Preparation and properties of novel oligo(phenylene oxide)-branched cyclophosphazenes

• Published in: Polymer chemistry Vol. 3; no. 1; pp. 2815 - 2824
• Main Authors: Tada, Yuji, Moriya, Narimasa, Kanazawa, Makoto, Asanuma, Kota, Suzuki, Atsuko, Koyama, Shigeto
• Format: Journal Article
• Language: English
• Published: 01.01.2012
• Subjects: Benzoyl peroxide; Dielectric constant; Electrical properties; Mass spectroscopy; Nuclear magnetic resonance; Oxides; Size exclusion chromatography; Terminals
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/c2py20433a

Novel oligo(phenylene oxide)-branched cyclophosphazenes (POPZs) were synthesised by a redistribution reaction of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) with 4-hydroxyphenoxycyclotriphosphazenes in the presence of benzoyl peroxide (BPO) as a free-radical initiator. The redistribution yielded benzoyl moiety-substituted cyclotriphosphazenes in addition to cyclotriphosphazene-branched oxy-2,6-dimethyl-1,4-phenylene (ODMP) repeating units in the hydroxyphenoxy group. The benzoyl moieties originated from the BPO and attached to the methyl side group and the terminal hydroxy group of a constitutional ODMP unit. The benzoyl moiety in the cyclophosphazenes was eliminated completely via hydrolysis with NaOMe, followed by chlorination with SOCl 2 and reduction with LiAlH 4 . Both the redistribution and elimination reactions were observed using FT-IR, LC-MS, 1 H NMR, 13 C NMR, 31 P NMR, MALDI-TOF mass spectroscopy, and size exclusion chromatography (SEC). The resulting POPZs were evaluated for their thermal and electrical properties and their flame retardancy. The benzoyl moiety-free POPZs exhibited high thermal stability up to 300 °C and electrical properties such as dielectric constants of 2.56-2.67 and dissipation factors of 0.0044-0.0049. Novel oligo(phenylene oxide)-branched cyclophosphazenes were synthesised by a redistribution reaction of poly(2,6-dimethyl-1,4-phenylene oxide) with 4-hydroxyphenoxycyclotriphosphazenes in the presence of benzoyl peroxide.