Adsorption of biopolymers onto nanocelluloses for the fabrication of hollow microcapsules

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Salvatore Lombardo ◽  
Bernard Cathala ◽  
Ana Villares
Keyword(s):  
Quartz Crystal Microbalance ◽  
Cellulose Nanocrystals ◽  
Quartz Crystal ◽  
Cellulose Nanofibers ◽  
Aqueous Media ◽  
Three Dimensional ◽  
Functional Materials ◽  
Crystalline Cellulose ◽  
Multilayer Adsorption ◽  
Adsorbed Polymer

Abstract In this work, we studied the multilayer adsorption of cellulose nanocrystals and cellulose nanofibers with other polysaccharides such as xyloglucan and chitosan. We showed that the specific interactions between these biopolymers can be exploited to prepare three-dimensional functional materials. Quartz crystal microbalance studies showed that both biopolymers were adsorbed irreversibly on the nanocellulose surfaces. In aqueous media, the maximum amount of adsorbed polymer was higher for the smaller and more crystalline cellulose nanocrystals, compared to cellulose nanofibers. For both nanocelluloses employed, the amount of xyloglucan of the first bilayer was larger than the amount of chitosan adsorbed. Ellipsometry showed that both xyloglucan and chitosan were adsorbed on nanocellulose surfaces. However, at the second layer no mass change was detected by quartz crystal microbalance when xyloglucan was added, while for addition of successive layers of chitosan a decrease of frequency was detected. The water uptake of multilayers was higher for cellulose nanocrystals than for nanofibers, which was ascribed the presence of voids in the nanocrystal layer. Finally, we demonstrated that multilayer adsorption of these biopolymers can be performed on calcium carbonate sacrificial templates, which can then be removed to yield hollow polysaccharide microcapsules.

scholarly journals Complex Aerogels Generated from Nano-Polysaccharides and Its Derivatives for Oil–Water Separation

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1593 ◽  
Author(s):  
Hajo Yagoub ◽  
Liping Zhu ◽  
Mahmoud H. M. A. Shibraen ◽  
Ali A. Altam ◽  
Dafaalla M. D. Babiker ◽  
...  
Keyword(s):  
Guar Gum ◽  
Corn Oil ◽  
Cellulose Nanofibers ◽  
Aqueous Media ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
Water Contact ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water

The complex aerogel generated from nano-polysaccharides, chitin nanocrystals (ChiNC) and TEMPO-oxidized cellulose nanofibers (TCNF), and its derivative cationic guar gum (CGG) is successfully prepared via a facile freeze-drying method with glutaraldehyde (GA) as cross-linkers. The complexation of ChiNC, TCNF, and CGG is shown to be helpful in creating a porous structure in the three-dimensional aerogel, which creates within the aerogel with large pore volume and excellent compressive properties. The ChiNC/TCNF/CGG aerogel is then modified with methyltrichlorosilane (MTCS) to obtain superhydrophobicity/superoleophilicity and used for oil–water separation. The successful modification is demonstrated through FTIR, XPS, and surface wettability studies. A water contact angle of 155° on the aerogel surface and 150° on the surface of the inside part of aerogel are obtained for the MTCS-modified ChiNC/TCNF/CGG aerogel, resulting in its effective absorption of corn oil and organic solvents (toluene, n-hexane, and trichloromethane) from both beneath and at the surface of water with excellent absorption capacity (i.e., 21.9 g/g for trichloromethane). More importantly, the modified aerogel can be used to continuously separate oil from water with the assistance of a vacuum setup and maintains a high absorption capacity after being used for 10 cycles. The as-prepared superhydrophobic/superoleophilic ChiNC/TCNF/CGG aerogel can be used as a promising absorbent material for the removal of oil from aqueous media.

scholarly journals Three-dimensional Hydrogels of Alginate/chitosan Semi-interpenetrating Polymer Networks and Nanocelluloses

2021 ◽  
Author(s):  
Priscila Siqueira ◽  
Ana de Lima ◽  
Felipe Medeiros ◽  
Augusta Isaac ◽  
Katia Novack ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dimensional Stability ◽  
Cellulose Nanocrystals ◽  
Biomedical Applications ◽  
Cellulose Nanofibers ◽  
Polymer Networks ◽  
Three Dimensional ◽  
Controlled Drug Release ◽  
Interpenetrating Polymer Networks ◽  
Post Treatment

Abstract The hydrogels are advanced materials used in biomedical applications during wound healing, controlled drug release and to prepare scaffolds. In this work are prepared hydrogels of alginate/chitosan (Alg/Ch) semi-interpenetrating polymer networks (semi-IPN’s) and nanocelluloses. The hydrogels after preparation by freeze drying are namely simply as gels. The cellulose nanocrystals (CNC’s) are obtained from acid hydrolysis of bleached Eucalyptus pulps and oxidized cellulose nanocrystals (CNCT’s) prepared by (2,2,6,6-tetramethylpiperidin-1-yl)oxyl radical catalyzed reaction as known as TEMPO reaction. The cellulose nanofibers (NFC’s) are obtained from mechanical shearing of cellulose pulps and oxidized NFC’s by TEMPO-mediated reaction (NFCT’s). The nanocellulose suspension and gels are characterized by FTIR at ATR mode, TGA, XRD, TEM, SEM, X-ray computed microtomography (micro-CT) and DMTA. The addition of CNC’s, NFC’s, CNCT’s or NFCT’s in the microstructure of gels increases their dimensional stabilities. The best results are obtained when CNCT’s and NFCT’s are added. The mechanical properties and dimensional stability of Alg/Ch semi-IPN’s increase after controlled thermal post-treatment. The heating during thermal post-treatment boosts the physicochemical interactions in the microstructures of semi-IPN’s. The biological assays show biocompatibility of fibroblast cells on the substrates, and differentiation and proliferation up seven days. The optimized mechanical properties, dimensional stability and biocompatibility of the gels studied in this work are important parameters for potential biomedical applications of these biomaterials.

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