Nanocellulose from fractionated sulfite wood pulp

Fine fibre fractions in wood pulp may contribute to advantageous paper properties, but in some instances their removal from pulp may be beneficial to the production process of certain paper grades. In order to study the suitability of fine fibre fractions for the production of nanocellulose as an alternative use option, sulfite pulp was fractionated and homogenised, and cellulose nanopapers were produced. Characterisation revealed that fine fibre fractions were more easily homogenised than long fibres. Aqueous suspensions of nanocellulose produced from fines showed remarkably reduced viscosity compared to nanocellulose derived from long fibres. Nanopapers produced from all nanocellulose variants showed roughly similar mechanical performance. Only nanopaper produced from primary fines-derived nanocellulose deviated in that it showed a comparably high modulus of elasticity at a low strain at failure. Overall, fine fibre fractions separated from wood pulp were found to be highly suitable for nanocellulose production.

Synthesis and characterization of hydrophobic, ultra-fine fibres based on an organic–inorganic nanocomposite containing a polyimide functionality

Ultra-thin polyimide fibres were fabricated by means of the electrospinning method by using precursor solutions consisting of the organotrialkoxysilanes (3-triethoxysilylpropyl)succinic anhydride (TESP-SA), (3-amino)propyltriethoxysilane (APTES), tetraethoxysilane (TEOS) and methyltriethoxysilane (MTEOS). TESP-SA and APTES were reacted to the corresponding poly(amic)acid (PAA) in an aqueous medium which was electrospun at 15 kV and at a tip to collector distance of 15 cm. TEOS and MTEOS were also incorporated into the precursor solution to modify the surface properties of the ultra-fine fibre mat. The fibre diameter distributions of the as-prepared PAA fibres were measured. The PAA fibres were thermally treated at 220°C resulting in the formation of an organic–inorganic hybrid polyimide fibre mat with ladder-like structure, as could be shown by Fourier transform infrared spectroscopy and X-ray powder diffraction. The ultra-fine fibre assemblies were also characterized by means of scanning electron microscopy, thermogravimetric analysis and water contact angle measurements.

Production, properties and processing of American bison (Bison bison) wool grown in southern Australia

American bison grow a thick coat of fibres which assists them to withstand severe climatic conditions. Bison fibre was traditionally used in textiles by native North Americans. This study aimed to quantify the production, fibre attributes and dehairing processing of bison fibre produced from bison grazed in north-eastern Victoria. Three age/sex classes were sampled (n = 16) at seven body positions in spring. The fibre growing area was measured. Fibre was tested for diameter distribution, clean washing yield, proportion of fine fibres <36 µm and fine fibre length, and processed by cashmere dehairing. Bison were 1–2 years of age, liveweights 160–450 kg and had mean fibre growing area of 1.4 m2. They produced an average 1184 g (range 530–1640 g) of fine fibre with mean fibre diameter 18.5 µm, clean washing yield 76.5%, wax content 9.8%, suint content 14.5%, clean fine fibre yield 56.4%, fine fibre length 37 mm and fibre curvature was 93°/mm. Mid-side fibre had a crimp frequency of 6.5/cm and mean resistance to compression of 6.6 kPa. Fibre had a tenacity of 8.7 cN/tex and an extension of 39.3%. Restricted maximum likelihood mixed model analysis showed age/sex class and sampling site significantly affected all fibre attributes. Finer and longer fibre was produced in anterior sites and in younger bison. Fibre curvature declined 5.3°/mm for each 1-µm increase in mean fibre diameter. Dehaired fibre had a mean fibre diameter of 17.8 µm and mid-length of 28 mm, suitable for woollen spinning. The production by bison of coats containing significant amounts of fibre indicates that careful harvesting of fibre could form an important source of income in bison enterprises.