Method for identifying polyformaldehyde

Abstract

The invention relates to a polyformaldehyde identification method. The method comprises the following steps of S1, preparing a detection solution, putting a sample into a nuclear magnetic tube, and pouring a deuterated reagent added with an internal standard for dissolving; S2, detecting the detection solution by using a nuclear magnetic resonance spectrometer to obtain a nuclear magnetic resonance hydrogen spectrum; and S3, analyzing the hydrogen spectrum, verifying that the chemical shift of the TMS internal standard is 0 ppm, and checking the characteristic peak of the spectrum region with the chemical shift of 1.7-4.88 ppm. According to the method, the technical scheme that the chemical shift of nuclear magnetic resonance hydrogen spectrum analysis is a characteristic peak of a spectrum region of 1.7-4.88 ppm is adopted, so the effect of quickly and efficiently identifying whether the sample is homopolymerized / copolymerized polyformaldehyde or not can be achieved.

Description

technical field [0001] The invention relates to the technical field of identification of polyoxymethylene, in particular to an identification method of polyoxymethylene. Background technique [0002] On October 23, 2017, the Ministry of Commerce issued Announcement No. 61 of 2017, announcing the final ruling on the anti-dumping investigation on imports of polyoxymethylene copolymer originating in South Korea, Thailand and Malaysia. The Ministry of Commerce ruled that the imports of polyoxymethylene copolymer originating in South Korea, Thailand and Malaysia were dumped, China’s domestic industry was substantially damaged, and there was a causal relationship between the dumping and the substantial damage, and decided to impose sanctions on imports originating in South Korea, Thailand and Malaysia. Polyoxymethylene copolymer to take anti-dumping measures. According to the ruling, starting from October 24, 2017, when importing polyoxymethylene copolymer originating in South Ko...

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Problems solved by technology

[0003] However, in the actual inspection process, due to the regeneration process of some imported recycled polyoxymethylene, the molecular chain is broken, the melting temperature is lowered, or the relevant parameters of the homopolyoxymethylene modified by polyurethane will be lower than those in the Ministry of Commerce Announcement No. 61 of 2017 Mentioned: melting temperature is less than 170 degrees Celsius, tensile yield stress is greater than or equal to 58 / 60MPa, nominal strain at break is greater than or equal to 50 / 15%, Charpy notched impact strength is greater than or equal to 5.5 / 4.5 / 3.0kJ / m 2 If you only use the indicators announced in the 2017 Ministry of Commerce Announcement No. 61 to judge whether the sample belongs to polyoxymethylene homopolymer or polyoxymethylene copolymer, it will be a misjudgment, so new methods are needed to identify the relevant structure of polyoxymethylene

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