p*****x
发帖数: 68 | 1 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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a***u
发帖数: 9 | 2 You can try distilling some DMF from the polymer solution under vacuum. If the
solution is too dilute, you may have fine powders which are extremely
diffucult to collect unless you use a very good centrifuge. Yes, getting rid
of DMF is tedious. But spending even an hour on that may save you many hours
in trying to recover the polymer. Also pouring CH3CN into DMF may give you
different result from pouring DMF into CH3CN, although I am not sure which way
is better for your experiment. In one word, |
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a***n
发帖数: 578 | 3 【 以下文字转载自 Chemistry 讨论区,原文如下 】
发信人: argon (argon), 信区: Chemistry
标 题: Possible to use polymer as stabilizer?
发信站: Unknown Space (Fri Aug 15 14:01:38 2003) WWW-POST
as stablilizer of nanoparticles? Thanks a lot.
If it is possible, can we make nanoparticle doped polymers?
CDS... :-) |
|
c*******n
发帖数: 1648 | 4 Actually I didn't read more than 2 of her papers. However I do not consider
the polymer is a support in her battery, instead it is the solid electrolyte
(instead of liquid one in traditional battery) which can be easily processed
in industry and can be formed in any shape(you can make a battery like a
film). This is the main reason why polymer lithium battery get popular these
days. |
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t******l
发帖数: 3060 | 5 my labmate did not get checked.
our major is Polymer chemistry.
but our research is not that polymer related, organometallics. |
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p*****d
发帖数: 40 | 6 kind of agree, but i am not expert at the chain theory. you mean polymer
people care more about application instead of fundamentals, i also agree, coz
thats what polymer is used for.
then, what do u think is the major advance in recent 10 years? |
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p******s
发帖数: 137 | 7 ACS Award in Polymer Chemistry sponsored by ExxonMobil Chemical Company
Purpose: To recognize outstanding contributions to polymer chemistry.
Nature: The award consists of $5,000 and a certificate. Up to $1,000 for
travel expenses to the meeting at which the award will be presented will be
reimbursed.
Establishment and Support: ExxonMobil Chemical Company assumed sponsorship of
this award in 1981. Witco Chemical Corporation Foundation established the
award in 1962.
Rules of Eligibility: The awar |
|
b**m
发帖数: 18 | 8
of
Thank you so much, wonderlich and dafeng. You two debugged a long-time
misunderstanding in my mind. :-)
BTW, sometimes we classify polymers into three catagories: thermoplastics,
rubber, and thermosets. In this case, "rubber" is refered to the cross-linked
rubber. Is this correct? The difference between the three is mainly the
cross-link density.
polymer
this |
|
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c*******n
发帖数: 1648 | 9 comments, just because I was a polymer engineer before. Nylon can be
extruded just above its melting temp, not necessary at as high as 300C. Think
about their molecular weight and rheological curves. Not much relate to Tg.
Most of properties relate to crystallizations and h-bonds. Of course polymers
can be processed at room temp. Check rubber injection molding work or anybody
you know in Isayev's group. Even nylon solid can be processed at room
temperatures by pulverniztion using a specific extr |
|
s*****y
发帖数: 27 | 10 I borrowed some polymer books, and iti s very hard to read them, I feel
hesitate to ask my advisre always. I try to understand by myself, but it is
too hard, could some guys give me some suggestion to read them. or share some
experience , I am a new polymer person, before I study physics. thanks
firstly. |
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p*********e
发帖数: 42 | 11 want to buy Flory's Principles of Polymer Chemistry, In Amazon, a guy is
selling brand new International Edition Principles of Polymer Chemistry for
less than 50 bucks, not sure why it is so cheap. (Amazon and other companies
sell for over $80).
Any suggestions?
Happy new year! |
|
d****i
发帖数: 360 | 12 怎样制备POLYMER BEADS？ 从Polymer solution 开始！ THANKS！ |
|
w********h
发帖数: 12367 | 13 that one is for unentangled branched polyesters.
I think it is quite different from polymer gel, which is defined very well on
Pages 199-206 in the same book.
That one is Rouse behavior which can be observed in any polymers in Glassy (or
Rouse) regime.
Ralph,Colby. |
|
w********h
发帖数: 12367 | 14 no longer there.
no hurt to try try.
since Dai Liming is gone, probably they want to get one for nano stuffs?
no idea.
if you don't seriously do something in polymer science,
I don't think you have much chance in that Polymer Science Dept. |
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c*******r
发帖数: 7296 | 15 It seems pretty hard to join Polymer Science.
