Epoxy Formulation Including an Acrylic Triblock Copolymer Adapted for Use in Filament Winding or Infusion Processes

LUCIANA SAIZ; ANTONELA OROFINO; EXEQUIEL S. RODRIGUEZ; ILEANA ZUCCHI; ROBERTO WILLIAMS

POLYMER ENGINEERING AND SCIENCE

JOHN WILEY & SONS INC

Lugar: New York; Año: 2016 vol. 56 p. 1153 - 1159

0032-3888

Commercial triblock copolymers with a poly(butyl acrylate) (PBuA) central block joined to two poly(methyl methacrylate) (PMMA) end blocks (denoted as MAM) or to two random copolymers end blocks based on MMA and N,N?-dimethylacrylamide (DMA) (denoted as MAM-N), were employed to toughen an epoxy formulation adapted for requirements of filament winding or infusion processes. The formulation was based on diglycidylether of bisphenol A (DGEBA), 4,4´-diamino-3,3´-dimethyldicyclohexylmethane (3DCM) and benzylamine (BA), with 20 % of amine hydrogens provided by BA. Cured materials containing 5 wt % MAM were opaque due to the phase separation of spherical domains with sizes ranging from about 0.3 to 1 μm. Those containing 5 wt % MAM-N were slightly translucent due to the generation of spherical domains with sizes comprised between 20 and 100 nm. Both morphologies produced the same increase in the critical stress intensity factor, from KIC = 0.63 MPa.m1/2 for the neat epoxy to about 1.0 MPa.m1/2 for the toughened epoxy. MAM was a better choice for the envisaged applications than MAM-N because it led to solutions of lower viscosity. The higher viscosity produced by MAM-N was explained by specific interactions between the epoxy-amine solvent and DMA units present in its terminal blocks.