w******e
发帖数: 953 | 1 Toward rapid aqueous RAFT polymerization of primary amine functional monomer
under visible light irradiation at 25 °C Guhuan Liu,a Hui Shi,a Yuru
Cui,a
Polym. Chem., 2013,4, 1176-1182
DOI: 10.1039/C2PY20810E
Thanks a lot! |
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t*****e
发帖数: 3544 | 2 价钱不错了。里面的主要成份monomer,oligomer才卖几美刀一磅。 |
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y***o
发帖数: 416 | 3 1. Comparative Theoretical Study on Homopolymerization of α-Olefins by Bis(
cyclopentadienyl) Zirconocene and Hafnocene: Elemental Propagation and
Termination Reactions between Monomers and Metals
Organometallics, 2010, 29 (7), pp 1541–1550
DOI: 10.1021/om900843h
http://pubs.acs.org/doi/pdf/10.1021/om900843h
2. Influence of the Ligand Structure of Hafnocene Polymerization Catalysts:
A Theoretical Study on Ethene Insertion and Chain Propagation
Organometallics, 2008, 27 (14), pp 3390–3398
DOI: 10... 阅读全帖 |
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c*******n
发帖数: 1648 | 4 是关于这个化合物的。
http://webbook.nist.gov/cgi/cbook.cgi?ID=C88584&Mask=200
我们用来做MONOMER的稳定剂。最近怀疑这个东西有问题，做了gc-ms，但是分析化学很
多方面都还给老师了。做出来的结果和上面那个link不一样。上面有222的峰，应该就
是这个分子本身。但我做GC出来两个东西，一个东西在MS上的峰是221，一个是223，其
他很多峰也是和NIST的这个分子量差一。是不是我们的做法不对？还是说可以肯定就不
是这个分子了。
红外上看不出和LIBRARY里的谱有太多差别，DSC上有新的MELTING PEAK. 不知到是否对
应GC上的小流出峰，还是不同的结晶形态。所以才去做GC-MS。 |
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p******s
发帖数: 193 | 5 想照着2009年邓春晖Angew chemie的Fe3O4@SiO2@PMMA 的文章，做这个东西，用来接功
能蛋白
大家看看，最后的聚合不需要引发剂么？
前文不赘述了，Fe3O4@SiO2-MPS 已经合成好了
要往上面修饰PMMA了，
The sandwich structured Fe3O4@SiO2@PMMA microspheres were synthesized via an
aqueous-phase radical polymerization. Typically, in a three-necked round
bottom flask (100 mL) equipped with a mechanical stirrer, a refluxing
condenser, and a nitrogen inlet, 10 mL of ethanol dispersion of Fe3O4@SiO2-
MPS microspheres were mixed
with 50 mL of aqueous solution containing 5.0 mg of ... 阅读全帖 |
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c*****u
发帖数: 439 | 6 请问，有什么小分子和protein（monomer）的结合强度可以接近biotin和
streptavidin?
我想找一个化学生成的linker 两端带上修饰，把两个不同的蛋白链接在一起。
可是streptavidin 是多聚物。 可能不太合适。
希望哪位做药物的或者做合成的可以给我提供一点线索。
谢谢了 |
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l*******e
发帖数: 40 | 7 Topochemical polymerization using bis-thyminyl monomers
Priscilla Johnston,a Dylan Wheldale,a Carl Braybrookb and Kei Saito*
Polym. Chem., 2014,5, 4375-4384
DOI: 10.1039/C4PY00265B
Thanks a million! |
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q****i
发帖数: 6923 | 8 Recent Developments in the Synthesis and Structure of Organosilanols
Vadapalli Chandrasekhar Ramamoorthy Boomishankar Selvarajan Nagendran
Chem. Rev., 2004, 104 (12), pp 5847–5910
Publication Date (Web): October 13, 2004 (Article)
http://pubs.acs.org/doi/abs/10.1021/cr0306135
Regiospecific Radical Polymerization of a Tetrasubstituted Ethylene Monomer
with Molecular Oxygen for the Synthesis of a New Degradable Polymer
Akikazu Matsumoto Shuji Taketani
J. Am. Chem. Soc., 2006, 128 (14), pp 4566–456... 阅读全帖 |
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z*******g
发帖数: 9 | 9 poly vinyl imidazole....