Dr Judit Puskas joined Department of Polymer Science last year, she once was a
student of Dr. Joseph P. Kennedy. Her research is pretty new compared with
the other professors'.Her research is kind of biorubber.
http://www2.uakron.edu/cpspe/DPS/Faculty/Puskas.htm
Last profess joined before Puskas was Wang, so u can calculate how many year
we have a new faculty.
About bio and nano, Dr Alexei Sokolov has a student doing nano currently, and
Dr Frank N. |
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S*****n
发帖数: 6055 | 16 maybe the guy is from a mechanical engineering background so he asked polymer
engineering, hehe:)
and I don't think that MIT has very good polymer program.
谢 |
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c****n
发帖数: 134 | 17 In MIT, there are many professors working on polymers...
In UMass, there are quite a few active young professors
Southern Mississippi seems not strong at all to me (who is real good?)
polymer
谢 |
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s*******n
发帖数: 121 | 18 【 以下文字转载自 Chemistry 讨论区,原文如下 】
发信人: shanshicn (zz), 信区: Chemistry
标 题: 那些溶剂可以除去polymer coating?
发信站: Unknown Space - 未名空间 (Wed May 4 22:39:30 2005) WWW-POST
我有一个silicon sample,表面有层polymer coating (PDDA),试了methanol,acetone 还
有piranha etch，都不行，大家一般常用什么呢？多谢。 |
|
r******0
发帖数: 2753 | 19 Does anyone know any vendors I can buy polymers from, except Aldrich and Scien
tific Polymers? Thanks. I need buy some polyacrylates copolymer with cations on side chains but the copolymer cannot be water-soluble. :) |
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a***n
发帖数: 578 | 20 防震的白色塑料型的POLYMER大部分是GRUBS POLYMER吧.听其组员讲的.误导末怪.赫赫. |
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a*****c
发帖数: 3525 | 21 【 以下文字转载自 Chemistry 讨论区 】
发信人: agostic (若即若离), 信区: Chemistry
标 题: Polymers With Safe Amounts Of Copper zt
发信站: BBS 未名空间站 (Wed Nov 1 00:40:56 2006)
Polymers With Safe Amounts Of Copper
New polymerization techniques that reduce catalyst contamination of products
could find broad industrial use
Stu Borman
Thanks to reduced requirements for metal catalysts, two new polymerization
techniques—one that modifies and improves an important polymerization
process and another that converts that process in |
|
d***a
发帖数: 73 | 22 The Virginia Tech Chemistry Department has the following position available:
Polymer Synthetic: The Department of Chemistry in the College of Science is
searching to fill a tenure track faculty position in synthetic
macromolecular chemistry. Candidates in all areas of synthetic polymer
chemistry will be considered. Candidates with backgrounds and active
research programs in the study of macromolecular chemistry relevant to
health/life sciences, particularly with respect to molecular and nanoscal |
|
y***e
发帖数: 6082 | 23 高分子在找工作的同志们上啊，VT高分子可是top10的啊
The Virginia Tech Chemistry Department has the following position available:
Polymer Synthetic: The Department of Chemistry in the College of Science is
searching to fill a tenure track faculty position in synthetic
macromolecular chemistry. Candidates in all areas of synthetic polymer
chemistry will be considered. Candidates with backgrounds and active
research programs in the study of macromolecular chemistry relevant to
health/life sciences, particularly with res |
|
s****e
发帖数: 2934 | 24 ☆─────────────────────────────────────☆
agostic (若即若离) 于 (Wed Nov 1 00:42:26 2006) 提到:
发信人: agostic (若即若离), 信区: Chemistry
标 题: Polymers With Safe Amounts Of Copper zt
发信站: BBS 未名空间站 (Wed Nov 1 00:40:56 2006)
Polymers With Safe Amounts Of Copper
New polymerization techniques that reduce catalyst contamination of products
could find broad industrial use
Stu Borman
Thanks to reduced requirements for metal catalysts, two new polymerization
techniques—one that modifies and improves an importa |
|
s****e
发帖数: 2934 | 25 ☆─────────────────────────────────────☆
dxupa (VA+fisherman) 于 (Tue Nov 7 03:24:28 2006) 提到:
The Virginia Tech Chemistry Department has the following position available:
Polymer Synthetic: The Department of Chemistry in the College of Science is
searching to fill a tenure track faculty position in synthetic
macromolecular chemistry. Candidates in all areas of synthetic polymer
