j*****n
发帖数: 26 | 1 大家好。
我是佛罗里达州立大学化学系的博后，有机化学专业。希望能得到一些审稿的机会。我
的研究领域包括：有机合成，光化学，电化学，超分子化学，大分子化学。从研究生开
始，具体参与的研究项目涉及：dendrimer，photochemistry，fluorescent probe，
click chemistry和copolymer等等。之前在RSC和ACS的杂志上有审稿的经历，期望能有
更多的审稿机会。
如果需要可以告诉我你的邮箱，我可以把我的简历发给你。
我的联系方式：z***[email protected]
Qq: 27582210
欢迎联系！谢谢。 |
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y***o
发帖数: 416 | 2 1. Thermorheological Behavior of Various Long-Chain Branched Polyethylenes
Macromolecules, 2008, 41 (4), pp 1328–1333
DOI: 10.1021/ma702367a
http://pubs.acs.org/doi/abs/10.1021/ma702367a
2.Influence of Type and Content of Various Comonomers on Long-Chain
Branching of Ethene/α-Olefin Copolymers
Macromolecules, 2006, 39 (4), pp 1474–1482
DOI: 10.1021/ma0514018
http://pubs.acs.org/doi/abs/10.1021/ma0514018
3. Influence of the Molecular Structure of Polyolefins on the Damping
Function in Shear
Macro... 阅读全帖 |
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a***u
发帖数: 335 | 3 A. Ghosh, P. Kofinas, Nanostructured block copolymer dry electrolyte
Journal of Eelectrochemical Society, 155 (2008), A428-A431
Thanks |
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q****i
发帖数: 6923 | 4 Surface-Functionalized Periodic Mesoporous Organosilica Hollow Spheres
Shi Zhang Qiao, Chun Xiang Lin, Yonggang Jin, Zhen Li, Zhimin Yan, Zhengping
Hao, Yining Huang and Gao Qing (Max) Lu
J. Phys. Chem. C, 2009, 113 (20), pp 8673–8682
33 Tang, J.; Liu, J.;Wang, P.; Zhong, H.; Yang, Q. Evolution fromhollow
nanospheres to highly
ordered FDU-12 induced by inorganic salts under weak acidic conditions.
Microporous
Mesoporous Mater. 2010, 127, 119–125.
34 Liu, X.; Li, X.; Guan, Z.; Liu, J.; Zhao, J.; ... 阅读全帖 |
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w******e
发帖数: 953 | 5 Dental Materials
Volume 9, Issue 2, March 1993, Pages 123–127
Properties of expanding SOC/epoxy copolymers for dental use in dental
composites
J.D. Eick, 1, T.J. Byerley2, R.P. Chappell1, G.R. Chen3, C.Q. Bowles4, C.C.
Chappelow2 |
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P******e
发帖数: 129 | 6 公司招几个实习生，要求至少有2年高分子合成经验的，特别是做过control radical
polymerization和Ionic polymerization的, 特别是合成过functional polymers和
block copolymers优先。有意请私信 |
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发帖数: 1 | 7 化学/高分子/材料 求推荐审稿机会
才完成PhD,准备开始申请绿卡,在这里向各位大牛求审稿机会
涉及的领域主要有polymer/macromoleculear chemistry, self-assembly, drug
delivery, organic electronic materials, hybrid materials, block copolymer,
stimuli-responsive polymer, micelles and hydrogels等
email:[email protected]
如需要更多信息（比如CV或者publication list）请email我，多谢多谢 |
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l**b
发帖数: 2 | 8 count me.
I am reading some paper about cryo-tem to characterize self-assemble
copolymer. |
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w********h
发帖数: 12367 | 9 来自主题: Macromolecules版 - 问题
一般全称是poly-L-lactic acid.
正如zhangzheng所言，
一般是在copolymer中来用的。
呵呵，你是说他should be土就土到底了? |
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w******r
发帖数: 43 | 10 I just gived a talk about cryo-TEM's application for micelle.
I paste the key points. In my opnion, it is hard to do and the sample
preparation, you must change the concentraion. In dilute solution, you will
not
change the morphology of micelle in these work.
