Relaxation Processes and Structure of Ultradrawn Polyethylene

MARCELO D. FAILLA; JOSÉ M. CARELLA; RAÚL DE MICHELI

JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS

JOHN WILEY & SONS INC

Lugar: New York; Año: 1988 vol. 26 p. 2433 - 2445

0887-6266

Solid-state extruded polyethylene fibers have been prepared, with a wide range of draw ratiosand constant processing temperature. The draw ratios vary from 4 up to 30, and the processingtemperature was always 398 K. The extruded material behaves anisotropically, owing to the highdegree of chain orientation in the drawing direction. The modulus and linear expansion coe5-cienta in the fiber axis direction have been measured, over a wide temperature range, from 140 Kup to 320 K. These two properties are closely related to the degree of structural continuity of thefibers. A fibrous structure model is proposed to explain the temperature effects and the valuesobtained for the modulus and expansion coefficients, in terms of crystallinity and volumetricfraction of extended-chains structure. At least three relaxation processes can be identified whichcaw the structural continuity of the fibers to change with temperature.