chemistry will be considered. Candidates with backgrounds and active
research programs in the study of macromolecu |
|
D********g
发帖数: 533 | 26 Ph.D. and Postdoctoral Positions in Polymer Science and Biomaterials at the
University of Tennessee, Knoxville (UTK)
Openings for two Ph.D. students and one postdoctoral fellow are available in
the group led by Professor Shanfeng Wang in the department of Materials
Science and Engineering at the University of Tennessee, Knoxville. The group
’s research interests include polymer science, rheology, biomaterials and
tissue engineering. Successful candidates are expected to develop novel
polymeric b |
|
y***e
发帖数: 6082 | 27 老王就开始招人啦？为啥一定要master，现在学生牛B轰轰的，不像四五年前啦
Ph.D. and Postdoctoral Positions in Polymer Science and Biomaterials at the
University of Tennessee, Knoxville (UTK)
Openings for two Ph.D. students and one postdoctoral fellow are available in
the group led by Professor Shanfeng Wang in the department of Materials
Science and Engineering at the University of Tennessee, Knoxville. The group
’s research interests include polymer science, rheology, biomaterials and
tissue engineering. Successful candidates a |
|
b****g
发帖数: 54 | 28 向制备一些polymer film，然后用这些film来做机械性能测试
一般情况下，这些film需要怎么制备？
看到一篇Biomacromolecules 上的 paper,
只是简单的把polymer solution然后涂到玻璃板上，然后让溶剂挥发掉
再真空干燥一下就可以
这样行么？ 能保证两面一样平整么？ |
|
w******r
发帖数: 13 | 29 We are currently looking for a Postdoc in the field of polymer chemistry at
the University of Wisconsin-Milwaukee. We intend to fill this position as
soon as possible. This Postdoc will be working on synthesizing novel
biomaterials for biomedical applications including drug delivery and tissue
engineering. Currently, this research group has eight research associates
conducting research related to biopolymers, biomaterials and polymer
nanocomposites. For those who are interested in this position, |
|
c****c
发帖数: 6 | 30 為甚麼simple hydrocarbon polymer do not mix?
我看了Flory-Huggins理論,根據方程式,因為mole of polymer很小,所以entropy更小了
,然後enthalpy不是正的就是0.所以gibbs free engergy is not negative enough for
mixing process 有沒有更好的解釋呢??
如果SEC所用的THF摻雜了methanol,測出來的average molecular weights 會如何呢??
這個是不是因為mentanol 的polarity而影響了calibration curve, 具體甚麼影響呢?? |
|
o******e
发帖数: 4 | 31 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 | 32 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 | 33 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！ |
|
z*****u
发帖数: 1875 | 34 Synthesis for poly(3-hexylthiophene) macroinitiator suitable for reversible
addition fragmentation chain transfer. Polymer Preprints (American
Chemical Society, Division of Polymer Chemistry) (2006), 47(2), 679-680.
my email address: j***[email protected]
Thanks a lot!! |
|
c********r
发帖数: 154 | 35 如果没有什么降解问题的话，一般干燥polymer都加热的，不然太慢了
或者把polymer弄成很小的颗粒或液滴 |
|
w********h
发帖数: 12367 | 36 主要还是看方便不方便，
如果polymer Tg已经在室温下，有必要在Tg下dry么？
对于Tg在室温以上的，将温度调在溶剂的沸点以上，甚至在polymer的Tg以上，
在没有降解、不用担心变形的情况下，自然可以加快干燥的过程。
至于bulky还是powder-like，
那已经属于moving target了，
同一样品在同等温度下，自然是样品越碎表面积越大溶剂挥发越快。
如果你用CH2Cl2这种低沸点的溶剂，
我看你根本不用等2个礼拜去dry sample，
一个晚上就好了。 |
|
D********g
发帖数: 533 | 37 【 以下文字转载自 Chemistry 讨论区 】
发信人: singa (瓦斯一号|我是中国人), 信区: Chemistry
标 题: Polymer Scientist Needed
发信站: BBS 未名空间站 (Sun Mar 9 20:18:38 2008), 转信
http://www.electromagneticcareers.com/Index.asp?ItemID=SearchJobs&Action=ViewJob&JobID=692
Location: Elkton Maryland USA
Job Description:
The Gore Fuel Cells Technology team is a leading global supplier of Membrane
Electrode Assemblies (MEAs) to the polymer electrolyte membrane fuel cell i
ndustry. The Gore MEA technology, based on a high power density a |
|
d*****u
发帖数: 233 | 38 可能有机会去Penn State跟Qingming zhang作dielectric polymer（他是南大的校友）
，但是一般的dielectric都是无机材料，不知道polymer的dielectric 如何。这个方面
的研究可以学到什么，毕业以后能干什么？
版内一定有内行人士能够给我一点启示吗？感激不尽 |
|
t***u
发帖数: 20182 | 39 我认为纯搞polymer没前途，应该走有机然后polymer然后工程材料比较好。 |
|
y***e
发帖数: 6082 | 40 你第一步就错了，就要认为有机比高分子好，请去化学版看看，版主友情推荐
俺在高分子系呆过，那种找工作的比例不知道要比化学系高多少倍
我认为纯搞polymer没前途，应该走有机然后polymer然后工程材料比较好。 |
|
c*s
发帖数: 2145 | 41 please use scientific language next time :)
first of all, it is not emulsion, it is dispersion polymerization.
the second, 全变成糊糊了 does not mean that the polymer spheres are deformed
, the state of your product migght be due to the low Tg OF THE polymer.
