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活性自由基聚合,总论

活性自由基聚合,总论
–Provide a concentration of radicals high enough to give a reasonable rate of polymerization
– Initiate polymerization quickly so that each chain begins at about the same time
低温光照聚合：活性，制备嵌段聚合物 光照乳液聚合：活性，制备嵌段聚合物
2001年12月
活性自由基聚合/总论
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常见的热分解型自由基聚合引发剂
2001年12月
活性自由基聚合/总论
15
自由基聚合实现活性化的思路：
不考虑链转移，抑制链终止
▪ Rp = kp[M][P*]
▪ Rt = 2kt[P*]2
▪ Rt/Rp = 2(kt/kp)[M]-1[P*] 0
19
活性聚合
IUPAC: A chain polymerization from which irreversible chain transfer and irreversible chain termination (deactivation) are absent.
IUPAC recommends to use the term "reversible-deactivation radical polymerization" instead of "living free radical polymerization
“活性”自由基聚合 “Living”/Controlled Radical
Polymerization
北京化工大学
2001年12月
活性自由基聚合/总论

原子转移自由基聚合概述

原子转移自由基聚合概述

原子转移自由基聚合概述1.引言“活性”/可控自由基聚合不同于传统意义上的自由基聚合反应。

它克服了分子量及其分布不可控，难以合成嵌段聚合物等缺陷，做到了分子量可控，分子量分布较窄，聚合物结构可控等一系列要求。

这类聚合反应主要是有效降低了增长活性中心的浓度，抑制了双基终止的发生，延长了自由基的寿命和分子量的统一性；使用快引发的方式，保证不同分子链同时增长。

目前大致有以下几种不同的机理得到了较为深入地研究:基于引发-转移-终止剂（Initiator-chain transfer-terminator）的活性自由基聚合(Iniferter法）、基于氮氧稳定自由基的活性自由基聚合（Living nitroxide-mediated stable free radical polymerization-SFRP）、原子转移自由基聚合（Atom transfer radical polymerization-ATRP）、基于可逆加成碎裂链转移剂的活性自由基聚合（Living radical polymerization in the presence of reversible addition-fragmentation chain transfer-RAFT）和退化转移自由基聚合（degenerative transfer process-DT）等等。

在这些不同的实现“活性”/可控自由基聚合的方法当中，原子转移自由基聚合是目前最有希望实现工业化的一种方法。

2.原子转移自由基聚合概述原子转移自由基聚合是1995年由卡内基梅隆大学Matyjaszewski课题组提出的一种“活性”/可控自由基聚合新机理Wang, J-S; Matyjaszewski, K. Controlled/"living" radical polymerization. Atom transfer radical polymerization in the presence of transition-metal complexes. J. Am. Chem. Soc. 1995, 117: 5614–5615.。

高分子化学 Polymer chemistry3自由基引论RADICAL POLYMERIZATION

高分子化学 Polymer chemistry3自由基引论RADICAL POLYMERIZATION
Transfer Reaction 3.5 Thermodynamics of Polymerization 3.6 Methods of Polymerization
An Important One of Chain Polymerization Family
Classified by the nature of reactive center: radical polymerization cationic polymerization anionic polymerization coordinating ionic polymerization and so on.
CH2C=CHCH2
CH2C=CHCH2 Cl
3.1 Radical Polymerization Mechanism
3.1.1 The activity and the reaction of the free radical
3.1.2 Monomer structure and types of polymerization
OCOCH3
polybutadiene PB CH2=CH CH=CH2
polyisoprene
CH2=C CH=CH2
PIP
CH3
polychloroprene PCP CH2=C CH=CH2 Cl
CH3 CH2C
COOCH3
CH2 CH CN
CH2 CH OCOCH3
CH2CH=CHCH2
CH3
The Order of the Relative Activity of Radicals
The Radicals in the last line are the inert radicals that have no ability of initiating olefinic monomers’ polymerization

