Driven Assembly of Lignin into Microcapsules for Storage and Delivery of Hydrophobic Molecules

Oil-filled microcapsules of kraft lignin were synthe- sized by first creating an oil in water emulsion followed by a high- intensity, ultrasound-assisted cross-linking of lignin at the water/oil interface. The rationale behind our approach is based on promoting documented lignin hydrophobic interactions within the oil phase, followed by locking the resulting spherical microsystems by covalent cross-linking using a high intensity ultrasound treatment. As further evidence in support of our rationale, confocal and optical microscopies demonstrated the uniformly spherical morphology of the created lignin microparticles. The detailed elucidation of the cross-linking processes was carried out using gel permeation chromatography (GPC) and quantitative 31P NMR analyses. The ability of lignin microcapsules to incorporate and release Coumarin-6 was evaluated in detail. In vitro studies and confocal laser scanning microscopy analysis were carried out to assess the internalization of capsules into Chinese hamster ovary (CHO) cells. This part of our work demonstrated that the lignin microcapsules are not cytotoxic and readily incorporated in the CHO cells

Application of ionic liquids and microwave activation in selected organic reactions

Abstract Ionic liquids and microwave heating have been studied in four different reactions namely esterifications, etherifications and ene and sulfonylation reactions. These techniques revealed several advantages over conventional methods. In esterification of alcohols with anhydrides in ionic liquid solvents, the low boiling acid by-product could be removed before product recovery. The acid by-product could be regenerated back to the anhydride. Similar or higher yields were observed from esterifications with acetic anhydride of carbohydrates than with conventional methods. Even cellulose and starch could be esterificated in ionic liquids in the homogenous phase. The etherification reaction in ionic liquid was challenging, due to the basic reaction conditions needed. 1-Methyl-3-butylimidazolium -cations ([BMIM]) could not be used in basic conditions. The new information was that [BMIM]-cation could not be used with epichlorohydrin. The ene reaction was carried out with microwave heating in various solvents. Ionic liquids could be used as a solvent, but the ene reaction between allyl benzene. The best results were obtained without additional solvent. The yields by using microwave heating were high and reaction times were relatively short. The sulfonylation reaction of aromatics could be catalyzed by metal bistriflimide complexes. Even chlorobenzene could be sulfonylated when Bi-complex was used as a catalyst. Ionic liquids could be used as a solvent, but sulfonylations were best carried out without additional solvents

Esterified lignin coating as water vapor and oxygen barrier for fiber-based packaging

Abstract Lignin, esterified with palmitic and lauric acid chloride, has been studied for the application as coating on fiber-based packaging material. The aim was to improve the barrier properties against water vapor and oxygen of paperboard. The esterification was followed by Fourier transform infrared spectroscopy, 31P nuclear magnetic resonance spectroscopy, and gel permeation chromatography measurements. The lignin esters were applied on paperboard and formed a continuous film. The moisture barrier property of the coated paperboards was characterized by the water vapor transmission rate (WVTR). A significant decrease in WVTR was observed, for example, 40 g m-2 (for 24 h) for a paperboard coated with 10.4 g m-2 hardwood kraft lignin palmitate. The contact angle of water on the lignin ester coatings was high and stable. For all paperboard samples coated with lignin esters, a significant decrease in oxygen transmission rate was observed. Accordingly, lignin palmitate and laurate have a high potential as a barrier materials in packaging applications.</jats:p