Multi-technique surface characterization of bio-based films from sisal cellulose and its esters: a FE-SEM, mu-XPS and ToF-SIMS approach

Author(s)

Rodrigues, Bruno V. M. ^{[1, 2]} ; Heikkila, Elina ^[1] ; Frollini, Elisabete ^[2] ; Fardim, Pedro ^{[1, 3]}

Affiliation

^[1] Abo Akad Univ, Lab Fibre & Cellulose Technol, SF-20500 Turku - Finland

^[2] Univ Sao Paulo, Macromol Mat & Lignocellulos Fibers Grp, Ctr Res Sci & Technol BioResources, Inst Chem Sao Carlos, BR-13560970 Sao Paulo - Brazil

^[3] King Abdulaziz Univ, Ctr Excellence Adv Mat Res CEAMR, Jidda 21589 - Saudi Arabia

• Document type: Journal article
• Source: Cellulose; v. 21, n. 3, p. 1289-1303, JUN 2014.
• Web of Science Citations: 7

Abstract

Bio-based films were prepared from LiCl/DMAc solutions containing sisal cellulose esters (acetates, butyrates and hexanoates) with different degrees of substitution (DS 0.7-1.8) and solutions prepared with the cellulose esters and 20 wt% sisal cellulose. A novel approach for characterizing the surface morphology utilized field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and contact angle analysis. XPS and ToF-SIMS were a powerful combination while investigating both the ester group distribution on the surface and effects of cellulose content on the film. The surface coverage by ester aliphatic chains was estimated using XPS measurements. Fibrous structures were observed in the FE-SEM images of the cellulose and bio-based films, most likely because the sisal cellulose chains aggregated during dissolution in LiCl/DMAc. Therefore, the cellulose aggregates remained after the formation of the films and removal of the solvent. The XPS results indicated that the cellulose loading on the longer chain cellulose esters films (DS 1.8) increased the surface coverage by ester aliphatic chains (8.2 % for butyrate and 45 % for hexanoate). However, for the shortest ester chains, the surface coverage decreased (acetate, 42 %). The ToF-SIMS analyses of cellulose acetate and cellulose hexanoate films (DS 1.8) revealed that the cellulose ester groups were evenly distributed across the surface of the films. (AU)

• FAPESP's process: 12/00813-9 - Preparation and characterization of biocomposites based on sisal cellulose esters/cellulose: use of XPS and ToF-SIMS techniques for surface analysis
• Grantee: Bruno Vinícius Manzolli Rodrigues
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• FAPESP's process: 10/00005-4 - Cellulose esters from homogeneous and heterogeneous media: optimization of parameters of synthesis and preparation of biocomposites based on cellulose esters and cellulose
• Grantee: Bruno Vinícius Manzolli Rodrigues
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)