Preparation of damping structural integration materials via the formation of nanostructure in triblock copolymer modified epoxy resins

Amphiphilic triblock copolymer Poly(ε-caprolactone)-block-polydimethylsiloxane-block-poly(ε-caprolactone) (PCL-b-PDMS-b-PCL, LDL) was synthesized via the ring-opening polymerization of ε-caprolactone in the presence of hydroxyl-terminated polydimethylsiloxane (HTPDMS) and was utilized to modify epoxy. The tensile strength and elongation at break were simultaneously enhanced when the triblock copolymer was incorporated. With increasing the concentration of the triblock copolymer, the damping temperature range (tanδ >0.25) was broadened from 21 °C to 34.5 °C. Meanwhile, the storage modulus of the composites and the values of tanδ had no significant decrease. When the concentration of the triblock copolymer was 20 wt%, the value of K IC attained 1.68 MN/m 3/2 , which was 1.56 times that of the neat epoxy (1.08 MN/m 3/2 ). Besides, the characterization of hydrophobic and hydrophilic performance indicated that the incorporation of the triblock copolymer made epoxy resins transformed from hydrophilic to hydrophobic. It is expected that damping composites obtained by this method may be used as damping structural integration materials in future.