• Advantages:
1. TEM is a good local structural probe and the only technique that allows
real-space imaging of three-dimensional object at high resolution;
2. It is model-independent direct imaging of the local microstructure of
compl |
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x*o
发帖数: 1037 | 11
STM or AFM can image 3D object at high resolution, can't they?
blotting,
in
of
it
a
1,
Phys. |
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p*****x
发帖数: 68 | 12 not a blend of two polymers?
the only difference of the two repeating units is the branch, one is neutral
the other is anionic
thanks |
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b**s
发帖数: 589 | 13 如果不是diblock or triblock型
C13 NMR 可以很容易看出来 |
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p*****x
发帖数: 68 | 14 不知道是什么型的,有可能是statistical,也可能是block
怎么从NMR上看啊?不是很熟悉的说
neutral |
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b**s
发帖数: 589 | 15 A: 连着neutral branch的主链碳
B: 连着anionic branch的主链碳
如果是这样的结构
ABBAAAAABBBBAAAABBBABBBABABABBBABBA
以三元组为例
会出现 ABA, AAB, ABB, BAB...的峰，用统计算一下，算出竟聚率
可以大概知道高分子的结构，
如果是AAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBBBB
或blend of two polymers
则只会有AAA, BBB的峰（没有AAB, ABB的峰）
另外还要考虑你的侧链的峰是否也会显出来 |
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t*g
发帖数: 300 | 16 作个DMA，要是混合物的话会看到两个玻璃化转变。 |
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w******r
发帖数: 43 | 18 If the blend is miscible, there should be only one Tg.
of |
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t*g
发帖数: 300 | 19 要是这两种polymer的分子量及其分布很接近呢？ |
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w*z
发帖数: 35 | 20 could anybody give a better method? my polymer is very special, not made by
condensation or ionic polymerization.
mixture |
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b**s
发帖数: 589 | 21 The property most commonly relied upon to answer this question is solubility
behavior. Homopolymer blends and copolymers respond to extraction with
selective solvents and to solvent-nonsolvent fractionating techniques such as
fractional precipitation, column fractionating, and turbidometric situations.
These methods are simple and reasonably effective, particularly with systems
containing segments that differ significantly in their chemical structure
and/or physical state, e.g., polar-nonpolar |
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b**s
发帖数: 589 | 22 Another distinguishing tool is based on the presence of single-mode or
bimodal molecular weight distributions. A block copolymer representing a
single chemical species should display essentially single-mode behavior. By
contrast, homopolymer blends are more likely to exhibit bimodal
characteristics. One of the better ways to investigate this phenomenon is
density gradient ultracentrifugation. Assuming the two components possess
different densities, a bimodal distribution will be detected in t |
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w********h
发帖数: 12367 | 23 ft...
shear就是在一个方向上施加力。
以前我做液晶高分子的时候，
聚合液取出来后用四氟乙烯辊在一个方向上推，
造成取向。
现在用流变仪也可以使得block-copolymer and self-organized structural systems
在一个方向上取向。
比如Science1997年有一期材料科学的专刊Caltech的Kornfield的一篇文章比较详细地介
绍
了这个方法。
Stephen Cheng组里也用shear的方法得到很好的结果，
见Phys Rev Lett, 2001
condition |
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k***i
发帖数: 2 | 24 now I have a SMA sample, Mw = 240kg/mol and MA = 2%(wt) (reported). I want to
analysize the maleic anhydride percentage in this random copolymer.
1, I coupled SMA with PEG-amine (5k), but it is difficult to seperate SMA-PEG
from the unreacted PEG-amine by solvent soluability; ( it is possible by GPC,
but i think it is boring, to slow)
2, By 13C-NMR, I got 4%. But I doubt this method.( could 13C-NMR be used to
analysize quantatively？）
are there any other better methods for this characterization? |
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u*****s
发帖数: 23 | 25 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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w******z
发帖数: 29 | 26 I am working on the synthesis of triblock copolymer of PLA-PCL-PLA using
Tin(II) as catalyst. just began this summer and meet a lot of problems.
anybody are good at the system? millions of thanks first!!!!!!!!!!!!!!!! |
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b**s
发帖数: 589 | 27 A novel hydrogel formed from amphiphilic diblock copolypeptides could have
potential uses in biomedical applications. Scientists at the University of
California, Santa Barbara and the University of Delaware found that a small
amount of a diblock copolypeptide amphiphile, when added to water, formed a
network of polymer chains or hydrogel [ Nature (2002) 417, 424].
Amphiphiles have hydrophobic and hydrophilic sections, but most diblock
copolymer amphiphiles assemble into vesicles in water, |
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w******r
发帖数: 43 | 28
For the block copolymer micelles:
DLS can tell you the Rh of your micelles, it is best for sphere.
The best way is cryo-TEM. You can watch the morphology directly.
