Influence of nanocellulose on mechanics and morphology of polyvinyl alcohol xerogels. (February 2019)

• Record Type: Journal Article
• Authors: Pramanik, R.; Ganivada, B.; Ram, Farsa; Shanmuganathan, Kadhiravan; Arockiarajan, A.
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 90(2019)
• Page Start: 275
• Page End: 283
• Publication Date: 2019-02
• Subjects: Xerogels -- Nanocellulose -- Mechanics -- Morphology; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2018.10.024
• Languages: English
• ISSNs: 1751-6161

Abstract

Abstract: Xerogels are porous networks of crosslinked polymers that are useful for biomedical applications such as drug delivery, scaffold engineering, tissue regeneration, cell culture and wound dressing. However, inferior mechanical properties curtail their applications to a considerable extent. Nanocellulose fibers and crystals are often added into the polymer matrix to improve their mechanical strength. Here, nanocellulose in the mass ratios of 7%, 13% and 18% are loaded into polyvinyl alcohol (PVA) matrix followed by thermo-morpho-mechanical characterization. With increase in nanocellulose content, thermal degradation occurs at a lower temperature. It is observed that addition of higher quantity of nanocellulose crystals leads to the formation of weak cellulose-rich regions causing xerogel rupture. This is predominantly observed for xerogel loaded with 18% nanocellulose crystals. Similarly, addition of higher quantity of nanocellulose fibers increase brittleness of the xerogels causing fracture. This is predominantly observed for xerogel loaded with 18% nanocellulose fibers. Creep strain and stress relaxation is observed to decrease with addition of nanocellulose loading owing to molecular chain restriction and polymer chain immobility. Abstract : Graphical abstract: Abstract : Highlights: Nanocellulose-loaded PVA xerogels are synthesized using solvent casting method. Morphological, thermal, crystallographic, chemical, mechanical and viscoelastic characterization is performed on these xerogels. Mechanical properties are observed to enhance with addition of nanocellulose upto a certain extent. Higher amount of nanocellulose fibers are observed to render brittleness to the xerogels; whereas, higher amount of nanocellulose crystals lead to the formation of mechanically-weak cellulose-rich regions in the PVA matrix Creep strain and stress relaxation decrease with addition of nanocellulose owing to increased molecular chain restriction and polymer chain immobility.