聚丙烯树脂等规指数测量不确定度的评定

Evaluation of Uncertainty in Measurement of Isotactic Index of Polypropylene Resin

根据 GB/T 2412—2008《聚丙烯( PP)和丙烯共聚物热塑性塑料等规指数的测定》和 JJF 1059. 1—2012《测量不确定度评定与表示》,针对聚丙烯树脂等规指数的测定过程,分析了不确定度的来源,建立了等规指数测量不确定度的数学模型,计算了测定过程中各试验条件的不确定度分量。通过不确定度分量的量化以及合成,当聚丙烯树脂的等规指数为 98. 42%时,其扩展不确定度为 0. 19%( k = 2)。结果表明,影响聚丙烯树脂等规指数测定的最大因素是试样萃取时的萃取速度,而且,萃取速度稳定在( 20 ± 5)次/h,连续萃取时间大于 6 h 时,试样能够萃取完成。

According to GB/T 2412-2008“Determination of Isotactic Index of Polypropylene ( PP) and Propylene Copolymer Thermoplastic Plastics”and JJF 1059. 1-2012“Evaluation and Representation of Uncertainty in Measurement”, aiming at the determination process of isotactic index of polypropylene resin ,the source of uncertainty was analyzed,the mathematical model of measurement uncertainty of isotactic index was established,and the uncertainty of test conditions in the determination process was calculated. The expanded uncertainty of polypropylene resin was 0. 19%(k = 2),when the isotactic index of polypropylene resin was 98. 42%. The results showed that the maximum factors of affecting the determination of isotactic index of polypropylene resin was sample extraction speed. Therefore,extraction rate should be stable in (20 ± 5) times/h,the continuous extraction time was at least 6 h at the same time. the sample could be extracted effectively.