w********h
发帖数: 12367 | 1 AlChE Journal
R. Langer and N. A. Peppas
2003, 49(12): 2990 |
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h***s
发帖数: 111 | 2 I just made SBS triblock by coupling of S-x and y-B-y. How can I prove that it
is a triblock insted of SB diblock? PB has a PDI of 2. It is hard to tell by
GPC.
Thanks! |
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b**s
发帖数: 589 | 3 try this link
http://mitbbs.com/cgi-bin/BBS0an?/groups/GROUP_4/Macromolecules/m3/m6/m13
this actually is an interesting question, many polymer guys are confused
with it. Because the only difference between S-B and S-B-S for spectroscopy
like IR and NMR is one or two bonds, which covered up by 1000000000000000000
bonds. So only thing you can do is counting on macroscopic methods.
it |
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h***s
发帖数: 111 | 4 Thanks, I am reading now, hehe.
that
by |
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h***s
发帖数: 111 | 5 My goal is to make triblock by in situ coupling during blending, not by anioic
polymerization.
that it
by |
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w********h
发帖数: 12367 | 6 too many.
depends on which part you want to say morphology is important.
if block copolymer,
try Frank Bates' review articles with Fredrickson. |
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t******l
发帖数: 3060 | 7 a huge topic.
for morhphology review. u can check Chem. Rev. 2001, Vol 101, p 3869 |
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t******l
发帖数: 3060 | 8 ft... i donot know.
let Wonderlich answer u bah. |
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c*****e
发帖数: 238 | 9 Generally the contour length is the number of physical segments, so depends
on the consistent length.
The molecular weight also depends on the chemical composition of each chemical
segments.
Actually in most physics context, the contour length might be the number of
physical segments scaled by the factor of a segmental volume devided by
the cube of a segment length (since the segment is not a strict cube) |
|
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D***e
发帖数: 435 | 11 要把diblock copolymer PB-PEO的PB block cross link, K2S2O8做 initiator
看到文献上说用argon protection.请问可以换做nitrogen protection吗？
实验室没有argon，也不知道该怎么买？是不是跟氮气一样买？
问题比较外行。从来没搞过polymer 的反应，没有经验
请大家指教，谢谢了。 |
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w********h
发帖数: 12367 | 12 个人感觉这个条件既不充分，也不必要。
倒象是block copolymer disorder to order transition在terminal regime的转折
点。
我们看一个东东是不是gel，首先要看这种weak association是不是足够强壮到出现
G'>G"的plateau regime. 如果作者根本就没有有强有力的证据说明这个gelation，
比如(1) 粘度是不是随温度etc有个sharp的增加？(2) 在某些 frequency region
G'>G". 如果这两个证据都没给，反而告诉我这个gel是fluid-like，我不能接受。
G">G'
】
is
differiente |
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w********h
发帖数: 12367 | 13 来自主题: Macromolecules版 - 推荐几篇文章 (1) 我说的是怎样才能证明是gel，不是说已知是gel怎么定gelation point；
(2) 对于我所说的gel，从G">G'到G"=G'最后到G'>G"是可以判定为gel的；
(3) 在我提供的第二篇文献中，谈到long chain branching与gelation的相似之处，
至于在第三篇文献中提到Winter用tan(delta)=G"/G'=constant来作为gelation point，
是指已知gelation或者类似的long chain
branching发生。但是不是损耗角一和frequency无关，就是gel呢？看看所有polymer的Ro
use region吧。另外有很多weakly associated的
gel有整个的flow regime, rubbery regime, glassy regime, 显然在大多数的情况
下G"/G'和频率是有依赖关系的，难不成它不是gel?所以我觉得Winter这个标准其实
只是一个general的标准，包括block copolymer disorder---order transition在
内的(如 |
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z**h
发帖数: 224 | 14 为什么在AB diblock copolymer phase diagram 上没有这么一个 disordered
microphase separated regime, 而只有 disorder-order line?
