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On the physical behavior of isotactic polypropylene fibers extruded at different draw‐down ratios. I. Optical properties and cold‐drawing
Author(s) -
ElDessouky Hassan M.,
Mahmoudi Mohammad R.,
Lawrence Carl A.,
Yassien Khaled M.,
Sokkar Taha Z.N.,
Hamza Ahmed A.
Publication year - 2009
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.21449
Subject(s) - materials science , birefringence , tacticity , optical microscope , composite material , polypropylene , refractive index , microscope , scanning electron microscope , optics , polymer , polymerization , optoelectronics , physics
As spun polypropylene fibers (iPP) with different draw‐down ratios (DDR) were produced at increasing take‐up speeds ranging from 200 m/min to 1000 min. Two interferometric techniques (Pluta and Interphako microscopes) were used to investigate the refractive indices and birefringence of the spun fibers. The use of the Interphako microscope enabled all the fiber diameters to be studied and avoid image overlap (Sokkar et al., Opt. Lasers Eng. , 45 , 431 (2007)). Previously reported software (Sokkar et al., Opt. Lasers Eng. , 45 , 431 (2007), Hamza et al., J. Appl. Polym. Sci. , 77 , 3099 (2000)) was used to determine the refractive index profiles for PP fibers at different DDR. An optothermomechanical (OTM) (Hamza et al., J. Appl. Polym. Sci. , 95 , 647 (2005)). device attached to the Pluta microscope was used to examine the drawability of the melt‐spun iPP fibers by cold‐drawing. The work is concerned with the importance of the difference between physical effects of DDR and DR. The influence of DDR on the relation between optical properties and solid state draw ratio (DR) was determined. The fibers spun at low DDR give high‐maximum draw ratio (DR max ) and higher birefringence (Δ n ) than those of higher DDR. Total attenuation ratio (TAR) of the melt‐spun iPP fibers was defined and calculated. The minimum (theoretical) birefringence (Δ n min ) and maximum (measurable) birefringence (Δ n max ) of iPP fibers were determined. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers