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Macromolecules版 - updated in reply # 12 请教一个最简单高分子聚合问题, 包子答
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相关话题的讨论汇总
话题: styrene话题: monomer话题: aibn话题: toluene话题: reaction
进入Macromolecules版参与讨论
1 (共1页)
d**a
发帖数: 3715
1
I recently synthesized a monomer with a styrene as one functional end group
(confirmed by NMR) and try to co-polymerize this monomer with commercially
available styrene
I ran the reaction in this way:
mix my monomer A, styrene, and AIBN in tolunene
A: 0.25 g, 0.48 mmol
styrene: 0.05 g, 0.48 mmol
AIBN 0.0055 g, 0.034 mmol, 3.5 mol% of monomers.
Freeze-thaw degas twice,nitrogen purge, in 50 mL of toluene at 80 degree C,
stirring for three days.
But it came out nothing has happened. I just checked
t***u
发帖数: 20182
2
1.need to remove the inhibitor
2.how pure is your monomer
3.toluene-chain transfer agent
4.AIBN at 80 oC has a half life of about 10min?
5.concentration too low
6.monomer to initiator ratio,like 10 to 1?
b******0
发帖数: 45
3
1. purify styrene by basic alumina column
2. conc. is too low. try polymerization without toluene if A can be
dissolved in styrene. Or just add 0.25~0.5ml toluene if the solubility of A
is not poor
3. three days seems too long using AIBN as initiator at 80C
d**a
发帖数: 3715
4
Thank you so much for your reply.
Can I purify the styrene using a silica gel column?
Yes. A is a aromatic solid compound and easy to dissolve in toluene.
Then what your suggestion for the reaction time,temperature, and the
selection of initiator?
Thanks.

A

【在 b******0 的大作中提到】
: 1. purify styrene by basic alumina column
: 2. conc. is too low. try polymerization without toluene if A can be
: dissolved in styrene. Or just add 0.25~0.5ml toluene if the solubility of A
: is not poor
: 3. three days seems too long using AIBN as initiator at 80C

m*****e
发帖数: 1506
5
很全面

【在 t***u 的大作中提到】
: 1.need to remove the inhibitor
: 2.how pure is your monomer
: 3.toluene-chain transfer agent
: 4.AIBN at 80 oC has a half life of about 10min?
: 5.concentration too low
: 6.monomer to initiator ratio,like 10 to 1?

d**a
发帖数: 3715
6
我现在开足马力争取先多合成一点Monomer。
r******0
发帖数: 2753
7
I guess the key problem is the concentration. And THF is a typical solvent
when AIBN is used as initiator. If your monomer and polymer can be dissolved
in THF, I would suggest that. For 0.3g of monomers, 1g THF should be good
enough. Anyway, good luck.
d**a
发帖数: 3715
8
Thank you. That is what I am thinking about. Last time too much solvent (50
mL of toluene) was added into the system. So next time I will try to run the
reaction in 1 g scale and use minimal amount of solvent.

dissolved

【在 r******0 的大作中提到】
: I guess the key problem is the concentration. And THF is a typical solvent
: when AIBN is used as initiator. If your monomer and polymer can be dissolved
: in THF, I would suggest that. For 0.3g of monomers, 1g THF should be good
: enough. Anyway, good luck.

a*i
发帖数: 1652
9
I would polymerize styrene first. If PS is obtained, I'll go ahead with
copolymerization under the same condition. Otherwise, you shouldn't worry
about copolymerization in the first place.

group
commercially
,

【在 d**a 的大作中提到】
: I recently synthesized a monomer with a styrene as one functional end group
: (confirmed by NMR) and try to co-polymerize this monomer with commercially
: available styrene
: I ran the reaction in this way:
: mix my monomer A, styrene, and AIBN in tolunene
: A: 0.25 g, 0.48 mmol
: styrene: 0.05 g, 0.48 mmol
: AIBN 0.0055 g, 0.034 mmol, 3.5 mol% of monomers.
: Freeze-thaw degas twice,nitrogen purge, in 50 mL of toluene at 80 degree C,
: stirring for three days.

a********c
发帖数: 60
10
I think the primary concern is the inhibitor. if you removed it, you
should be able to polymerize under the inert condition(oxygen-free
environment). BPO is a better initiator than AIBN.
Obviously, higher monomer concentration will help. Why do you need
solvent?
good luck. let us know your progress.

