Crosslinking of polyimides via spirodilactone unit in polymer backbone

✍ Scribed by Fushe Han; Mengxian Ding; Lianxun Gao

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 161 KB
• Volume: 37
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19991001)37:19<3680::aid-pola3>3.0.co;2-z

✦ Synopsis

A new approach for the crosslinking of polyimides via the lactamization of spirodilactone unit in polyimide backbone was studied by two means: model reaction and the comparison of the properties of the polyimide precursors to those of the crosslinking polymers. Polyimides 4 and 5 were soluble in N,NЈdimethylacetamide (DMAc), dimethylformamide (DMF), dimethylsulfoxide (DMSO), NЈ-methylpyrrolidone (NMP), and other common organic solvents, whereas their corresponding crosslinking polymers were insoluble in these solvents. The glass transition temperatures for polyimide 5 and its crosslinking polymer were 262°C and 291°C, whereas those for polyimide 4 and its crosslinking polymer were 265°C and 360°C. The weight-loss rate of the crosslinking polymers was apparently slower than that of the precursors when the temperature was Ͼ400°C. The 10% weight-loss temperature for the polyimides 4 and 5 was Ͻ500°C, whereas that for the crosslinking polymers was close to or above 600°C. The results indicate that this type of crosslinking polymer has good thermal properties. The temperature for the formation of lactam was above 180°C.