英文版自由基简介

英文版自由基简介

Free Radicals and Anti-oxidants in NeurodegenerativeDiseases.Xuemin Ye, Ph.D.NYS/Institute for Basic Research1050 Forest Hill Road,Staten Island, NY 10314 USAPresentation at in York Env. Center, New Jersey Institute of Technology (NJIT), NJ. USA. March 14, 2003.Yin and yang are one of the most fundamental concepts in Traditional Chinese Medicine (TCM) because it makes up such a large chunk of the foundation of diagnosis and treatment. First appearing in the Book of Changes (Yi Jing), the theory has probably been around since prior to the Warring States Period (pre 221 B.C.). I believe that the oxidative/reductive stage of our body can be explained by Yin and yang theory, which reflected by Qi circulation, Yang Deficiency or Heat Xu, Yang Excess of Heat Shi, Yin Deficiency or Cold Xu, Yin Excess or Cold Shi, it can also be diagnosis with the color of our tongue. The treatment of TCM including formular herbal medicine, moxibustion (moxa), acupuncture, or acupressure can adjust the oxidative/reductive enviroment of our body, therefore, they can help us reduce free radicals damage. I urge science and medical research pay attention to the function of TCM and free radicals caused degeneration.There are four basic properties that help to understand the relationship of yin and yangand make it easier to apply these prinicples to the microcosm that is the human body.1) The Opposition of Yin & YangYin and Yang are oppossite, however only relative to each other. Nothing is wholly yinor wholly yang. Each contains even the smallest of seeds of the other inside it. At anygiven time the two are in a constantly changing balance, with each vying for that one step ahead. Yang natured things (e.g., heat) counter and dispel yin natured things (e.g., cold)and vice-versa. If one predominates, it can overact on the other, cause imbalance and leadto disease.2) The Interdependence of Yin & YangYin and yang, though relatively opposite to one another, can not exist independently.They define each other, much as night and day do. One cannot know light without dark,or dark without light. They only exist in relation to the other. In addition, they feed off ofeach other. Yang is energy, and it needs nutrients to exert itself. Yin is nutrient and needs energy to form.3) The Mutual Consuming & Supporting Nature of Yin & YangBeing in a constant balance, yin and yang are constantly attempting to adjust to levels ofthe other. Outside influences may cause levels of one to either become significantlygreater or lesser than the other. Four possibilities can occur: Yang Deficiency or Heat Xu,Yang Excess of Heat Shi, Yin Deficiency or Cold Xu, Yin Excess or Cold Shi.There are two things to take note of here. The first is to pay attention to the heatand the cold attributes. Interchanging the words yang and yin with heat and cold respectively, plus combining with deficiency (xu) and excess (shi), you can get a rathergood sense how to apply this to the body imbalances. For example, yin deficiency canalso be thought of as cold deficiency. With a lack of cold in the body, false heat signs canbe seen. The second thing to note is the level of the non-deficient part of a xu/deficient condition. Since yin & yang draw off each other to exist, any deficient condition will cause a general deficiency of both yin and yang. For example, yin deficiency will alsohave a minor deficiency of yang that puts it just below its balanced level.4) The Intertransformation of Yin & YangThe dynamic balance of yin & yang is such that the two can transform into each other. Summer will eventually turn to winter, day will become night, even the most wild sugarrush will eventually lead to a resounding depression. The change is not spontaneous butneeds certain factors or precursors to exist. Internal factors are primary, yet externalfactors also have an effect. In addition, the timing of these things must be right. Considerthe transformation of matter to energy. The internal conditions of the composition ofmatter must be right and external factors must be applied at the right time for Massto multiply by C2 and cross over that equal sign to Energy (wonder where Einstein reallygot the notion of E=MC2 ?).叶学敏山东潍坊欣健生物科技有限公司Xye1630@。

活性自由基聚合,TEMPO

活性自由基聚合,TEMPO

2. NMP的聚合机理 2.1 平衡的建立： persistent radical effect
R·Y· , 活泼自由基，则产物有三种, 1:2:1。 R· 活泼自由基，Y· persistent radical, 产物只有一种
2. NMP的聚合机理 2.1 平衡的建立： persistent radical effect
the term living, controlled and step growth were used.
N O N O
polystyrene
CH 2
CH
polystyrene
CH 2
CH
Polymerization Systen: Monomer: Styrene 双分子体系 Initiator: BPO BPO:TEMPO=1:1.3 Additive: TEMPO Conditions: Initial heating at 95oC for 3.5h, followed by heating at 123oC for 69h. Poorly defined nature of the initiating species Results: Narrow molecular weight polystyrene with polydispersity of 1.26. The number-average molecular weight increased linearly
2. NMP的聚合机理
2.1 平衡的建立： persistent radical effect
Radicals (2) and (4) are present at very low concentrations (approx. 10-8 M) but the persistent radical (6) is at a concentration around 10-3 M. It is critical to note that the PRE is a very important concept, which is at the heart of both NMP and ATRP. it is possible to enhance the PRE by the addition of stable radicals at the beginning of the polymerization. The Persistent Radical Effect: A Principle for Selective Radical Reactions and Living Radical Polymerizations Hanns Fischer Chem. Rev. 2001, 101, 3581-3610

