STUDY OF MASS REDISTRIBUTION ASSOCIATED WITH THE DRAWING PROCESS OF POLYPROPYLENE FIBERS

A fine system for measuring the density of fibres has been constructed. The measuring technique was based on the concept of vibrating strings. Density of polypropylene fibres, originally drawn to known ratios, was measured. The fibre diametre was measured by the laser forward diffraction technique. Behaviour of fibre density at different draw ratios and different molecular orientations was discussed. The bundle model for the polymeric microstructure was recommended in this study in order to explain the mass redistribution associated with the drawing process of the polypropylene fibres. X-ray diffraction technique was used to explain the share of crystalline phase in the mass redistribution process. The applicability of Gladston-Dale equation to mechanically drawn fibres was discussed.