Detection of necking deformation along polypropylene fibres axis at low draw ratios using multiple-beam microinterferometry

Multi-mode opto-thermo-mechanical stretching system for determination of 3D refractive index along the axis of stretched and/or heated fibres

“…5, values of the distances along the fibre axis were given in steps, each step equal to 3636 mm. The necking region was observed in the region (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) steps, which is equivalent to (36,360-72,720) mm. It is detected as an elevation in the values of the birefringence and narrowing in the cross-section.…”

“…The necking phenomenon can be avoided by controlling the rate of drawing of the fibre. It is recommended to stretch the iPP fibres with slow (step) drawing to avoid the necking deformation [20].…”

Characterization of the 3Dimension optical, geometrical, and mechanical profiles of iPP fiber with necking deformation

“…Necking region can be defined as the region which has large amounts of localized strain in a small region of the sample under study (Bridgman, ; Kinloch & Young, ). Neck is a decrease in local transverse sectional area (Hamza, Belal, Sokkar, El‐ Dessouky, & Yassien, ). Hamza et al () studied the detection of the necking deformation that occurs along polypropylene fibers axis and how to avoid it.…”

“…Neck is a decrease in local transverse sectional area (Hamza, Belal, Sokkar, El‐ Dessouky, & Yassien, ). Hamza et al () studied the detection of the necking deformation that occurs along polypropylene fibers axis and how to avoid it. An insitu‐ opto‐ mechanical device was designed to characterize the different properties of fibers dynamically as a function of strain rates (Sokkar, El‐Tonsy, El‐Bakary, El‐Morsy, & Ali, ).…”

Experimental investigation of craze morphology of isotactic polypropylene using computed tomography

“…Also, molecular orientation increases the modulus and onset of strain hardening (Govaert & Tervoort, ; Hine et al ., ; De Focatiis et al ., ), material anisotropy, the stress at which the craze is initiated (Retting, ; Maestrini & Kramer, ) and the fracture toughness (Broutman & McGarry, ; Curtis, ; Wright et al ., ; Gotham & Scrutton, ; Retting, ; Embery et al ., ). Parallel molecular orientation can be induced by Appling load to the polymeric material parallel to its axial direction (Hamza et al ., , ). Also, it may preexist in the polymeric material due to different fabrication schemes, for example fibre spinning.…”