可控活性聚合

可控活性聚合

那么问题来了。
究竟要采取什么策略才能使自由基再聚合过程中保持如 此低的浓度，从而使自由基聚合由不可控变为可控？
策略
通过可逆的链转移或链终止，使活性种（具有链 增长活性）和休眠种（暂时无链增长活性）进行快 速可逆转换：
• 以上活性种与休眠种的快速动态平衡的建立，使体系
中自由基的浓度控制得很低，便可控制双基终止，实
概述
在聚合体系中引入一种特殊的化合物，它与活性种链自由基
进行可逆的链终止或链转移反应，使其失活变成无增长活性的休 眠种，而此休眠种在实验条件下又可分裂成链自由基活性，这样 便建立了活性种与休眠种的快速动态平衡。这种快速动态的平衡 反应不但使体系中的自由基浓度控制得很低而且抑制双基终止， 而且还可以控制聚合产物的分子量和分子量分布，实现活性/可 控自由基聚合。
现活性可控。
主要的可控/活性聚合方法
(NMRP)
(ATRP) (RAFT)
引发转移终止剂法（iniferter）
• 引发转移终止剂：在聚合过程中同时起到引发、转移、
终止作用的一类化合物。根据目前已发现的可分为光
活化型和链活化型两种。
光引发转移终止剂
一般含有S-S键或者C-S弱键，主要指含有二硫
双基终止的解决办法
假若能使自由基浓度降低到某一程度，即可维持可观 的链增长速率，又可使链终止速率减少到相对于链增长 速率而言可以忽略不计，这样便消除了自由基可控聚合 的主要症结双基终止。 根据动力学参数估算： 当[P· ]≈10-8mol/L时，此时 Rt/Rp≈10-3~-4，即Rt相对 于Rp实际上可以忽略不计。
. NHCCH2 , CH3CH2OCCH2 . O O CH2OCCH2 .
. CH3CH2CH2CH2OCCH2 ,

活性自由基聚合 英文幻灯片

Living Radical Polymerization to New Macromolecules
The discovery of ‘‘living’’ or ‘‘controlled’’ radical polymerizations has spurred extensive research efforts during the past decade. The ability to achieve a high degree of control over polymer microstructure under relatively mild conditions signifies a marked increase in the ease with which structures such as di- and triblock polymers, star polymers, and comb-like graft polymers can be prepared.
(D) The DTC radicals then re-cap the new carbon radical.
Steps (A)through (D) continue until UV light is terminated or all of the materials are consumed.
RAFT and utilize a chain transfer agent that reacts with a propagating macroradical initiated by a conventional free radical initiator.
Structures of RAFT agents commonly used in (mini)emulsion

乳液体系中的RAFT可控_活性自由基聚合研究进展

基金项目:国家自然科学基金资助项目(20276044),江苏省高校自然科学研究指导性计划项目(03KJD150188);作者简介:周晓东,男,硕士研究生,研究方向为乳液体系的活性聚合。

*联系人.Email:phni@.乳液体系中的RAFT 可控 活性自由基聚合研究进展周晓东,倪沛红*(苏州大学化学化工学院,江苏省有机合成重点实验室,苏州 215123)摘要:可逆加成 断裂链转移聚合(RAFT )是新近发展起来的可控 活性自由基聚合方法。

由于该方法具有适用单体范围广、反应条件温和、可采用多种聚合实施方法等优点,已成为一种有效的分子设计手段。

本文总结了近几年文献报道的在乳液和细乳液体系中实施RAFT 聚合反应的研究进展,对非均相体系的稳定性、聚合反应过程中的动力学特点、以及聚合产物的分子量及其分布等方面的研究进行了综述。

关键词:乳液聚合;细乳液聚合;可逆加成-断裂链转移(RAFT);活性聚合引言传统的自由基聚合由于慢引发、快增长、速终止的特点,难以获得分子量可控及分子量分布可控的聚合物,也不能合成嵌段共聚物和精致结构的聚合物。

而各种活性自由基聚合方法却能克服上述不足。

近年来,先后出现了多种活性自由基聚合体系,例如:TE MPO 稳定自由基存在下的可控自由基聚合[1]、原子转移自由基聚合(ATRP)[2]和可逆加成-断裂链转移聚合(RAFT)[3~5]。

RAFT 可控 活性自由基聚合方法是在传统的自由基聚合体系中加入二硫代酯类化合物作为链转移剂,通过可逆加成-断裂链转移聚合机理得到 活性 聚合物链,RAFT 聚合的一般机理如图1所示。

[4]图1 RAFT 聚合反应机理[4]Figure 1 Mechanism of the RAFT polymerization process [4]RAFT 聚合适用的单体范围广,带有羧基、羟基、叔胺基等官能团的单体都可以通过这种方法实现聚合。

聚合过程中,二硫代酯基S=C(Z)S 在活性链和休眠种之间转移,使得聚合物链保持活性,由此可以合成各种结构精致、且具有可控分子量和窄分子量分布的嵌段[6~9]、星型[10~13]、接枝[14]等特殊结构的聚合物。

活性自由基聚合,ATRP


SO2Cl O S O Cl O S O
星形聚合物的合成:
CH 2Cl O Cl 2CH ClCH 2 CH 2Cl O CH 2 CH 2 O O CHCl 2
O Br O
O Br O
O
O
Br
超枝化聚合物的合成:
CH 2Cl
H 2C
CH O O CH 2 CH 2 O Br O
Results of ATRP:
The logarithmic conversion data, ln([m]0/[M]), plotted
against time t, gave straight lines passing through the origin, which shows constant concentrations of the growing species during the polymerization. The number-average molecular weights increased in direct proportion to monomer conversion and agreed well with the calculated values based on the assumption that one molecule of the initiators generated one living polymer chain. The polydispersity indexes were smaller (generally lower than 1.3).
Br
CH
CH 2
CH
Br
Br
CH
CH 2
CH
CuBr/bipy CuBr2/bipy

活性氧自由基

活性氧自由基活性氧自由基__________________________活性氧自由基（Reactive Oxygen Species，ROS）是指氧的各种活性形态，它们有一个或多个单非共价键的氧原子。

