c*****e
发帖数: 238 | 1 Still some questions remain.
First, can you tell the composition within the phase boundaries?
Second, does the pattern persist if you increase/decrease the annealing time?
Third, what kind of change is induced by changing the volume fractions?
Fourth, what kind of monomer interactions (\chi) can be assumed for A and B?
是
的
同 |
|
a***n
发帖数: 578 | 2 CNT is actually a kind of Macromolecule. hehe. Polymer usually has a monomer.
Protein another kind of macromolecule can't be treated as polymer as well. |
|
s****e
发帖数: 2934 | 3 Polymerization is very complicated, you cannot simplize it like this way. To
choose the solvent for the polymerization, you need to consider many factors.
If your target is only to synthesize a new polymer, you dont need to think too
much about it only if you get polymer, then you can publish an ok paper. If
you want to find the best condition for the polymerization to publish good
paper,you need to know well about the properties of the initiator (catalyst?)
,monomer and polymer. so that you ca |
|
s****e
发帖数: 2934 | 4 If you just want to immobilizate protein in hydrogels, there are many
methods. Just search with protein and hydrogel, you can find many paper
about this area.
Basically,I guess you can mix protein together with the monomer and
hydrolysis. |
|
s****e
发帖数: 2934 | 5 ☆─────────────────────────────────────☆
wcy3029 (燕子) 于 (Thu Jul 27 20:51:45 2006) 提到:
I am doing DX delivery by hydrogels.I just begin. Most papers said loading
drug before polymerization and releasing it after polymerization. But I am so
confused how to purify the polymer after polymerization. There must be some
unreacted monomers residues in the polymer. During purifacation, the drug will
be released. Now I want to load drug after purification. I didn't get the
results yet.
☆───────────── |
|
b****g
发帖数: 54 | 6 在做一个lactone的开环反应，只用了monomer和solvent，加催化剂
引发剂的话，应该是反应体系里没有除干净的水
我看到好多相关的paper，都说到反应一定分子量的时候
加过量的Chloroform去终止反应
为什么呢？ chloroform是怎么终止反应的？ 得到的polymer是如何封端的呢？
多谢？ |
|
d******i
发帖数: 4222 | 7 【 以下文字转载自 Chemistry 讨论区 】
发信人: delvieri (leon), 信区: Chemistry
标 题: paper help!
发信站: BBS 未名空间站 (Tue Jul 10 23:38:09 2007), 转信
Title: Resin composites in dentistry: The monomer systems
Author(s): Peutzfeldt A
Source: EUROPEAN JOURNAL OF ORAL SCIENCES 105 (2): 97-116 APR 1997
Document Type: Review
Language: English
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids
=9151062&dopt=Abstract
To e-mail: c*************[email protected]
Thanks a lot! |
|
r******0
发帖数: 2753 | 8 Poor guy. I am sorry if I make you confused.
The part before "On the contrary" was right. Although, more importantly the
high temperature initiators were used where slow initiation is desireed, for
example, casting process.
Low temperature initiators can polymerize sluggish monomer as well. t-butyl
peroxy dicarbonate is a low temperature initiator, but it generates highly
reactive radical which is the same as t-butyl peroxide.
Again, everything I am saying and have said here could be wrong. You |
|
a*i
发帖数: 1652 | 9 来自主题: Macromolecules版 - 请教ATRP How many monomers can be polymerized to 100K?
Can it be an interesting research topic to increase the MW limit of ATRP?
