Determining the opto-mechanical and geometrical properties of high-density polyethylene fibres

A method is described to determine the opto-mechanical and geometrical properties of high-density polyethylene, HDPE, fibres at the same time for the same region from the fibre. Variations of the transverse sectional shapes, areas, optical and mechanical properties of fibres during the cold drawing process were investigated. A rotator-mechanical drawing device was used for rotating the fibre around its longitudinal axis during the cold drawing process. The Pluta polarizing two-beam interference microscope was attached with the rotator-mechanical drawing device for detecting these variations under the interferometer. The rotator-mechanical drawing device permits determining the tensile stress–strain curve, Poisson's ratio and strain optical coefficient for HDPE fibres. Also, it permits determining the refractive index profile of the drawn fibres taking into considering the transverse sectional area and the enclosed area under the fringe shift. The optical orientation factor and orientation angle was calculated for HDPE fibre to clarify the orientation of molecules during the cold drawing process. Microinterferograms are utilized for illustrations.