In this paper, the stability of POM and the effect of stabilizer on the modification of polyoxymethylene was studied。 Mainly through the addition of different stabilizers in POM to study the stability of different stabilizers on the stability of POM。 In this experiment, TPU were used as the stabilizer to be studied。 POM were blended separately to obtain different polyoxymethylene system。 The main experimental content is to study the thermal degradation process of three different polyoxymethylene mixtures (POM, TPU, POM / TPU), and to estimate the effect of TPU on the reaction mechanism and stability of POM, the addition of TPU in the experiment was 5%。 The reaction conditions were that the temperature was raised from 40 °C to 500 °C at a rate of 10 °C/min in a nitrogen atmosphere and the mass fraction and infrared spectrum of the corresponding polyformaldehyde were measured at different temperatures。 TG-FTIR diagram was analyzed in order to study the stability of different POM system。

The main research contents include:

(1) Thermogravimetric analysis: The TGA curve was obtained by TG diagram。 The change of the mass of the polyoxymethylene system with temperature was analyzed by TG and TGA。 And the temperature at which the decomposition start temperature, the end temperature and the decomposition rate are maximized are determined。 The effect of the stabilizer on the stability of the polyoxymethylene system was obtained by comparing the addition of the stabilizer system, the blank POM system and the blank TPU system。

It can be seen from the results: When the TPU as a stabilizer, compared to the blank sample, the system began to increase the degradation of the initial temperature, and degradation of the end of the temperature is not significant。 And the effect on the maximum degradation rate is small, and the overall mass loss curve is similar to that of the blank sample。 From here we can see that TPU as a stabilizer on the stability of POM is not very satisfactory。

(2) TG-FTIR combination: The degradation process of POM can be pided into several stages by TG and DTG curves。 The infrared spectra of the   polyoxymethylene

system at different temperatures were obtained by recording the absorbance of different POMs at different wavelengths。 By analyzing the infrared spectrum at a particular temperature in a given stage, the degradation product of POM at this temperature can be obtained。 So that the decomposition of POM at this stage can be analyzed。 By analyzing and comparing the infrared spectra of polyoxymethylene products at multiple temperatures, the decomposition state and decomposition mode of polyoxymethylene in the whole reaction process under nitrogen atmosphere can be obtained。

Finally, the infrared spectra of polyoxymethylene at all temperatures can be obtained。 The three-dimensional image of polyoxymethylene can be obtained by the stereogram。 From that we can see the change of the absorbance of different wavelength position with the temperature。

毕业论文关键词：聚甲醛；TPU；热降解；稳定化；TGA-FTIR

Keyword: Polyoxymethylene; TPU; Thermal degradation; Stabilization; TGA-FTIR

目录

1 绪论 1

1。1 聚甲醛概述 1

1。2 国内外聚甲醛源Q于D优G尔X论V文Y网wwW.yOueRw.com 原文+QQ75201`8766 的生产与开发 2

1。3 聚甲醛的种类与性能 3

1。4 聚甲醛的热降解机理 5

1。5