I regularly finger through Macromolecules website---there are so many papers
dealing with controlled radical polymerizations. |
|
m***n
发帖数: 70 | 10 来自主题: Macromolecules版 - 请教ATRP 一般常用的monomer如styrene, methacrylates, acrylates, acrylonitrile都可以的
。但是其他如acrylamides比较困难。
关于高分子量ATRP的文章好像已经有一些了，你可以查一下。
papers |
|
s****e
发帖数: 2934 | 11 这个东西很毒，千万不要碰到皮肤上，手套至少要带3层，在hood里用，我们用0.5%的
溶液10分钟，sample放在一个玻璃的jar里面（close system），样品放在一个垫子上
，周围瓶底滴上RuO4溶液利用它的vapor就足够stain了，盖上盖子（盖子如果是金属的
，要垫上teflon sheet），10分钟，然后把sample拿走，用styrene monomer kill剩下
的RuO4，保证反应完全。sample拿去vacuum 几个小时，或overnight除水，因为RuO4是
aqueous。
非常非常毒，千万小心！！！尤其你第一次做没有经验，最好是和做过的人一起做。 |
|
o******e
发帖数: 4 | 12 Dilute solutions have strong hydrodynamic interactions. The Zimm modelworks
well and essntially all the solvent within the pervaded volume ofthe
polymer coil moves with the coil.
The situation is very different foran unentangled polymer melt.
Hydrodynamic interactions are screened andthe Rouse model applies. The Rouse
model will only describe your data at lowfrequency (frequencies below the
reciprocal of the Kuhn monomer time TAU0). But there is always a regime at
higher frequency (motions in |
|
o******e
发帖数: 4 | 13 Dilute solutions have strong hydrodynamic interactions. The Zimm modelworks
well and essntially all the solvent within the pervaded volume ofthe
polymer coil moves with the coil.
The situation is very different foran unentangled polymer melt.
Hydrodynamic interactions are screened andthe Rouse model applies. The Rouse
model will only describe your data at lowfrequency (frequencies below the
reciprocal of the Kuhn monomer time TAU0). But there is always a regime at
higher frequency (motions insid |
|
a*****s
发帖数: 3643 | 14 有一个polymer 70K分子量，monomer A 分子量206
要配成0.02M A 浓度的 溶液 100ml，要去几克Polymer呀？
谢谢！ |
|
c*****e
发帖数: 238 | 15 有点误导吧。
上文中说溶剂对Rg的影响，应该是根本上改变了monomer之间的相互作用，不仅仅是
stiff那么简单，stiff chain还是gaussian的，in the long range limit.
Rg简单说就是一个polymer在溶液中的线性尺寸，和end-to-end distance只有一个
factor的区别，说的都是一回事。
Rg是一个系综的平均值。
Rg可以描述光散射的性质，和流体力学的性质，尽管两者有subtle但是重要的区别。 |
|
D********g
发帖数: 533 | 16 看看用索氏提取器提取你的样品很长时间 这样就能基本上排除被吸附的monomer把 |
|
y***e
发帖数: 6082 | 17 啥是索氏提取器啊，俺比较无知，闻所未闻的说，是专门用来提取非专一性吸附的么？
看看用索氏提取器提取你的样品很长时间 这样就能基本上排除被吸附的monomer把 |
|
y***e
发帖数: 6082 | 18 看了下微机拜客，这个提取器根本不合适俺这个系统啊
看看用索氏提取器提取你的样品很长时间 这样就能基本上排除被吸附的monomer把 |
|
D********g
