Preparation and properties of rigid polyimide foams derived from dianhydride and isocyanate

• Published in: Journal of applied polymer science Vol. 127; no. 6; pp. 5075 - 5081
• Main Authors: Yu, Fei, Wang, Kai, Liu, Xiao-Yan, Zhan, Mao-Sheng
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.03.2013; Wiley; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Bulk density; Cellular; Compressive strength; Dianhydrides; Exact sciences and technology; Foams; Forms of application and semi-finished materials; Isocyanates; Materials science; Moisture content; polyimide foam; Polyimide resins; Polymer industry, paints, wood; Polymers; Prepolymers; Rigid; Technology of polymers; thermal properties; polyimide foam; Polyimide; Closed cell; Mechanical properties; Compressive strength; Hardness; Experimental study; Cellular plastic; Polyaddition; Glass transition temperature; Thermal stability; Thermal properties; Preparation; Crosslinked polymer; Water content; Reaction mechanism; Plastics; Rigid
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.38121

A series of rigid polyimide (PI) foams were synthesized via the reaction of a first solution with a second solution. The first solution was isocyanate‐terminated polyimide prepolymers; the second solution contained deionized water and surfactant. The effect of different water contents and isocyanate index on the structures and properties of rigid PI foams were investigated. The apparent density, hardness, compressive strength, and the 5% weight loss temperatures (T5%) decreased with the increase of water content. With the increase of isocyanate index, the apparent density and the T5% values decreased, whereas the glass transition temperatures (Tg) increased and the hardness, compressive strength first increased and then decreased. The rigid PI foams composed of closed‐cells were confirmed by scanning electron microscopy. The maximum compressive strength of rigid PI foams prepared was up to 1.31 MPa. Moreover, excellent thermal stability was presented with the T5% values were all above 360°C and the residual weights of the foams (Rw) were more than 50% at 800°C. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013