聚乙烯咔唑嵌段共聚物的合成

 2022-01-22 11:01

论文总字数:27100字

摘 要

聚乙烯咔唑(PVK)是一种带π电子系支链基的非共轭类聚合物,它稳定、具有光导性,因此是一种有开发价值的功能材料,其最重要的性质是具有较好的空穴传输能力。聚乙烯吡咯烷酮(PVP)是一种水溶性好,且性能优异的功能高分子。由于它具有生物相容性好、低毒性、优异的溶解性能,同时还具有易成膜、化学稳定、粘结性好等优点,在工农业生产不同领域中得到广泛地应用。此外,以PVP为亲水链段的双亲性嵌段共聚物由于其优异的性能在医药载体、生物材料、药物缓控性释放等领域都具有潜在的应用价值。

嵌段共聚物是一类软物质材料,可以通过微相分离在溶液、本体、薄膜中产生多种多样的纳米结构。由于其优异的光电性能,咔唑类嵌段共聚物成为当前重要的有机光电材料。利用微相分离对其薄膜光电性质进行优化是一个重要的研究课题。由于咔唑环使得乙烯基双键富电子,造成NVK单体聚合活性非常高,可控聚合难度加大。可逆加成断裂链转移(RAFT)自由基聚合是应用最广的一种活性/可控自由基聚合方法,研究最多的是以黄原酸酯为链转移试剂(CTA)进行的非共轭单体的聚合,这种聚合方法高效、可控,已被成功运用于PVK的聚合。

首先,论文以正十二硫醇,二硫化碳,三氯甲烷为原料合成了三硫代碳酸酯作为RAFT试剂。在氯乙基咔唑的合成中,根据咔唑难溶的特点,我们采用相转移催化的方法,在常温、常压下合成了氯乙基咔唑,利用消除反应得到聚合单体——乙烯基咔唑。聚合实验采用RAFT聚合,以三硫代碳酸酯为链转移试剂,偶氮二异丁腈(AIBN)为引发剂,用氮气作为聚合反应的保护气体,合成了聚乙烯咔唑大分子链转移试剂(PVK-CTA)。以此为大分子RAFT试剂,乙烯基吡咯烷酮为单体,调控聚合获得聚乙烯咔唑-b-聚乙烯吡咯烷酮嵌段共聚物(PVK-b-PVP)。采用凝胶渗透色谱法(GPC),傅里叶红外光谱(FT-IR),核磁共振氢谱(1HNMR)聚合物进行表征PVK-b-PVP的结构,并且采用紫外-可见吸收光谱(UV-vis)以及荧光发射光谱(PL)对合成的聚合物的性能做了测定。

关键词:PVK, 嵌段共聚物, RAFT聚合, PVP

SYNTHESIS OF BLOCK COPOLYMER POLY(VINYLCARBAZOLE)

Abstract

Poly(N-vinylcarbazole) (PVK) is a non-conjugated polymers with π electron type branch group. PVK is a kind of value to the development of functional materials because of its stability, optical conductivity, extremely the high capability of hole transportation. Poly(N-vinylpyrrolidone) (PVP) is a kind of functional polymer with good solubility and excellent properties. PVP has been widely applied in variable areas of industrial and agricultural production according to its excellent biocompatibility, low toxicity, high solubility and also offers easy to deposition, chemical stability, good adhesion, etc. In addition, the amphiphilic PVP block copolymer has potential applications in the fields of pharmaceutical carrier, biological material, drugs release and so on.

Block copolymers are a class of the soft matter material, which can form many nanostructures in solutions and films via micro-phase separation. Carbazole-based block copolymers have been thought as important organic photoelectric materials due to their excellent optoelectronic properties. The optimization of the optoelectronic properties of their films is an important research issue via micro-phase separation. However, the high activity of N-vinylcarbazole (NVK) increases the difficulty of controllable polymerization due to vinyl with electron-rich caused by carbazole ring. Reversible addition fragmentation chain transfer (RAFT) radical polymerization is the most widely used as a living/controlled radical polymerization methods. Most studies were focused in the RAFT polymerization of non-conjugated monomers by using xanthate as chain transfer agent (CTA). Such polymerization method is efficient and has been successfully applied to the controllable polymerization of PVK.

