Effects of different heat-conditions on mechanical performance and structural properties of high density polyethylen materials

Nowadays, materials obtained from polyethylene have an important place. Polyethylene materials used in many areas have an especially significant place in the construction of drinking water pipes. In this study, the mechanical strength formed as a result of keeping the high-density polyethylene (YYPE), which is used most in polyethylene pipe production, under different temperature conditions was examined. 9 tensile samples obtained from the high-density polyethylene pipe according to the standards of TS EN ISO 6259 – 1 and ISO 6259 – 3 were kept in a drying oven at 150°C, 120°C, and 90°C for 40 minutes. Out of the 9 samples which were kept in each degree, 3 were kept in 78°C water for slow cooling; 3 were kept in 0°C icy water for fast cooling; and 3 were kept in -195°C liquid nitrogen for very fast cooling for 3 minutes each. 9 parameters were obtained since 3 temperature conditions were provided in heating and cooling. A total of 27 samples, thus 3 for each parameter, were used. After that, the cooled samples were subjected to tensile testing at the speed of 50 mm/min. The mean average of the 3 samples used for each parameter were taken. At the end of the experiment, the modulus of elasticity, maximum stress and percent elongation which vary according to the temperature conditions were examined.