Biomimetic adsorption of zwitterionic–xyloglucan block copolymers to CNF: towards tailored super-absorbing cellulose materials. Issue 24 (7th March 2017)

• Record Type: Journal Article
• Authors: Hatton, F. L.; Engström, J.; Forsling, J.; Malmström, E.; Carlmark, A.
• Is Part Of: RSC advances. Volume 7:Issue 24(2017)
• Page Start: 14947
• Page End: 14958
• Publication Date: 2017-03-07
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6ra28236a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Block-copolymer of xyloglucan and zwitterionic PSBMA prepared by RAFT as a biomimetic adsorbent for cellulose nanofibrils to create super-adsorbing gels. Abstract : A biomimetic, facile approach to cellulose modification is the utilisation of self-adsorbing, naturally occurring biopolymers, such as the hemicellulose xyloglucan (XG). Herein, XG- block -poly(sulfobetaine methacrylate) (XG- b -PSBMA) zwitterionic block copolymers have been prepared and assessed for their ability to adsorb to cellulose, specifically cellulose nanofibrils (CNF). The polymers were synthesised using reversible addition–fragmentation chain-transfer (RAFT) polymerisation, employing an XG macromolecular RAFT agent (XG-RAFT), polymerising a sulfobetaine methacrylate (SBMA) under aqueous conditions. The incorporation of the XG block shifted the upper critical solution temperature (UCST) values to higher temperatures (20 and 30 °C) compared with the PSBMA homopolymers (17 and 22 °C) and the transition was also broadened. The adsorption of the polymers to a CNF surface was monitored using quartz crystal microbalance with dissipation monitoring (QCM-D), showing that the XG block enhanced the adsorption of the zwitterionic polymer. The formation of CNF-composite films was achieved utilising a facile vacuum filtration methodology, and the targeted compositions were confirmed by FT-IR and TGA analyses. The films exhibited high degrees of swelling in water, which were investigated at two different temperatures, 5 and 60 °C (below and above the polymer USCT values). These results highlight the advantage of using an XG block for the biomimetic modification of cellulose to form new cellulose-composite materials such as super-absorbing films.