Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Jan 18;11(1):249.
doi: 10.3390/nano11010249.

Mechanical Properties and Bioactivity of Poly(Lactic Acid) Composites Containing Poly(Glycolic Acid) Fiber and Hydroxyapatite Particles

Han-Seung Ko  1 , Sangwoon Lee  1 , Doyoung Lee  1 , Jae Young Jho  1
Affiliations

Mechanical Properties and Bioactivity of Poly(Lactic Acid) Composites Containing Poly(Glycolic Acid) Fiber and Hydroxyapatite Particles

Han-Seung Ko et al. Nanomaterials (Basel). .

Abstract

To enhance the mechanical strength and bioactivity of poly(lactic acid) (PLA) to the level that can be used as a material for spinal implants, poly(glycolic acid) (PGA) fibers and hydroxyapatite (HA) were introduced as fillers to PLA composites. To improve the poor interface between HA and PLA, HA was grafted by PLA to form HA-g-PLA through coupling reactions, and mixed with PLA. The size of the HA particles in the PLA matrix was observed to be reduced from several micrometers to sub-micrometer by grafting PLA onto HA. The tensile and flexural strength of PLA/HA-g-PLA composites were increased compared with those of PLA/HA, apparently due to the better dispersion of HA and stronger interfacial adhesion between the HA and PLA matrix. We also examined the effects of the length and frequency of grafted PLA chains on the tensile strength of the composites. By the addition of unidirectionally aligned PGA fibers, the flexural strength of the composites was greatly improved to a level comparable with human compact bone. In the bioactivity tests, the growth of apatite on the surface was fastest and most uniform in the PLA/PGA fiber/HA-g-PLA composite.

Keywords: hydroxyapatite; mechanical properties; poly(glycolic acid) fiber; poly(lactic acid); polymer composite; polymer grafting.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
(a) FT-IR, (b,c) XPS for N1s, and (d) TGA of surface-grafted hydroxyapatite (HA): (b) HA-Hexamethylene diisocyanate (HMDI); (c) HA-HMDI-ethylene glycol (EG).
Figure 2
Figure 2
SEM images of fracture surface of (a) PLA/HA5, (b) PLA/HA10, (c) PLA/HA15, (d) PLA/HA-g-PLA(m)5, (e) PLA/HA-g-PLA(m)10, (f) PLA/HA-g-PLA(m)15, (g) PLA/PGA fiber10, (h) PLA/PGA fiber20, and (i) PLA/PGA fiber30.
Figure 3
Figure 3
(a) Flexural stress–strain curves, (b) flexural modulus, and (c) flexural strength of PLA and its composites: PLA (black solid line); PLA/PGA fiber30 (black dash line); PLA/PGA fiber30/HA10 (gray solid line); PLA/PGA fiber30/HA-g-PLA(m)10 (gray dash line).
Figure 4
Figure 4
(a) Weight loss by phosphate buffer saline (PBS) and (b) weight increase by simulated body fluid (SBF) solution of the composites: ■ PLA/PGA fiber30; ● PLA/PGA fiber30/HA10; ▲ PLA/PGA fiber30/HA-g-PLA(m)10.
Figure 5
Figure 5
Surface SEM images of the composites before and after apatite growth by immersing PLA/PGA fiber30 (A), PLA/PGA fiber30/HA10 (B), and PLA/PGA fiber30/HA-g-PLA(m)10 (C) in SBF solution. The subscript number represents the immersing days of the composites.
See this image and copyright information in PMC

References

    1. Ridzwan M.I.Z., Shuib S., Hassan A.Y., Shokri A.A., Ibrahim M.N.M., Mohammad Ibrahim M.N. Problem of stress shielding and improvement to the hip implant designs: A review. J. Med. Sci. 2007;7:460–467. doi: 10.3923/jms.2007.460.467. - DOI
    1. Garlotta D. A Literature Review of Poly(Lactic Acid) J. Polym. Environ. 2001;9:63–84. doi: 10.1023/A:1020200822435. - DOI
    1. Naghieh S., Foroozmehr E., Badrossamay M., Kharaziha M. Combinational processing of 3D printing and electrospinning of hierarchical poly(lactic acid)/gelatin-forsterite scaffolds as a biocomposite: Mechanical and biological assessment. Mater. Des. 2017;133:128–135. doi: 10.1016/j.matdes.2017.07.051. - DOI
    1. Van de Velde K., Kiekens P. Biopolymers: Overview of several properties and consequences on their applications. Polym. Test. 2002;21:433–442. doi: 10.1016/S0142-9418(01)00107-6. - DOI
    1. Sabir M.I., Xu X., Li L. A review on biodegradable polymeric materials for bone tissue engineering applications. J. Mater. Sci. 2009;44:5713–5724. doi: 10.1007/s10853-009-3770-7. - DOI