Improving Laccase‐Facilitated Grafting of 4‐Hydroxybenzoic Acid to High‐Kappa Kraft Pulps

Laccase was reacted with 4‐hydroxybenzoic acid (4‐hba) and high‐kappa (91) kraft pulp to gain a better understanding of the reaction parameters contributing to improved laccase‐facilitated grafting of 4‐hba to a high‐kappa kraft pulp. Reacting 4‐hba and laccase in the absence of pulp resulted in an increase in molecular weight of the 4‐hba. Performing the reaction in a vessel pressurized with oxygen did not aid in laccase‐facilitated coupling of 4‐hba to the pulp; however, reaction consistency and dosage of the 4‐hba were shown to be most influential in affecting the results. The reaction was also shown to be slightly enhanced by adding 4‐hba periodically throughout the course of the reaction.