Shapeable cellulosic materials

Licentiate thesis, 2013

ABSTRACT A palette of materials has been developed by the oil and gas sector. The expected depletion of fossil resources and the stress on the climate from burning them has, however, turned the world’s attention to renewable resources. To develop competitive high quality products from renewable resources, is indeed a challenge for the research community. Cellulose is a renewable material with a variety of properties depending on source, processing and other modifications. In liquid food packaging the cellulose-based carton is combined with plastics to make the package impermeable to water. The production of carton packages with a shapeable cellulosic material would be an interesting way to enhance its function, reduce the amount of fossil-based material in it and to make it more competitive towards plastic bottles. In this work, cellulose was made shapeable through blending with moldable polyethene. Esterified cellulose was used in order to increase the interfacial adhesion and the dispersion of cellulose in composites. Esters with various hydrophobicities, carbonyl hydrogen-bonding and degree of substitution were prepared. It was concluded that the fiber dispersion in the composites could be both improved and impaired by the esterification. Moreover, the eventual benefits of esterification on the interfacial adhesion, was counteracted by weakening and fragmentation of the fibers because of the chemical treatment and the mechanical processing. Cellulose was also made shapeable through coagulation of the cellulose-ionic liquid solutions with a coagulation agent (e.g. water), to obtain shapeable three-component gels. The strength, the stiffness and the thermal degradation, were found to depend on the types and amounts of the gel constituents. By regeneration of cellulose, from the gels, stiff regenerated cellulose was obtained.