Although exploring the homestead withdrawal (HW) mechanism can optimize the allocation of land resource elements, the livelihood sources of farmers will change and face different sources of risk. Many studies have explored various factors affecting the HW. However, studies simultaneously exploring the relationship among farmers’ internal livelihood capital and external risk prevention capabilities and HW including differences among various HW models are still limited. The present study constructed a simple theoretical framework and used the probit model to analyze the decision-making behavior of 367 farmers in the Jinjiang Pilot in Fujian Province of China. Specifically, this study explored the impact of farmers’ livelihoods including natural, financial, and human capitals and risk expectations. Such risk expectations involve living conditions, social security, residential environment, and psychological conditions on HW in asset replacement, index replacement, and monetary compensation model. The empirical findings indicated that the farmers’ livelihoods and risk expectations have inconsistent effects on farmers’ HW decision-making in all the models, except for risk expectations. In other words, social security and residential environment have a significant inhibitory effect. These results implied that differentiated policies for HW should be considered to enhance the farmer’s sustainable livelihood capacity and controllability of risk.
Supramolecular hydrogels have attracted great attention due to their special properties. In this research, bio-based supramolecular hydrogels were conveniently constructed by heating and ultrasounding two components of dehydroabietic acid with a rigid tricyclic hydrophenanthrene skeleton and morpholine. The microstructures and properties of hydrogels were investigated by DSC, rheology, SAXS, CD spectroscopy, and cryo-TEM, respectively. The critical gel concentration (CGC) of the hydrogel was 0.3 mol·L−1 and the gel temperature was 115 °C. In addition, the hydrogel showed good stability and mechanical properties according to rheology results. Cryo-TEM images reveal that the microstructure of hydrogel is fibrous meshes; its corresponding mechanism has been studied using FT-IR spectra. Additionally, oil-in-water gel emulsions were prepared by the hydrogel at a concentration above its CGC, and the oil mass fraction of the oil-in-water gel emulsions could be freely adjusted between 5% and 70%. This work provides a convenient way to prepare bio-based supramolecular hydrogels and provides a new method for the application of rosin.
Water pollution is one of the major problems that need to be solved in modern society, and there is a need to develop an effective adsorbent to purify the polluted water. In this article, three supramolecular metallohydrogels containing a three-dimensional network structure have been prepared from rosin derivatives. The supramolecular metallohydrogels have good thermal stability and maintain mechanical strength at high temperatures. Interestingly, the sodium N-(dehydroabiety1)maleamate/Ca2+ supramolecular metallohydrogels exhibit rare multi-stimulus responsiveness (mechanical vibration, temperature, pH, EDTA, etc.), especially to mechanical vibration with over 10 cycles, indicating ultra-mechanical response properties. More importantly, the unique three-dimensional network structure of the metallohydrogels can effectively adsorb cationic dyes in the wastewater. The adsorption amount and adsorption rate of this supramolecular metallohydrogels for rhodamine 6G after 48 h were at least 160.6 mg/g and 97%, respectively. The adsorption kinetic process of this metallohydrogel follows a quasi-secondary kinetic model, where the adsorption process is mainly electrostatic and weak π–π interactions. And the metallohydrogels can also be recovered by 0.5 mol/L hydrochloric acid solution desorption after adsorption of the dye. This is the first supramolecular metallohydrogel system prepared from the natural product rosin and applied to dye adsorption. This broadens the application of rosin in the field of supramolecular gel and dye adsorption and recycling.
Environment friendly and intelligent surfactants have attracted great attention in recent years. A bio-based CO 2 responsive surfactant rosin acid dimaleimide choline (R-BMI-C) with an extremely rigid skeleton was prepared using rosin and choline as raw materials by Diels-Alder addition reaction and acid-base neutralization reactions. Its structure was confirmed by IR and 1 H NMR spectra. The foams' properties of R-BMI-C could be adjusted by bubbling CO 2 /N 2 to change the structure of the surfactant. At pH 10.4, R-BMI-C forms an unstable foam with a half-life of 1.5 h. When the pH was reduced to 7.4 by bubbling CO 2 , R-BMI-C forms an extremely stable foam with a half-life of 336 h. The surfactant R-BMI-C changed from bola type to conventional type when bubbling CO 2 . And the internal aggregation structure of R-BMI-C aqueous solution changed from spherical micelles to laminar micelles according to the cryogenic-transmission electron microscope. We know that the lamellar structure tends to adsorb at the air/water interface or is trapped in the foam film, which slows down the foam coarsening and agglomeration process, resulting in a significant increase in foam stability. R-BMI-C could be used in oil extraction, fire-fighting and chemical decontamination due to its excellent foaming, stabilization and defoaming properties.
The emerging nanomaterials single‐walled carbon nanotube (SWNTs) with large specific surface area, excellent electrical conductivity and high mechanical strength, has been used to fabricate electronic devices. However, the extremely strong π‐π interactions make SWNTs easy to agglomerate, thus limiting their application. In this work, a novel method was applied to disperse SWNTs by using rigid rosin‐based CO2 responsive surfactant rosin acid dimaleimide choline (R‐BMI‐C). When pH 10.4, SWNTs can be uniformly and stably dispersed, and at pH 6.3, SWNTs aggregated. The dispersed SWNTs was then integrated into diglycidyl ether of bis phenol A (DGEBA) to fabricate high conductive epoxy composites. Their properties were characterized by SEM, TG, high resistivity meters, etc.. The results showed that the modified SWNTs/DGEBA composites obtained an ultra‐low percolation threshold (0.025 wt.%). Compared with the original SWNTs/DGEBA composite, its tensile strength and elastic modulus were enhanced by 17 % and 96 %, respectively, when the SWNTs content was 0.5 wt.%.
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