group
commercially
degree C,

【在 d**a 的大作中提到】
: I recently synthesized a monomer with a styrene as one functional end group
: (confirmed by NMR) and try to co-polymerize this monomer with commercially
: available styrene
: I ran the reaction in this way:
: mix my monomer A, styrene, and AIBN in tolunene
: A: 0.25 g, 0.48 mmol
: styrene: 0.05 g, 0.48 mmol
: AIBN 0.0055 g, 0.034 mmol, 3.5 mol% of monomers.
: Freeze-thaw degas twice,nitrogen purge, in 50 mL of toluene at 80 degree C,
: stirring for three days.

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问一个聚合速率的问题Help! interview this morning
进入Macromolecules版参与讨论
d**a
发帖数: 3715
11
Thank you all for your help. The reason I used a solvent is that because my
monomer is a solid at R.T. As agi suggested, I will try to polymerize
styrene first in a 5 g scale, using 1/100 molar ratio of AIBN in THF at 65 oC overnight.
l*****o
发帖数: 52
12
I think you can add more AIBN to counteract the existence of inhibitor, also
the monomers cocentration is too low. Just curious,why not using TEMED+APS
as the initiator system at room temperature? Is solubility a problem at low
temperature?
d**a
发帖数: 3715
13
Update:
Reaction 1: polymerize styrene
After removing the inhibitor originally in styrene by passing a
chromatographic column, 5 gram of styrene were mixed with 1 mol % of AIBN in
5 mL of anhydrous THF. The reaction solution was then stirred overnight at
80 oC with a gentle nitrogen purge. In the next morning, all the THF was
found to be blew off and the entire styrene was polymerized to form one
piece of rigid clear material, which was then dissolved in hot toluene and
precipitate in cold met

【在 d**a 的大作中提到】
: I recently synthesized a monomer with a styrene as one functional end group
: (confirmed by NMR) and try to co-polymerize this monomer with commercially
: available styrene
: I ran the reaction in this way:
: mix my monomer A, styrene, and AIBN in tolunene
: A: 0.25 g, 0.48 mmol
: styrene: 0.05 g, 0.48 mmol
: AIBN 0.0055 g, 0.034 mmol, 3.5 mol% of monomers.
: Freeze-thaw degas twice,nitrogen purge, in 50 mL of toluene at 80 degree C,
: stirring for three days.

c*s
发帖数: 2145
14
zan!
maybe add some ddm to improve PDI? or using living polymerizaiton technique?
t***u
发帖数: 20182
15
lol,4.4?
u dont need to purge the solution all the time,purge at the begning and keep
it sealed or under nitrogen. 80oC? so the solution was boiling and the
temperature may not be 80 oC indside.
anyway,glad to hear that u got the polystyrene.
d**a
发帖数: 3715
16
The reaction was run at 65 oC. This crude product has not been purified,
which may boarden the PDI. I will be aware the nitrogen purge next time.

keep

【在 t***u 的大作中提到】
: lol,4.4?
: u dont need to purge the solution all the time,purge at the begning and keep
: it sealed or under nitrogen. 80oC? so the solution was boiling and the
: temperature may not be 80 oC indside.
: anyway,glad to hear that u got the polystyrene.

d**a
发帖数: 3715
17
ddm: Diphenyldiazomethane?

technique?

【在 c*s 的大作中提到】
: zan!
: maybe add some ddm to improve PDI? or using living polymerizaiton technique?

a*i
发帖数: 1652
18
if you want to narrow PDI, try to get PS with narrow PDI first. you didn't
mention the PDI of the first reaction.
if you want to publish papers, try to make the first reaction better. THF
runaway is not good (you can avoid that by assembling proper glasswares); is
AIBN necessary?
It seems to me that you haven't got solid proof of copolymerization.
Purification is quite easy: try toluene/methanol cycles and then dry the
polymer in vacuum oven. Once copolymerization is successful, you can make
pro

