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Title: Rubber-modified epoxies: Analysis of the phase-separation process

Conference ·
OSTI ID:76240
; ;  [1]; ; ;  [2]
  1. Institut National des Sciences Appliquees de Lyon, Villeurbanne (France)
  2. Univ. of Mar del Plata (Argentina)

The phase-separation process of a diepoxide based on bisphenol A diglycidyl ether cured with a cycloaliphatic diamine in the presence of an epoxy-terminated butadiene-acrylonitrile random copolymer (ETBN) was experimentally studied and theoretically simulated. The increase in the average molecular weight of the epoxy-amine polymer is shown to be the main thermodynamic factor leading to phase separation. The competition between nucleation-growth and spinodal decomposition is analyzed. Low values of interfacial tensions and polymerization rates favor the first mechanism in most cases. A secondary phase separation must occur inside the dispersed particles, leading to a segregated epoxy-amine phase. The theoretical simulation explains the increase of the average diameter of dispersed-phase particles with increasing polymerization temperature. The volume fraction of dispersed phase is the dominating factor affecting fracture toughness. 49 refs., 16 figs.

OSTI ID:
76240
Report Number(s):
CONF-900802-; TRN: 94:009880-0021
Resource Relation:
Conference: 200. American Chemical Society (ACS) national meeting, Washington, DC (United States), 26-31 Aug 1990; Other Information: PBD: 1993; Related Information: Is Part Of Toughened plastics I: Science and engineering; Riew, C.K.; Kinloch, A.J. [eds.]; PB: 567 p.
Country of Publication:
United States
Language:
English