Characterization and Studies of Designed Photodefinable CoPoly(amic Acid) Ionic Salt Solutions
Abstract:In an attempt to develop a very stable photodefinable ionic salt solution, we synthesized two series of co-poly(amic acid)s(CoPAAs)by reacting 3,3′,4,4′-biphenyl tetracarboxylic dianhydride(BPDA)or 3,3′,4,4′-benzophenone tetracarboxylic dianhydride(BTDA)with various mole percents ofortho-Tolidine(o-TDA)and 1,3-bis(3-aminopropyl)tetramethyl disiloxane(SiDA). Subsequently, two series each of the ionic bond type photodefinable co-poly(amic acid)salts(CoPAS)were made, using 2-(diethylamino)ethyl methacrylate(DEEM)and 2-(dimethylamino)ethyl methacrylate(DMEM). NMR studies were carried out on bisphthalamic acid ofo-TDA and SiDA model compounds to identify weak linkage in the above PAAs. Bulk viscosity, inherent viscosity, acid number, and molecular weight of CoPAA and CoPAS solutions decreased drastically as the storage time increased. CoPAS was less stable than CoPAA. BPDA-based PAA showed less viscosity drift thanthe BTDA-based PAA. Both CoPAA and CoPAS samples showed a two-step weight loss in air atmosphere. The first step was attributed to imidization and the second step to thermal degradation. The activation energy for thermal degradation was determined using Coats-Redfern and Chang methods and the values were found to be comparable.
Document Type: Research Article
Affiliations: Polyimide Project Group, Advanced Polymers and Chemicals Cluster, Molecular and Bio-Materials Laboratory, Institute of Materials Research and Engineering (IMRE), Singapore
Publication date: January 1, 2004