这类物质可以通过活化氧，活化氢氧化物，卤素活性物质等多种方式产生。

它们具有极强的氧化能力，可以对多种物质进行氧化作用，使其发生变化。

ROS是有害的，它们可以对细胞和组织结构造成损害，导致疾病的发生。

一、活性氧自由基的产生ROS是一种活性物质，它可以通过多种途径产生。

主要包括：1、光反应产生在生物体内，当太阳光的紫外线照射到蛋白质、碳水化合物和脂质中时，就会发生光化学反应，产生大量的活性氧自由基。

2、代谢反应产生在体内各类代谢反应中，也会产生大量的ROS。

例如，在呼吸过程中，氧分子会与氧分子共价键形成O2-、H2O2、OH-等活性物质；在酶催化反应中也会产生ROS。

3、外界因素产生一些外界因素，如X射线、γ射线、辐射、污染物、化学药物等都能够产生ROS。

二、活性氧自由基的作用1、促进新陈代谢ROS不仅能够产生新的物质，而且还可以促进新陈代谢，使生物体保持健康。

例如，ROS可以促进血液循环，增强免疫力，促进新陈代谢，并使机体能够更好地抵御外来侵害。

2、参与细胞信号传导ROS在细胞信号传导中也扮演着重要的角色。

它们可以影响细胞分裂、凋亡和存活，还可以促进器官的再生和修复。

3、诱导DNA修复ROS能够诱导DNA的修复，使DNA能够恢复正常的功能。

它们还能帮助DNA识别和修复受到损伤的DNA，减少DNA突变的发生。

三、ROS的危害1、诱导炎症ROS过多会使机体内部发生氧化应激，诱导机体产生大量的炎性因子，对机体造成伤害。

2、诱导衰老ROS过量可以诱导机体老化，使机体出现衰老症状，如皮肤松弛、皱纹出现、色斑增加等。

3、诱导癌变当机体内部ROS水平过高时，它们会对DNA造成损伤，诱导正常细胞出现异常增殖，从而诱发癌症。

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Mechanism (i) the induction corresponds to the time required to produce sufficient radicals to convert all of the Co(II) species into Co(III)–R, which controls the polymerization via a slow RDC mechanism. (ii) The continued influx of radicals from V-70 changes the process to a faster DT-based polymerization in which both ln([M]0/[M]) vs. time and Mn vs. conversion increase linearly. (iii) After the influx of new radicals from V-70 has ended, the polymer ization reaction reverts to the slower RDC pathway .
reversible deactivation by coupling (RDC) mechanism F. di Lena, K. Matyjaszewski / Progress in Polymer Science 35 (2010) 959–1021
Catalytic chain transfer (CCT) , when its rate is sufficiently high, the molecular weight distribution of the resulting oligomers can be described by a Shultz–Flory statistics (Mw/Mn ∼2). Efficient CCT has been reported with certain Mo, Fe, and especially Co complexes.
Degenerative transfer (DT) process F. di Lena, K. Matyjaszewski / Progress in Polymer Science 35 (2010) 959–1021
Since the Co–C bond cleavage of Organo cobalt(III) complexes can be achieved under mild conditions, organocobalt complexes have been used as sources of carboncentered radicals for organic synthesis and in polymer chemistry.
A. Debuigne et al. / Progress in Polymer Science 34 (2009) 211–239
(TMP)Co-CH2C-(CH3)3 1 Addition of (TMP)CoII ·reduces the rate of polymerization, and the poly merization process can be effectively stopped and restarted repetitively by cycling the reaction temperature between 5 ℃ and 60 ℃. A linear increase in Mn with MA conversion along with relatively small PMA polydispersities (Mw/Mn = 1.1-1.2) indicates that a preponderance of the polymer chains are growing in a manner characteristic of a living polymerization process.
Bradford B. Wayland / J. Am. Chem. SOC. 1994,116, 7943-7944
In 2004, the Wayland research group showed that, in the presence of a radical source such as AIBN or V-70, the polymerization of MA could be mediated by catalytic amounts of (TMP)Co. At 60◦C and in benzene, after a short induction period, PMA of molecular weight up to 120,000 and polydispersity as low as 1.06 were produced. Low polydispersity poly(MA-b-BA) copolymers were also efficiently synthesized.
F. di Lena, K. Matyjaszewski / Progress in Polymer Science 35 (2010) 959–1021
Transition metal complexes that have been reported to polymerize olefins via a RDC mechanism include Ti, Mo, Os, Co, and Rh compounds.
(TMP)Co-MA 2
Reaction of 2 wiБайду номын сангаасh MA at 60 ℃ in benzene results in formation of PMA with relatively small polydispersity (1.1-1.3) and linear increase in Mn (1 X 104 to 1.7 X 105) with MA conversion (5-80%, DP = 125-2000). In spite of the processes that can limit polymer growth , observation of linear increases in Mn with conversion, formation of block copolymers, and relatively small polydisper- sities clearly demonstrate that 1 and 2 initiate an effective living radical polymerization of acrylates.
F. di Lena, K. Matyjaszewski / Progress in Polymer Science 35 (2010) 959–1021
Organometallic mediated radical polymerization, is based on the fast and reversible homolytic cleavage of a metal-carbon bond in the metal complex. Depending on the type of monomer used, the specific metal/ligand combination and the initiation strategy, OMRP can occur through either RDC or DT or both mechanisms. Chain-breaking reactions such as CCT may also competitively take place.
Free Radical Polymerization
Controlled Radical Polymerization
requirements
(i) The rate of initiation is faster than that of propagation, so that all chains form and grow simultaneously. (ii) The concentration of active radicals is low in order to slow down termination reactions. (iii) The concentration of propagating chains is high so only a small fraction of them are terminated. (iv) The polymerization system remains sufficiently homogeneous, so that the active centers are readily available.
F. di Lena, K. Matyjaszewski / Progress in Polymer Science 35 (2010) 959–1021
The accuracy of theoretical calculations in terms of molecular structure, energetics and physical properties has made enormous progress in the last couple of decades. The application of computational tools, especially Density Functional Theory (DFT) methods, in view of their relatively good performance at comparatively low computational cost, is becoming routine in a variety of different areas of chemistry and controlled radical polymerization is no exception.