The use of nanocelluloses as a reinforcing filler is the object of research efforts since several decades, and intensified those last years. In the particular case of elastomers, it requires both a good level of dispersion and a high density of covalent bonds, together with a simple melt process of mixing, like carbon black or silica.<br/>We designed first a drying process that allows the conservation of the individual fibrilar shape for both cellulose nanocrystals (CNC) and microfibrillated cellulose (MFC) that lead to nanocelluloses aerogels with high specific surface area. We developed also a gas-phase modification procedure that allows to graft different acyl chloride with substitution degree from 0 to almost 3, depending on the operating parameters . Incidently, we discover also that difunctional reagents (diacyl chlorides, but also anhydrides…) are blocked at the surface of the nanocelluloses, allowing a gentle and controlled modification of the fillers.<br/>By choosing reactive grafting moieties, we obtained nanofillers with high surface area covalently bound to the matrix and easily dispersible. We prepared materials dispersing those fillers in a styrene butadiene elastomer by melt processing, and we characterized both the filler state of dispersion by transmission electron microscopy and the mechanical properties by tensile tests. When the filler interface create covalent bonds with the matrix, the resulting material presents a dispersion of nanometric rod particles and a strong mechanical reinforcement while preserving a large extensibility (Figure 1). This material is thus similar to silica or carbon black filled elastomer, and is an interesting achievement in the field of nanocellulose composite considering both the process employed and the properties obtained .

Processing and properties of elastomer covalently bound to nanocellulose aerogel

253rd National Meeting (2017)

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