Melt-blowing is a technique of producing a nonwoven web of microfibres directly from polymer form to web form. Until now, this production method has been used almost exclusively with thermoplastic resins to produce webs suitable for filtration, insulation or absorption because of the small diameter of the fibres. It is known that for thermoplastics, equipment variables, process conditions, as well as selected raw material characteristics (e.g. molecular weight) have a significant influence on fibre diameter. However, much less is known on the influence of such variables on the melt-blowing of non-thermoplastic materials, such as cellulose solutions.
Recently, the melt-blowing of lyocell solutions and the influence of selected process parameters have been reported. It has been shown that some process parameters affect the fibre fineness significantly but till now, no report is yet available on how the solution characteristics may influence the eventual fibre size in this new way of processing lyocell fibres. In this paper, the influence of some solution characteristics on melt-blown fibre fineness is reported. A 33 factorial experimental design was used to produce solutions having different cellulose content, average degree of polymerisation and molecular weight distributions. A total of 27 solutions were hence produced by dissolving wood pulp into N-methyl morpholine-N-oxide. The solutions were characterised and melt-blown under fixed process conditions. The average fibre fineness was then obtained for each sample produced.
The results show that the cellulose content and the average degree of polymerisation have significant effects on the fibre fineness. As these two parameters are increased, a corresponding increase in fibre fineness can be noticed. By contrast, the influence of molecular weight distribution on fibre fineness is not as pronounced or systematic. The results are interesting and promising, particularly since extremely fine fibr
By: S. Lam Po Tang and S. K. Mukhopadhyay
University of Leeds School of Textiles and Design, Leeds LS2
Submit Date: 6/7/2010 18:00