If so, no matter how you do, you can not get nice pictures. Otherwise, just
go ahead to take image of it. |
|
w********h
发帖数: 12367 | 42 Chemical Engineering Faculty Position: Rheology of Polymers and Soft
Materials
The Department of Chemical Engineering at Texas Tech University invites
applications for a tenure track position at the assistant or associate
professor level. Outstanding candidates with expertise in rheology of
polymers and soft materials are encouraged to apply. Other materials
specialties will also be considered. Applicants must have a Ph.D. degree in
Chemical Engineering or a closely related field; however, on |
|
c********r
发帖数: 2227 | 43 【 以下文字转载自 Chemistry 讨论区 】
发信人: camoufleur (USCIS 批了 journey begins....), 信区: Chemistry
标 题: 文献求助Journal of Polymer Materials～
发信站: BBS 未名空间站 (Wed Oct 1 21:57:04 2008), 转信
Amrutia, R. R.; Parsania, P. H.
Synthesis and characterization of poly(4,4'-cyclohexylidene diphenyloxy-4,4'
-diphenylene sulfone).
Journal of Polymer Materials (2007), 24(1), 77-83.
CODEN: JOPME8 ISSN:0973-8622. AN 2007:1352954 CAPLUS
非常感谢 |
|
a**e
发帖数: 168 | 44 各位大侠帮个忙， 我正在做些纳米颗粒， 用疏水的高分子做ligands，
高分子ligands 和纳米颗粒 （10 nm 的粒径) 接上之后如何移除 free polymer 呢？
polymer 是疏水性的， 所以不能用透析的方法，
能否用ultra centifuge的方法？
谢先了 。 |
|
s*****n
发帖数: 741 | 45 最近在想做一个具有helix性质的polymer， 但是不想用侧链的位阻来产生helix。
我所知道的有些PU是可以的，除了这些之外，还有其它办法不？
请问有没有专门的书籍全面的介绍helix polymer 的？
欢迎大家指导！ |
|
w********h
发帖数: 12367 | 46 Immediate Postdoctoral Research Position Opening in Polymer Processing
Application
We have an immediate opening for a postdoctoral research position in our
rheology,
modeling and simulation group in the Chemical Engineering Department at
University
of Delaware, on a Dow Chemicals-funded project and this announcement is to
ask for
help in identifying candidates. The general area of research is in the
processing of
polymer melts. The successful candidate is expected to carry out a
comprehensive
r |
|
f*******1
发帖数: 1 | 47 It's pretty interesting...
CALL it the yoga polymer: Nafion, a material used in some fuel cells, has an
unrivalled memory for contortions.
Tao Xie at General Motors in Warren, Michigan, has twisted and stretched a
Nafion strip into three distinct shapes, and found that it will revert to
each shape at the appropriate temperature.
Nafion becomes softer as it is heated. At 140 °C Xie stretched it into a
particular shape, which was locked in the polymer's "memory" as it cooled to
107 °C and stiffene |
|
b***e
发帖数: 1008 | 48 刚刚接触polymer free volume concepts,请问下大概都有哪些办法能定量测定/确定某
polymer在glass transition temperature前后的free volume的变化？因为刚接触，查
阅相关文献一时挺难找到切入点。非常感谢高手提点下！
谢谢 |
|
O*g
发帖数: 70 | 49 We are looking for enthusiastic and self-motivated person who is interested
in pursing Ph.D. degree in Biomedical Engineering. Position starts in
January 1st, 2011 (spring semester) or sooner with full financial support.
Candidates should have strong organic and/or polymer synthesis background,
since our group focuses on new molecule and polymer synthesis. Strong lab
work experience, hard-working habit and some engineering background are plus
. The candidate who has already had a M.S. degree is |
|
h**i
发帖数: 8 | 50 if a large scale of polymer has been dissolve in nonpolar solvent and washed
by water, the polymer would be contain small trace of water in it. Anyone
suggest a way to remove the trace of water by a simple method without
bringing any chemical change? Thanks. |
|
