Waste Materials as a Resource for Production of CMC Superabsorbent Hydrogel for Sustainable Agriculture

Waste materials are receiving more attention as concerns about the future of our planet increase. Cellulose is the most common substance in agricultural waste. Agricultural wastes containing cellulose are misplaced resources that could be reused in various fields for both environmental and economic benefits. In this work, 32 different kinds of waste are investigated for chemical modification in order to obtain carboxymethyl cellulose for the production of a superabsorbent hydrogel that can be applied in agriculture. A brief literature review is provided to help researchers wishing to obtain carboxymethyl cellulose by carboxymethylation starting with waste materials. We also provide details about methods to obtain as well as verify carboxymethylation. Carboxymethyl cellulose (CMC), as a constituent of cellulosic water and superabsorbent hydrogels with applications in agriculture, is described. Superabsorbent hydrogels with CMC are able to absorb huge amounts of water and are biodegradable.

Biomimetic cellulose-based superabsorbent hydrogels for treating obesity

In the treatment of obesity, nutritional and behavioral modifications are difficult to implement and maintain. Since vegetable consumption is a fundamental part of many dietary interventions and daily nutrient requirements, we developed a novel cellulose-based superabsorbent hydrogel (CB-SAH) platform, inspired by the composition and mechanical properties of raw vegetables, as a mechanobiological therapy. The CB-SAHs properties were studied in a simulated gastrointestinal environment, while their impact on gut tissue was investigated by an ex vivo organ culture (EVOC) model. Functional fibers and raw vegetables were used as reference. CB-SAHs demonstrated orders of magnitude higher elasticity in comparison to the tested functional fibers, however performed similar to the tested raw vegetables. Notably, the biomimetic CB-SAHs with elasticity levels similar to raw vegetables showed benefits in preserving and regulating the gut tissue in the EVOC model. Non-systemic oral mechanotherapeutics based on this technology were advanced through clinical studies, with a first product cleared as an aid for weight management in the US and Europe.

Development of Novel Superabsorbent Hybrid Hydrogels by E-Beam Crosslinking

In this study, several superabsorbent hybrid hydrogel compositions prepared from xanthan gum (XG)/sodium carboxymethylcellulose (CMC)/graphene oxide (GO) were synthesized by e-beam radiation crosslinking. We studied and evaluated the effects of GO content from the chemical structure of the hydrogels according to: sol-gel analysis, swelling degree, diffusion of water, ATR-FTIR spectroscopy, network structure, and dynamic mechanical analysis. The gel fraction and swelling properties of the prepared hydrogels depended on the polymer compositions and the absorbed dose. The hybrid XGCMCGO hydrogels showed superabsorbent capacity and reached equilibrium in less than 6 h. In particular, the XGCMCGO (70:30) hydrogel reached the highest swelling degree of about 6000%, at an irradiation dose of 15 kGy. The magnitude of the elastic (G′) and viscous (G″) moduli were strongly dependent on the absorbed dose. When the degree of crosslinking was higher, the G′ parameter was found to exceed 1000 Pa. In the case of the XGCMCGO (80:20) hydrogel compositions, the Mc and ξ parameters decreased with the absorbed dose, while crosslinking density increased, which demonstrated that we obtained a superabsorbent hydrogel with a permanent structure.