On the relationship between fibre composition and material properties following periodate oxidation and borohydride reduction of lignocellulosic fibres

Periodate oxidation followed by borohydride reduction was performed on four structurally different pulp fibres to clarify the effect of chemical composition on the structural and mechanical properties of sheets made from these fibres. The main purpose was to explore the possibility of extending the use of lignocellulose fibres in novel applications. The degree of oxidation, morphological changes, chemical and physical structure of the fibres, the supramolecular ordering of the cellulose and the mechanical performance of handsheets made from the fibres were studied. The results showed that both periodate oxidation and borohydride reduction are more reactive towards the carbohydrates of the fibres and as a result, there is an improvement in the tensile properties of the sheets. If the carbohydrates of the fibres are only periodate oxidised to produce dialdehydes, inter- and intra-fibre crosslinks can be formed, leading to paper with increase strength and higher stiffness. The borohydride reduction results in fibres and papers with a greater strength and ductility. It was also found that the characteristic ductility of these modified papers, emanating from the dialcohol cellulose produced, is limited with lignin-rich fibres.