microphase |
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c****n
发帖数: 134 | 15 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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p******s
发帖数: 137 | 16 来自主题: Macromolecules版 - 问个傻问题 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. |
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C***S
发帖数: 175 | 17 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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p******s
发帖数: 137 | 18 来自主题: Macromolecules版 - 问个傻问题 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. |
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p******s
发帖数: 137 | 19 来自主题: Macromolecules版 - 问个傻问题 it is a multi-block copolymer
there
try
higher |
|
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w********h
发帖数: 12367 | 22 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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o****n
发帖数: 25 | 23 用NMR测啊
计算俺就不知道了，还能算么？
共聚那个单体更容易加到链里面不也需要测么 |
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C***S
发帖数: 175 | 24 Well, NMR doesn't work well on this system. two strong F-F interaction. |
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w********h
发帖数: 12367 | 25 thanks for your answer.
then, if A block is much longer than B block in ABA copolymer,
and B has a lower degradation temperature, T
we can expect ABA----->2A at T? |
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s*****y
发帖数: 37 | 26 我需要购买他家的一种copolymer,polyisobutylene-co-polyethyleneamine,但是在他们
主页上怎么都找不到这种产品叫什么名字，发email问都不理睬我。有没有达人能帮帮俺
，谢了 |
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w********h
发帖数: 12367 | 27 well, then some lamellar structure formed by some di- or tri-block copolymers
indicate that while glass transition may be a single one. |
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S*****n
发帖数: 6055 | 28
么
"
,
system
I guess colloidal crystal is kind of plastic crystal formed by colloidal
particles.
particles
can
easily
temperature.
just check order-disorder transition for block copolymers
查 |
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s****e
发帖数: 2934 | 29 关于方法一：比如P1的官能团是已知的，但已知的P2的官能团没有反应性，不会和P1发生
反应，怎么接着做P2呢？这时加入催化剂使P2聚合，最后只能得到p1,p2的均聚物吧
关于方法二：P2的端基不知道是什么，怎么偶合啊？ |
|
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s****e
发帖数: 2934 | 31 关于方法一：比如P1的官能团是已知的，但已知的P2的官能团没有反应性，不会和P1发生
反应，怎么接着做P2呢？这时加入催化剂使P2聚合，最后只能得到p1,p2的均聚物吧
关于方法二：P2的端基不知道是什么，怎么偶合啊？ |
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S*****n
发帖数: 6055 | 32 做block copolymer的那些组，大多数都做阴离子的吧，不过不怎么单独发合成的文章，
呵呵。 |
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y***e
发帖数: 6082 | 33 没啥意思啊，搞来搞去最多macro，大牛们都喜欢diblock或者triblock然后自组装成千奇
百怪的东西，ibm现在搞得太火了
做block copolymer的那些组，大多数都做阴离子的吧，不过不怎么单独发合成的文章，
呵呵。 |
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s****e
发帖数: 2934 | 34 【 以下文字转载自 Chemistry 讨论区 】
发信人: BigBig (bigbig), 信区: Chemistry
标 题: 又来问问题
发信站: BBS 未名空间站 (Thu Aug 24 01:34:44 2006), 转信
我要做一个Copolymer，用我的Mn2000左右的引发剂 I 跟另外一种单体共聚,得到A
不过水也是可以做单体聚合的引发剂，得到一个polymer B
那么我如何去确定我得到的产品是I 和 B得混合物，还是A呢？
当然也可能是 I+A+B |
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s****e
发帖数: 2934 | 35 质量很差，比如diblock copolymer里面有很多homopolymer等等，大家有好一点的地方
推荐吗？ |
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b****g
发帖数: 54 | 36 polymer A 结晶度 30%
polymer B 结晶度 20%
如果把这两个做成copolymer，结晶度 会怎么变化？ |
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b****g
发帖数: 54 | 37 会不会出现两个Tg, 一个A units的， 一个B units的？ |
|
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A****e
发帖数: 184 | 39 if they phase separate, 2 peaks usually; if not, one tg in between them |
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s****e
发帖数: 2934 | 40 ☆─────────────────────────────────────☆
BigBig (bigbig) 于 (Thu Oct 26 02:34:38 2006) 提到:
polymer A 结晶度 30%
polymer B 结晶度 20%
如果把这两个做成copolymer，结晶度 会怎么变化？
☆─────────────────────────────────────☆
Synthon (合成子·小冥王) 于 (Thu Oct 26 10:16:52 2006) 提到:
一切皆有可能
☆─────────────────────────────────────☆
DigitalPig (我需要的是实干) 于 (Thu Oct 26 18:10:29 2006) 提到:
个人觉得可能结晶度连20%都没有。要看链的结构还有两者各自的规整度了。
说说看你是哪两种polymer? |
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s****e
发帖数: 2934 | 41 ☆─────────────────────────────────────☆
BigBig (bigbig) 于 (Sat Oct 28 09:56:42 2006) 提到:
会不会出现两个Tg, 一个A units的， 一个B units的？
☆─────────────────────────────────────☆
Synthon (合成子·小冥王) 于 (Sat Oct 28 10:57:11 2006) 提到:
possible
☆─────────────────────────────────────☆
AngLee (AngLee) 于 (Fri Nov 3 13:13:31 2006) 提到:
if they phase separate, 2 peaks usually; if not, one tg in between them |
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s*****i
发帖数: 146 | 42 Zhong Z, Lok MC, Dijkstra PJ, et al.
