Cytocompatibility and Mechanical Properties of Short Phosphate Glass Fibre Reinforced Polylactic Acid (PLA) Composites: Effect of Coupling Agent Mediated Interface

Abstract

In this study three chemical agents Amino-propyl-triethoxy-silane (APS), sorbitol ended PLA oligomer (SPLA) and Hexamethylene diisocyanate (HDI) were identified to be used as coupling agents to react with the phosphate glass fibre (PGF) reinforcement and the polylactic acid (PLA) polymer matrix of the composite. Composites were prepared with short chopped strand fibres (l = 20 mm, ϕ = 20 µm) in a random arrangement within PLA matrix. Improved, initial composite flexural strength (~20 MPa) was observed for APS treated fibres, which was suggested to be due to enhanced bonding between the fibres and polymer matrix. Both APS and HDI treated fibres were suggested to be covalently linked with the PLA matrix. The hydrophobicity induced by these coupling agents (HDI, APS) helped to resist hydrolysis of the interface and thus retained their mechanical properties for an extended period of time as compared to non-treated control. Approximately 70% of initial strength and 65% of initial modulus was retained by HDI treated fibre composites in contrast to the control, where only ~50% of strength and modulus was retained after 28 days of immersion in PBS at 37 °C. All coupling agent treated and control composites demonstrated good cytocompatibility which was comparable to the tissue culture polystyrene (TCP) control, supporting the use of these materials as coupling agent’s within medical implant devices.

Manufacturing and characterization of poly(lactic acid) composites with hydroxyapatite

“…Another desirable attracting property in materials for fixation devices is the ability to absorb energy during fracture. helped retain mechanical properties for a long period since hydrolysis at interface was delayed [35].…”

Changes in the mechanical properties of bioactive borophosphate fiber when immersed in aqueous solutions

“…Only in the case of significant increase in anisotropy, an increase in E is suspected to occur when the diameter of metaphosphate fibers decreases 43,44 . While, the tensile strength and Young's modulus of the investigated fibers are similar to those reported for other bioactive phosphate glass fibers, while having a larger diameter, 18,22‐24,45 the change in the Young's modulus with decreasing the fiber diameter cannot, at present, be explained. Possible assumptions include (a) the slipping of the large fibers in the grip which would lead to an underestimation of the Young's modulus and/or (b) the aging (and water retention) of the fibers.…”

“…A large number of studies were reported on phosphate glasses and fibers for medical applications from invert phosphate glasses 17,18 that cannot be drawn into fibers to metaphosphate glasses/fibers 19 . Ahmed et al evidenced that the addition of boron oxide or iron oxide into the phosphate network can lead to fibers with higher tensile strength and Weibull modulus than the silica‐based bioactive fibers 20‐24 . With regards to application in biosensing, Sglavo et al developed calcium phosphate fibers and capillaries with tensile strength of 200‐350 MPa and Weibull modulus ranging from 3 to 6 25 .…”

Magnesium coated phosphate glass fibers for unidirectional reinforcement of polycaprolactone composites

“…The composite obtained was compatible with MC3T3-E1 murine pre-osteoblast cell line. The P45 phosphate glass fiber-reinforced PLA composites investigated by Hasan MS et al 26 who also demonstrated cytocompatibility with the human MG63 cell line.…”