Synthetise Research Of Biphenyltetracarboxylic Dianhydried And Biphenyl-Polimide

Biphenyltetracarboxylic dianhydried(BPDA) was synthesis as a monomer to improve the property of macromolecule material-Aromatic polyimides with .BPDA has three isomer include: 2,2' ,3,3' -Biphenyltetracarboxylic dianhydride (i-BPD A),2,3' ,3,4' -Biphenyltetracarboxylic dian-hydride(a-BPDA), 3,3',4,4'-Biphenyltetracarboxylic dianhydride(s-BPDA). When the monomer was added ,The Aromatic polyimides was found has excellent thermal and chemical stability, good mechanical properties, low dielectric constants and intrinsic purity.The key to development the PI is the industrialization of Biphenyltetracarboxylic dianhydride(BPDA). In our dissertation the BPDA is prepared by the coupling action of 3-chlorophthalic dianhydride and 4-chlorophthalic dianhydride. The different catalyst system and The effects of reaction conditions on yields were investigated ,then select the best condition.Random copolymers derived from i-BPDA and s-BPDA with ODA has differentproperty.biphenyl-polimide not only has thermal tability but also has good resolvable.PI derived from isomer BPDA and ODA showed high glass transition .Tg . 330℃ and degradation .Td5 . 550℃. Biphenyltetracarboxylic dianhydried (BPDA) has torsional non-coplanar structure which can decrease molecular regularity and increase its processability. Then improve the property of PI. biphenyl-polimide can be prepared to high property PI film resi, foam and electronic material.These material is in dire need of industry in national defence, electron, aviation.The product is charactered by TG A, DSC, IR, XRD and SEM.