Synthesis and characterization of poly{hexakis[(methyl)(4‐hydroxyphenoxy)]cyclotriphosphazene}

Abstract

ABSTRACT:The reaction of methylhydroquinone with hexachlorocyclotriphosphazene in the presence of a base, 4-picoline, in cyclohexane was investigated. Nuclear magnetic resonance spectroscopy, multiangle laser light scattering, and elemental analyses were performed on the product and two other related phosphazene materials produced by analogous synthetic routes: poly[hexakis(4-hydroxyphenoxy)cyclotriphosphazene] (1) and hexakis[(3-tert-butyl)(4-hydroxyphenoxy)]cyclotriphosphazene (2). Unlike the data for 2 where the tert-butyl moiety enforced regiospecific nucleophilic addition, the data for the methylhydroquinone-substituted cyclotriphosphazene product indicate that the less sterically bulky methyl group provides only limited protection for the adjacent hydroxyl group. The result is the formation of a low molecular weight oligomer, poly{hexakis[(methyl)(4-hydroxyphenoxy)]cyclotriphosphazene} (3), instead of a discrete cyclic trimer species.

Fully Crosslinked Poly[cyclotriphosphazene‐co‐(4,4′‐sulfonyldiphenol)] Microspheres via Precipitation Polymerization and Their Superior Thermal Properties

“…The best known and extensively studied phosphazene materials are linear polymers with an alternating PN backbone 25. Nonetheless, their main disadvantage, in further widening the application of linear polyphosphazenes, is their relatively low yield and high cost 26,27. Cyclolinear and cyclomatrix‐type polymers are other kinds of phosphazene‐containing polymers, in which phosphazene rings are linked via exocyclic groups to form linear chains or a crosslinked matrix.…”

Thermal Stability, Pyrolysis Behavior, and Fire-Retardant Performance of Melamine Cyanurate@Poly(cyclotriphosphazene-co-4,4′-sulfonyl diphenol) Hybrid Nanosheet-Containing Polyamide 6 Composites

“…For the synthesis of the supramolecular MCA@PZS hybrid, the MCA nanosheets acted as a hard template for the growth of the PZS nucleus on the substrate. The synthetic procedure followed the absorption and polymerization mechanism previously reported for oligomeric species. − Thus, the polymerization between hexachlorocyclo-triphosphazenes (HCCPs) and 4,4′-dihydroxydiphenyl sulfone (BPS) in the presence of triethylamine (TEA) primarily proceeded via the generation of the PZS nucleus on the surface of the MCA nanosheets along with the release of HCl as a by-product. This by-product was then recaptured by TEA, thereby accelerating the polymerization reaction until the polymerization of HCCP and BPS was completed.…”

Preparation and Properties of Novel Crosslinked Polyphosphazene-Aromatic Ethers Organic–Inorganic Hybrid Microspheres

“…In the past few decades, various phosphonitrile polymers have been reported. Because of their high thermal stability, they are used widely in adhesives [4], flame-retardant polymer additives [5][6][7] and thermosetting resins [8,9]. Most cyclic polymers are synthesized through many complex procedures: the phosphonitrile ring is first joined to bifunctional compounds such as hydroquinone or aminophenol, and then the precursors are crosslinked with other bifunctional compounds such as anhydride and carbonyl chloride.…”