Please use this identifier to cite or link to this item:
Title: Bulk viscosity and its unstable behavior upon storage in polyimide precursor solutions
Authors: Tong, Y.
Liu, T.
Veeramani, S.
Chung, T.-S. 
Issue Date: 21-Aug-2002
Citation: Tong, Y.,Liu, T.,Veeramani, S.,Chung, T.-S. (2002-08-21). Bulk viscosity and its unstable behavior upon storage in polyimide precursor solutions. Industrial and Engineering Chemistry Research 41 (17) : 4266-4272. ScholarBank@NUS Repository.
Abstract: The bulk viscosity behavior of poly(amic acid) and its amine salt solutions, PAA(ODPA/o-tolidine) and PAS(ODPA/o-tolidine), has been investigated. Both PAA(ODPA/o-tolidine) and PAS(ODPA/o-tolidine) solutions show strong concentration and molecular weight dependence on bulk viscosity, and display critical values on the concentration dependence of bulk viscosity because of increasing the molecular chain interactions and entanglements. PAA(ODPA/o-tolidine) possesses a higher bulk viscosity than PAS(ODPA/o-tolidine) at the same concentration, indicating a stronger resistance to shear flow. The temperature dependence of bulk viscosity follows the exponential Arrhenius type relation. The activation energies of the fluids depend on the nature, concentration, and molecular weight of the polymers used. It has been found that both PAA(ODPA/o-tolidine) and PAS(ODPA/o-tolidine) solutions inherently have poor bulk viscosity stability upon storage. The bulk viscosity of the polymer solutions decreases dramatically with time upon storage at room temperature while increasing during the storage at -18 °C. A molecular mechanism in terms of a "temporary junction" is suggested to explain the bulk viscosity behavior of PAA(ODPA/o-tolidine) and PAS(ODPA/o-tolidine) in concentrated solutions.
Source Title: Industrial and Engineering Chemistry Research
ISSN: 08885885
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

Page view(s)

checked on Feb 2, 2019

Google ScholarTM


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.