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zhangfangzhi

木虫 (职业作家)

分子量小 就不好办了
11楼2009-12-27 12:38:59
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holysong

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引用回帖:
Originally posted by shixf1120 at 2009-12-26 14:09:
请问甲基丙烯酸-苯乙烯嵌段用什么沉淀剂, 我看文献上说是二氯甲烷,可我试了下, 只是浑浊沉淀不下来

这种物质看上去是两亲的,所以具有很好的表面活化剂性能,换句话说在溶液中形成了乳状液,这是很稳定的,你可以尝试改变温度。。。还有制备的时候选用的溶剂最好不含水。
学习贯穿在生活之中!学无止境!
12楼2009-12-27 14:34:24
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shixf1120

新虫 (小有名气)

引用回帖:
Originally posted by bravestone at 2009-12-27 02:28:
In which solvent is your block copolymer dissolved?
The concentration is important for the precipitation of your polymer. Sometimes when the concentration is too low, they just form very fine part ...

乙醚可以,但是聚甲基丙烯酸也是不溶于乙醚的,我该怎么排除这个均聚物呢
13楼2009-12-28 08:49:26
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bravestone

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so what is your purpose of the precipitation?
To purify your block copolymer from the mixture?
If there is homopolymer of PMAA, you can try to dissolve your polymer in aqueous basic solution. Then try dialysis to remove PMAA by selecting appropriate membrane molecular weight cutoff(pore size big enough to remove the PMAA, but small enough to keep the block copolymer). In this case, your block copolymer should form micelles, while the PMAA is fully soluble.
14楼2009-12-30 05:03:46
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zdongyun

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引用回帖:
Originally posted by bravestone at 2009-12-30 05:03:
so what is your purpose of the precipitation?
To purify your block copolymer from the mixture?
If there is homopolymer of PMAA, you can try to dissolve your polymer in aqueous basic solution. The ...

是啊,你都没说你的目的是什么。要是要除去均聚PMAA,你可以试试甲醇。要除去均聚PS,你可以试试乙酸乙酯。
15楼2009-12-30 08:39:36
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