Ultrasonic measurements of the elastic stiffness constants of oriented polyethylene

摘要: Abstract High density polyethylene (Rigidex 9), a high copolymer of and poly(butene-1) 2000), low (Alkathene WJG 11) were oriented by hot drawing. The crystalline texture, as determined wide- low-angle X-ray diffraction, was highly chain axis in the draw direction with random orientation transversely lamellae surfaces perpendicular to direction. Elastic stiffness constants measured contact-probe ultrasonic pulse technique at 2.5 MHz both before after annealing temperature range which did not significantly alter texture. Assuming orthorhombic symmetry nine Rigidex 2000 three longitudinal shear 9 drawing subsequent annealing. Only Alkathene measured, waves could be transmitted. markedly affected annealing, while texture remained substantially unchanged; comparison other showed little change. Drawn reached tensile modulus 69 GPa. results are compared ‘static’ frequency measurements reported literature.