AIBN is the initiator...very similar to the ppl in the previous
post.just the ratio of initiator to monomer is far higher than
that(solution polymerization)..
Thanks! |
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c*********e
发帖数: 119 | 10 It should be "melting ploymerization". In order to keep very low water content
and oxygen content, it must be in vacuum or Nitrogen gas. There must be
catalyst and stirring. But I also do not the details. It depends on the
different monomers.
groups(4-hydroxyphenyl-). |
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F***F
发帖数: 7 | 11 This is a purification process. Coz NIPAAM monomers are well
dissolved in Hexane/acetone (I can not remember the volume ratio).
Then place it into refrigerator at 4 degree C for one night. Needle like
NIPAAM crystall can precipite at the bottom. The impurity still dissolve
in the solvent. You can use extraction method to separate crystal like NIPAA
M.
After that, you should use hexane to wash impurities out from NIPAAM, Coz tr
ace of impurity
absorb on the crystalls.
This is a general purificati |
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w******r
发帖数: 43 | 12 Depend on the amout of water in the monomer.
So, he should give the detail information about his solution.
和 |
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u*****s
发帖数: 23 | 13 maybe you can use 2D H1 NMR. I have seen some book said that the monomer
percetange of random copolymer can be gotten from this method.
to
SMA-PEG
GPC, |
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y****u
发帖数: 50 | 14 basically the original question was about wt% or mol%. obviously it is wrong
to use mol%.
yes, we can. once we know the Mn of diblock and wt% of MMA, the second monomer
doesn't matter for the answer.
but
My understanding: "segment"="block". |
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w********h
发帖数: 12367 | 15 anyway, Mn Mw issue is just for the sake of physics.
block copolymer chain: (Sty)n-----b-----(MMA)m
n Styrene segments and m MMA segments.
monomer |
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y****u
发帖数: 50 | 16 In ATRP, the concentraion of free radicals is kept very low
so as to minimize chain transfer and termination.
Most polymer chains are dormant with a halogen atom as endgroup.
A typical ATRP system consists of a monomer, initiator (usually alkyl halide),
catalyst (transition-Metal complexes), and ligand.
The added amide might react with other component instead of the free radical.
Quenching is used in living anionic polymerization to
prepare end-functionalized polymers,
but in ATRP, the halogen c |
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y****u
发帖数: 50 | 17 is it possible to polymerize the monomer with such simple structure? |
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y****u
发帖数: 50 | 18 it is intriguing that there is almost no publication on the polymerization of
this monomer.
If I can polymerize it...something will happen. :)
but i don't think radical polymn will work. it could be copolymerized. |
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c*******n
发帖数: 1648 | 19 I don't think the free radical can make it, degradative chain transfer could
happen. However, the cationic polymerization probably do. If you have time,
check out some textbook on polymerization, such as Odian's. Take a look at the
table for monomer and corresponding polymerization method. Generally vinyl
ether can not be polymerized by free radical.
of |
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c****n
发帖数: 134 | 20 for well-defined polymers, NMR can be used to evaluate MW
If every polymer chain has a head group or end group,
we can use its integration intensity and that of the monomer units to cal. MW.
However, when MW is high, as the relative concentration of head group or end
group is quite low,
great error may occur.
