Living Anionic Polymerization of 1,4-Divinylbenzene Macromolecules, 2011, 44, 4579–4582 Advisor :...
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Transcript of Living Anionic Polymerization of 1,4-Divinylbenzene Macromolecules, 2011, 44, 4579–4582 Advisor :...
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Living Anionic Polymerization of1,4-Divinylbenzene
Macromolecules, 2011, 44, 4579–4582
Advisor : Professor Guey-Sheng Liou
Reporter : De-Cheng Huang
Date : 2015/01/09
Akira Hirao,* Shunsuke Tanaka, Raita Goseki, and Takashi Ishizone
Course : 高分子合成特論
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Abstract
1. Initiator system : oligo(α-methylstyryl)lithium and KOBut
2. Polymerization : at -78oC for 1 min
3. Repeating units : pendent vinyl group
4. Mn = 11,000~26,000 g/molPDI < 1.05
5. Copolymerization
Akira Hirao, Macromolecules, 2011, 44, 4579–4582
Li+
α-MeStSec-BuLi
Initiator
R
vinyl group
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Living polymerization
1. High molecular weight polymer
2. High yield
1. Low molecular weight polymer
2. Broad molecularWeight distribution
Akira Hirao NTU(1)11072014.pdf
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Introduction of monomer
1,4-divinylbenzene (1) 1,3-divinylbenzene 1,2-divinylbenzene
Isomers
Cross-linking agent
Other vinyl monomers
Cross-linked polymer
insoluble
Akira Hirao, Macromolecules, 2011, 44, 4579–4582
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Stabilize the chain end Become inactive toward the
pendant double bond
Li
NLi
HNexcess
• soluble polymers
• high yields ( 90%)∼
• This system was far from living polymerization
Teiji Tsuruta, J. MACROMOL. SCI.-CHEM., 1989, A26(8), 1043
LDA
DPA
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Lead to the cross linkingLead to the soluble polymer
Lower reactivityHigher reactivity
Assumption
Akira Hirao, Macromolecules, 2011, 44, 4579–4582
1. kinetic studies of the polymerization of 1,4-divinylbenzene 2. NMR analysis of the resulting polymers and model compounds
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ExperimentSynthesis of 1,4-Divinylbenzene O H
P+H3CBr-
CH3
OKH3CH3C
4-formylstyrene methyltriphenylphosphonium bromide
Potassium tert-butoxide
4-formylstyrene
70.5mmol 9.30g
THF
60ml
mixture A
methyltriphenylphosphonium bromide
81.1mmol 29g
potassiumtert-butoxide
88.1 mmol 9.88g
+ + THF
40ml
mixture B
mixture A mixture Bdropwise into stir25oC
2h
extraction
diethyl ether
concentrated hexane
excess
precipitation
filtration column chromatography
Akira Hirao, Macromolecules, 2011, 44, 4579–4582
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Anionic Polymerization of 1,4-divinylbenzene
α-methylstyrene + sec-BuLi + THF + KOBut (at -78oC) mixture A (initiator)
THF + 1,4-divinylbenzene (at -78oC) mixture B
Mixture B is added to mixture A vigorous shaking
1. For 1 min 2. Quenched with degassed methanol3. Precipitated in methanol
Akira Hirao, Macromolecules, 2011, 44, 4579–4582
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Result and Discussion
Akira Hirao, Macromolecules, 2011, 44, 4579–4582
The fisrt successful demonstration of the living anionic polymerization of (1)
THF , -78oCInitiator system : sec-BuLi
30 min
1 min
Insoluble polymer
soluble polymer
Highly branched not cross-linked product
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SEC profiles of polymers
DVB-1
DVB-5
DVB-4
DVB-3
Akira Hirao, Macromolecules, 2011, 44, 4579–4582
Initiator sec-BuLi sec-BuLi/α-MeSt /KOBut
sec-BuLi/α-MeSt /KOBut
sec-BuLi/α-MeSt /KOBut
KOBut (eq) 0 12 12 5
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Table 1 : Anionic Polymerization of 1 in THF at 78 C for 1 mina
Akira Hirao, Macromolecules, 2011, 44, 4579–4582
Adding excess LiCl didn’t influence polymerization.
The addition reaction of the living poly(1) to the pendant vinyl group in another polymer chain.
DVB-4 system was at a higher monomer to initiator ratio.
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Monomer (1) v.s Poly (1)
H2C= -CH2-CH-
113.9ppm
113.1ppm Lower reactivity(electrophilicity)
Akira Hirao, Macromolecules, 2011, 44, 4579–4582
Monomer (1)
Poly (1)
(1)vinyl polymerization
poly(1)
[pendant vinyl group]
K
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AB diblock copolymer : poly-(1)-block-poly(tBMA)
K OO
At -78oC 3hr
Orange red → colorless
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The formation of the AB diblock copolymer
→ To support the live nature of the polymerization of (1)
Akira Hirao, Macromolecules, 2011, 44, 4579–4582
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Conclusion
Living polymerization of (1) ----- excess KOBut
Soluble polymer : narrow molecular weight distribution
Poly(1)-block-poly(tBMA)
Akira Hirao, Macromolecules, 2011, 44, 4579–4582
Atom size : replace Li+ with K+
→ chain-end anion shifted to ion-pair
Steric effect : KOBut
Higher reactivity
lower reactivity
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P.9
根據老師提及 Wittig reaction 最早利用於聚合具光電性質的高分子 ,至所以可用於做高分子 , 在於其產率相當的高
R. N. McDonald and T. W. Campbell, ibid., 14, 1969 (1959).
1. 轉化率高 ( 可運用於聚合反應 )2. 當 Modal compound 產率接近 100% : 分子量大 polymer 不需要鑑定 ( 耗時耗成本 )
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P.15
對於 divinylbenzene 之共軛性極佳 , 吸收位置為藍光波長 , 所以相對的所放出的光為橘色 , 但當我們具有拉電子基性能的 Methacrylate,會造成藍位移 , 所具有的平面堆疊能力下降 , 造成 polymer 的顏色變為無色
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P.17
即便是 Atom size : K + >Li + 然而兩者都會由鏈末端陰離子轉移變成離子對其中要考慮的是 Solvent effect 當溶劑為極性溶劑 使得 Li+ 所支配的鏈末端陰離子其反應性會比 K + 來得高 , 因此可以證明 K + 所分配的鏈末端陰離子較能攻擊 monomer 形成可溶性高分子