The convient and good is SAXS, you fitting the fact S(q) with different model.
The most accurate way is SANS. The recent results show that the micelle core
is not exactly close-packed.(Mortensen)
You can also measure the d1 by NMR to infer the micelle structure.
Another very good way is fluorescene spectrum. |
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w******r
发帖数: 43 | 29 These papers are non-equilibrium system, because they use PS as one of blocks.
PS has high Tg than rm T.
There are a lot work is about both the hydrophobic and hydrophilic have low
Tg,
so they can reach equilibrium.
Bates have a paper in JPS 2002 using cryo-TEM to characterize the micelle
morphology.
I know amphiphilic block copolymer can form spherical, cylinder, versicle,
flower and onion and networw or bicontinuous micelles. |
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w********h
发帖数: 12367 | 30 今天系里面举行纪念研讨会暨仪式，
纪念著名的高分子化学家Michael Szwarc (1909-2000).
并将他引入International Rubber Science Hall of Fame.
前来做报告的有：
USC的Thieo Hogen-Esch,
UMass@Lowell的Rudolph Faust,
Toronto的Michael K. Georges,
CMU的Matyjazewski,
Cornell的Geoff Coates,
还有我们系的Quirk.
我只听了Matyjazewski的报告,
The Art of ATRP...
95年的那篇王锦山和他写的发明ATRP的两篇文章,
如今已经被引用600多次.
偶不做化学,
对他讲的机理什么的不是十分明白,
他用动画的方式演示了如何大分子单体引发长成聚合物长链.
用ATRP聚合成的Block copolymer, molecular brush, hypebranched multifunctional,
functional colloids可以用AFM很漂亮地表征.
http://pubs.acs.or |
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y****u
发帖数: 50 | 31 thank you wonderlich. hi everybody!
I am working on synthesis of block copolymers...hope to communicate with new
friends here...Happy new year----good results the easy way! |
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w********h
发帖数: 12367 | 32 (1) Molecular weight is not repeating unit number.
(2) Mn can be considered as Mw roughly only when DP is close to 1.
(3) There is a slight difference between M(Sty) and M(MMA).
PS unit molecular weight is 104 g/mol
while PMMA is 100 g/mol.
(4) So, how many PMMA segments in a copolymer chain?
(10000 g/mol * 7%) / (100 g/mol) = 7. |
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w********h
发帖数: 12367 | 33 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 | 34 I am a little puzzled. what is your question again?
If your concern is about the (number) average molecular weight of PMMA in
PSt-PMMA diblock copolymer: First get wt% of PMMA (by NMR or whatever), then
get Mn of diblock from GPC. |
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y****u
发帖数: 50 | 35 what is amphiphilic side chain? do you mean amphiphilic block copolymer
grafted onto the backbone of a polymer chain? I don't know anything about such
kind of material, but it is technically possible.
what do you mean by "all the side chains attached to one side of the polymer
backbone"? do you mean 100% isotactic? that makes mission impossible.
if there is a way to synthesize your material, there will be a way to tailor
the content of each component. |
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b*****h
发帖数: 29 | 36 sorry, it is ambigious on what kind of polymer you want to know.
But concerned with leaving all amphi groups on one side, you can find some
paper on copolymer sufatants. Face seperation is a useful method to relize
some fansy architecture. |
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y****u
发帖数: 50 | 38 polymer sources.
what kind of triblock do you want? |
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c*********e
发帖数: 119 | 39 www.dexcopolymers.com
www.kraton.com |
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z**h
发帖数: 224 | 40 PEO-dPPO-PEO, 5000$,1g, is that expensive? |
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d**m
发帖数: 94 | 41 PEO-deuterium-PPO-PEO?? |
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y****u
发帖数: 50 | 42 wow! but you should expect that.
polymer sources is a small company.
if they have very good business, the price can be lower.
otherwise I will start my own company :P |
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z**h
发帖数: 224 | 43 yes, where can i buy cheaper polymers? |
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c*******n
发帖数: 1648 | 45 Very useful for polymer blends. Compatibilizers are surfactants basically.
However, small molecular surfactants are more complicated than block
copolymers.
Very interesting. |
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p**y
发帖数: 95 | 46 就是链段分布没什么规律，随机分布。
r1*r2=1 |
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b***e
发帖数: 115 | 47 应该有个量来表示的
D，具体的计算公式可以自己去查 |
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b***e
发帖数: 115 | 48 A,B, 两种单体，D=FaaFbb/(FabFba)
D的值越靠近1，越random. |
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