Method for measuring thermal stability of polyformaldehyde

A measurement method and thermal stability technology, applied in chemical analysis by titration, etc., can solve problems such as inability to directly reflect the decomposition of polyoxymethylene

Inactive Publication Date: 2012-07-04
上海蓝星聚甲醛有限公司
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Problems solved by technology

[0004] In order to overcome the thermal stability measurement of polyoxymethylene in the prior art, the defect that cannot directly reflect the concrete decomposition situation of polyoxymethylene, the purpose of the present invention is to provide a kind of thermal stability determination method of polyoxymethylene

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  • Method for measuring thermal stability of polyformaldehyde
  • Method for measuring thermal stability of polyformaldehyde
  • Method for measuring thermal stability of polyformaldehyde

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Embodiment

[0035] 1. Heat up the heating oil bath of the reaction device. The temperature of the oil bath is strictly controlled at 223±2°C. Before putting in the test sample, it needs to be kept warm for 20 minutes until the temperature is stable before the test can be started. When the heat preservation is started, the nitrogen valve is opened, and the nitrogen flow rate Control it at 1000±2ml / min to completely discharge the air in the reaction device.

[0036] 2. Prepare a sodium sulfite solution with a concentration of 0.05N and a sulfuric acid standard titration solution with a concentration of 0.05N. Take 200ml of sodium sulfite solution with a 250ml beaker, add a small amount of formaldehyde solution therein, because sodium sulfite and formaldehyde generate sodium hydroxide, the pH value of the sodium sulfite solution rises to more than 10 (rough test), then use sulfuric acid titration solution to titrate, finally The pH of the sodium sulfite solution was adjusted to 9.20.

[003...

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Abstract

The invention relates to a method for measuring thermal stability of polyformaldehyde, which includes the following steps: the polyformaldehyde is heated and smelted; the formaldehyde gas generated by resolving is brought out by the fed-in inertia carrier gas, so as to be fed in the sodium sulfite solution; the formaldehyde gas is absorbed by the sodium sulfite solution to generate sodium hydroxide, and sodium hydroxide is generated by titration reaction of sulfuric acid titration liquid; and the quantity of formaldehyde gas can be calculated through conversion as per the consumption amount of sulfuric acid, so as to analyze the thermal stability of polyformaldehyde. The technical scheme provided by the invention provides the simple, convenient and feasible method for measuring thermal stability of polyformaldehyde, can be used for confirming the formaldehyde content generated after the pyrolysis of polyformaldehyde through titration, and can visually reflect the resolving rate of polyformaldehyde and the specific condition of resolving at different time ranges, thereby obtaining more accurate thermal stability of the polyformaldehyde, and providing accurate reference to the follow-up processing.

Description

technical field [0001] The invention relates to the field of performance measurement of polyoxymethylene, in particular to measuring the thermal stability of polyoxymethylene by a titration method. Background technique [0002] POM products (mainly in the form of powder and pellets) contain a certain amount of free formaldehyde and some unstable terminal groups. During post-processing and subsequent processing, free formaldehyde will be released if heated, and unstable terminal groups and polymer backbones will also decompose to release formaldehyde gas. The amount of POM decomposition directly determines the thermal stability of POM powder and pellet products, and also determines the processing performance of POM products. [0003] At present, the thermal stability of polyoxymethylene is measured by the thermal weight loss of polyoxymethylene, but this method can only obtain the absolute decomposition amount of polyoxymethylene, and cannot distinguish the amount of free fo...

Claims

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Application Information

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IPC IPC(8): G01N31/16
Inventor 朱培红
Owner 上海蓝星聚甲醛有限公司
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