Processable, tunable thio-ene crosslinked polyurethane shape memory polymers
An embodiment includes a platform shape memory polymer system. Such an embodiment exhibits a blend of tunable, high performance mechanical attributes in combination with advanced processing capabilities and good biocompatibility. A post-polymerization crosslinking synthetic approach is employed that combines polyurethane and thiol-ene synthetic processes. Other embodiments are described herein.
1. A polymer composition comprising:
a thermoplastic polymer comprising crosslinkable alkene groups spaced along a polymer chain;
a polythiol crosslinker; and
an initiator including at least one of a UV photoinitiator, a thermal initiator, or combinations thereof;
wherein (a) the thermoplastic polymer is configured so crosslinking the alkene groups with the polythiol crosslinker via a thiol-ene reaction forms a thermoset polymer having shape memory properties; (b) the thermoplastic polymer includes trimethylolpropane allyl ether (TMPAE), and (c) the initiator is configured to initiate the thiol-ene reaction to form the thermoset polymer.
2. The polymer composition of claim 1 wherein the thermoset polymer is a poly(thioether-co-urethane).
3. The polymer composition of claim 1 wherein the thermoset polymer is a poly(thioether-co-ester).
4. The polymer composition of claim 1 wherein the polythiol crosslinker includes at least one of ethylene glycol bis(3-mercaptopropionate) (EGBMP), dipentaerythritol hexakis(3-mercaptopropionate) (DPHMP), tris[2-(3-mercaptopropionyloxy)ethyl] isocyanurate (3TI), pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), or combinations thereof.
5. The polymer composition of claim 4 wherein the thermoset polymer includes a poly(thioether-co-ester).
6. The polymer composition of claim 5 , wherein the thermoplastic polymer further comprises at least one monomer selected from the group consisting of Hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), dicyclohexylmethane 4,4′-diisocyanate (DCHMDI), Isophorone diisocyanate (IPDI), 2-butene-1,4-diol (2-but), diethylene glycol (DEG), diethanolamine (DEA), 4-dimethylaminopyridine (DMAP), triethylamine (TEA), allyl alcohol (AA), 3-methyl-1,5-pentanediol (3-MPD), diethylene glycol (DEG), 3 methylpentanediol (3-MPD), 1,4-butanediol (1,4-BD), 2-methylpropanediol (2-MPD), 2,2′-dimethylpropanediol (2,2-DMPD), and 1,4-cyclohexanedimethanol (CHDM), or combinations thereof.
7. The polymer composition of claim 1 wherein the initiator includes the UV photoinitiator.
8. The polymer composition of claim 4 wherein the initiator includes the UV photoinitiator.