Authors: C J Luo E Stride S Stoyanov E Pelan M Edirisinghe
Publish Date: 2011/08/20
Volume: 18, Issue: 6, Pages: 2515-2522
Abstract
Ultra fine short fibres have a variety of applications Short aligned fibres or a mixture of short and long fibres can reinforce brittle materials alter the appearance texture and durability of synthetic fibres and adjust the strength toughness and stiffness of a composite material Among electrospun products short fibres are usually produced by secondary processing of continuous asspun fibres However this is not entirely straightforward or costeffective due to the efficiency of the secondary process and the relatively low tensile strength of the electrospun ultrafine fibres Besides submicrometre size fibres with an average aspect ratio AR 200 have not been directly produced without further processing by changing collector geometry in electrospinning Using a model polymer polymethylsilsesquioxane PMSQ short microfibres with 10 AR 200 were electrospun directly in this work ie without the need for a secondary process The AR and particularly fibre length were shown to be strongly influenced by the solvent system used for electrospinning and the molecular weight overline M w of the polymer When using PMSQ1 overline M w =7500 in methanol instead of acetone short fibres with AR 200 were produced instead of continuous fibres Moreover when overline M w of the polymer was decreased from 7500 PMSQ1 to 4300 PMSQ2 with all other conditions kept constant significant reduction in the AR of the asspun fibres was observed Short fibres with average AR of 15 were produced from PMSQ2 solution in 32 v/v dimethylsulphoxide2nitropropane The average AR of short fibres spun from PMSQ2 solution in 23 v/v methanolpropanol was 31 Also PMSQ1 in both of the abovementioned binary solvent systems produced long continuous fibres with AR 3000 under the same spinning conditions
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