Novel star-shaped and hyperbranched phosphorus-containing flame retardants in epoxy resins

This report presents the synthesis and use of novel derivatives of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO, 1) and 5,5-dimethyl-1,3,2-dioxaphosphorinan-2-one (DDPO, 2) as flame retardant additives for epoxy resins. DOPO-based and DDPO-based compounds were synthesized via nucleophilic substitution with 1,3,5-tris-(2-hydroxyethyl) isocyanurate (THIC, 3) and subsequent oxidation (Schemes 1 and 2). Another trivalent DOPO derivative recently reported by our group was obtained by transamination followed by a Michaelis–Arbuzov rearrangement (Scheme 1). These products were blended into two epoxy resin systems [DEN 438 and diglycidyl ether of bisphenol A (DGEBA), both cured with dicyandiamide (DICY) and Fenuron] to obtain flame retardant thermosets. The flame retardancy and thermal properties of these epoxy resin systems were examined by UL 94-V, Thermogravimetric analysis, and differential scanning calorimeter analysis. Furthermore, all reactions with phosphorus-containing compounds were iterated employing the THIC oligomer, which was prepared via polycondensation of THIC (Scheme 3) using catalytic amounts of p-toluenesulfonic acid. In addition, Atherton–Todd reaction with the THIC oligomer was studied as a novel synthetic method for phosphorus-containing flame retardants (Scheme 4). The resulting products were utilized as flame retardants in epoxy resins and compared with the analogous monomeric compounds. Copyright © 2011 John Wiley & Sons, Ltd.

[1]  M. Döring,et al.  Recent Developments in Halogen Free Flame Retardants for Epoxy Resins for Electrical and Electronic Applications , 2010, Materials.

[2]  M. Döring,et al.  Novel efficient DOPO-based flame-retardants for PWB relevant epoxy resins with high glass transition temperatures† , 2008 .

[3]  P. Jiang,et al.  Thermal degradation behaviors and flame retardancy of PC/ABS with novel silicon‐containing flame retardant , 2007 .

[4]  M. Döring,et al.  A Novel and Effective Synthetic Approach to 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) Derivatives , 2007 .

[5]  M. Döring,et al.  Synthesis and properties of flame‐retardant epoxy resins based on DOPO and one of its analog DPPO , 2007 .

[6]  A. I. Balabanovich,et al.  Influence of the oxidation state of phosphorus on the decomposition and fire behaviour of flame-retarded epoxy resin composites , 2006 .

[7]  S. Levchik,et al.  Overview of recent developments in the flame retardancy of polycarbonates , 2005 .

[8]  Baljinder K. Kandola,et al.  Developments in flame retardant textiles – a review , 2005 .

[9]  Edward D. Weil,et al.  A Review of Current Flame Retardant Systems for Epoxy Resins , 2004 .

[10]  M. Hussain,et al.  Synthesis, thermal behavior, and cone calorimetry of organophosphorus epoxy materials , 2003 .

[11]  I. Hamerton,et al.  RECENT DEVELOPMENTS IN THE CHEMISTRY OF HALOGEN-FREE FLAME RETARDANT POLYMERS , 2002 .

[12]  Ying‐Ling Liu,et al.  Preparation of phosphorous-containing poly(epichlorohydrin) and polyurethane from a novel synthesis route , 2002 .

[13]  M. L. La Guardia,et al.  Flame retardants: Persistent pollutants in land-applied sludges , 2001, Nature.

[14]  S. Levchik,et al.  Some Mechanistic Aspects of the Fire Retardant Action of Red Phosphorus in Aliphatic Nylons , 2000 .

[15]  T. Davidson,et al.  Plasma Modifications to the Interface in Carbon Fiber Reinforced Thermoplastic Matrices , 1994 .

[16]  F. Jones,et al.  The role of sizing resins in carbon fibre-reinforced polyethersulfone (PES) , 1994 .

[17]  F. R. Atherton,et al.  129. Studies on phosphorylation. Part III. Further observations on the reaction of phosphites with polyhalogen compounds in presence of bases and its application to the phosphorylation of alcohols , 1947 .

[18]  H. Openshaw,et al.  174. Studies on phosphorylation. Part II. The reaction of dialkyl phosphites with polyhalogen compounds in presence of bases. A new method for the phosphorylation of amines , 1945 .

[19]  H. Openshaw,et al.  94. Studies on phosphorylation. Part I. Dibenzyl chlorophosphonate as a phosphorylating agent , 1945 .