p******s
发帖数: 137 | 1 在端基影响不大的情况下，
两种不同聚合物的blend和这两种聚合物的copolymer在NMR上有什么区别？
怎么可以肯定聚合不是各聚合各的？多谢。
除了端基FTIR,DSC中的glass transition. | C***S
发帖数: 175 | 2 如果是固体的话，我有办法。
我可以检测特征基团间的距离，定性的话，可以做2D Exchange.
(sorry, I do not learn NMR in China, so I do not know the Chinese translations.)
In 2D exchange, you can see the cross peaks related to the characteristic
group of the two monomer will show up at different mixing time. Of course,
the more close of the copolymer to random polymer, the obvious the difference.
In other words, solid state NMR can differenciate the nanosize heterogeneity.
You can give the detail of these polymers, and I could possibly | C***S
发帖数: 175 | 3 In fact, the monomer series can also be done by NMR.
【在 p******s 的大作中提到】
: 在端基影响不大的情况下，
: 两种不同聚合物的blend和这两种聚合物的copolymer在NMR上有什么区别？
: 怎么可以肯定聚合不是各聚合各的？多谢。
: 除了端基FTIR,DSC中的glass transition.
| c****n
发帖数: 134 | 4 1. if homopolymers and copolymer have different solubilities, you may try
separation by extraction.
2. if it is copolymer instead of homopolymer mixture, MW should be higher
3. new NMR peak could arise for copolymer, attributable to groups connecting
two monomer units.
【在 p******s 的大作中提到】
: 在端基影响不大的情况下，
: 两种不同聚合物的blend和这两种聚合物的copolymer在NMR上有什么区别？
: 怎么可以肯定聚合不是各聚合各的？多谢。
: 除了端基FTIR,DSC中的glass transition.
| p******s
发帖数: 137 | 5 thanks, guys.
answer:
1. Yes, I thought of this.
However, it can get rid of only one homopolymer because I believe both
copolymer and another homo have similar solubility in organic solvent.
2. Mw is not necessarily larger because A component can react with itself;
B can react with it self too.
3. I said 端基影响不大.
【在 c****n 的大作中提到】
: 1. if homopolymers and copolymer have different solubilities, you may try
: separation by extraction.
: 2. if it is copolymer instead of homopolymer mixture, MW should be higher
: 3. new NMR peak could arise for copolymer, attributable to groups connecting
: two monomer units.
| c****n
发帖数: 134 | 6 3. It is not about end group. If the copolymer is random to some degree, there
will be a lot of AB or BA sequences, which are not available in respective
homopolymers and could have new peaks in NMR. (It is true for my random
copolymer. but it is only supporting information and can't rule out the
presence of homopolymers.)
connecting
【在 p******s 的大作中提到】
: thanks, guys.
: answer:
: 1. Yes, I thought of this.
: However, it can get rid of only one homopolymer because I believe both
: copolymer and another homo have similar solubility in organic solvent.
: 2. Mw is not necessarily larger because A component can react with itself;
: B can react with it self too.
: 3. I said 端基影响不大.
| p******s
发帖数: 137 | 7 it is a multi-block copolymer
there
try
higher
【在 c****n 的大作中提到】
: 3. It is not about end group. If the copolymer is random to some degree, there
: will be a lot of AB or BA sequences, which are not available in respective
: homopolymers and could have new peaks in NMR. (It is true for my random
: copolymer. but it is only supporting information and can't rule out the
: presence of homopolymers.)
:
: connecting
| C***S
发帖数: 175 | 8 this is not easy to tell.
Your system is worth for solid state NMR study.
I can not find a easy way to tell the difference. Spin diffusion may help.
【在 p******s 的大作中提到】
: it is a multi-block copolymer
:
: there
: try
: higher
|
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