, especially the chitosan modified with larger P4VP chains.…”