Thermal study on the copolymers of phthalonitrile and phenylnitrile-functional benzoxazines

✍ Scribed by Zdenka Brunovska; Hatsuo Ishida

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 396 KB
• Volume: 73
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19990929)73:14<2937::aid-app18>3.0.co;2-e

✦ Synopsis

Ortho-, meta-, and para-phenylnitrile-functional benzoxazines are polymerized at different compositions with phthalonitrile-functional monomers providing copolybenzoxazines of high thermal stability and easy processability. The most positive effect on these properties is obtained on copolymerizing phthalonitrile-and orthophenylnitrile-functional benzoxazines. Thermal decomposition of these polybenzoxazines is studied by thermogravimetry (TGA). It is demonstrated that only 30 mol % of phthalonitrile-functional benzoxazine added to the ortho-phenylnitrile-substituted monomer improves char yield significantly from 59 to 77 wt %, which is the value of neat phthalonitrile-based polybenzoxazine. Glass transition temperature (T g ) also dramatically increases from 180°C for neat ortho-phenylnitrile polymer to 294°C for the copolymer with 30 mol % of phthalonitrile-functional monomer. Additionally, the high melt viscosity of phthalonitrile-functional benzoxazines is dramatically decreased upon blending with phenylnitrile-functional monomer.