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US 12,286,508 B2Granted
Melt-processable shape-memory elastomers containing bisurea segments
AssigneeUniversity of Rochester
InventorMitchell Anthamatten
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AssigneeUniversity of Rochester
InventorMitchell Anthamatten
Estimating the term…
A shape-memory polymer that is melt-recyclable with high processability and little performance loss, in contrast to known Crosslinked semicrystalline shape-memory networks that are capable of storing large amounts of elastic energy with negligible plastic deformation but as thermosets are not easily melt-processed or recycled. In examples herein, catalyst-free isocyanate chemistry is used to prepare two linear poly(caprolactone)s with bisurea hydrogen bonding groups periodically positioned along the main chain. Compared to an entangled poly(caprolactone) homopolymer of similar molecular weight, the segmented poly(bisurea)s exhibit minimal stress relaxation when elastically strained at identical conditions. Furthermore, the materials' single relaxation times indicate chain reptation, and at sufficient temperatures, disentanglement occurs rapidly enough to perform melt-processing. The polymers show excellent shape fixity and recovery before and after shredding, melt-pressing, and annealing into a reprocessed film.
A method of producing a semicrystalline shape-memory material that (i) is configured to be melt processed or reprocessed while above a processing temperature TMP into a shape that serves as a permanent shape in the shape-memory cycle thereof, and (ii) is configured to be elastically deformed beneath TMP into a temporary shape that can be fixed into a temporary shape by maintaining strain while cooling beneath the shape-memory transition temperature TSM (TSM<TMP) and subsequently reverted to the permanent shape by heating above TSM, comprising:
Dependencies are inferred from the claim text.