【在 d**a 的大作中提到】
: Update:
: Reaction 1: polymerize styrene
: After removing the inhibitor originally in styrene by passing a
: chromatographic column, 5 gram of styrene were mixed with 1 mol % of AIBN in
: 5 mL of anhydrous THF. The reaction solution was then stirred overnight at
: 80 oC with a gentle nitrogen purge. In the next morning, all the THF was
: found to be blew off and the entire styrene was polymerized to form one
: piece of rigid clear material, which was then dissolved in hot toluene and
: precipitate in cold met

b******0
发帖数: 45
19
If you use THF as solvent, you should not blow N2 during the whole reaction.
In a sealed system, blow N2 for 20mins and keep positive pressure before
reaction.
It is difficult to get 100% conversion of the polymerization. If you want
remove the unreacted monomers to purify your polymer, it is easy by
redissolving and reprecipitating.

in
at
and

【在 d**a 的大作中提到】
: Update:
: Reaction 1: polymerize styrene
: After removing the inhibitor originally in styrene by passing a
: chromatographic column, 5 gram of styrene were mixed with 1 mol % of AIBN in
: 5 mL of anhydrous THF. The reaction solution was then stirred overnight at
: 80 oC with a gentle nitrogen purge. In the next morning, all the THF was
: found to be blew off and the entire styrene was polymerized to form one
: piece of rigid clear material, which was then dissolved in hot toluene and
: precipitate in cold met

r******0
发帖数: 2753
20
It might be easy to do the polymerization but it could be a little bit
harder to prove that your monomer COPOLYMERIZED with styrene.
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进入Macromolecules版参与讨论
a*i
发帖数: 1652
21
he does need to show convincingly that copolymerization happens.
Depending on the functional group, it could be easy.

【在 r******0 的大作中提到】
: It might be easy to do the polymerization but it could be a little bit
: harder to prove that your monomer COPOLYMERIZED with styrene.

d**a
发帖数: 3715
22
How about a high resolution NMR? I think it is easy to prove the existence
of my monomer but not styrene.
r******0
发帖数: 2753
23
It could be hard to prove that you get the copolymer instead of a mixture of
two homopolymers. Now u may have proved that your monomer can be
polymerized but u cannot say it can copolymerize with styrene.

【在 d**a 的大作中提到】
: How about a high resolution NMR? I think it is easy to prove the existence
: of my monomer but not styrene.

D********g
发帖数: 533
24
if you are using small amount of polymer, GPC column is a very good way to
purify based on the molecular weight... you can treat it as one HPLC

in
at
and

【在 d**a 的大作中提到】
: Update:
: Reaction 1: polymerize styrene
: After removing the inhibitor originally in styrene by passing a
: chromatographic column, 5 gram of styrene were mixed with 1 mol % of AIBN in
: 5 mL of anhydrous THF. The reaction solution was then stirred overnight at
: 80 oC with a gentle nitrogen purge. In the next morning, all the THF was
: found to be blew off and the entire styrene was polymerized to form one
: piece of rigid clear material, which was then dissolved in hot toluene and
: precipitate in cold met

D********g
发帖数: 533
25
you may try hot toluene -> cold methanol twice to see if it works better.

【在 d**a 的大作中提到】
: The reaction was run at 65 oC. This crude product has not been purified,
: which may boarden the PDI. I will be aware the nitrogen purge next time.
:
: keep

d**a
发帖数: 3715
26
You mean I dissolve my product in hot toluene and then precipitate it into
cold methanol twice? Thank you.

【在 D********g 的大作中提到】
: you may try hot toluene -> cold methanol twice to see if it works better.
b******0
发帖数: 45
27
The PDI of your product is too high, so they think you may get two kinds of
homopolymers rather than a copolymer. Usually unreacted monomer will not
make PDI so high.

【在 d**a 的大作中提到】
: You mean I dissolve my product in hot toluene and then precipitate it into
: cold methanol twice? Thank you.

l****8
发帖数: 7
28
1.检查你的单体是否可以自聚,如果不能,说明你的聚合物是共聚物。如果可以,就要
测竟聚率。比较麻烦了。
2.溶液聚合最好在封闭体系做。
3。PDI的问题要等你确认聚合是共聚后,再解决。例如在一定的转化率就停止聚合。分
级等等。
1 (共1页)
进入Macromolecules版参与讨论
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相关话题的讨论汇总
话题: styrene话题: monomer话题: aibn话题: toluene话题: reaction