Melting Behaviour of Polypropylene Fibres Studied by Differential Scanning Calorimetry
| Title |
Melting Behaviour of Polypropylene Fibres Studied by Differential Scanning Calorimetry |
| Publication year |
1995 |
| Language |
English |
| Author |
Andreassen, Erik |
| Co-Authors |
Grøstad, Kristin - Hinrichsen, Einar L. - Braathen, Marianne Dale - Syre, Anne Mari Vardenar - Myhre, Ole Jan (Norner) - Løvgren, Tor Bertel (Norner) |
| Source |
Journal of Applied Polymer Science, 57(9), 1995, 1075-1084 |
| Abstract |
Polypropylene fibres produced in a compact-spinning process were studied by differential scanning calorimetry (DSC). With unrestrained fibres, the onset of melting increases with decreasing draw ratio, increasing Mw/Mn, decreasing extrusion temperature, increasing annealing ratio and increasing draw-down ratio. These trends are discussed in terms of restraints and reorganisation. The onset of melting is shifted to lower temperatures as the heating rate increases for all combinations of material and processing parameters, indicating suppressed reorganisation. At low draw ratios, the height and width of the endotherm are affected by the spinline stress, and a secondary peak or shoulder is observed on the high temperature side of the main peak. The magnitude of the secondary peak increases with decreasing Mw/Mn, increasing draw ratio, decreasing draw-down ratio and decreasing heating rate, but its position mainly depends on the heating rate. This indicates that the secondary peak may be due to the melting of structures that have been reorganised during the heating scan. As the draw ratio increases, the melting regime broadens, especially towards lower temperatures, and several maxima emerge on the DSC curve. Reorganisation and shrinkage during heating may explain these observations. |