d******y
发帖数: 121 | 1 问题是这个玩意它不溶。。。。
CuI可以用THF溶掉吧 |
|
b****n
发帖数: 379 | 2 有没有办法溶解Polyethylene terephthalate而不破坏结构？分子量在20000～30000之
间。有人说用THF可以，但我试了不行啊。谢哈！
另外，有没有这方面比较好的书或者review啊？以后会涉及更高分子量的各种polymer
。 |
|
G***O
发帖数: 839 | 3 非得用水相？acryloyl chloride 太活泼了，聚合都不需要加热，氮气保护加避光可能
会好点，最好还是用acid或phenyl ester。溶剂最好THF。acn 都可以。
你的基础有点弱，不过有机也没啥前途，做了10多年最后连工作都没有。哎。 |
|
J******t
发帖数: 32 | 4 你老板是搞理论的嘛？
cyclohexane, THF...
早都有专门的一套仪器来精制了
纯度都可用于阴离子聚合了 |
|
t***m
发帖数: 114 | 5 这个一般用钠（比较便宜）和二苯甲酮回流，
俺们这里搭了n个溶剂回流装置
THF/CHCl2/CH2Cl2/hexane |
|
b**s
发帖数: 589 | 6 找到一片文章，人家是用溶液聚合，跟你的本体聚合不一样。你这是叫自加速现象，
高分子的东东忘光了？呵呵
PVI was prepared by solution polymerization using
2,2'-azobis(isobutyronitrile) (AIBN) as initiator. 1-Vinylimidazole (20 ml)
was dissolved in 50 ml absolute ethanol and dry nitrogen was bubbled through
the solution with vigorous stirring. AIBN (0.04 g) was added to the solution
and polymerization was carried out at 70°C for 40 h. PVI was obtained by
precipitating the ethanol solution in excess THF/hexane (3:8, v/v) solution. |
|
|
|
|
|
c*s
发帖数: 2145 | 11 maybe inaddition,
the nature of the interaction between the template and final product is also
intersting...
is that Vander Walls force? complexing bong between metal ions and O atom( not
plausible cuz teh media of reaction is THF)
but it seems there existes special interaction, based on the fact thta there
is no isolated CdS PARTICLES isolated from the template..
Nanohelices
that
HELICE |
|
c******h
发帖数: 4573 | 12 我怀疑millpore的油膜会吸附PNIPAM
在THF中的PNIPAM过膜老是有灰尘。TNND
动态还好说，这个静态和zimm作图怎么办啊
55555555555 |
|
b**s
发帖数: 589 | 13 Poly(vinyl acetate)
Catalog # : 347
CAS : 9003-20-7
Physical Form : Pellets
Approx Mw : 100,000
Density (g/cc) : 1.18
Refractive Index : 1.4665
Inherent viscosity : 0.42
Softening Point (C) : 97
TSCA : TSCA listed
Tg (C) : 30
Soluble in : Acetone, benzene, butyl acetate, carbon tetrachloride,
chloroform, dichloroethylene, ethanol, ethyl acetate, methanol, MIBK, THF,
toluene |
|
w********h
发帖数: 12367 | 14 你列出的网站最多只能算商品说明而已，
随手查点东西都没有。
，
等
连
THF, |
|
c****n
发帖数: 134 | 15 There is an amphiphilic triblock copolymer.
The center is hydrophobic, and the end blocks hydrophilic.
The hydrophilicity of the end blocks can be controlled
as the content of the -OH group can be controlled during polymn.
when the block copolymer with high -OH content is dissolved in THF,
it looks clear and homogeneous.
but the solution can't pass through a membrane for GPC sample preparation.
I believe it is because of the physical association of the end blocks...
but a group member said it co |
|
f**********e
发帖数: 16 | 16 What's the normal way in lab? I know in industry people use hot THF or toluene
or xylene to dissolve PE copolymer, but not sure about the exact procedure. I
have this blend with small amount of PP and the PE matrix. My purpose is to
dissolve PE and leave the PP which is highly oriented. Thanks a lot! |
|
p*****d
发帖数: 40 | 17 r u kidding? you must be a math major or you are from Mar...
try CHCl3, THF, toluene.... |
|
o**r
发帖数: 11 | 18 你是学高分子化学的么？
比较好奇，
就算你得到这份工作，估计也会比较辛苦
这种技术支持的东西，没有实际的经验很容易
抓不到重点，往往干上半年也找不到方向..................
我做聚氨酯就是这样，聚THF的低聚物
分子量只有500-800之间才能符合公司的需要
另外一个类似前体就必须500以下，
公司要我们给个具体原因，我们2个人用了2年
才做出来。
.............................. |
|
B****W
发帖数: 100 | 19 Actually I did find a paper using NMR to characterize the MW and
endgroup. I am going to try it.
