The addition of poly(vinyl alcohol) fibres to apatitic calcium phosphate cement can improve its toughness

• Calcium phosphate cements, and in particular hydroxyapatite cements, have been widely investigated for use as bone void fillers due to their chemical similarity to bone and related osteoconductivity. However, they are brittle, which limits their use to non-load-bearing applications.The aim of the current study was to improve the toughness of hydroxyapatite cements through fibre reinforcement. The effect of the addition of hydrophilic, poly(vinyl-alcohol) (PVA) fibres to hydroxyapatite cement was evaluated in terms of mechanical properties, including compressive strength, diametral tensile strength and toughness (work of fracture), as well as setting time, phase composition and cement morphology. The fibre reinforcement enhanced the fracture resistance of the hydroxyapatite cement, but also simultaneously reduced the compressive strength and setting time of the cements. However, cement with 5 wt% of fibres (of powder component) could be considered a good compromise, with a compressive strength of 46.5 ± 4.6 MPa (compared to 62.3 ± 12.8 MPa of that without fibres), i.e. still much greater than that of human trabecular bone (0.1-14 MPa). A significantly higher diametral tensile strength (9.2 ± 0.4 MPa) was found for this cement compared to that without fibres (7.4 ± 1.5 MPa). The work of fracture increased four times to 9.1 ± 1.5 kJ/m2 in comparison to the pristine apatite. In summary, the hydroxyapatite cements could be reinforced by suitable amounts of PVA fibres, which resulted in enhancing the material’s structural integrity and ductility, and increased the material’s resistance to cracking.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Keramteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Ceramics (hsv//eng)

Nyckelord

fibre reinforcement

apatite cement

poly(vinyl alcohol)

composite

compressive strength

work of fracture

diametral tensile strength

toughness

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