s*****o
发帖数: 65 | 1 I was asked to determine cyanoacrylate monomer end group by GPC. I only know
how to get molecular weight by GPS. Don't know how to test end group by GPC.
Can anyone give me a hand. Thanks a lot! |
a***n
发帖数: 578 | 2 what is GPC? it is likely that the interviewer doesn't know as well. hehe
【在 s*****o 的大作中提到】
: I was asked to determine cyanoacrylate monomer end group by GPC. I only know
: how to get molecular weight by GPS. Don't know how to test end group by GPC.
: Can anyone give me a hand. Thanks a lot!
|
t*******n
发帖数: 66 | 3 Of course. You can use the UV dector or the Fluorescence detctor for the end
group. good luck
【在 s*****o 的大作中提到】
: I was asked to determine cyanoacrylate monomer end group by GPC. I only know
: how to get molecular weight by GPS. Don't know how to test end group by GPC.
: Can anyone give me a hand. Thanks a lot!
|
o**r
发帖数: 11 | 4 用皮定或者三苯基磷引发可以看到紫外信号
如果光聚合呢
【在 t*******n 的大作中提到】
: Of course. You can use the UV dector or the Fluorescence detctor for the end
: group. good luck
|
s*****o
发帖数: 65 | 5 Thank you so much for your reply. It is very helpful.
They told me they have two batches of cyanoacrylate monomer. Chemically they
are same. The react and polymerized differently. They think this is because
the end group difference. The did GC and find no difference. So they like an
intern go there to do some GPC and tell the end group difference. It looks
they have a GPC.
They will make discision on this position today or Monday. So can I email them
and say: I can use GPC fractionate each monom
【在 o**r 的大作中提到】
: 用皮定或者三苯基磷引发可以看到紫外信号
: 如果光聚合呢
|
o**r
发帖数: 11 | 6 It has been reported that the material's stability
depends upon the nature of the polymerisation
initiator, and that degradation occurs by unzipping to produce
almost entirely monomer. Zip lengths greater than
2350 units have been observed. On the basis of these
observations it has been presumed that degradation is
initiated at the chain end containing the polymerisation
initiator residue and that the character of this group determines
thermal stability.
Macromol. Rapid Commun. 2001, 22, 1158±11
【在 o**r 的大作中提到】
: 用皮定或者三苯基磷引发可以看到紫外信号
: 如果光聚合呢
|
s*****o
发帖数: 65 | 7 It is true. The reaction of end group with initiator is very critical to the
polymer property. They have trouble on this now. So they also ask me study
stability.
Frictionate means to seperate it. I am think the end group may be seprated
from monomer by GPC. I am not sure too.
Two batches of monomer maybe means that they used different methods to make
it. I was surprised too. I asked two time. They told me two batch monomer are
really different.
they
because
like an
looks
email them
fractions.
【在 o**r 的大作中提到】
: It has been reported that the material's stability
: depends upon the nature of the polymerisation
: initiator, and that degradation occurs by unzipping to produce
: almost entirely monomer. Zip lengths greater than
: 2350 units have been observed. On the basis of these
: observations it has been presumed that degradation is
: initiated at the chain end containing the polymerisation
: initiator residue and that the character of this group determines
: thermal stability.
: Macromol. Rapid Commun. 2001, 22, 1158±11
|
o**r
发帖数: 11 | 8 还是不懂，这个单体一般是这样做的
CN-CH2-COOR + 甲醛
在碱性下脱水生成高分子，高温下加抗氧剂裂解生成的
一般不会啊，
did they mention anything about the difference of monomers?
is there any NMR or MS?
【在 s*****o 的大作中提到】
: It is true. The reaction of end group with initiator is very critical to the
: polymer property. They have trouble on this now. So they also ask me study
: stability.
: Frictionate means to seperate it. I am think the end group may be seprated
: from monomer by GPC. I am not sure too.
: Two batches of monomer maybe means that they used different methods to make
: it. I was surprised too. I asked two time. They told me two batch monomer are
: really different.
:
: they
|
s*****o
发帖数: 65 | 9 They didn't mention the difference. I was stupid today. I should ask very
clearly. I am afraid to ask too much to lose face.
This noon after I come back I sent a thank you note and asked the monomer
prepartion methods. I aslo suggested use UV, NMR,or IR. But I also said I keep
research to say if I can use GPC to find out the end group. The manager didn't
reply my email. Maybe no hope.
the
make
are
【在 o**r 的大作中提到】
: 还是不懂，这个单体一般是这样做的
: CN-CH2-COOR + 甲醛
: 在碱性下脱水生成高分子，高温下加抗氧剂裂解生成的
: 一般不会啊，
: did they mention anything about the difference of monomers?
: is there any NMR or MS?
|
s*****o
发帖数: 65 | 10 Thank you so much for you advice. Can you tell me waht UV or Fluoresence can
detact what?
know
GPC.
【在 t*******n 的大作中提到】
: Of course. You can use the UV dector or the Fluorescence detctor for the end
: group. good luck
|
s*****o
发帖数: 65 | 11 acording this normal methods, what end groups do they mean. The CH2 or CHOH? I
am very frustrated.
the
make
are
【在 o**r 的大作中提到】
: 还是不懂，这个单体一般是这样做的
: CN-CH2-COOR + 甲醛
: 在碱性下脱水生成高分子，高温下加抗氧剂裂解生成的
: 一般不会啊，
: did they mention anything about the difference of monomers?
: is there any NMR or MS?
|
o**r
发帖数: 11 | 12 你是学高分子化学的么？
比较好奇，
就算你得到这份工作，估计也会比较辛苦
这种技术支持的东西，没有实际的经验很容易
抓不到重点，往往干上半年也找不到方向..................
我做聚氨酯就是这样，聚THF的低聚物
分子量只有500-800之间才能符合公司的需要
另外一个类似前体就必须500以下，
公司要我们给个具体原因，我们2个人用了2年
才做出来。
..............................
【在 s*****o 的大作中提到】
: acording this normal methods, what end groups do they mean. The CH2 or CHOH? I
: am very frustrated.
:
: the
: make
: are
|
s*****o
发帖数: 65 | 13 Thanks a lot for your help. You must be very good at polymer chemistry. I
have studied a polymer chemistry course. But I almost never used it. I mainly
work on polymer materails. So it is a hard job for me.
I plan to call or email the manager monday. I will tell him I can't test the
end group by GPC alone. I will combine some other methods.
I will send them email or call them monday ask
can
end
only
by
【在 o**r 的大作中提到】
: 你是学高分子化学的么？
: 比较好奇，
: 就算你得到这份工作，估计也会比较辛苦
: 这种技术支持的东西，没有实际的经验很容易
: 抓不到重点，往往干上半年也找不到方向..................
: 我做聚氨酯就是这样，聚THF的低聚物
: 分子量只有500-800之间才能符合公司的需要
: 另外一个类似前体就必须500以下，
: 公司要我们给个具体原因，我们2个人用了2年
: 才做出来。
|
