Multi-component shape memory threads, fibers, tubes, tapes and method for producing the same
The invention relates to multi-component shape memory threads, fibers, tubes, or tapes, which includes at least two shape-memory polymeric (SMP-N) components. Each of the at least two SMP-N components is of at least 1% of the total weight, and N is a positive integer starting from 1, and the SMP-N components have a selectively engineered shape recovery temperature (T r ) between approximately 0° C. to 130° C. Also, when T rN and T rN+1 are higher than room temperature, the threads, fibers, tubes, or tapes are configured to assume a substantially helical configuration upon heating to above T rN and lower than T rN+1 by a stimulus when an elongation of the threads, fibers, tubes, or tapes is approximately 30% to approximately 300%, and having a coil diameter from 0.5 to 10 mm and a number of the turns per cm from 5 to 30.
1. Multi-component shape memory threads, fibers, tubes, or tapes comprising:
at least two shape-memory polymeric (SMP-N) components, wherein each of the at least two SMP-N components is of at least 1% of the total weight, and N is a positive integer starting from 1;
wherein each of the at least two shape-memory polymeric components is selected from the group consisting of a polyester-based polyurethane shape memory material and a polyether-based polyurethane shape memory material;
wherein the SMP-N components have a selectively engineered shape recovery temperature (T r ) between approximately 0° C. to 130° C., and when T rN and T rN+1 are higher than room temperature and wherein T rN+1 is greater than T rN , the threads, fibers, tubes, or tapes are configured to assume a first shape change from an original shape to a straight, elongated shape in response to an elongation of the threads, fibers, tubes, or tapes to approximately 30% to approximately 300% of an original length and are configured to assume a second shape change to a substantially helical configuration upon heating to a temperature above the T rN and lower than the T rN+1 and to assume a third shape change substantially back to the original shape upon heating to a temperature above T rN+1 .
2. The multi-component shape memory threads, fibers, tubes, or tapes according to claim 1 , when the at least two SMP-N components are SMP-1 and SMP-2, the SMP-1 and SMP-2 are co-extruded at a weight ratio of 1-10: 10-1.
3. The multi-component shape memory threads, fibers, tubes, or tapes according to claim 2 , wherein the T r (T r1 )of SMP-1 is lower than that of the SMP-2(T r2 ), and the T r is either the melting point or glass transition temperature of the SMP-1 and the SMP-2.
4. The multi-component shape memory threads, fibers, tubes, or tapes according to claim 3 , wherein the T r1 of the SMP-1 is approximately 40° C., and the T r2 of the SMP-2 is approximately 60° C.
5. The multi-component shape memory threads, fibers, tubes, or tapes according to claim 1 , wherein the cross-sections of the at least two SMP-N components are in side-by-side, eccentric sheath/core, circumferential, or layer-by-layer structure.
6. The multi-component shape memory threads, fibers, tubes, or tapes according to claim 1 , wherein the threads or fibers have a diameter in a range of approximately 0.1 to 2 mm.
7. The multi-component shape memory threads, fibers, tubes, or tapes according to claim 1 , wherein the tubes or tapes have a thickness in a range of approximately 0.5 to 1 mm.
8. A method for producing the multi-component shape memory threads, fibers, tubes, or tapes according to claim 1 , comprising co-extruding multi-components together to form the threads, fibers, tubes, or tapes, wherein the multi-components comprise at least two shape-memory polymeric (SMP-N) components, wherein each of the at least two SMP-N components is of at least 1% of the total weight, and N is a positive integer starting from 1.
9. The method according to claim 8 , wherein the SMP-N components have a selectively engineered shape recovery temperature (T r ) between approximately 0° C. to 130° C., and when T rN and T rN+1 are higher than room temperature, the threads, fibers, tubes, or tapes are configured to assume a substantially helical configuration upon heating to above the T rN and lower than the T rN+1 by a stimulus when an elongation of the threads, fibers, tubes, or tapes is approximately 30% to approximately 300%, and having a coil diameter from 0.5 to 10 mm and a number of the turns per cm from 5 to 30.
10. The method according to claim 9 , when the at least two SMP-N components are SMP-1 and SMP-2, the SMP-1 and SMP-2 are co-extruded at a weight ratio of 1-10:10-1.
11. The method according to claim 10 , wherein the T r (T r1 ) of SMP-1 is lower than that of the SMP-2 (T r2 ), and the T r is either the melting point or glass transition temperature of the SMP-1 and the SMP-2.
12. The method according to claim 11 , wherein T r1 of the SMP-1 is approximately 40° C., and T r2 of the SMP-2 is approximately 60° C.
13. The method according to claim 9 , wherein the stimulus comprises temperature, moisture/water, light, pH, and radiation.
14. The method according to claim 9 , wherein the threads, fibers, tubes, or tapes are configured to assume a substantially linear shape upon heating to above the T rN+1 by the stimulus.
15. The method according to claim 8 , wherein the at least two SMP-N components are co-extruded through a spinneret, T-die, a side-by-side nozzle, or a slot die coater.
16. The multi-component shape memory threads, fibers, tubes, or tapes according to claim 1 , wherein the polyester-based polyurethane shape memory material is a polycaprolactone-based shape memory material.
17. The multi-component shape memory threads, fibers, tubes, or tapes according to claim 1 , wherein the helical configuration has a coil diameter from 0.5 to 10 mm and a number of the turns per cm from 5 to 30.