Morphology and thermomechanical properties of nanostructured thermosetting blends of epoxy resin and poly(ɛ-caprolactone)-block-polydimethylsiloxane-block-poly(ɛ-caprolactone) triblock copolymer

Abstract: Poly(ɛ-caprolactone)-block-polydimethylsiloxane-block-poly(ɛ-caprolactone) triblock copolymer (PCL-b-PDMS-b-PCL) was synthesized via the ring-opening polymerization of ɛ-caprolactone with dihydroxypropyl-terminated PDMS (HTPDMS) as the initiator. The triblock block copolymer was characterized by means of Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). The triblock copolymer was incorporated to prepare nanostructured thermosetting blends. The morphology of the epoxy thermosets containing PCL-b-PDMS-b-PCL were investigated by means of atomic force microscopy (AFM), transmission electronic microscopy (TEM) and small-angle X-ray scattering (SAXS). The thermomechanical properties of the nanostructured blends were investigated by means of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The formation of the nanostructures in the thermosetting composites was judged to follow the self-assembly mechanism in terms of the difference in miscibility of PDMS and PCL subchains with epoxy resin after and before curing reaction. [Copyright &y& Elsevier]