Porous poly(vinyl alcohol)/sepiolite bone scaffolds: Preparation, structure and mechanical properties

Abstract

Porous poly(vinyl alcohol) (PVA)/sepiolite nanocomposite scaffolds containing 0-10wt.% sepiolite were prepared by freeze-drying and thermally crosslinked with poly(arylic acid).The microstructure of the obtained scaffolds was characterised by scanning electron microscopy and micro computer tomography, which showed a ribbon and ladder like interconnected structure. The incorporation of sepiolite increased the mean pore size and porosity of the PVA scaffold as well as the degree of anisotropy due to its fibrous structure.The tensile strength, modulus and energy at break of the PVA solid material that constructed the scaffold were found to improve with additions of sepiolite by up to 104%, 331% and 22% for 6wt.% clay. Such enhancements were attributed to the strong interactions between the PVA and sepiolite, the good dispersion of sepiolite nanofibres in the matrix and the intrinsic properties of the nanofibres. However, the tensile properties of the PVA scaffold deteriorated in the presence of sepiolite because of the higher porosity, pore size and degree of anisotropy.The PVA/sepiolite nanocomposite scaffold containing 6wt.% sepiolite was characterized by an interconnected structure, a porosity of 89.5% and a mean pore size of 79μm and exhibited a tensile strength of 0.44MPa and modulus of 14.9MPa, which demonstrates potential for this type of materials to be further developed as bone scaffolds.

Recent Developments of Foamed Polymer/Layered Silicates Nanocomposites

“…The addition of sepiolite changed the degree of anisotropy due to its fibrous structure, and increased the average pore size from 50 (0 wt % sepiolite) to 92 mm (10 wt % sepiolite) and the porosity from 84.6 % to 93.2 %. However, the mechanical properties of the PVA nanocomposite foams were found to worsen with sepiolite additions due to an increase in the porosity and the degree of anisotropy [99].…”

PMMA-sepiolite nanocomposites as new promising materials for the production of nanocellular polymers

“…A 9% of sepiolite was found to reduce the cell size from 160 to 100 μm and to increase the Young's modulus from 1.5 MPa to 6 MPa. In the work of Killen et al [37] porous poly(vinyl alcohol) was produced using sepiolites. Although the incorporation of sepiolites increased the mean pore size, the tensile strength, modulus and energy at break were improved with the addition of sepiolite contents up to a 6 wt%.…”

Polyvinyl alcohol and polyvinyl alcohol/ polyvinyl pyrrolidone biomedical foams crosslinked by gamma irradiation

“…More importantly, the foams must be biocompatible with body tissues for biomedical applications such as absorption of serum in eye surgery, making scaffolds for cell growth, and in drug delivery systems. [1][2][3][4][5][6][7][8][9] Various methods for preparation of biomedical foams have been reported including gas foaming of N 2 or CO 2 , overrun process (mechanical mixing of polymer solution at low temperature to entrap air bubbles) 10,11 and using a foaming agent. [12][13][14][15] These techniques are usually associated with polymer cross-linking methods.…”