Abstract
To improve the performance and reduce raw material costs, blocked isocyanates were prepared with mixture of blocking agents in many industries. Three blocked isocyanates (adducts) namely ε-caprolactam/benzotriazole- blocked 4,4′-diphenylmethane diisocyanate (MDI), toluene-2,4-diisocyanate (TDI) and 4,4′-dicyclohexylmethane diisocyanate (H12MDI) were synthesized. Six reference adducts were also prepared by blocking MDI, TDI, and H12MDI with ε-caprolactam (ε-CL) or benzotriazole. The reactions were carried out in acetone medium and dibutyltin dilaurate (DBTDL) was used as a catalyst. The progress of the blocking reaction was monitored by IR spectroscopy. De-blocking temperatures (dissociation temperatures) of these adducts were studied using DSC and TGA and the results were correlated. As expected, the thermal analysis data showed that de-blocking temperature of blocked aromatic isocyanates was lower than that of the blocked aliphatic isocyanates. The low de-blocking temperature of blocked aromatic isocyanate could be due to electron withdrawing benzene ring present in the blocked isocyanates. It was also found that benzotriazole-blocked adducts de-blocked at higher temperature compared with ε-CL-blocked adducts.
| Original language | English |
|---|---|
| Pages (from-to) | 427-434 |
| Number of pages | 8 |
| Journal | Macromolecular Research |
| Volume | 13 |
| Issue number | 5 |
| Publication status | Published - 2005 Oct 1 |
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All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Organic Chemistry
- Polymers and Plastics
- Materials Chemistry
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Thermal decomposition behavior of blocked diisocyanates derived from mixture of blocking agents. / Jung, Min Lee; Subramani, Sankaraiah; Young, Soo Lee; Kim, Jung-Hyun.
In: Macromolecular Research, Vol. 13, No. 5, 01.10.2005, p. 427-434.Research output: Contribution to journal › Article
TY - JOUR
T1 - Thermal decomposition behavior of blocked diisocyanates derived from mixture of blocking agents
AU - Jung, Min Lee
AU - Subramani, Sankaraiah
AU - Young, Soo Lee
AU - Kim, Jung-Hyun
PY - 2005/10/1
Y1 - 2005/10/1
N2 - To improve the performance and reduce raw material costs, blocked isocyanates were prepared with mixture of blocking agents in many industries. Three blocked isocyanates (adducts) namely ε-caprolactam/benzotriazole- blocked 4,4′-diphenylmethane diisocyanate (MDI), toluene-2,4-diisocyanate (TDI) and 4,4′-dicyclohexylmethane diisocyanate (H12MDI) were synthesized. Six reference adducts were also prepared by blocking MDI, TDI, and H12MDI with ε-caprolactam (ε-CL) or benzotriazole. The reactions were carried out in acetone medium and dibutyltin dilaurate (DBTDL) was used as a catalyst. The progress of the blocking reaction was monitored by IR spectroscopy. De-blocking temperatures (dissociation temperatures) of these adducts were studied using DSC and TGA and the results were correlated. As expected, the thermal analysis data showed that de-blocking temperature of blocked aromatic isocyanates was lower than that of the blocked aliphatic isocyanates. The low de-blocking temperature of blocked aromatic isocyanate could be due to electron withdrawing benzene ring present in the blocked isocyanates. It was also found that benzotriazole-blocked adducts de-blocked at higher temperature compared with ε-CL-blocked adducts.
AB - To improve the performance and reduce raw material costs, blocked isocyanates were prepared with mixture of blocking agents in many industries. Three blocked isocyanates (adducts) namely ε-caprolactam/benzotriazole- blocked 4,4′-diphenylmethane diisocyanate (MDI), toluene-2,4-diisocyanate (TDI) and 4,4′-dicyclohexylmethane diisocyanate (H12MDI) were synthesized. Six reference adducts were also prepared by blocking MDI, TDI, and H12MDI with ε-caprolactam (ε-CL) or benzotriazole. The reactions were carried out in acetone medium and dibutyltin dilaurate (DBTDL) was used as a catalyst. The progress of the blocking reaction was monitored by IR spectroscopy. De-blocking temperatures (dissociation temperatures) of these adducts were studied using DSC and TGA and the results were correlated. As expected, the thermal analysis data showed that de-blocking temperature of blocked aromatic isocyanates was lower than that of the blocked aliphatic isocyanates. The low de-blocking temperature of blocked aromatic isocyanate could be due to electron withdrawing benzene ring present in the blocked isocyanates. It was also found that benzotriazole-blocked adducts de-blocked at higher temperature compared with ε-CL-blocked adducts.
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M3 - Article
VL - 13
SP - 427
EP - 434
JO - Macromolecular Research
JF - Macromolecular Research
SN - 1598-5032
IS - 5
ER -