给水用PP-R管材熔融温度不确定度评定

Uncertainty Evaluation of Melting Temperature of PP-R Pipe for Water Supply

通过差示扫描量热仪测定了给水用无规共聚聚丙烯(PP-R)管材的熔融温度。研究了仪器校准、校准温度用标准物质铟、测试重复性、测试结果数值修约等4个方面对熔融温度不确定度评定的影响,分析了样品质量对熔融温度测定的影响。结果表明:测试重复性引入的不确定度占比最多,其次是测量仪器校准和测试结果数值修约,校准温度用标准物质铟引入的不确定度占比最少;与5.0 mg样品相比,10.0 mg样品的熔融温度更高,熔融温度不确定度更低,所以样品质量尽量接近10.0 mg。

The melting temperature of random copolymerized polypropylene(PP-R)pipes for water supply was measured by differential scanning calorimetry.The effects of instrument calibration,standard material indium used for temperature calibration,test repeatability and numerical rounding of test results on the evaluation of uncertainty in melting temperature were studied,and the influence of sample quality on melting temperature measurement was analyzed.The results show that the proportion of uncertainty introduced by test repeatability is the highest,followed by the calibration of measuring instruments and numerical rounding of test results.The proportion of uncertainty introduced by the calibration temperature standard material indium is the lowest.Compared to the 5.0 mg sample,the 10.0 mg sample has a higher melting temperature and lower uncertainty in melting temperature,so the sample quality should be as close as possible to 10.0 mg.