GPC is good. but for a new polymer, you have need to know the dn/dc first. |
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t*******n
发帖数: 66 | 21 Actually another one important characterication about living polymierzation is
that block compolymer should be formed upon adding another monomer.
realm
is
RAFT,
is |
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r******0
发帖数: 2753 | 22 How long do you want your nano fibers to be? Did u calculate how long it will
take for the monomer to fill your 100-200nm channel by capillary force? If you
want a long fiber and count on the capillary force, this may not be a good way
to do it.
inside
will |
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b*****h
发帖数: 29 | 23 some suggestion for me to use 二茂铁衍生物 synthesis magnetic polymer is
correct or not?
since I have check the paper, this kind of polymer or even monomer itself is
paramagnetic that means non-mag at least in room temperature.
can some one know anything or have found any paper with this?
how about Sol-gel or composites?
or ferroplating?
I am amazed by how hard to fabricate some magneic fibres array!
maybe i should found another way to simulate the cilia movement.
since I can not use this as a large r |
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b**s
发帖数: 589 | 24 radical can be transferred to catalyst, solvent..., but compared to the
reaction with monomer, it's slow or negilible |
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p*****x
发帖数: 68 | 25 i made some polymer which is soluble in DMF and monomers are soluble in CH3CN,
so i tried to precipitate from CH3CN, but it seems to lose quite some material
in that process. can i decrease the loss by using more CH3CN?
i also tried to wash with CH3CN and filter, then dissolve the polymer off the
filter and pump off DMF, but since DMF is quite high boiling, it is quite
tedious.
any suggestions? |
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c*******n
发帖数: 1648 | 26 After a cum, I don't really wanna think anything more. However I cannot resist
this thread:) Please let me jump in. In my last post, I already mentioned it's
very interesting to know that Bio pointed out the same dimension scaling come
from the different driving force, which turns out a confusing problem for me.
If it's true, I would have agreed what wonderlich suspect.
But there are some premises in Bio's story. Firstly, Bio consider monomer as a
good solvent for the polymer, and the second pre |
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c*****e
发帖数: 238 | 27 First of all, I think the /chi parameter only contains enthalpic interactions,
but the /chi term in the Flory-Huggins free energy contains both enthalpic
and entropic contributions.
Thus from the definition, if the polymer chain is dissolved in its monomer
solvent, /chi parameter is exactly zero. Usually(I guess) people refer to
good solvent as /chi<0, while poor solvent as /chi>0. The thing is that in
experiments, this criterion is usually shifted to shift to some /chi
since usually it is |
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c*******n
发帖数: 1648 | 28 Great summary, sounds very convincing for me. BTW: I have a interesting
question, you basically says that the scaling will be the same, but how about
the exact dimensions? For example, in monomer solvent and good solvent, the
scaling is the same, and the dimensions are the same or different?
real
polymer
But
my |
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c*****e
发帖数: 238 | 29 Well, first I doubt the conclusion that the scaling is the same in
monomer solvent as in good solvent. It should be mentioned that the entropic
interactions generally lead to Gaussian chain behavior, it is the enthalpic
interactions that shift this scaling. Thus in the athermal solution, the
maximized entropy should give a Gaussian distribution.
Second, if the scaling is the same, then the dimension is the same, the
difference lies in the prefactor or higher order scalings, say
Rg\simN^(-1/2)+N^ |
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w********h
发帖数: 12367 | 30 根据我的理解，这个correlation length (also screening length)意义为
长链分子中的重复单元感受到另外一条链的重复单元的最小长度。在这个长
度以内，所有的重复单元均为单一的polymer chain的monomer，超过这个长
度，此polymer chain开始感受到另外的polymer chain的存在。故而，在稀
溶液中ξ是和R同一个数量级，溶液浓度超过overlap concentration φ*的时
候，ξ随浓度下降（依赖性分θ-solvent和good solven之别），而R在good
solvent case对浓度有依赖性。
我的问题是，ξ和我们说的entanglement molecular weight有什么必然关系？
从感知另外一条链的存在到缠结之间的过程是什么？ |
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m**l
发帖数: 15 | 31 I am reading on hyperbranched materials and lots of people mention gel points,
but I can't find any detailed discription of what it is and what it looks
like. For example, is it a function of monomer concentration or something
else? Is it literally a gel or just a insoluble solid?
