Probing the complex thermo-mechanical properties of a 3D-printed polylactide-hydroxyapatite composite using in situ synchrotron X-ray scattering.
J Adv Res
; 16: 113-122, 2019 Mar.
Article
em En
| MEDLINE
| ID: mdl-30899594
ABSTRACT
Polylactide (PLA)-hydroxyapatite (HAp) composite components have attracted extensive attentions for a variety of biomedical applications. This study seeks to explore how the biocompatible PLA matrix and the bioactive HAp fillers respond to thermo-mechanical environment of a PLA-HAp composite manufactured by 3D printing using Fused Filament Fabrication (FFF). The insight is obtained by in situ synchrotron small- and wide- angle X-ray scattering (SAXS/WAXS) techniques. The thermo-mechanical cyclic loading tests (0-20â¯MPa, 22-56⯰C) revealed strain softening (Mullins effect) of PLA-HAp composite at both room and elevated temperatures (<56⯰C), which can be attributed primarily to the non-linear deformation of PLA nanometre-scale lamellar structure. In contrast, the strain softening of the PLA amorphous matrix appeared only at elevated temperatures (>50⯰C) due to the increased chain mobility. Above this temperature the deformation behaviour of the soft PLA lamella changes drastically. The thermal test (0-110⯰C) identified multiple crystallisation mechanisms of the PLA amorphous matrix, including reversible stress-induced large crystal formation at room temperature, reversible coupled stress-temperature-induced PLA crystal formation appearing at around 60⯰C, as well as irreversible heating-induced crystallisation above 92⯰C. The shape memory test (0-3.75â¯MPa, 0-70⯰C) of the PLA-HAp composite demonstrates a fixing ratio (strain upon unloading/strain before unloading) of 65% and rather a â¼100% recovery ratio, showing an improved shape memory property. These findings provide a new framework for systematic characterisation of the thermo-mechanical response of composites, and open up ways towards improved material design and enhanced functionality for biomedical applications.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
J Adv Res
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Reino Unido