The physicochemical properties of cellulose surfaces modified with (depolymerised) suberin and suberin fatty acid

Abstract This paper provides evidence for the adsorption of suberin onto cellulose and illustrates the effect of suberin and suberin fatty acid (SFA) treatment on the physicochemical surface properties of the modified cellulose substrate. Suberin and SFA were extracted from the outer bark of birch (Betula pendula Roth) and characterized by Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry (GC–MS). The results confirmed the extracts to comprise primarily of depolymerised suberin and SFA. The adsorption of suberin and SFA on cellulose was studied by treating the filter paper with solutions of suberin and SFA. Changes in the surface topography of the filter paper following treatment were analysed with atomic force microscopy and the effect on wettability assessed through contact angle measurement. X-ray photoelectron spectroscopy analysis showed that the cellulose substrate was evenly covered. GC–MS analysis showed which suberin monomers were preferentially adsorbed on the cellulose surfaces. Based on these results, it can be inferred that suberin and SFA have the potential for cellulose surface modification. This finding supports the view that suberin and SFA could be used to improve the interfacial properties of cellulose fibre reinforced composites. The novelty in this study is that it provides detailed information, derived though advanced experimental techniques, about the manner and mechanisms behind changes in surface physiochemical properties of cellulose obtained through suberin and SFA adsorption.