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

Conference · Thu Dec 30 23:00:00 EST 1993

OSTI ID:76240

Verchere, D; Sautereau, H; Pascault, J P ^[1]; Moschiar, S M; Riccardi, C C; Williams, R J.J. ^[2]

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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--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACRYLONITRILE
ACTIVATION ENERGY
CURING
EPOXIDES
ETHERS
FRACTURE PROPERTIES
PARTICLE SIZE
PHASE STUDIES
POLYMERIZATION
RUBBERS
SOLUBILITY
SURFACE TENSION
TEMPERATURE DEPENDENCE
VISCOSITY