参加塑料氧化诱导时间能力验证试验结果与分析

Proficiency Testing Results and Analysis of Plastic Oxidation Induction Time

能力验证是国际通行的实验室质量控制方法之一,对评判实验室检测能力和技术水平具有不可替代的作用。本试验室参加CNAS PT0017能力验证,采用GB/T 19466.3-2004测定塑料的熔融温度,结果满意。采用GB/T19466.6-2009测定塑料氧化诱导时间,结果偏长。该文对塑料氧化诱导时间能力验证(CNAS PT0017)不满意结果进行了多方面的原因排查,考察了温度准确度、氧气纯度等对测定结果的影响,造成结果偏长的原因是炉子中氧气纯度不够造成的,具体是DSC盖子不在炉子中心,氮气进入炉子中,导致氧气纯度下降,进行试验验证,并及时采取了纠正措施。

Proficiency testing is one of the most popular methods of laboratory quality control in the world.It plays an irreplaceable role in judging laboratory testing ability and technical level.The laboratory participated in the proficiency testing of CNAS PT0017.The melting temperature of plastics was determined by GB/T 19466.3-2004 with satisfactory results.The plastic oxidation induction time was determined by GB/T 19466.6-2009 and the results were longer.In this paper,the reasons for unsatisfactory results of CNAS PT0017 were investigated including the effects of temperature accuracy and oxygen purity on the results.The reason was that the oxygen purity in the furnace was not enough.The DSC cover was not in the center of the furnace,and nitrogen entered the furnace,which resulted in the decrease of oxygen purity.The experimental verification was carried out and the corrective action were taken in time.