GB/T 34247.2-2018Determination of the unsaturation of isobutene-isoprene rubber—Part 2:1H-NMR method (English PDF)

Foreword

GB/T 34247 "Isobutylene-isoprene rubber (IIR) unsaturation determination" is divided into two parts.

--- Part 1. Iodometric method;

--- Part 2. Nuclear magnetic resonance spectroscopy.

This part is the second part of GB/T 34247.

This part is drafted in accordance with the rules given in GB/T 1.1-2009.

1 Scope

This part of GB/T 34247 specifies the determination of isobutylene-isoprene rubber by nuclear magnetic resonance spectroscopy [commonly known as butyl rubber (IIR)] Method of unsaturation. This section applies to IIR raw rubber.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 6379.2 Accuracy of measurement methods and results (accuracy and precision) Part 2. Determining Basic method of sex and reproducibility

GB/T 15340 natural and synthetic raw rubber sampling and its sample preparation method

3 Method summary

A certain amount of IIR sample is dissolved in deuterated chloroform, and the nuclear magnetic resonance spectrum of the sample is measured under the specified parameters to obtain a different The peak area of different protons in the structure of pentadiene and isobutylene. Through the chemical shift of the protons in different chemical environments and the integral area value Determine the degree of unsaturation of the IIR.

4 Reagents

Deuterated chloroform (CDCl3). purity greater than 99.8% (molar fraction), containing 0.03% (volume fraction) of tetramethylsilane (TMS) as internal Standard, NMR grade.

5 Instruments and equipment

5.1 Nuclear magnetic resonance spectrometer. Fourier transform nuclear magnetic resonance spectrometer (FT-NMR) with a frequency of 400 MHz or higher.

5.2 Analytical balance. can be accurate to 0.1mg.

5.3 Sample tube. 5mm outer diameter.