Synthesis of Polyphosphazene Derivatives via Thiol‐ene Click Reactions in an Aqueous Medium

Abstract

A green route is reported for functionalizing polyphosphazene via the thiol-ene click reaction in an aqueous medium. Poly[bis(allylamino)phosphazene] is used as the precursor polymer, which is easily dissolved in water containing 5% (v/v) phosphoric acid, but barely dissolved in other acidic aqueous solutions with the same pH value. Three thiol reagents, namely, 3-mercapto-1,2-propanediol, 2-mercaptoethoxy ethanol, and L -cysteine, are then reacted with the precursor in the phosphoric acid aqueous solutions. 1 H and 31 P NMR analyses confi rm that the allyl polyphosphazene can be quantitatively modifi ed by the mercaptans without hydrolysis degradation during the synthesis and purifi cation processes. Moreover, these polyphosphazenes exhibit higher regioselectivity than those functionalized in organic solvents. This method provides a facile route for the green synthesis of functional polyphosphazenes without organic solvents.

Degradable, Dendritic Polyols on a Branched Polyphosphazene Backbone

“…The addition of 1-thioglycerol via photochemical thiol–yne addition led to a star-shaped hydroxyl-polyphosphazene (polymer 2 ). The thiol–yne addition method provides a fast and convenient alternative for the insertion of thio-glyceryl moieties onto a [NPCl 2 ] n backbone, 29 which otherwise would require extensive protecting group strategies. 30 The substitution of two groups per alkyne moiety further multiplies the functional groups to eight per phosphazene repeat unit.…”

A Green Water-Soluble Cyclophosphazene as a Flame Retardant Finish for Textiles

“…The NMR data were in full agreement with those reported. To obtain a water-based solution of CPZ, the method of Qian et al [76,77] for allylamino-polyphosphazenes was adopted, which proved that the phosphazenes remained stable under acid conditions. Therefore, the solubility of the CPZ was tested in different aqueous acids (H 3 PO 4 , H 2 SO 4 , HCl).…”

“…For this reason, an allylamino cyclotriphosphazenes (CPZ) was synthesized and tested with regard to its efficiencies as a flame retardant for CO, PET, PA, and CO/PET- or COPA-blended textiles in the presented study. Inspired by the work of Qian et al [76,77] who demonstrated thiol-ene reactions in water with allylamine and propargylamine polyphosphazenes, water-soluble cyclotriphosphazene derivatives were thus adapted for textile finishing. Up to now, no work has been reported on the utilization of CPZ as a green flame retardant in water-based finishing protocols of textiles.…”

Polyphosphazenes for the delivery of biopharmaceuticals

“…These polymers cover a broad range of materials with tunable cytocompatibility and biodegradability, and thus the following discussion is centered on these PPZs. A considerable number of organic side chains have been introduced in PPZs, including amino acid esters, peptides, saccharides, arylcarboxylates, ethylene oxide/PEG, and other biomolecules (purine and pyrimidine bases, vitamins, etc.) .…”