Synthesis of Polycardanol Using BF₃.O(C₂H₅)₂ as Initiator: Influence of Polymerization Conditions on Reaction Products

Cardanol acts to stabilize asphaltene particles in crude oil, but its derivative polycardanol, synthesized with BF₃.O(C₂H₅)₂ as initiator, exhibits divergent behavior, acting as both asphaltenes stabilizer and flocculant. This behavior could be related to structural differences in polycardanol samples. Therefore, in this work, we study the influence of some polymerization conditions (monomer purity, initiator concentration, and reaction time) on the structures and molar masses of the reaction products, and the reaction conversion. The materials were characterized by size exclusion chromatography and hydrogen and carbon nuclear magnetic resonance. When reacting with distilled cardanol, the conversion, the molar mass, and the homogeneity of structures increased as increasing initiator concentration in the range tested (1-3% m/m). For both monomers (different purity degrees), when using a lower initiator concentration (1% m/m), the product contained a larger amount of unreacted monomer and different structures were obtained due to the occurrence of rearrangements. The presence of triolefinic molecules in the monomer provoked crosslinked structures for higher initiator concentration (2-3% m/m). This study elucidated the differences among the reaction products of polycardanol.

Keywords:
cardanol; polycardanol; boron trifluoride; Friedel-Crafts; polymerization