Surface Esterification of Sisal Fibres for use as Reinforcement in Cementitious Matrix

Vegetable fibres have been shown to be promising as reinforcement in composites because they are abundant, renewable, and low cost. However, the fibre-matrix interaction can be damaged by dimensional variation of vegetable fibres, due to moisture variations. The alkaline medium of cementitious matrix is aggressive to natural fibres, compromising their durability. The aim of this study was to modify sisal fibres (Agave sisalana) by esterification with acyl chlorides to improve their stability and compatibility with the cementitious matrix in order to optimize the performance and durability of composites. The esterified fibres were characterized by moisture absorption, tensile tests, Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM) and the composites by bending tests and SEM. The results showed that esterification changed both the morphology and physical properties of sisal fibres. The composite produced using esterified fibres with octanoyl chloride maintained the properties of 28 to 90 days of age, which represented an improvement in the fibre stability compared to natural fibre composite.