发帖数: 533 | 19 你的样品大么？我在一些文章上读过，grafting 一个polymer brush系统 然后要表征
这个薄膜的厚度 这种情况下面一般wafer不大 放到这个索氏提取器里面 回流
overnight 然后基本上就能除去大部分的未graft的polymer 具体可以查查Sergy Minko
，Clarkson U的一些文章
还有就是ultrasonic，用monomer良溶剂然后超声一段时间 monitor膜厚 如果不变了基
本上洗干净了 这个的不好的地方就是条件稍稍强烈了点，说不准polymer有没有同时被
洗掉，所以如果你的polymer和substrate结合的不是那么稳定 还是第一个方法比较保险 |
|
y***e
发帖数: 6082 | 20 好啊，俺看看去第一种方法去，多谢了
你的样品大么？我在一些文章上读过，grafting 一个polymer brush系统 然后要表征
这个薄膜的厚度 这种情况下面一般wafer不大 放到这个索氏提取器里面 回流
overnight 然后基本上就能除去大部分的未graft的polymer 具体可以查查Sergy Minko
，Clarkson U的一些文章
还有就是ultrasonic，用monomer良溶剂然后超声一段时间 monitor膜厚 如果不变了基
本上洗干净了 这个的不好的地方就是条件稍稍强烈了点，说不准polymer有没有同时被
洗掉，所以如果你的polymer和substrate结合的不是那么稳定 还是第一个方法比较保险 |
|
m*********t
发帖数: 295 | 21 你用的应该是grafting from的方法吧，如果是silicon wafer，把片子放到polymer和
monomer的良溶剂里面，用超声波超几分钟，吹干了换溶剂继续超，搞个三四次就可以
把物理吸附的去掉了
如果不放心，可以考虑用ellipsometer测膜厚，如果膜厚没变化了，物理吸附的肯定除
掉了
不知道你做surface grafting的时候加不加free initiator，很多group都证明了表面
聚合和溶液聚合得到的polymer差不多一样的，可以预见在表面上也将会共聚，但实验
结果才能说明问题，建议你在做surface grafting的时候在溶液里加free initiator，
如果表征的结果表面上没有惰性单体共聚的发生，将会是一个比较好的结果，但个人觉
得这个可能性不大
表面的表征，你可以用FTIR-ATR，做个homo的表面作为参照；其它还可以考虑用AFM，
如果两个polymer的phase image之类的会不一样的话；还可以考虑contact angle，然
后是grafting density，楼上有人提到同位素示踪应该不失为一个好方法，XPS |
|
y***e
发帖数: 6082 | 22 good point，多谢了
你用的应该是grafting from的方法吧，如果是silicon wafer，把片子放到polymer和
monomer的良溶剂里面，用超声波超几分钟，吹干了换溶剂继续超，搞个三四次就可以
把物理吸附的去掉了
如果不放心，可以考虑用ellipsometer测膜厚，如果膜厚没变化了，物理吸附的肯定除
掉了
不知道你做surface grafting的时候加不加free initiator，很多group都证明了表面
聚合和溶液聚合得到的polymer差不多一样的，可以预见在表面上也将会共聚，但实验
结果才能说明问题，建议你在做surface grafting的时候在溶液里加free initiator，
如果表征的结果表面上没有惰性单体共聚的发生，将会是一个比较好的结果，但个人觉
得这个可能性不大
表面的表征，你可以用FTIR-ATR，做个homo的表面作为参照；其它还可以考虑用AFM，
如果两个polymer的phase image之类的会不一样的话；还可以考虑contact angle，然
后是grafting density，楼上有人提到同位素示 |
|
y***e
发帖数: 6082 | 23 说道AFM，俺现在特羡慕Russell的仪器，做polymer morphology真是绝了
good point，多谢了
你用的应该是grafting from的方法吧，如果是silicon wafer，把片子放到polymer和
monomer的良溶剂里面，用超声波超几分钟，吹干了换溶剂继续超，搞个三四次就可以
把物理吸附的去掉了
如果不放心，可以考虑用ellipsometer测膜厚，如果膜厚没变化了，物理吸附的肯定除
掉了
不知道你做surface grafting的时候加不加free initiator，很多group都证明了表面
聚合和溶液聚合得到的polymer差不多一样的，可以预见在表面上也将会共聚，但实验
结果才能说明问题，建议你在做surface grafting的时候在溶液里加free initiator，
如果表征的结果表面上没有惰性单体共聚的发生，将会是一个比较好的结果，但个人觉
得这个可能性不大
表面的表征，你可以用FTIR-ATR，做个homo的表面作为参照；其它还可以考虑用AFM，
如果两个polymer的phase image之类的会不一样的话；还可以 |
|
c*s
发帖数: 2145 | 24 Thanks for your infos, especially the monomers that can be polymerized via
atrp.
