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毕业论文网 > 毕业论文 > 材料类 > 高分子材料与工程 > 正文

温度对衰减链转移聚合的影响毕业论文

 2022-03-30 20:44:52  

论文总字数:15680字

摘 要

本文一开始对衰减链转移聚合,普通的链转移自由基聚合,活性衰减链转移聚合,衰减链转移聚合的发展稍稍总结和描述,并翻阅了相关论文和期刊。最后,简述了MMA衰减链转移聚合研究意义。

链引发再增长速率lt;链增长速率;链终止速率lt;链转移速率;符合以上为衰减链转移。在偶氮二异丁氰引发的甲基丙烯酸甲酯自由基反应体系中放入一定烷基碘,成功使得体系转变为衰减链转移反应体系。使用GPC测定的Mn和相关数据算出的分子链数目与正常链转移聚合体系一起比对。在MMA本体聚合中发现聚合前期也出现了活性衰减链转移,但是后期由于烷基碘被包埋,使得聚合后期只有正常的链转移的聚合。

由自由基聚合动力学可知其影响衰减链转移的因素有引发剂浓度,单体浓度,温度。

相比较正常自由基聚合体系来说随着温度的提升大分子链生成速率越快,聚合度则越来越迅速。为了探究温度对衰减链转移的影响,设定不同的温度下进行聚合反应,通过测定聚合的分子量或分子量分布系数Mw/Mn来反应不同的温度对衰减链转移的影响。通过改变温度来体现温度对衰减链转移的影响,并计算相应的活化能。

关键词:衰减链转移;自由基聚合;甲基丙烯酸甲酯;碘仿

Effect of Temperatures on the Degenerative Transfer Polymerization

Abstract

This paper begins with a summary and description of the decay chain transfer polymerization, ordinary chain transfer radical polymerization, activity decay chain transfer polymerization, and the development of decay chain transfer polymerization, and read the relevant papers and journals. Finally, the significance of the study on the decay chain transfer polymerization of methyl methacrylate was introduced.

Chain initiation rate of re growth lt; chain growth rate; chain termination rate lt; chain transfer rate; in line with the above for attenuation chain transfer. In the free radical polymerization of Methyl Methacrylate Initiated by azo two, the system is put into a certain alkyl iodide, which makes the system transform into a decay chain transfer polymerization system. Compared with the normal chain transfer polymerization system, the molecular weight and the theory calculated by GPC were compared. Found in the bulk polymerization of MMA polymerization early also appeared the activity decay chain transfer, but later due to an alkyl iodide entrapped, making at the end of polymerization only normal chain transfer polymerization.

The kinetics of free radical polymerization showed that the factors influencing the transfer of the chain transfer were initiator concentration, monomer concentration and temperature.

For normal free radical polymerization, the higher the temperature is, the faster the chain formation rate is, the smaller the degree of polymerization is. In order to explore the temperature to attenuate the effect of chain transfer, the experimental set to carry out polymerization under different temperature. Through determination of polymer molecular weight and the molecular weight distribution coefficient Mw / Mn to response to different temperature to attenuate the effects of chain transfer.

Keywords: Attenuation Of chain transfer; Free radical polymerization; Methyl methacrylate; Iodoform

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1 衰减链转移聚合 1

1.1.1 碘元素参与的衰减链转移聚合 1

1.1.2 活性衰减链转移聚合 2

1.2 衰减链转移(DT)聚合发展 4

1.3甲基丙烯酸甲酯衰减链转移聚合的研究意义 4

第二章 实验与表征 6

2.1 实验原料 6

2.2 实验步骤 6

2.3 测试和表征 6

2.3.1 单体转化率 6

2.3.2 分子量及分子量分布测试 7

第三章 结果与讨论 8

3.1 聚合动力学 8

3.2聚合反应活化能 11

3.3 分子量及分子量分布 12

3.4 GPC分析 14

3.5 分子链数量 15

第四章 结论 18

致 谢 19

参考文献 20

第一章 绪论

1.1 衰减链转移聚合

所谓链转移是链自由基Mn•取代其他分子XY里结合较弱的原子Y(如氢,卤素原子),使得其中止。而XY失去Y后则成为新自由基X•,类似活性种在转移,转移常数为ktr

(1-1)

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