Nylon dissolves pretty well in fluorinated solvent, and some alcohols. B
ut unfortunately, we only use THF for GPC in my school. Anyway, thanks :) |
|
w********h
发帖数: 12367 | 20 ft....now matter how to dissolve the sol fraction,
the final gel fraction will be fixed bah....
in my case, I use THF on Soxhlet extraction apparatus.
溶 |
|
b****g
发帖数: 54 | 21 Polyhydroxybutyrate用那种溶剂会比较好？
试了THF,DMF，Chloroform好像溶解性都不好
还有那些溶剂可以用啊？ 多谢
另外，一般在计算摩尔比的时候，使用Mn 还是Mw ? |
|
c**********d
发帖数: 12 | 22 从GPC上得到的分子量很小. 不清楚为什么. 不知道是否是表面活性剂的影响.
大体操作是--聚合时是水性溶液, 然后冷冻干燥, 然后溶解在THF大概两天, 然后过滤,
取样做GPC. |
|
s****e
发帖数: 2934 | 23 Thank you very much for your comprehensive information!
I need to measure electric properties of my compound, so a thin layer of
PMMA is not ok for me. My compound is also a silicone compound, which is a
nonpolar. I have tried xylene, toluene, hexane, THF, ether. For xylene and
toluene, only 50%-40% can fully wet the wafer before I spin the spinner. So
all the other concentration can not fully wet the surface, everything is
gone when spin for 2mins at 1500RPM. For the 40% one, crystalline is big |
|
h***s
发帖数: 111 | 24 What's the MW of your PEG? PEG solubility depends on its MW. If MW<10k,
methanol/acetone or methanol/
hexzane might be worth trying. If MW is >>10k, I think you might be able to
try THF/methanol.
You can look its solubility data in polymer handbook. |
|
s****e
发帖数: 2934 | 25 ☆─────────────────────────────────────☆
BigBig (bigbig) 于 (Mon Sep 4 23:27:42 2006) 提到:
Polyhydroxybutyrate用那种溶剂会比较好？
试了THF,DMF，Chloroform好像溶解性都不好
还有那些溶剂可以用啊？ 多谢
另外，一般在计算摩尔比的时候，使用Mn 还是Mw ?
☆─────────────────────────────────────☆
singye (温润如玉) 于 (Tue Sep 5 12:23:28 2006) 提到:
你的polymer是hydrophilic的，用极性的溶剂试试吧，比如water ， acetone。。。
嗯，这个问题提得挺好。。小分子的Mn和Mw是一样的，而大分子就不同了。
我想对于高分子，计算摩尔比的时候要看Mn和Mw哪个更重要，没有PDI的Mn或者Mw都是
无意义的。不知道这个回答对不对。。。
☆─────────────────────────────────────☆
BigBig (bigbig) |
|
s****e
发帖数: 2934 | 26 大家平时用什么氘代溶剂啊？帮别人问一下，懒得查了。分子量很低的话用什么，分子
量高的呢？用氘代水看不到PEO—OH上的氢吧？可以用水峰来做内标吗？用DMSO可以吗
？THF老贵了。还有如果用甲醇的话不会像水一样有exchange的问题吧？现在他手上2个
样品一个
CH3O－PEO－OH，一个磺化端基的PEO（不含hydroxyl了）
这个磺化的PEO不能用CDCl3了吧？（分特这个问题不该问，该让这老兄自己去试） |
|
|
s****e
发帖数: 2934 | 28 This is a hydrophilic polymer,water. THF |
|
c****c
发帖数: 6 | 29 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?? |
|
p****e
发帖数: 40 | 30 关于1： 不清楚，不过觉得应该不是结构单元数。应该是和detector信号强度对应的，
所以我认为对应着不同size的population，就是个相对值，和质谱峰强度的意义差不多。
关于2：我自己的经验（不是很丰富，只测过我自己的一个样品，供参考）。我用的是
DMSO做流动相，也是考虑到标样选择的问题，我查了文献，这样的体系的确不多，不过
有人用dextran 或者pullulan做标样，其实这两种标样一般是用于水相GPC的，考虑到
他们的极性也都比较大（聚糖），应该还是有对比价值的。最后我用了detran，我实际
上是用它作为一个对比样品（因为我们只有一个分子量的样品），并非严格意义的标样
。GPC系统的标定其实还是用的PS（THF流动相），然后测了那个detran（DMSO流动相w/
1g/L LiBr），结果和标签值吻合，我也就据此认为用这个体系测我的样品数据是可靠
的。 |
|
s**********e
发帖数: 181 | 31 柱子厂家说明书说use a linear gradient at a rate of change of 2% per minute.