Thanks! |
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w********h
发帖数: 12367 | 32 hehe, you must be in polymer engineering.
our languages are quite different.
my understanding is this:
your crosslink density is my entanglement molecular weight Me,
the lower Me, the higher crosslink density.
when Me=M0 (monomer molecular weight), it is crosslinked (also called
thermoset). is that right?
PS Tg=100C Me=18000g/mol
PBD Tg=-100C Me=1543g/mol
PS is normally glass-like (or thermoplastic) at room temperature because of
its high Tg.
When you increase your temperature to 130 to 150C,
yo |
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m**l
发帖数: 15 | 33 If I need a polymer chain 5-10 nm's long when extended, how many monomers
should I have in each chain? Thanks! |
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w********h
发帖数: 12367 | 34 you can calculate.
first you should know the length of a C-C bond,
then know how many C-C bond in a repeating unit,
then you can get how many monomer (if also eaqual to a repeating unit) for
5-10 nm. |
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c*****e
发帖数: 238 | 35 It is not difficult to extend the FH free energy to the case of polymer blends.
The entropy term should be independent of the species of monomer, and only
dependent on the chain length. The enthalpic term is zero in this case. |
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r******0
发帖数: 2753 | 36 I don't think so. The methacrylate radical is more stable and less reactive.
The methacrylate monomer is more reactive.
个快 |
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c****n
发帖数: 134 | 37 people don't solve all the problems; rather, they leave the real challenge
behind.
1) For ATRP: several papers attempted preparing triblock copolymers as
Thermoplastic elastomers, but without decent properties (I would say results
are lousy).
2) It was claimed in a review "virtually all monomers are polymerized in
living XXXX polymerization". A critical review would add "but only a few are
truly living and in most cases the polydispersity is too large". |
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w***o
发帖数: 3830 | 38 Cp2ZrMe2/BARF
should be very reactive
but if your monomer kills the catalyst
forget it.. |
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w***o
发帖数: 3830 | 39 hehe
will not tell u wt my monomer is
very bulky, but adds:)
the catalyst nowadays, even the Pd/Ni catalyst, are pretty bulky.. |
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C***S
发帖数: 175 | 40 来自主题: Macromolecules版 - 问个傻问题 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 |
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C***S
发帖数: 175 | 41 来自主题: Macromolecules版 - 问个傻问题 In fact, the monomer series can also be done by NMR. |
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c****n
发帖数: 134 | 42 来自主题: Macromolecules版 - 问个傻问题 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. |
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w***o
发帖数: 3830 | 43 啊？
这个很容易啊
时间别太长
monomer要pure |
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s*****o
发帖数: 65 | 44 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! |
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o**r
发帖数: 11 | 45 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 |
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o**r
发帖数: 11 | 46 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? |
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s*****o
发帖数: 65 | 47 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 |
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C***S
发帖数: 175 | 48 Say, in random polymer AB, what is the probability of 30mer,
P^30, if the reactivity of either of is P.
Any paper talking about this, Book is also good.
Thanks! |
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w********h
发帖数: 12367 | 49 if polycondensation (yes for your assumption "random"),
you can find the calculation in any polymer textbook on step-polymerization.
here is one practical example of AA, B1B1, and B2B2:
OSAHENI JA, JENEKHE SA
ELECTROACTIVE AND PHOTOACTIVE ROD-COIL COPOLYMERS - DESIGN, SYNTHESIS, AND
SUPRAMOLECULAR REGULATION OF PHOTOPHYSICAL PROPERTIES
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 117 (28): 7389-7398 JUL 19 1995
Times Cited: 66
I also published one paper on a more complicated AA, BB, AB case.
However |
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C***S
发帖数: 175 | 50 Thanks.
My purpose is to calculate the TFE sequence length in Nafion, which
is crucial for the crystalization of Nafion.
Based on this, we can cooperate our NMR data to propose a reasonable
morphology of Nafion. |
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