My difficulty here is that the first block is non-soluble in water, this is
fixed. I was just wondering how can I run aqueous ATRP with the oil soluble
macroinitiator.
For example, the first bloack is PnBA or PtBA.
Maybe I can use methanol as solvent and at higher temperature, it might be a
good solvent for both PtBA and PSS?
Any comments?
Thanks a lot
酸( |
|
i********t
发帖数: 1148 | 25 个人觉得先合成dendronized monomer应该更好一些。如果先合成polymer以后，
polymer在溶剂中都是以entanglement的形式存在，不利于dendron的attack。当然也根
据具体情况而定吧，如果polymer backbone的共轭度比较高，应该会更rigid一点，
divergent似乎也不会差。 |
|
m*****e
发帖数: 1506 | 26 来自主题: Macromolecules版 - 外行求助 those are bis-substituted vinyl monomers |
|
j***n
发帖数: 19 | 27 来自主题: Macromolecules版 - 外行求助 isn't lz asking about bis-substituted monomer? |
|
c*******n
发帖数: 1648 | 28 可以这么理解。其实就是十几二十个MONOMER UNITS的COLLECTIVE MOTION. COARSE
GRAIN一下，键长键角都没有了。一个segment就是一个球，除了受链连接的约束外，就
是RANDOM的布朗运动。 |
|
y****1
发帖数: 34 | 29 to my opinion, B would not participate as it is an electron-rich vinyl
monomer and is not very reactive under radical conditions. |
|
m*****e
发帖数: 1506 | 30 Monomer A will be homopolymerized and only small porsion of B unit will be
incorporated into the final product. Check (Q,e) values of A and B, do an
Alfrey-Price calculation, the contrast values of r1 and r2 could support
this point. |
|
k*******n
发帖数: 2399 | 31 本人本身不是做高分子聚合的，只是在一个particle stablized emulsion体系里面用
了styrene作聚合单体。发现增加里面的particle浓度导致聚合速率降低，该particle
是7% 的SWNT负载在SiO2上。增加particle浓度从表观上是减小了聚合物颗粒的大小(~
um)。我看见不少emulsion polymerization都是增加particle浓度增加了反应速率，因
为emulsion droplet变小的话会导致反应体系compartamentalization降低bimolecular
termination的可能。我现在怀疑是不是该颗粒会quench聚合的radical，本人用AIBN
作为引发剂。该颗粒具有SWNT, COOH, Co, Mo和SiO2在表面上。本人提出另外一个可能
是emulsion drop变小，减少了monomer bimolecular reaction的速率。 那种更具有可
能性。先谢谢了。 |
|
r******0
发帖数: 2753 | 32 你咋也开始乱说了。不应该啊！！
initiator和monomer的ratio怎么会跟着particle numbers来变？！在bulk里是多少，分成100个 particles那ratio还是那么多，分成1000000000个particles那ratio也是一样的。我不知道他实验的details，但他那个case看起来更象是包在外面的particles 会quench radicals，所以drops越小被quench掉的机率越大，所以速度越慢。当然这里说的速度不是聚合速度而是 conversion / time。 |
|
d**a
发帖数: 3715 | 33 我现在开足马力争取先多合成一点Monomer。 |
|
a********c
发帖数: 60 | 34 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, |
|
d**a
发帖数: 3715 | 35 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 | 36 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? |
|
b******0
发帖数: 45 | 37 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 |
|
r******0
发帖数: 2753 | 38 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 | 39 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 | 40 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. |
|
b******0
发帖数: 45 | 41 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. |
|
D********g
发帖数: 533 | 42 真没想到不除阻聚剂都能聚合。。。
我建议还是别偷懒 提纯你的monomer先 |
|
t***u
发帖数: 20182 | 43 how did u purify it? it has poor solubility in any solvent? |
|
a*****h
发帖数: 13 | 44 maybe you can use benzene
but that is toxic... |
|
x*****g
发帖数: 82 | 45 国内有机硕士毕业，博士期间的工作经历如下
Synthesis and characterization of Polymer & monomer, Modification functional
molecules to polymer scaffolds
The application of synthetic biocompatible polymers, like drug and gene
delivery
Operating Instrumentals, NMR, HPLC, GPC, MS (MALDI-TOF),TEM, Confocals IR,
DLS etc.
