SH/T 1827-2019Plastics. Determination of crystallinity. X-ray diffraction (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009 this standard was proposed by China Petrochemical Corporation this standard is under the jurisdiction of the Petrochemical Plastic Resin Products Branch of the National Plastics Standardization Technical Committee (SAC/TC15/SC1) Responsible for drafting this standard. China National Petroleum Corporation Petrochemical Research Institute, Beijing Yanshan Petrochemical High-tech Technology Company Limited liability company Participated in the drafting of this standard. Tianjin University, Shanghai Jiaotong University, China Petroleum & Chemical Corporation Beijing Research Institute of Chemical Industry, China Petroleum & Chemical Corporation Zhenhai Refining & Chemical Company, China National Petroleum Corporation Liaoyang Petrochemical Company, Bruker (Beijing) Technology Co., Ltd., Thermo Fisher Scientific (China) Co., Ltd., Dandong Haoyuan Instrument Co., Ltd., Dandong Tongda Technology Co., Ltd.

Co., Ltd., Shanghai Ruoyi New Material Technology Co., Ltd.

1 Scope

This standard specifies the method for determining the crystallinity of polyethylene (PE) and polypropylene (PP) by X-ray diffraction this standard is applicable to the determination of crystallinity of granular or powdered polyethylene and polypropylene (alpha crystal form, beta+alpha crystal form) compression-molded or injection-molded specimens this standard does not apply to the determination of the crystallinity of filled polyethylene and polypropylene Note. The determination of the crystallinity of polyethylene and polypropylene products can refer to this standard. The high ethylene content ethylene-propylene copolymer polypropylene can also refer to this standard.

2 Normative references

The following documents are indispensable for the application of this document. All dated reference documents only the dated version applies to this article the latest version (including all amendments) of undated reference documents is applicable to this document GB/T 1845.2 Plastic Polyethylene (PE) Molding and Extrusion Materials Part 2: Sample Preparation and Performance Determination GB/T 2546.2 Plastic polypropylene (PP) Moulding and extrusion materials Part 2: Sample preparation and performance measurement GB/T 2918 Standard environment for condition adjustment and testing of plastic samples JJG 629-2014 Polycrystalline X-ray Diffractometer

3 Terms and definitions

The following terms and definitions apply to this document 3.1 Crystallinity (X-ray diffraction method) the degree of crystallinity calculated based on the percentage of the contribution of the crystal region in the total area of the X-ray diffraction intensity peaks of the partially crystalline polymer[1]Xc

4 Method summary

The crystallinity of the polymer is proportional to the integrated area of the X-ray diffraction peaks of the crystalline phase. Collect 2theta at an angle of 5° under the specified test conditions.

The copper Kalpha X-ray diffraction data of the sample within the range of 35° is obtained by using the chemometric peak analysis software to obtain the measured crystal plane diffraction peak and amorphous scattering the peak 2theta angle and peak area count value are calculated by the ratio of the sum of the peak area of the crystalline peak and the sum of the sum of the peak area of the amorphous peak.

Kind of crystallinity

5 Reference materials

Powder alpha-SiO2 or Si standard material that meets the technical requirements of JJG 629-2014

6 Equipment

7 Samples

8 Condition adjustment

According to GB/T 2918, the state is adjusted at a temperature of 23°C ± 2°C. The state adjustment time is in accordance with GB/T 1845.2 and GB/T 2546.2.

9 Test procedure

10 Test data processing

11 Precision

In.2018, X-ray diffraction method was carried out to determine the crystallinity of 3 typical PE and 4 typical PP compression molded samples in 8 laboratories.

The precision test of each laboratory repeats the measurement for each sample twice. The precision calculation results are shown in Table 2.

Note 1.The precision of this standard is calculated according to GB/T 6379.2-2004[2], where Sr is the repeatability standard deviation, and SR is the reproducibility standard deviation and r is the repeatability.

Limit R is the limit of reproducibility

Note 2.The samples for the precision test are selected from samples with a crystallinity of 37.8% to 81.2% the test report should include the following.

a) Indicate the reference to this standard.

b) All data and information of the test sample.

c) The working conditions of the instrument.

d) Details of sample preparation, sampling and sample state adjustment, test conditions, etc.

e) Sample size,

f) The test results include the two test results and the arithmetic mean value.

g) Details of any abnormal phenomena observed in the measurement and their descriptions, such as unqualified background, inconsistent crystal form of the sample, etc.

h) Date of analysis, etc.

Appendix A

(Informative appendix) PE and PP (alpha crystal form, beta+alpha crystal form) typical stoichiometry (Pearson-VII) peak shape fitting graph