Radiation crosslinking and shape-memory behavior of blends of poly(ε-caprolactone) and polyfunctional polyester acrylate

The radiation-crosslinking and shape-memory behavior of the blends of poly(epsilon-aprolactone) (PCL) and polyfunctional polyester acrylate (PEA) were studied. The influences of the usage of PEA, the number of functional group and radiation dose on radiation crosslinking, dynamic mechanical properties and shape memory behaviors of PCL were investigated. It was concluded that radiation crosslinking of PCL/PEA blends didn't follow the classic Charlesby-Pinner equation, but was in agreement with Chen-Liu-Tang relation. The efficiency of radiation crosslinking of PCL could be distinctively improved by using polyfunctional PEA. The more the usage and the functional group number, the more the gel content and the more distinctive the radiation crosslinking effects. This also indicated that the polyfunctional PEA directly participated in the crosslinking reaction. The DMA analysis indicated that enhanced radiation cross-linking raised the heat deformation temperature of PCL and presented a higher and wider rubbery state plateau, whereas rendered more enough strength at temperatures above the melting point of PCL and provided enough force to recover more strain than in the case of pure PCL. The shape memory results revealed that the well crosslinked PCL presented 100% strain recovery with quick recovery rate.