First of all, trithiocarbonate was preparation by using raw materials including n-dodecyl mercaptan, carbon disulfide and chloroform. The thesis adopts the method of phase transfer catalysis to prepare N-chlorine ethy carbazole at room temperature and atmospheric pressure according to the poor solubility of carbazole. And then, PVK has been prepared from NVK via RAFT polymerization by using the trithiocarbonate as the chain transfer agent and azobisisobutyronitrile (AIBN) as the initiator, with nitrogen atomosphere. The macro-RAFT of PVK as the RAFT agent, viny-lpyrrolidone is polymerized to obtain block copolymer, poly(vinyl carbazole)-b-poly(vinyl pyrrolidone) (PVK-b-PVP). Finally, the structures of PVK and PVK-b-PVP have been characterized via gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectrum (1HNMR). At last, the ultraviolet visible absorption spectroscopy (UV-vis) and photoluminescence (PL) spectra of the synthetic polymers were measured.

KEY WORDS: PVK, block copolymer, RAFT polymerization, PVP

目 录

摘要 I

Abstract II

第一章 绪论 1

1.1 聚乙烯咔唑的研究进展 1

1.1.1 聚乙烯咔唑的发展 1

1.1.2 聚乙烯吡咯烷酮的发展 2

1.1.3 聚乙烯咔唑的合成方法 2

1.1.4 合成聚乙烯咔唑嵌段共聚物的常用方法 3

1.1.5 聚乙烯咔唑衍生物的应用 3

1.2 RAFT聚合 4

1.2.1 RAFT聚合简介 4

1.2.2 RAFT试剂的结构特点 5

1.2.3 RAFT试剂的合成 7

1.2.4 RAFT聚合原理 7

1.2.5 RAFT试剂制备嵌段共聚物 8

1.3 课题的研究内容和意义 8

第二章 聚乙烯咔唑嵌段共聚物的合成与表征 10

2.1 引言 10

2.2 实验试剂及实验仪器 10

2.3 RAFT试剂的制备 11

2.4 聚乙烯咔唑——大分子RAFT试剂的合成 12

2.2.1 氯乙基咔唑的合成 13

2.2.2 乙烯基咔唑的合成 14

2.2.3 聚乙烯咔唑(PVK)的合成 14

2.5 聚乙烯咔唑嵌段共聚物的合成 15

2.6 化合物表征 15

2.6.1 中间产物的表征 15

2.6.2 共聚物的表征 22

2.7 本章小结 27

第三章 聚乙烯咔唑嵌段共聚物的性能 28

3.1 共聚物的发光性能 28

3.1.1 PVK和PVK-b-PVP的紫外-可见吸收(UV-vis)光谱表征 28

3.1.2 PVK和PVK-b-PVP的PL光谱 29

3.1.3 PVK的激发发射光谱 29

3.2 本章小结 30

第四章 全文总结 31

致谢 32

参考文献(Reference) 33

  1. 绪论

在高分子发光邻域中,有机聚合物半导体的研究越来越受到科学家们的青睐。有机聚合物半导体具有优异的性能,它不仅仅具有有机荧光性能,这类半导体大多数都大面积的π-π共轭离域体系,范围较大的π-π*能带[[1]],能够通过掺杂或化学修饰来调控材料的发光性能,因此这类化合物种类繁多,色彩丰富,可调性好,色彩纯度高,分子设计相对灵活。还具有聚合物的柔韧性和可加工型,易加工成型,不易结晶,具有优良的机械性能和良好的成膜性,能够制作大面积的柔性器件[[2]][[3]]。这些优势吸引了大批学者的探索和研究。

嵌段共聚物是一类软物质材料,可以通过微相分离,这类聚合物可以在溶液、本体、薄膜中产生多种多样的纳米结构。[[4]]制备咔唑类嵌段共聚物,采用微相分离结构来对有机光电材料进行构造和优化是一个重要的研究方向。[[5]]

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