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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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Outline Abstract Introduction Experiment Result and Discussion Conclusion

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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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Introduction Chain polymerization

Akira Hirao NTU(1)11072014.pdf

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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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Thank you for your attention

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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.14

藉由末端基 -CH2-CH2- 的 protons 對應到的 NMR 上的 peak並且藉由判斷其主鏈上 -CH2-CH- 之 protons 的比例關係可以推敲其高分子的分子量

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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

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額外 : 2013 年 Hirao 教授所做的 paper 差異為何 ?

1.添加劑不同2.異構物上的效應