화학공학소재연구정보센터
Journal of Applied Polymer Science, Vol.90, No.12, 3191-3207, 2003
Effect of stabilization on creep crack growth in high-density polyethylene
Polyolefins, particularly polyethylene, are known to fail via crack initiation and crack propagation when exposed to multiaxial long-term static stresses at elevated temperatures. Using concepts of linear elastic fracture mechanics, this article describes and discusses the effects of stabilization on the kinetics of creep crack growth (CCG) in high-density polyethylene (PE-HD) and the failure micro-mechanisms involved. As for the influence of stabilization, six PE-HD formulations (two polymer types, each with three stabilizer systems) were investigated. CCG initiation times and CCG rates were determined at 60 and 80degreesC in distilled water as functions of the crack tip stress field characterized by the stress intensity factor. Although no influence of the stabilizer type was found in either polymer type for CCG initiation times and CCG rates at high crack speeds, significant effects of the added stabilizer type and concentration were detected for low CCG rates. The observed phenomena were explained in terms of local aging processes in the immediate vicinity of the crack tip, which were controlled by the presence and content of various stabilizers. (C) 2003 Wiley Periodicals, Inc.