ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Preoriented isotactic polypropylene was used to clarify the molecular process in zone-drawing with which the necking part is confined in a thin heating zone during uniaxial drawing. The process was analyzed on the basis of rate process, the mechanical properties of zone-drawn samples, and the superstructural change during zone-drawing. The values of activation energy for deformation, ΔH*, and the activation volume, ΔV*, were affected by the deformation mechanisms preferentially taking place during the zone-drawing. The attainable maximum modulus of zone-drawn sample at θ = 45° was larger than those at θ = 0° and 90°. The highest strength was also obtained at θ = 45°. The values of modulus and strength strongly depended on both the orientation function of the crystal c-axis and the orientation function of amorphous chains. In the region of a very high zone-drawing rate, in which microcracks are preferentially formed, both modulus and strength decreased, whereas they increased with increasing the zone-drawing rate below this region, giving the optimum condition for achieving the maxima in the modulus and strength.
Additional Material:
13 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1982.070270621
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