| 查看: 765 | 回复: 7 | |||
| 当前主题已经存档。 | |||
| 【有奖交流】积极回复本帖子，参与交流，就有机会分得作者 lumeng 的 2 个金币 | |||
[交流]
【求助】NCO基团测定
|
|||
| 如何监测反应液中的异氰酸根的所剩含量啊？滴定法用什么滴定？谢谢大家！ |
回复此楼» 猜你喜欢
求调剂
已经有4人回复
-
一志愿 西北大学 总分282 英语一62 求调剂
已经有3人回复
-
调剂310
已经有4人回复
-
北科281学硕材料求调剂
已经有16人回复
-
一志愿上海交大生物与医药专硕324分，求调剂
已经有6人回复
-
一志愿哈工大，085400，320，求调剂
已经有4人回复
-
316求调剂
已经有9人回复
-
085600 材料与化工 329分求调剂
已经有8人回复
-
0856求调剂
已经有6人回复
-
299求调剂
已经有4人回复
fangxingbaixue
木虫 (知名作家)
gxgm111
- 应助: 1 (幼儿园)
- 金币: 3786.3
- 散金: 263
- 红花: 3
- 帖子: 8385
- 在线: 320.1小时
- 虫号: 324877
- 注册: 2007-03-16
- 性别: GG
- 专业: 催化化学
2楼2010-03-22 18:56:51
蓝色游鱼归情
铁杆木虫 (著名写手)
鱼
- 应助: 1 (幼儿园)
- 贵宾: 0.03
- 金币: 8379.9
- 散金: 6
- 红花: 25
- 帖子: 1211
- 在线: 434.3小时
- 虫号: 943848
- 注册: 2010-01-17
- 专业: 高分子合成化学
3楼2010-03-22 20:09:05
4楼2010-03-22 21:10:50
5楼2010-03-22 22:52:29
zyming20051
铁杆木虫 (正式写手)
- 应助: 1 (幼儿园)
- 金币: 12498.7
- 帖子: 386
- 在线: 499.9小时
- 虫号: 343106
- 注册: 2007-04-11
- 性别: MM
- 专业: 功能与智能高分子
★
lumeng(金币+2): 2010-03-23 09:00
薰衣草儿(金币+1):版内奖励 2010-03-23 09:24
lumeng(金币+2): 2010-03-23 09:00
薰衣草儿(金币+1):版内奖励 2010-03-23 09:24
|
Determination of % NCO in Prepolymer The method for the determination of the isocyanate level is based on that given by Wright and Cummins (1969). The NCO content of diisocyanates can be determined by the reaction with an excess of a standard solution of dibutylamine in chlorobenzene (or dry toluene) and titration of the excess with hydrochloric acid. The dibutylamine is prepared by dissolving 129 g of freshly distilled dibutylamine in 871 g of redistilled chlorobenzene and storing the resultant solution in the dark. The solution is relatively stable, but it is advisable to determine the amine content weekly by titration with 1 N hydrochloric acid in methanol. In the determination, 2 g of the diisocyanate should be accurately weighed out into a conical flask and 5 ml of chlorobenzene added. In the case of naphthalene diisocyanate, it is recommended that the mixture be warmed slightly to assist dissolution. To this mixture there is then added 25 ml of the standard dibutylamine solution. The reaction is rapid and takes only a few minutes for completion, when a clear solution is obtained. After adding 2 or 3 drops of a 1% alcoholic solution of bromophenol blue and 100 ml of methanol, the excess dibutylamine can be titrated with 1 N hydrochloric acid. If W = weight of sample in grams V1 = volume in ml of HCl solution required for titration of the sample V2 = volume in ml of HCl solution required for 25 ml of dibutylamine solution (blank) %NCO={[4.2*（v2-V1）*N]/1000W}*100 贴上一段 |
6楼2010-03-23 08:52:53
7楼2010-03-23 09:12:25
china_rocket
木虫 (小有名气)
- 应助: 0 (幼儿园)
- 金币: 3759.5
- 帖子: 159
- 在线: 140.9小时
- 虫号: 424104
- 注册: 2007-07-21
- 性别: GG
- 专业: 高分子
8楼2010-03-23 20:46:31
