Flame retardancy and dielectric properties of dicyclopentadiene-based benzoxazine cured with a phosphorus-containing phenolic resin

• Published in: Journal of applied polymer science Vol. 110; no. 4; pp. 2413 - 2423
• Main Authors: Hwang, Hann-Jang, Lin, Chi-Y, Wang, Chun-Shan
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.11.2008; Wiley
• Subjects: Applied sciences; Chemical properties; crosslinking; curing of polymers; dielectric properties; Exact sciences and technology; flame retardance; Polymer industry, paints, wood; Properties and testing; Technology of polymers; thermosets; curing of polymers; Electrical properties; Dielectric properties; Curing (plastics); Experimental study; Property processing relationship; Phenolic resin; Thermal stability; Phosphorus polymer; Aminoplast; Thermal properties; flame retardance; Humidity resistance; thermosets; Flammability; Organo non metallic polymer; Chemical properties; crosslinking
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.28787

A dicyclopentadiene-based benzoxazine (DCPDBZ) was prepared and separately copolymerized with melamine-phenol formaldehyde novolac or phosphorus-containing phenolic resin (phosphorus-containing diphenol) at various molar ratios. Their curing behaviors were characterized by differential scanning calorimetry. The electrical properties of the cured resins were studied with a dielectric analyzer. The glass-transition temperatures were measured by dynamic mechanical analysis. The thermal stability and flame retardancy were determined by thermogravimetric analysis and a UL-94 vertical test. These data were compared with those of bisphenol A benzoxazine and 4,4'-biphenol benzoxazine systems. The effects of the diphenol structure and cured composition on the dielectric properties, moisture resistance, glass-transition temperature, thermal stability, and flame retardancy are discussed. The DCPDBZ copolymerized with phosphorus-containing novolac exhibited better dielectric properties, moisture resistance, and flame retardancy than those of the melamine-modified system. The flame retardancy of the cured benzoxazine/phosphorus-containing phenolic resins increased with increasing phosphorus content. The results indicate that the bisphenol A and 4,4'-biphenol systems with a phosphorus content of about 0.6% and the dicyclopentadiene system with a phosphorus content of about 0.8% could achieve a flame-retardancy rating of UL-94 V-0.