Rheology of epoxidized cellulose pulp gel-like dispersions in castor oil: Influence of epoxidation degree and the epoxide chemical structure. (1st November 2018)

• Record Type: Journal Article
• Authors: Cortés-Triviño, E.; Valencia, C.; Delgado, M.A.; Franco, J.M.
• Is Part Of: Carbohydrate polymers. Volume 199(2018)
• Page Start: 563
• Page End: 571
• Publication Date: 2018-11-01
• Subjects: Cellulose pulp -- Multi-functional epoxides -- Epoxy index -- Castor oil -- Rheology; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2018.07.058
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Epoxidized cellulose pulp allows to thicken castor oil medium for bio-lubricant applications. Epoxidation improves cellulose pulp/castor oil compatibilization. Epoxidation degree and epoxide chemical structure noticeably impact the rheological properties of cellulose pulp dispersions. Rheology is consequence of the balance between cellulose pulp/castor oil compatibility and a chemical crosslinking. The use of aromatic epoxides allows to obtain more cross-linked structures with higher consistency. Abstract: Several di- or tri-functional epoxides were used to chemically modify an industrial grade cellulose pulp from Eucalyptus globulus in order to thicken castor oil by dispersing epoxidized cellulose pulp fibers, resulting gel-like formulations with potential applications as biolubricants. Rheological properties of these colloidal suspensions were evaluated by analysing the effects of epoxidation degree and the epoxide chemical structure. With this aim, epoxidized cellulose pulp samples were characterized by means of epoxy index determination, thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. It was found that linear viscoelastic functions, determined in small-amplitude oscillatory shear (SAOS), and viscosity values of epoxidized cellulose pulp gel-like dispersions decreased by increasing the epoxy index, whereas the shear-thinning character was dampened with the extension of epoxidation. Aromatic di-functional epoxides provide higher values of these rheological functions than aliphatic ones.