publication现在只有一篇jacs和国内时候发的几篇有机方向文章，还有4-5篇已经投出
或者即将投出。
明年五月份毕业，不知道能不能在毕业前找到位子。
将来何去何从还没有打算。
请大家给点建议，现在心里很忐忑，谢谢 |
|
w*******8
发帖数: 865 | 46 和monomer的reactivity有关吧，什么r1 r2的好多书都有讲 |
|
a*i
发帖数: 1652 | 47 来自主题: Macromolecules版 - eATRP New method allows for more precise control over ATRP
http://www.rdmag.com/News/2011/04/Manufacturing-Materials-New-M
Scientists led by Carnegie Mellon Univ. chemist Krzysztof Matyjaszewski are
using electricity from a battery to drive atom transfer radical
polymerization (ATRP), a widely used method of creating industrial plastics.
The environmentally friendly approach, reported in Science, represents a
breakthrough in the level of control scientists can achieve over the ATRP
process, which will... 阅读全帖 |
|
e****m
发帖数: 8 | 48 Thanks for the reply.
Actually I am making Polyacrylamide gel under room temperature. My current
working formula is list below:
Acrylamide (monomer) (~ 8%, wt)
bis-acrylamide (crosslinker)
Redon: Tetramethylethylenediamine/ammonium persulfate
solvent: water/ethylene (10:1)
This formula works pretty well. However, I am trying to replace water/
ethylene glycol with pure ethylene glycol but the crosslinking cannot be
initiated even after two days. I tried to vary the reaction temperature but
it did... 阅读全帖 |
|
w********h
发帖数: 12367 | 49 1 PROG POLYM SCI 22.870
2 POLYM REV 8.000
3 ADV POLYM SCI 6.723
4 BIOMACROMOLECULES 5.325
5 MACROMOLECULES 4.837
6 SOFT MATTER 4.457
7 MACROMOL RAPID COMM 4.365
8 J POLYM SCI POL CHEM 3.894
9 POLYMER 3.828
10 J MEMBRANE SCI 3.673
11 CARBOHYD POLYM 3.463
12 MACROMOL BIOSCI 3.458
13 CELLULOSE 2.817
14 J BIOACT COMPAT POL 2.610
15 POLYM DEGRAD STABIL 2.594
16 REACT FUNCT POLYM 2.546
17 EUR POLYM J 2.517
18 COLLOID POLYM SCI 2.443
19 MACROMOL CHEM PHYS 2.437
20 EUR PHYS J E 2.096
21... 阅读全帖 |
|
w********h
发帖数: 12367 | 50 1 PROG POLYM SCI 22.870
2 POLYM REV 8.000
3 ADV POLYM SCI 6.723
4 BIOMACROMOLECULES 5.325
5 MACROMOLECULES 4.837
6 SOFT MATTER 4.457
7 MACROMOL RAPID COMM 4.365
8 J POLYM SCI POL CHEM 3.894
9 POLYMER 3.828
10 J MEMBRANE SCI 3.673
11 CARBOHYD POLYM 3.463
12 MACROMOL BIOSCI 3.458
13 CELLULOSE 2.817
14 J BIOACT COMPAT POL 2.610
15 POLYM DEGRAD STABIL 2.594
16 REACT FUNCT POLYM 2.546
17 EUR POLYM J 2.517
18 COLLOID POLYM SCI 2.443
19 MACROMOL CHEM PHYS 2.437
20 EUR PHYS J E 2.096
21... 阅读全帖 |
|
