In this paper the structural properties of polypropylene (PP) nanofibres fabricated by meltblowing
process by injecting fluids such as air and water at different flow rates in an extruder during meltblowing have been
discussed. The nanofibres were characterised by differential scanning calorimetry (DSC), thermo gravimetric
analysis (TGA), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR). DSC results indicated that the
PP polymer and the as-spun fibres (fabricated without any fluid) exhibited a higher melting point than the nanofibres.
The lowering of the melting endotherm indicated a change of the crystalline phase which may be due to the thermal
degradation caused by the higher temperature during meltblowing. This was verified by thermo gravimetric analysis
(TGA) which showed that the PP polymer and as-spun fibres have higher thermal stability (indicated by the weight
loss starting at higher temperature) compared to the nanofibres. The XRD results indicated that the nanofibres
possess relatively lower and broader peaks compared to the higher and sharper peaks of PP polymer and as-spun
fibres. This indicated that the nanofibres have a very low degree of crystallinity, which could be due to the rapid
cooling after exiting the die allowing limited time for crystal formation. NMR results showed that the nanofibres
fabricated with the fluids do not change in molecular structure.
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