Polybenzoxazines have the potential to become more sustainable when traditionally used oil-based starting molecules are replaced by bio-based and sometimes less toxic compounds. In such a perspective, several natural phenolic building blocks are available and can be used as source of phenol. Among them, cardanol, a by-product of food industry extracted from the cashew nut shell liquid, can be used to design benzoxazine monomers, thus taking advantage of the flexibility of its long aliphatic side chain. The present work aims at progressively substituting phenol with cardanol leading to the synthesis of three benzoxazine monomers, starting from the diphenolic monomer (EDBZ) used as reference, to an asymmetric phenol/cardanol benzoxazine (asymBZ), and a di-cardanol monomer (dicardBZ). The relations between the reactivity, the cross-linked structures and the properties have been investigated by Differential Scanning Calorimetry (DSC), Chemo-rheology, FT-IR spectroscopy, Thermogravimetric Analysis (TGA) and Dynamical Mechanical Analysis (DMA). The role of cardanol on the kinetic of polymerization and on vitrification was elucidated. Interestingly, the presence of cardanol increases the molecular mobility within the materials and greatly improves the thermal stability of the material by delaying the decomposition of about 150°C. This was explained by a modification of the <i>intra</i> and <i>inter</i> chain H-bonding network in presence of the aliphatic side chain of cardanol.

Cardanol as natural source of phenol for preparation of polybenzoxazines thermosets: Effect of the aliphatic side chain on the properties

255th National Meeting (2018)

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