Preparation of polyimides derived from biphenyltetracarboxylic dianhydrides and aromatic diamines bearing alkylene spacers

✍ Scribed by Akinori Shiotani; Masafumi Kohda

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 157 KB
• Volume: 74
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19991205)74:10<2404::aid-app8>3.0.co;2-z

✦ Synopsis

Four series of aromatic polyimides (PIs V-VIII) composed of biphenyltetracarboxylic dianhydrides (BPDAs) and aromatic diamines bearing alkylene spacers were prepared by two methods. Most polymers could be readily prepared in a one-step method for the combination of a-BPDA with ␣,-bis(3-aminophenoxy)alkanes, a-BPDA with ␣,-bis(4-aminophenoxy)alkanes, and s-BPDA with ␣,-bis(3-aminophenoxy)alkanes. However, the polymerization of s-BPDA with ␣,-bis(4-aminophenoxy)alkanes gave powders. On the other hand, all four monomer combinations afforded the desired polyamic acid solution in a two-step method. These polymer solutions could be cast into tough and flexible films, which were characterized by their inherent viscosity, differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical spectrometry measurements. The glass transition temperatures (T g s) of the polymers were in the range of 110 -240°C, but they were not clearly defined for PIs VIII and VI. The 5% weight loss temperatures were around 450°C for all prepared PIs. For PI VIII an "odd-even" behavior of the tensile properties of the films was detected, corresponding to the reported behavior of the melting temperatures.