Natural Fiber Welded Composite Yarns

In this application, an ionic liquid (IL), specifically 1-ethyl-3-methylmidazolium acetate (EMIAc), well known for its ability to dissolve a variety of biopolymers^1-3, is used in conjunction with molecular co-solvents to prepare biopolymer composite yarns by a process we call natural fiber welding (NFW).  NFW uses controlled amounts of IL and a molecular co-solvent to swell and mobilize portions of the biopolymer substrate.  By carefully selecting factors controlling NFW such as time, temperature and solvent system composition, partial dissolution occurs, mobilizing and redistributing only a small portion of the natural fibers and leaving much of the underlying substrate intact.^4-7  This results in fibers with a shell of dissolved polymer, permanently adhered and hydrogen bonded to both the outer diameter of the fiber and (depending on the extent of welding) to the surface of adjacent fibers.  

With the addition of a small amount of biopolymer into the IL solution, a NFW composite yarn can be created with the pre-dissolved biopolymer acting as an additional binder.  Different combinations of biopolymer binder and substrate take advantage of the functional and structural benefits of both biopolymers.  Binder can also be used to facilitate incorporation of functional materials (e.g., magnetic, electronic, photonic) into the yarn fiber matrix.

References

 

1. Swatloski, R. P.; Spear, S. K.; Holbrey, J. D.; Rogers, R. D. J. Am Chem Soc, 2002, 124, 4974.
2. Phillips, D. M.; Drummy, L. F.; Conrady, D. G.; Fox, D. M.; Naik, R. R.; Stone, M. O.; Trulove, P. C.; De Long, H. C.; Mantz, R. A. J Am Chem Soc., 2004, 126, 14350.
3. Xie, H.; Zhang, S.; Li, S. Green Chem., 2006, 8, 630.
4. Haverhals, L. M.; Reichert, W. M.; De Long, H. C.; Trulove, P. C. Cellulose, 2010, 2985, 425.
5. Haverhals, L. M.; Sulpizio, H. M.; Fayos, Z. A.; Trulove, M. A.; Reichert, W. M.; Foley, M. P.; De Long, H. C.; Trulove, P. C.Cellulose, 2012, 19, 13.
6. Haverhals, L. M.; Nevin, L. M.; Foley, M. P.; Brown, E. K.; De Long, H. C.; Trulove, P. C. Chem.Commun., 2012, 48, 6417.
7. Haverhals, L. M.; Brown, E. K.; Foley, M. P.; De Long, H.; Trulove P. ECS Trans, 2012, 50, 603.