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Uniaxial roll‐drawing of isotactic polypropylene sheet
Author(s) -
Burke P. E.,
Weatherly G. C.,
Woodhams R. T.
Publication year - 1987
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.760270707
Subject(s) - materials science , composite material , tacticity , polypropylene , aramid , ultimate tensile strength , anisotropy , modulus , uniaxial tension , transverse plane , polymer , fiber , structural engineering , physics , engineering , polymerization , quantum mechanics
The process described as “roll‐drawing” has been applied to commercial extruded sheets of isotactic polypropylene (M̄ n = 70,900). Preheated billets were drawn into thin, clear, transparent sheets in a single pass, producing uniaxial orientation of the polymer molecules in the draw direction. At the maximum draw ratio of 20, the ultimate tensile strength and Young's modulus in the draw direction were 0.5 GPa and 20 GPa respectively. The mechanical properties transverse to the draw direction were virtually unchanged. The theory of fiber reinforcement for unidirectional anisotropic plates was applied to interpret the orientation dependence of the stress‐strain behavior of the drawn sheets. From these results, it was estimated that the mechanical properties of biaxially laminated polypropylene sheets equaled the performance of aramid and carbon fiber composites, The roll‐drawing process appears to be economically attractive for the production of ultra‐high modulus crystalline thermoplastics in sheet form having excellent uniaxial or biaxial properties.