Structurally well-defined copolymers of poly(ethylene glycol) and low
molecular weight linear polyethylenimine as vectors for gene delivery
JOURNAL OF CONTROLLED RELEASE 101 (1-3): 406-408 Sp. Iss. SI JANg 3 2005
also working on PEG-PEI |
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s*****i
发帖数: 146 | 43 【 以下文字转载自 Chemistry 讨论区 】
发信人: shaxixi (stupid), 信区: Chemistry
标 题: ask for a paper
发信站: BBS 未名空间站 (Tue Nov 21 07:19:06 2006)
Graft copolymers that exhibit temperature-induced phase transitions over a
wide range of pH
Guohua Chen & Allan S. Hoffman*
Center for Bioengineering, FL-20, University of Washington
thank you very much |
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s****e
发帖数: 2934 | 44 【 以下文字转载自 NanoST 讨论区 】
发信人: maodouzi (毛豆子), 信区: NanoST
标 题: Advanced materials上最近几篇太阳能电池文章
发信站: BBS 未名空间站 (Wed Jun 6 10:33:41 2007), 转信
１.Amphiphilic Diblock Copolymer Compatibilizers and Their Effect on the
Morphology and Performance of Polythiophene:Fullerene Solar Cells**
２. Design Rules for Donors in Bulk-Heterojunction Solar Cells—Towards 10
% Energy-Conversion Efficiency**
By Markus C. Scharber,* David Mühlbacher, Markus Koppe, Patrick Denk,
Christoph Waldauf,
Alan J. Heeger, and Christo |
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r******0
发帖数: 2753 | 45 Actually, they are low MW PEO copolymers. Pure PEO doesn't work very well. |
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s****e
发帖数: 2934 | 46 copolymer就是好，比homopolymer还好 |
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s****e
发帖数: 2934 | 47 已知amphiphilic block copolymer B-b-C能形成micelle
nonpolar的organice solvent，加入20％的nonpolar homopolymer A， 20％×15％＝3
％的B-b-C，能形成micelle吗？ |
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c*s
发帖数: 2145 | 48
Bates fundamental and insightful
Eisenberg too old
Winnik not in this field
Lodge very nice person very active, block copolymer application in materials
Wooley vrey popular and active shell-crosslink triblock and new
polymerization chem
Armes not like his style, publish like a crazy dog
Lecommandoux self-assembly of bio-macromolecules not very impressive
Guojun Liu one of the best chinese polymer physicist, but very pushy
+ manners ian
每个教授的侧重点不一样，多看看他们的代表作，卡看你自己的兴趣在什么地方， 我
也是新手，但是也见过其中几个，和其中两个 |
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u***n
发帖数: 1263 | 49 CO copolymer with ethylene.
NMR analysis用 1，1，1，3，3，3-hexafluoro-2-propanol-C6D6
溶剂，但是大部分文献都没有写两个溶剂的比列
是不是用大量的hexafluoro来溶解，小量的C6D6来lock....??? |
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a*i
发帖数: 1652 | 50 the solubility depends on copolymer composition, I guess?
As long as your polymer dissolves, you should be good. |
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