关键词: 滴灌带, 人工紫外老化, 热老化, 氧化诱导时间, 保持率

Abstract: An artificial accelerated UV aging experiment and a thermal aging test at 50 ℃ were carried out on a drip tap. The changes in oxidation induction time （OIT）， melting temperature （Tm）， tensile strength （σm）， tensile fracture strain （εm）， melt flow rate （MFR）， and carbon black content （c） before and after aging were investigated. The changes of flow uniformity， burst pressure， water pressure resistance， drawing resistance， and sediment blockage resistance hydraulics after thermal aging at 50 ℃ as well as their accordance with national standards were also studied. The results indicated that the variation range of performance indexes of the drip tape after the accelerated UV aging was significantly greater than that after the thermal aging at 50 ℃， especially fir OIT. After aging for 624 h， the OIT obtained from artificial accelerated UV aging was 4.25 times the decrement rate of that from the thermal aging at 50 ℃. The σm， εm， c， Tm and MFR from the artificial accelerated UV aging are 1.24， 1.17， 1.11， 1.02 and 1.01 times as decrement rates of those from the thermal aging at 50 ℃， respectively. The changes in the retention rates of OIT， σm， εm and c of the drip tape were very significant after the accelerated UV aging. After thermal aging at 50 ℃， the change in the OIT retention rate was greater than that of other indexes. The hydraulic performance was less influenced by the thermal aging at 50 ℃， which could meet the requirement of the national standard for the 624 h aging. As for the OIT of no more than 5 minutes in the national standard， the retention rate of σm reaches a failure level at 21 %. Therefore， the OIT of drip tapes should not be less than 1.05 min to avoid the invalidation of practical use.

Key words: drip tape, artificial accelerated ultraviolet aging, thermal aging, oxidation induction time, retention rate