可是我们的GPC只有一个管子进溶剂. 直接用acetone 柱子没问题吧? |
|
m*****e
发帖数: 1506 | 32 千万别信metathesis in water，那种催化剂需要自己合成，很容易失活，而且反应条
件及其严格。记得有人用一代催化剂开了带PEG的norbornene大单体，产物作为催化活
性种，在水相做了romp好像还不错，不过可惜只能开norbornene。
romp用一代催化剂只能在ch2cl2里做，试过thf效果不好，而且溶剂要纯化，二代后就
在手套箱里搞吧。 |
|
a**e
发帖数: 168 | 33 我最近在做PCL的合成，溶剂为THF,80 C,Sn(oct)2 作为催化剂， 反应时间为24 小时
， 但分子量总是上不去， targeting 20k, 我总只能得到10 K 左右， PDI=1.1
yield 为85%
是不是反应时间不够？ |
|
a**e
发帖数: 168 | 34 我正在用atrp做一两亲高分子，PS-PEO， 反应完后想用millipore 的Centriprep
filter 来分离未反应的PEO MM 单体。
但， 今天早上打电话问millipore 的tenichcian， 他说这filter 和THF不兼容。
大家都是用什么来分离这类单体的？ |
|
a**e
发帖数: 168 | 35 这在做一ATRP PS Brush PEO 共聚物， 引发剂带两个 T butyl 连着 一Tertiary
amine，
做 PS 段的时候 GPC 很正常， 但合成完 PS-PEO block copolymer后 就很难通过
Al2O3 柱
子， 过gpc 时， 拖尾很厉害， 甚至超过了 THF 的淋出时间。
是不是这个 Tertiary amine 末端和GPC 柱子相互作用了呢？ |
|
|
t***u
发帖数: 20182 | 37 btw, polymer lab is part of varian now |
|
t***u
发帖数: 20182 | 38 不知道啊，一般搞micelle应该这么做吧，用良溶剂把polymer溶掉，然后慢慢滴加到某一
block的不良溶剂。先用THF，然后滴加hexanes？ |
|
S*****n
发帖数: 6055 | 39 我的实验要求最后形成在纯hexane里面的分散体系
请问THF如何除去比较好？
多谢！
某一 |
|
t***u
发帖数: 20182 | 40 我从来没做过啊。找个篇文献，应该可以找到更多的。hexane boiling point 69oC,
THF 66, 不知道
能不能行。
n-Alkanes (heptane, octane, decane, and dodecane), N,N1-dimethylformamide,
N,N1-dimethylacetamide, and methyl ethyl ketone used
as selective solvents for the block copolymers were of AnalaR grade.
The micellar solutions were prepared by using tetrahydrofuran un-
I less stated otherwise. The block copolymers were first dissolved in
small amounts of tetrahydrofuran to which the selective solvent was
I subsequently added. Tetrahyd |
|
|
|
d**a
发帖数: 3715 | 43 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. |
|
a*i
发帖数: 1652 | 44 if you want to narrow PDI, try to get PS with narrow PDI first. you didn't
mention the PDI of the first reaction.
if you want to publish papers, try to make the first reaction better. THF
runaway is not good (you can avoid that by assembling proper glasswares); is
AIBN necessary?
It seems to me that you haven't got solid proof of copolymerization.
Purification is quite easy: try toluene/methanol cycles and then dry the
polymer in vacuum oven. Once copolymerization is successful, you can make
pro |
|
b******0
发帖数: 45 | 45 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 |
|
b******0
发帖数: 45 | 46 transparent completely? Not cloudy or some light blue?
The solution should not be transparent completely, if it is difficult to
pass 0.45um filter. And it should not be due to high molecular weight. At least, PS of 500,000g/mol can pass through the filter smoothly. It is possible that
there are some micelles formed in the THF solution due to the solubility
issue.
By the way, you should not use larger size filter, or else you may clog the
column. Try other GPC, toluene or DMF. |
|
l*******g
发帖数: 82 | 47 稀溶液中30万的分子应该没有那么大，用Cinfinity估计一下在THF里应该多大
考虑一下你的高分子是不是纯的，之间相互作用强不强，还有滤膜的材料和溶液有没有
作用。 |
|
d**a
发帖数: 3715 | 48 If my monomer (aromatic compound) has a very poor solubility in THF or
toluene, then how it can be polymerized? |
|
D********g
发帖数: 533 | 49 that might be the problem. iPrOH is too polar that it tend to elute with the
copper-ligand complex out of the column. Try neutral Alumina column,
evaporate the isopropanol, redissolve into THF or dioxane or less polar
solvent. pass the column again. |
|
|
