Abstract

The present work focuses on the preparation of poly(l–lactide)–magnesium oxide whiskers (PLLA–MgO) composites by the in-situ polymerization method for bone repair and implant. PLLA–MgO composites were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and solid-state 13C and 1H nuclear magnetic resonance spectroscopy (NMR). It was found that the whiskers were uniformly dispersed in the PLLA matrix through the interfacial interaction bonding between PLLA and MgO; thereby, the MgO whisker was found to be well-distributed in the PLLA matrix, and biocomposites with excellent interface bonding were produced. Notably, the MgO whisker has an effect on the crystallization behavior and mechanical properties; moreover, the in vivo degradation of PLLA–MgO composites could also be adjusted by MgO. These results show that the whisker content of 0.5 wt % and 1.0 wt % exhibited a prominent nucleation effect for the PLLA matrix, and specifically 1.0 wt % MgO was found to benefit the enhanced mechanical properties greatly. In addition, the improvement of the degrading process of the composite illustrated that the MgO whisker can effectively regulate the degradation of the PLLA matrix as well as raise its bioactivity. Hence, these results demonstrated the promising application of PLLA–MgO composite to serve as a biomedical material for bone-related repair.

Highlights

  • Biodegradable polymers have been widely utilized as materials for biomedical applications

  • These results demonstrated the promising application of PLLA–magnesium oxide (MgO) composite to serve as a biomedical material for bone-related repair

  • It can be seen that the Mη of PLLA is higher than the nancomposite, which is probably due to several polymer chains of nanocomposite growing on the surface of the MgO nanowhisker, which led to stearic hindrance from neighboring polymer chains

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Summary

Introduction

Biodegradable polymers have been widely utilized as materials for biomedical applications. There have been some defects including high brittleness, low strength and hydrophobicity and acidic products from its degradation, limiting its practical usage widely [1,2,3]. To overcome these drawbacks, the study of polymer–inorganic composites has attracted great interest since they exhibit greatly enhanced properties. Li et al prepared PLLA–MgO nanocomposites with a weight-average molecular weight of 55,500 by in-situ melt polycondensation from l–lactic acid and surface-hydroxylated MgO, in spite of the nanocomposite achieving better mechanical properties than pristine PLLA; MgO still needed be modified, and the biocompatibility of the synthesized composite has not been investigated [24]. The effect of the MgO whisker on regulating the degradation of PLLA was evaluated through the in vivo experiments

Experimental Materials
Preparation of Magnesium Oxide Whiskers
In-Situ Polymerized PLLA–MgO Composites
Characterization
(Supplementary
Animal Models
Routine Pathological Examinations
Molecular Weight
X-Ray Diffraction
Fourier
Scanning Electron Microscopy
The nanocomposites a continuous morphology measurements and in in
Synthesized Mechanism of PLLA-MgO Composite
Schematic mechanism of of PLLA–MgO
Crystallization Property of PLLA–MgO Composites
In Vivo
Conclusions
Full Text
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