Reprocessed and shape memory networks involving poly(hydroxyl ether ester) and polydimethylsiloxane through Diels-Alder reaction

Abstract

• Poly(hydroxyl ether ester) vitrimers were prepared via D-A reaction. • Polydimethylsiloxane was used as the modifier to improve the properties. • The vitrimers were microphase-separated and had shape memory properties. • The original shapes can be reprogrammed with the reprocessing properties. In this contribution, we reported a novel synthesis of poly(hydroxyl ether ester)-polydimethylsiloxane vitrimers through Diels-Alder (DA) reaction. Poly(hydroxyl ether ester) with furan rings in the main chain (denoted PHEE-F) was synthesized by the step-growth polymerization between diglycidyl ether of bisphenol A and 2,5-furan dicarboxylic acid. The as-obtained PHEE-F was crosslinked with bismaleimide (BMI) via DA reaction to obtain the networks. To improve the thermomechanical properties of the networks, an α,ω-dimaleimido-terminated polydimethylsiloxane telechelics (denoted MA-PDMS-MA) was then synthesized and additionally used as the macromolecular co-crosslinker. It was found that the PDMS-modified networks were microphase-separated; the PDMS blocks were segregated into the microdomains with the size of 20 ∼ 30 nm. The thermomechanical properties of PHEE-F-PDMS networks were dependent on the contents of PDMS. More importantly, the crosslinked networks can be reprocessed (or recycled) at the retro -DA reaction temperature (>120 °C). In addition, the vitrimers exhibited the excellent shape memory properties. The reprocessability of the vitrimers can be exploited to reprogram the original shapes of the shape memory polymers.