Self-assembly of alkyl chains of fatty acids in papermaking systems: A review of related pitch issues, hydrophobic sizing, and pH effects

Abstract

This review article considers the role of fatty acids and the mutual association of their long-chain (e.g. C18) alkyl and alkenyl groups in some important aspects of papermaking. In particular, published findings suggest that interactions involving fatty acids present as condensed monolayer films can play a controlling role in pitch deposition problems. Self-association among the tails of fatty acids and their soaps also helps to explain some puzzling aspects of hydrophobic sizing of paper. When fatty acids and their soaps are present as monolayers in papermaking systems, the pH values associated with their dissociation, i.e. their pKa values, tend to be strongly shifted. Mutual association also appears to favor non-equilibrium multilayer structures that are tacky and insoluble, possibly serving as a nucleus for deposition of wood extractives, such, as resins and triglyceride fats, in pulp and paper systems.

Impact of residual extractives on the thermal stability of softwood Kraft pulp

“…Waxes and fats are readily hydrolyzed whereas sterol esters seem to be more reluctant towards hydrolysis under the given conditions. A certain extractive fraction re-precipitates on the pulp fiber surfaces in the final stage of the Kraft cook when the pH is lowered (Hubbe et al 2020). These re-precipitated compounds can cause problems during paper manufacturing.…”

“…These re-precipitated compounds can cause problems during paper manufacturing. They decrease inter-fiber bonding due to their hydrophobicity, impair the mechanical or optical properties (Sundberg et al 2000;Kokkonen et al 2002;Koljonen et al 2004;Hubbe et al 2020) of the products due to their color or contribute to chromophore formation, cellulose hydrolysis upon aging and accelerated brightness reversion if they contain reactive carbonyl or carboxyl groups (Rosenau et al 2004;Korntner et al 2015;Ahn et al 2019).…”

Thermodynamic Parameters of Berberine with Kolliphor Mixtures Adsorption and Micellization

“…On the other hand, it is possible that the hydrophilic group in the Ber molecule causes its orientation at the W-A interface in the form of an inclined plane. A greater tendency of hydrophobic chains composed of –CH 3 , –CH 2 – or =CH– groups for horizontal orientation than toward reorientation is suggested by the investigators on the basis of thermodynamic considerations of the adsorption processes of different compounds at the W-A interface [ 38 , 39 , 40 ]. Indeed, this orientation depends largely on the packing of the compound molecules being influenced by the strong intermolecular interactions in the surface region.…”

Effects of phospholipid type and concentration on the emulsion stability and in vitro digestion behaviors of fish oil-loaded emulsions

“…PL and GTN might have different electrical and steric properties at the water/ oil interface: the hydrophobic part of PL and GTN enters the fish oil core, and the fatty acid chain of PL may be located on the surface of the fish oil; the phosphoric acid group in the phospholipid is hydrophilic and distributed on the water surface to form a relatively stable O/W structure. As the carbon content of fatty acids increases, the hydrophobic effect of PL increases (Hubbe et al, 2020;Mezzetta et al, 2019). The content of LA in SPL (54.55 ± 0.06%) was significantly higher than that of EPL (15.14 ± 0.42%) (P < 0.01), and the content of palmitic acid in SPL (15.46 ± 0.71%) was significantly lower than EPL (29.87 ± 0.20) %) (P < 0.01).…”