炭黑分散度检测标准GB/T 18251应用过程中遇到的问题浅析

主要对GB/T 18251—2019《聚烯烃管材、管件和混合料中颜料或炭黑分散度的测定》标准中给出的炭黑分散度检测过程中试样厚度范围、厚度测量方法及切片法中试样形状、试样幅宽、试样制备过程中遇到的问题做了讨论研究。试样厚度是制备试样的一个重要参数，标准中未给出具体测量方法，应予以补充，建议采用显微镜测量法。标准中给出的炭黑分散度试样厚度范围（20±10）μm不合适，实际检测过程中发现能用于试验的试样厚度小于10μm。标准中未给出切片法制备试样的形状和幅宽，建议使用正方形试样，幅宽4 mm，切片过程中可能会遇到无法切到指定厚度范围的试样，可以采用低温冷冻后再切样的办法解决。

Analysis of problems encountered in the application of carbon black dispersion test standard GB/T 18251

The assessment method of the degree of pigment or carbon black dispersion in polyolefin pipes， fittings， and compounds based on the Chinese national standard GB/T 18251—2019 is the current standard method for measuring the dispersion of carbon black in plastic pipes. This paper mainly discusses the thickness range of samples， thickness measurement method， and the sample shape， width， and problems encountered in sample preparation through a slicing method in the process of carbon black dispersion measurement based on this standard. The thickness of the sample was an important parameter for the preparation of samples. The specific measurement method was not given in the current standard and therefore should be supplemented. The microscope measurement method was recommended for use. The thickness range （20±10） μm of carbon black dispersion sample presented in the standard is not suitable. It was found that the thickness of the sample used for the test should be less than 10 μm. The standard does not give the shape and width of the sample prepared by using a slicing method. A square sample with a width of 4 mm was recommended for use. During the slicing process， the sample could be cut to the specified thickness range. This encountered problem could be solved through cutting the sample after low?temperature freezing.