Flame retardance and shrinkage reduction of polystyrene modified with acrylate-containing phosphorus and crosslinkable spiro-orthoester moieties

• Published in: Polymer degradation and stability Vol. 92; no. 8; pp. 1482 - 1490
• Main Authors: Canadell, J., Hunt, B.J., Cook, A.G., Mantecón, A., Cádiz, V.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-08-2007; Elsevier Science
• Subjects: Applied sciences; Cationic crosslinking; Copolymerization; Exact sciences and technology; Heteroatom-containing polymer; Organic polymers; Physicochemistry of polymers; Preparation, kinetics, thermodynamics, mechanism and catalysts; Radical polymerization; Spiro-orthoester; Styrene; Spiro-orthoester; Styrene; Radical polymerization; Heteroatom-containing polymer; Cationic crosslinking; Ring opening polymerization; Terpolymer; Molecular structure; Cationic polymerization; Lateral group; Thermal stability; Crosslinked copolymer; Spiran copolymer; Acrylate copolymer; Flame retardant; Solution copolymerization; Crosslinking; Organic phosphonate; Shrinkage; Experimental study; Thermal properties; Flammability; Orthoester; Prepolymer; Methacrylate copolymer; Radical copolymerization; Styrene copolymer
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2007.05.017

Styrene was radically copolymerized with a spiro-orthoester with an acrylate group (SOE-AC), and terpolymerized with SOE-AC and diethyl(methacryloyloxymethyl)phosphonate (DEMMP). This was done for several different feed ratios, to obtain polymers with spiro-orthoester moieties in the side chain. These polymers were then crosslinked with ytterbium triflate, as cationic initiator, via the double ring-opening polymerization. The thermal stability and fire retardant properties of these materials were evaluated by TGA and LOI. The DEMMP-containing polymers give materials which were significantly more flame retardant than the nonphosphorus-containing materials, as indicated by the LOI measurements. The volume changes measured upon crosslinking of the polymers were evaluated by density measurements with a gas pycnometer. In all the cases, expansion was observed. This indicates that SOE-AC is an effective monomer for crosslinkable polymers without volume changes.