Accession Number : ADA300916

Title :   Interaction Between Microorganisms and Polymers Used for Layering in the Electronic Industry.

Descriptive Note : Final rept. 1 Feb 92-31 Jul 95,

Corporate Author : HARVARD UNIV CAMBRIDGE MA DIV OF APPLIED SCIENCES

Personal Author(s) : Mitchell, Ralph

PDF Url : ADA300916

Report Date : 10 OCT 1995

Pagination or Media Count : 30

Abstract : Microbial degradation of electronic insulation polyimides has been evaluated using electrochemical impedance spectroscopy (EIS). A fungal consortium isolated from degrading polyimides, was used in this study. Degradation of polyimide films was observed during incubation, showing two steps of development. The Bode magnitude, the phase angle, and the Nyquist plots were all in good agreement with the data obtained. The first reaction resulted in penetration of water and solutes into the polymer matrix during the early stage of polymer-water contact. This was followed by the deterioration of the polymer, indicated by a large decrease of impedance in the Bode magnitude, progressive bending in the phase angle, and the appearance and compression of the semicircles in the Nyquist plots. These reactions strongly suggest polymer degradation and delamination. However they were not observed with sterile control EIS cells. The three fungi isolated and identified, Aspergillus versicolor, Cladosporidium cladosporidae and a Chaetomium species, are commonly found environmental contaminants. Our results suggest that polyimides used in the electronic industry are susceptible to microbial degradation.

Descriptors :   *ELECTRONICS, *INTERACTIONS, *POLYMERS, *MICROORGANISMS, CONTROL, ANGLES, ENVIRONMENTS, DEGRADATION, SPECTROSCOPY, WATER, INSULATION, FILMS, ELECTROCHEMISTRY, MATRIX MATERIALS, PHASE, PENETRATION, RESPONSE, FUNGI, CONTAMINANTS, INCUBATION, IMPEDANCE, CONSORTIUMS, DETERIORATION, DELAMINATION, COMPRESSIVE PROPERTIES, STERILIZATION, BIODETERIORATION, POLYIMIDE RESINS.

Subject Categories : Polymer Chemistry
      Biology
      Physical Chemistry
      Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE