Morphology of Rubber Modified Vinyl Ester Resins Cured at Different Temperatures

M. L. AUAD; J. BORRAJO; M. I. ARANGUREN

JOURNAL OF APPLIED POLYMER SCIENCE

Wiley

Lugar: New York; Año: 2003 vol. 89 p. 274 - 283

0021-8995

ABSTRACT: The morphologies of styrene (St) crosslinked divinylester resins (DVER) modified with elastomers were analyzed. The primary focus of this study was on the effect of the molecular weight of the resins, the reactivity of the elastomeric modifiers, and the temperature of curing. All of these variables have a strong influence on both the miscibility and the viscosity of the system, affecting the phaseseparation process that takes place in the unreacted and the reacting mixture. The selected liquid rubbers were carboxylterminated poly(butadiene-co-acrylonitrile) (CTBN), a common toughening agent for epoxy resins, and an almost unreactive rubber with the DVER; and St comonomers and vinyl-terminated poly(butadiene-co-acrylonitrile (VTBN), a reactive rubber. Different morphologies potentially appear in these systems: structures formed by DVER–St nodules surrounded by elastomer and spanning the whole sample; dual cocontinuous micron-size domains formed by elastomer- rich or resin-rich domains; and a continuous DVER– St-rich phase with included complex nodular domains. These microstructures can be varied by just changing the nature and concentration of the elastomer, the molecular weight of the resin, or the curing temperature. The appearance of these morphologies is discussed as a function of the above variables. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 274–283, 2003 Key words: elastomers; modified vinyl ester resins; morphology; curing temperature; crosslinking