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

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 alpha,omega-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 similar to 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 degrees 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.

Automated summary

A novel synthesis of poly(hydroxyl ether ester)-polydimethylsiloxane vitrimers was reported in this study, with microphase-separated networks and excellent shape memory properties. The crosslinked networks showed reprocessability at high temperatures and could be used to reprogram the original shapes of shape memory polymers.