@article{li_xie_wilt_willoughby_rojas_2018, title={Thermally Stable and Tough Coatings and Films Using Vinyl Silylated Lignin}, volume={6}, ISSN={["2168-0485"]}, DOI={10.1021/acssuschemeng.7b03387}, abstractNote={We modified lignin, a renewable biomacromolecule with high carbon density, with silicon-containing vinyl groups via a highly efficient silylation reaction that achieved ∼30% substitution of lignin’s hydroxyl units. This exothermic process was carried out in the melt state, in situ, in a reactive extruder. 1H, 13C, and 31P NMR and FTIR confirmed the success of the silylation and were used to access the reactivity of the vinyl silylated lignin for copolymerization with polyacrylonitrile (PAN). Copolymers of the unmodified lignin and PAN were also produced as a reference. Importantly, the rheological behaviors of the copolymers of lignin and PAN were suitable for application in surface coating and films that were not possible if lignin or physical mixtures of lignin and PAN were used. Glass surfaces were treated via solution casting followed by oven drying, yielding films that were evaluated regarding their morphology (SEM) and thermal properties (TGA and DSC). The films produced with copolymers based on vin...}, number={2}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Li, Shuai and Xie, Wenyi and Wilt, Meghan and Willoughby, Julie A. and Rojas, Orlando J.}, year={2018}, month={Feb}, pages={1988–1998} }
 @article{li_ogunkoya_fang_willoughby_rojas_2016, title={Carboxymethylated lignins with low surface tension toward low viscosity and highly stable emulsions of crude bitumen and refined oils}, volume={482}, ISSN={["1095-7103"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84979781362&partnerID=MN8TOARS}, DOI={10.1016/j.jcis.2016.07.063}, abstractNote={Kraft and organosolv lignins were subjected to carboxymethylation to produce fractions that were soluble in water, displayed a minimum surface tension as low as 34mN/m (25°C) and a critical aggregation concentration of ∼1.5wt%. The carboxymethylated lignins (CML), which were characterized in terms of their degree of substitution ((31)P NMR), elemental composition, and molecular weight (GPC), were found suitable in the formulation of emulsions with bitumens of ultra-high viscosity, such as those from the Canadian oil sands. Remarkably, the interfacial features of the CML enabled fuel emulsions that were synthesized in a very broad range of internal phase content (30-70%). Cryo-replica transmission electron microscopy, which was used here the first time to assess the morphology of the lignin-based emulsions, revealed the droplets of the emulsion stabilized with the modified lignin. The observed drop size (diameters<2μm) was confirmed by light scattering, which revealed a normal size distribution. Such characteristics led to stable emulsified systems that are amenable for a wide range of applications. Emulsification with CML afforded bitumen emulsions with very high colloidal stability (no change was noted for over one month) and with a strong shear thinning behavior. Both features indicate excellent prospects for storage, transport and spraying, which are relevant in operations for power generation, which also take advantage of the high heating value of the emulsion components. The ability of CML to stabilize emulsions and to contribute in their combustion was tested with light fuels (kerosene, diesel, and jet fuel) after formulation of high internal phase systems (70% oil) that enabled operation of a fuel engine. A significant finding is that under certain conditions and compared to the respective pure fuel, combustion of the O/W emulsions stabilized by CML presented lower NOx and CO emissions and maintained a relatively high combustion efficiency. The results highlight the possibilities in high volume application for lignin biomacromolecules.}, journal={JOURNAL OF COLLOID AND INTERFACE SCIENCE}, author={Li, Shuai and Ogunkoya, Dolanimi and Fang, Tiegang and Willoughby, Julie and Rojas, Orlando J.}, year={2016}, month={Nov}, pages={27–38} }
 @article{li_willoughby_rojas_2016, title={Oil-in-Water Emulsions Stabilized by Carboxymethylated Lignins: Properties and Energy Prospects}, volume={9}, ISSN={["1864-564X"]}, DOI={10.1002/cssc.201600704}, abstractNote={AbstractWe take advantage of the amphiphilic properties of technical lignin macromolecules and their inherent high calorific values to formulate oil‐in‐water (O/W) fuel emulsions with high internal‐phase ratios. For the oil phase, we used a combustible hydrocarbon (kerosene) with a measured equivalent alkane carbon number of 12. To adjust the balance of affinity with the oil and water phases and their surface activity, pine kraft lignins were carboxymethylated to different degrees, as quantified by 13C NMR spectroscopy, potentiometric titrations, and zeta potential measurements. Carboxymethylated lignins (CMLs) with a degree of substitution of 30 % displayed a critical aggregation concentration of 3 %. The salinity and pH of the aqueous phase were chosen as formulation variables and adjusted within the Winsor framework. The O/W emulsions were produced by following standard protocols. The drop‐size distributions of emulsions with varying pH, degree of substitution, and composition (water‐to‐oil ratio, WOR) were determined, and the long‐term stabilities and rheological behavior of these emulsions were analyzed. Most of the obtained O/W fuel emulsions showed shear‐thinning behavior with a drop size of approximately 2.5 μm and were stable for over 30 days. The combustion of the lignins and their respective emulsions was performed, and their higher heating values (HHVs) were quantified. The HHVs of CML and a high‐internal‐phase (WOR=30:70) O/W emulsion were 20 and 30 MJ kg−1, respectively. Overall, we propose the stabilization of O/W fuel emulsions by lignin as an important avenue in the utilization of this abundant biomacromolecule.}, number={17}, journal={CHEMSUSCHEM}, author={Li, Shuai and Willoughby, Julie A. and Rojas, Orlando J.}, year={2016}, month={Sep}, pages={2460–2469} }
 @article{cao_guenther_sit_lommel_opperman_willoughby_2016, title={Development of abamectin loaded lignocellulosic matrices for the controlled release of nematicide for crop protection}, volume={23}, ISSN={["1572-882X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84955651797&partnerID=MN8TOARS}, DOI={10.1007/s10570-015-0817-6}, number={1}, journal={CELLULOSE}, publisher={Springer Science and Business Media LLC}, author={Cao, Jing and Guenther, Richard H. and Sit, Tim L. and Lommel, Steven A. and Opperman, Charles H. and Willoughby, Julie A.}, year={2016}, month={Feb}, pages={673–687} }