Chang-Zhou Chen

Modification of lignin with dodecyl glycidyl ether and chlorosulfonic acid for preparation of anionic surfactant

Lignin was modified through incorporation of lipophilic and hydrophilic groups for the preparation of a surfactant. In this case, alkaline lignin reacted with dodecyl glycidyl ether in the presence of dimethyl benzyl amine to incorporate lipophilic long alkyl chains, and then sulfonated with chlorosulfonic acid for the introduction of hydrophilic sulfonic acid groups. Results showed that the reaction between dodecyl glycidyl ether and carboxy group in lignin was the predominant reaction at 95–110 °C. It was found that the surface tension of the synthesized lignin surfactant solution was lower than that of commercial surfactant sodium dodecylbenzenesulphonate when the concentration was below 0.4%, indicating that the surfactant prepared from alkaline lignin had a good surface activity. A lowest critical micelle concentration of 0.50 g L−1 and the corresponding surface tension at 29.17 mN m−1 were achieved when the surfactant was derived from the lignin grafted with dodecyl glycidyl ether at 110 °C. The anionic lignin surfactants prepared in this study are a promising feedstock as detergents or to enhance oil recovery.

Torrefaction of corncob to produce charcoal under nitrogen and carbon dioxide atmospheres

Corncob was torrefied under nitrogen and carbon dioxide atmospheres at 220-300 °C, obtaining solid products with mass yields of 69.38-95.03% and 67.20-94.99% and higher heating values of 16.58-24.77 MJ/kg and 16.68-24.10 MJ/kg, respectively. The changes of physicochemical properties of the charcoal was evaluated by many spectroscopies, contact angle determination, and combustion test. Hemicelluloses were not detected for the torrefaction under the hard conditions. As the severity increased, C concentration raised while H and O concentrations reduced. Combustion test showed that the burnout temperature of charcoal declined with the elevation of reaction temperature, and torrefaction at a high temperature shortened the time for the whole combustion process. Base on the data, torrefaction at 260 °C under carbon dioxide was recommended for the torrefaction of corncob.

Lignin-based highly sensitive flexible pressure sensor for wearable electronics

The development of flexible sensors with low cost, facile preparation and good reproducibility is of profound significance for wearable electronics and intelligent systems. Lignin is an aromatic composition of lignocellulosic biomass and known as a cheap, renewable, and environmentally friendly resource available everywhere. In this study, we present a simple and low-cost approach for the preparation of a highly electrically sensitive and flexible composite with polydimethylsiloxane and carbonized lignin via a facile process (CL/PDMS). This electrically sensitive flexible composite can be used in the preparation of a piezo-resistive sensor, which exhibits stable and fast response to loading and unloading stress in 60 ms and 40 ms, respectively. The sensor prototype displayed high sensitivity (57 kPa−1), wide range of working pressure (from 0 to 130 kPa) and excellent durability. The signals of pulse rates and the force needed for picking up items were successfully collected with this CL/PDMS sensor prototype. With the simple process for fabrication, low-cost of the filling material and excellent performance, we believe that the lignin-based sensitive flexible composite CL/PDMS is promising for applications in wearable electronics and intelligent systems such as health monitoring, smart skins, sports and other related areas.