Silica Coated Hemp Fabrics and Microfibers through a Green Ecofriendly Chemical Approach

Through a new and ecofriendly chemical approach, using inexpensive waterglass solutions, a silica-based coating was promoted on hemp fabrics which allows, also, to obtain silica coated micro-hemp particles, with an average aspect ratio of 7.1, from rags. This green coating is able: (i) to act as a thermal shield, (ii) to tailor the surface with specific coupling agents for suitable polymer matrices. The study was performed with the aid of multiple investigation techniques: Fourier-Transform InfraRed Spectroscopy, FTIR, Scanning Electron Microscopy, SEM, X-Ray powder Diffraction, XRD. The fire behavior, that, owing to severe regulations (i.e., in aerospace engineering), often prevents composites applications, was also studied. Cone calorimetry and vertical burning tests showed a considerable improvement in terms of fire behavior in the case of silica coated fiber reinforced polymer composites.