尼龙66无氧热降解交联行为的研究

发布时间：2018-05-13 14:31

  本文选题：尼龙66 + 热降解　； 参考：《东华大学》2017年硕士论文

【摘要】：尼龙66(PA66)热稳定性差,无氧条件下也易在熔点以上的温度发生热降解反应,并伴有交联反应。交联反应会进一步生成凝胶,会影响PA66工业化生产中的管道运输以及后续的纺丝工作,给企业造成经济损失。因为凝胶的产生是PA66无氧热降解过程中的一个伴随反应,所以要达到抑制凝胶产生的目的,必须对PA66无氧热降解的反应过程和机理进行研究。国内外对无氧热降解机理有较为深入的研究,但对抑制凝胶产生的研究较少。本文首先对PA66在热降解过程中结构以及热性能的变化进行了测试和分析。然后研究了不同受阻胺对PA66热处理过程中凝胶含量、热性能和结构变化的影响。最后通过原位聚合制备含有受阻胺的PA66以及PA66和PA6T共聚产物PA6AT,对制备的产物进行了结构的表征,测试了凝胶含量以及热性能随热处理时间的变化。主要研究内容如下:(1)随着热处理时间的增加,凝胶含量先缓慢增长,到达一定时间后,凝胶含量迅速增加,最后增长速度逐渐变慢。热处理过程中PA66样品中的酰胺键浓度降低,生成末端氨基和含有环戊酮基团的物质,末端氨基也进一步发生了反应。PA66的熔融峰温度和结晶峰温度随着热处理时间的延长逐渐向低温方向移动,说明随热处理时间延长,PA66晶体稳定性下降,结晶困难。(2)使用熔融共混的方法制备了PA66/受阻胺A(PA66/HAA)、PA66/受阻胺B(PA66/HAB)和PA66/受阻胺C(PA66/HAC)。在相同热处理时间内,PA66/HAA和PA66/HAB的凝胶含量均低于PA66,其中PA66/HAA的凝胶含量最低,而PA66/HAC的凝胶含量比PA66高。热处理后的PA66/HAA和PA66/HAB的熔融峰温度和结晶峰温度下降幅度均小于PA66。而热处理6h的PA66/HAC的熔融峰温度和结晶峰温度下降幅度大于PA66。(3)制备了PA6T盐,然后通过聚合的方式制备了PA66、PA66/HAA、PA66/HAB和PA6AT。确认了PA6T盐的结构以及PA6AT是由PA66盐和PA6T盐共聚制备的。在相同热处理时间内,聚合制备的PA66/HAA和PA66/HAB的凝胶含量仍低于PA66,且PA66/HAA效果最好。制备的PA6T质量分数为10%的PA6AT的凝胶含量比PA66高。未热处理的PA66/HAA、PA66/HAB和PA6AT的熔融峰温度分别比PA66低了0.1℃、1.1℃和2.9℃。热处理6h后,PA66/HAA、PA66/HAB的熔融峰温度和结晶峰温度向低温方向的偏移量比PA66小,其中PA66/HAA最小。热处理6h后PA6AT的熔融峰温度和结晶峰温度向低温方向偏移最大。
[Abstract]:The thermal stability of nylon 66 / PA66 is poor, and the thermal degradation reaction is easy to occur at the temperature above the melting point in the absence of oxygen, accompanied by crosslinking reaction. The crosslinking reaction will further produce gels, which will affect the pipeline transportation and subsequent spinning in the industrial production of PA66, and cause economic losses to the enterprises. Because the production of gel is an accompanying reaction in the process of anaerobic thermal degradation of PA66, it is necessary to study the reaction process and mechanism of anaerobic thermal degradation of PA66 in order to inhibit the formation of PA66. The mechanism of anaerobic thermal degradation has been studied deeply at home and abroad, but little research has been done on the inhibition of gel production. In this paper, the structure and thermal properties of PA66 during thermal degradation were tested and analyzed. The effects of different hindered amines on the gel content, thermal properties and structure of PA66 during heat treatment were studied. Finally, PA66 containing hindered amine and PA6ATs of PA66 and PA6T were prepared by in-situ polymerization. The structure of the prepared products was characterized and the changes of gel content and thermal properties with heat treatment time were tested. The main contents of the study are as follows: (1) with the increase of heat treatment time, the gel content increases slowly at first, after a certain time, the gel content increases rapidly, and finally the growth rate becomes slower. During heat treatment, the concentration of amide bonds in PA66 samples decreases to form terminal amino groups and substances containing cyclopentanone groups. The melting peak temperature and crystallization peak temperature of reaction .PA66 moved gradually to low temperature with the prolongation of heat treatment time, which indicated that the crystal stability decreased with the prolongation of heat treatment time. The PA66/ hindered amine APA66 / Ha-PA66 / PA66/ hindered amine CPA66 / HAB2 were prepared by melt-blending method. The gel content of PA66% HAA and PA66/HAB was lower than that of PA66 at the same heat treatment time, and the gel content of PA66/HAA was the lowest, while that of PA66/HAC was higher than that of PA66. The melting peak temperature and crystallization peak temperature of PA66/HAA and PA66/HAB decreased less than that of PA66 after heat treatment. However, the melting peak temperature and crystallization peak temperature of PA66/HAC after 6 h heat treatment decreased more than that of PA66. (3) PA6T salt was prepared, and then PA66 / PA66 / HAA PA66 / HAPA 66 / HAB and PA6ATs were prepared by polymerization. The structure of PA6T salt and the preparation of PA6AT by copolymerization of PA66 salt and PA6T salt were confirmed. The gel content of PA66/HAA and PA66/HAB prepared by polymerization is still lower than that of PA66 in the same heat treatment time, and PA66/HAA is the best. The gel content of PA6AT with 10% PA6T was higher than that of PA66. The melting peak temperatures of PA66 / HA / PA66 / HAB and PA6AT were 0.1 鈩，

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