| abstract |
There is disclosed a film comprising 40-100% by weight of polyimide. The polyimide is derived from a dianhydride component and a diamine component. The dianhydride component consists of at least 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) and optionally also of pyromellitic dianhydride (PMDA) in a molar ratio of 50-100: 50-0 (BPDA: PMDA). The diamine component comprises 1,5-naphthalenediamine (1,5-ND) and 1,4-diaminobenzene (PPD) and / or metaphenylenediamine (MPD) in a molar ratio of 15-95: 85-5 (1,5-ND : PPD + MPD). The films have an exceptional high temperature storage modulus (elastic modulus) and exceptionally low high temperature creep (e plast ). |