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本文以对羟基苯甲酸、2,7-萘二酚、对苯二甲酸和少量的聚2,6-萘二甲酸乙二酯为单体制备了一系列具有不同配比的液晶共聚芳酯。用红外光谱法、直接裂解质谱法和裂解气相色谱法鉴定了共聚芳酯的分子链结构,指出共聚芳酯的分子链结构与所加5种单体链节结构基本一致。借助于热重分析仪研究了共聚芳酯的热稳定性及其与分子链结构之间的关系。结果表明:在空气介质中该共聚芳酯开始裂解的最低温度为320℃,裂解反应速度最快时的温度均高于490℃;并且发现,共聚芳酯的分子链结构对热稳定性有较明显的影响,链结构规整性好的共聚芳酯具有较高的热稳定性。实验结果指出,共聚芳酯在空气及氮气介质中的热裂解反应均分两步完成。正像文中的3号样品,空气中的第一步裂解反应在326℃开始发生,第二步裂解反应则发生在540℃左右。本文还探讨了共聚芳酯的热裂解机理。
In this paper, a series of liquid crystal copolyaryl esters with different ratios were prepared using p-hydroxybenzoic acid, 2,7-naphthalenediol, terephthalic acid and a small amount of polyethylene-2,6-naphthalate as monomers. The molecular chain structure of copolyester was identified by infrared spectroscopy, direct cleavage mass spectrometry and pyrolysis gas chromatography. The molecular chain structure of the copolyarylate was basically the same as that of the five monomers. The thermogravimetric analysis was used to investigate the thermal stability of copolyarylate and its relationship with molecular chain structure. The results show that the lowest temperature of the copolyester in the air is 320 ℃ and the temperature of the pyrolysis reaction is faster than 490 ℃. And it is found that the molecular chain structure of the copolyester has more thermal stability Significant effect, good chain structure regularity of copolyarylate ester has high thermal stability. Experimental results show that copolymerization of aromatic esters in air and nitrogen pyrolysis reaction in two steps are completed. Just as sample No. 3 in the text, the first step pyrolysis reaction in the air begins at 326 ° C and the second step cleavage reaction takes place at about 540 ° C. This article also explores the pyrolysis mechanism of copolyaryl esters.