| 查看: 1225 | 回复: 3 | ||
| 当前只显示满足指定条件的回帖,点击这里查看本话题的所有回帖 | ||
胡程耀铁杆木虫 (著名写手)
|
[求助]
环氧树脂和大分子量聚醚胺之间的反应,需要催化剂吗? 已有1人参与
|
|
|
聚醚胺D4000为近末端含胺基的长链二胺,按照2015的一篇Macromolecules (2015, 48, 7495−7502)的文章,与环氧树脂在80度反应,他们是用的近红外光谱检测固化过程,发现在20个小时固化度为70%,但是我们一样的条件,直接将环氧树脂和聚醚胺D4000共混反应,但是在80度反应24个小时,还是颜色不怎么变,用中远红外检测,发现环氧树脂基团变化不大,请高手赐教,是否需要加催化剂,加什么催化剂,加多少呢? 文献原话: PRS was produced by adding/mixing stoichiometric blends of PPODA(Jeffamine D-4000) and DGEBA at 80 °C. The chemical conversion of these mixtures was monitored using a Nexus 870 FTIR spectrometer (Thermo Nicolet Corp.) in the near-IR region. Figure 2a shows representative FTIR spectra taken over a period of time for this reaction. The peak at 4530 cm−1 corresponds to the stretching and bending of oxirane bands, and the peak at 4930 cm−1 corresponds to the NH2 combination bands.19,20 The decrease of epoxy and amine concentrations signifies the presence of epoxy−amine reactions. Figure 2b shows the fractional conversion of epoxy with respect to time obtained using the epoxy peak area. Additionally, the approximate gel point was measured using a steady shear viscosity measurement during curing reactions using a TA rheometer apparatus AR2000. Gelation is known to happen at the point where steady shear viscosity rises rapidly to infinity.21 A combined viscosity−conversion measurement on DGEBA−PPODA systems at 80 °C showed that the approximate gel point for these systems is taking place at around 84% oxirane conversion. |
» 猜你喜欢
291求调剂
已经有15人回复
材料学硕333求调剂
已经有17人回复
070300化学求调剂
已经有5人回复
070300一志愿211,312分求调剂院校
已经有6人回复
物理学调剂
已经有3人回复
08工科,295,接受跨专业调剂
已经有5人回复
材料科学与工程调剂
已经有12人回复
本2一志愿C9-333分,材料科学与工程,求调剂
已经有5人回复
一志愿西交288化工专硕求调剂
已经有4人回复
308求调剂
已经有8人回复
» 本主题相关商家推荐: (我也要在这里推广)
zj34331197
木虫 (正式写手)
木虫
- PEPI: 2
- 应助: 60 (初中生)
- 金币: 2742.3
- 散金: 129
- 红花: 24
- 帖子: 610
- 在线: 222.1小时
- 虫号: 672954
- 注册: 2008-12-12
- 性别: GG
- 专业: 聚合物共混与复合材料

4楼2016-12-08 10:47:18

2楼2016-12-04 11:04:11
zj34331197
木虫 (正式写手)
木虫
- PEPI: 2
- 应助: 60 (初中生)
- 金币: 2742.3
- 散金: 129
- 红花: 24
- 帖子: 610
- 在线: 222.1小时
- 虫号: 672954
- 注册: 2008-12-12
- 性别: GG
- 专业: 聚合物共混与复合材料

3楼2016-12-08 10:46:39














回复此楼
10