Tham khảo tài liệu 'handbook of polymer synthesis second edition episode 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 9 Polyimides Javier de Abajo and Jose G. de la Campa Institute of Polymer Science and Technology Madrid Spain I. INTRODUCTION Polyimides are polymers incorporating the imide group in their repeating unit either as an open chain or as closed rings. However only cyclic imides are actually of interest concerning polymer chemistry. Thus under the generic name polyimides we will exclusively refer to cyclic polyimides in this chapter. The first reference to a polyimide was dated at the beginning of the 20th century 1 but the actual emergence of polyimides as a polymer class took place in 1955 with a patent of Edwards and Robinson on polymers from pyromellitic acid 1 2 4 5-tetracarboxy-benzene and aliphatic diamines 2 . Since then growing interest in polyimides has brought about a big expansion of the science and technology of this family of special polymers which are characterised by excellent mechanical and electrical properties along with outstanding thermal stability. Among the wide list of reported heat-resistant condensation polymers 3-5 polyimides have gained a prominent position due to their good properties-price-processability balance. And from the production figures it can be inferred that polyimides stand virtually alone with respect to providing useful available technological materials. Furthermore while at the beginning polyimides found application in a rather restricted variety of technologies mainly on the form of films and varnishes for the aerospace and electrical industries the discovering of addition polyimides and more recently of thermoplastic processable aromatic polyimides has widened the range of properties and application possibilities to a great extent. Presently they should be considered as versatile polymers with an almost unlimited spectrum of applications as specialty polymers for advanced technologies 6-12 . In a list of applications of polyimides the following should be included Insulating films coatings and laminates Molded parts .
