Dimensionally Stable Cellulose Aerogel Strengthened by Polyurethane Synthesized In Situ. Issue 1 (15th October 2018)

• Record Type: Journal Article
• Authors: Verdolotti, Letizia; Stanzione, Mariamelia; Khlebnikov, Oleg; Silant'ev, Vladimir; Postnova, Irina; Lavorgna, Marino; Shchipunov, Yury
• Other Names: Froimowicz Pablo guestEditor.; Zhang Kan guestEditor.; Ran Qichao guestEditor.
• Is Part Of: Macromolecular chemistry and physics. Volume 220:Issue 1(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-10-15
• Subjects: aerogels -- biocomposites -- cellulose -- coating -- polyurethane; Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.201800372
• Languages: English
• ISSNs: 1022-1352

Abstract

Abstract: Fibrillary cellulose and nanocellulose are widely applied as fillers for the improvement of the mechanical properties, thermostability, and biodegradability of polymers. Here, an opposite concept is suggested which is to use cellulose for structure‐forming and directing the scaffold, whereas polymers serve for its modification. Cellulose possesses excellent properties, but they are badly affected by water; its mechanical strength drops sharply, cellulosic materials swell, become dimensionally unstable, and susceptible to fungal degradation. The deterioration of properties gives no way of using methods of wet chemistry for cellulose treatment. To obviate this problem, dimensionally stable aerogels are prepared from microfibrillated cellulose. Their stability allows them to be treated in solutions of isocyanate. Polyurethane synthesized in situ is attached covalently to cellulose through hydroxyl groups. Polymer coating further stabilizes the 3D microfibrillar network, Young's modulus increases by more than two orders of magnitude and differences in the properties of aerogels in the dried and wetted states are minimized. Improvement of the mechanical strength makes cellulose aerogels better suitable for various applications than present cellulosic materials. Abstract : Cellulose serves as a main structure‐forming scaffold for coating by polyurethane synthesized in situ. To perform treatment in solutions, dimensionally stable aerogels from microfibrillated cellulose are prepared. Diisocyanate interacts with hydroxyl groups with the formation of polymer on polysaccharide macromolecules that increases mechanical strength by two orders of magnitude, and minimizes the difference in properties of aerogels in dried and wetted states.