Development and characterisation of hybrid composite skin simulants based on short polyethylene fibre and bioactive glass particle-reinforced silicone

Abstract

Silicone elastomers are widely recognised as artificial skins for medical prosthesis and cranial injury assessment. Since silicone is not an ideal skin simulant due to the lack of mechanical stiffness and a fibrous structure, the present study aimed to tailor the mechanical and structural characteristics of silicone by integrating biocompatible reinforcements (namely, short polyethylene fibres and bioglass particles) to develop suitable bio-integrative skin simulant candidates. The influences of short polyethylene fibres and bioglass particles in the selected platinum silicone on the mechanical properties of silicone-based composite skin simulants were investigated with various factors, including filler concentration, KMnO₄ surface treatment of the polyethylene fibre, and particle size. A comprehensive assessment of the tensile, compressive, and hardness properties of the examined composites was conducted, and they were compared with the properties of human biological skin. The results exhibited that the elastic moduli and the hardness of all composites increased with the concentration of both reinforcements. While integrating only the bioglass particles had the advantage of an insignificant effect on the hardness change of the silicone matrix, the composite with polyethylene fibres possessed superior tensile elastic modulus and tensile strength compared to those of the bioglass reinforced composite. The composites with 5% untreated polyethylene fibres, KMnO₄ surface-treated fibres, and bioglass reinforcements enhanced the tensile elastic moduli from the pure silicone up to 32%, 44%, and 22%, respectively. It reflected that the surface treatment of the fibres promotes better interfacial adhesion between the silicone matrix and the fibres. Moreover, the smaller bioglass particle had a greater mechanical contribution than the larger glass particle. Systematically characterised for the first time, the developed composite skin simulants demonstrated essential mechanical properties within the range of the human skin and constituted better skin alternatives than pure silicone for various biomedical applications.

Keywords: Discontinuous reinforcement; Elastomer-matrix composites; Mechanical properties; Skin simulant.