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Polyhydroxyalkanoates (PHAs) are a family of biodegradable and biocompatible polyesters that have recently attracted much industrial attention. The most representative PHA is poly(3-hydroxybutyrate) (PHB), though it presents several shortcomings such as brittleness and poor impact resistance. 3-hydroxy- hexanoate units can be incorporated in PHB to obtain poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx), a copolymer with improved mechanical properties, processability and biodegradability, more suitable for biomedical applications. In this study, chitosan-grafted polycaprolactone (CS-g- PCL)/PHBHHx fiber blends in different compositions were developed by wet electrospinning, and their morphology, biodegradability, mechanical and tribological properties were investigated. A direct correlation was found between the wear rate and the mechanical properties, pointing that fiber breakage is the mechanism responsible for both the abrasive wear and yield. The interactions between the components led to a synergistic effect on tensile and tribological properties at a blend composition of 70/30, resulting in an optimum combination of maximum stiffness, strength, ductility and toughness and minimum coefficient of friction and wear rate, ascribed to the lower porosity and higher crystallinity of this sample. Further, it exhibits the slowest degradation rate. These fiber blends are ideal candidates as scaffolds for tissue engineering applications.
chitosan, electrospinning, fiber blend, polyhydroxyalkanoates, polycaprolactone, tribologi- cal properties, tissue engineering
[1] Laycock, B., Halley, P., Pratt, S., Werker, A. & Lant, P., The chemomechanical properties of microbial polyhydroxyalkanoates. Progress Polymer Science, 38, pp. 536–583, 2013. https://doi.org/10.1016/j.progpolymsci.2012.06.003
[2] Mekonnen, T., Mussone, P., Khalil, H. & Bressler, D., Progress in bio-based plastics and plasticizing modifications. Journal of Materials Chemistry A, 1, pp. 13379–13398, 2013. https://doi.org/10.1039/c3ta12555f
[3] Chang, H.M., Wang, Z.H., Luo, H.N., Xu, M., Ren, X.Y., Zheng, G.X., Wu, B.J., Zhang, X.H., Lu, X.Y., Chen, F., Jing, X.H. & Wang, L., Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)-based scaffolds for tissue engineering. Brazilian Journal of Medical and Biological Research, 47, pp. 533–539, 2014. https://doi.org/10.1590/1414-431X20143930
[4] Qu, X.H., Wu, Q., Zhang, K.Y. & Chen, G.Q., In vivo studies of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) based polymers: biodegradation and tissue reactions. Biomaterials, 27, pp. 3540–3548, 2006. https://doi.org/10.1016/j.biomaterials.2006.02.015
[5] Zhao, Q., Wang, S., Kong, M., Geng, W., Li, R.K., Song, C. & Kong, D., Phase morphology, physical properties, and biodegradation behavior of novel PLA/PHBHHx blends. Journal Biomedical Materials Research Part B: Applied Biomaterials, 100, pp. 23–31, 2012. https://doi.org/10.1002/jbm.b.31915
[6] Ladd, M.R., Hill, T.K., Yoo, J.J. & Lee, S.J., Electrospun Nanofibers in Tissue Engineering, InTechOpen: Rijeka, 2011.
[7] Zong, X., Kim, K.S., Fang, D., Ran, S., Hsiaoa, B.S. & Chu, B., Structure and process relationship of electrospun bioabsorbable nanofiber membranes. Polymer, 43, pp. 4403–4412, 2002. https://doi.org/10.1016/S0032-3861(02)00275-6
[8] Reneker, D.H., Kataphinan, W., Theron, A., Zussman, E. & Yarin, A. L. Nanofiber garlands of polycaprolactone by electrospinning. Polymer, 43, pp. 6785–6794, 2002. https://doi.org/10.1016/S0032-3861(02)00595-5
[9] Zong, X., Ran, S., Kim, K.S., Fang, D., Hsiao, B.S. & Chu, B., Structure and morphology changes during in vitro degradation of electrospun poly(glicolide-co-lactide) nanofiber membrane. Biomacromolecules, 4, pp. 416–423, 2003. https://doi.org/10.1021/bm025717o
[10] Diez-Pascual, A.M. & Diez-Vicente, A.L., Electrospun fibers of chitosan-grafted polycaprolactone/poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) blends. Journal of Materials Chemistry B, 4, pp. 600–612, 2016. https://doi.org/10.1039/C5TB01861G
[11] Liu, L., Li, Y., Liu, H. & Fang, Y., Synthesis and characterization of chitosan-graft-polycaprolactone copolymers. European Polymer Journal, 40, pp. 2739–2744, 2004. https://doi.org/10.1016/j.eurpolymj.2004.07.016
[12] Callister, W.D., Materials Science and Engineering: An introduction, John Wiley & Sons, Inc.: New York, 2007.
[13] Michlera, G.H. & Baltá-Calleja, F.J., Mechanical Properties of Polymers based on Nanostructure and Morphology, CRC press: Florida, p. 407, 2005. https://doi.org/10.1201/9781420027136
[14] Patel, H. N. Fibro-porous poliglecaprone/polycaprolactone conduits: synergistic effect of composition and in vitro degradation on mechanical properties. Polymer International, 64, pp. 547–555, 2015. https://doi.org/10.1002/pi.4834
[15] Takayama, T. & Todo, M., Improvement of fracture properties of PLA/PCL polymer due to LTI addition. Journal of Materials Science, 41, pp. 4989–4992, 2006. https://doi.org/10.1007/s10853-006-0137-1
[16] Shi, S.F.E.L., Guo, Z.G. & Liu, W.M., The recent progress of tribological biomaterials. Biosurface and Tribology, 1, pp. 81–97, 2015. https://doi.org/10.1016/j.bsbt.2015.06.002
[17] Suh, N.P., Tribophysics, Prentice-Hall: New Jersey, 1986.
[18] Lancaster, J.K., Abrasive wear of polymers. Wear, 14, pp. 223–239, 1969. https://doi.org/10.1016/0043-1648(69)90047-7
[19] Mannarino, M.M. & Rutledge, G.C., Mechanical and tribological properties of electrospun PA 6(3)T fiber mats. Polymer, 14, pp. 3017–3025, 2012. https://doi.org/10.1016/j.polymer.2012.04.039
[20] Naffakh, M. & Díez-Pascual, A.M., WS2 inorganic nanotubes reinforced poly(L-lactide acide)/hydroxyapatite hybrid composite biomateriales. RSC Advances, 5, pp. 65514–65525, 2015. https://doi.org/10.1039/C5RA10707E
[21] Wang, Y., Mo, W., Yao, H., Wu, Q., Chen, J. & Chen, G., Biodegradation studies of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate). Polymer Degradation Stability, 85, pp. 815–821, 2004. https://doi.org/10.1016/j.polymdegradstab.2004.02.010