Catalysis of cure reaction of ɛ-caprolactam-blocked polyisocyanate with diol using non-tin catalysts.
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| Title: | Catalysis of cure reaction of ɛ-caprolactam-blocked polyisocyanate with diol using non-tin catalysts. |
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| Authors: | Libni, G.1, Ali, B. Mohamad1, Sathiyaraj, S.1, Nasar, A. Sultan1 drasultannasar@yahoo.com, drasultannasar@unom.ac.in |
| Source: | Journal of Macromolecular Science: Pure & Applied Chemistry. 2018, Vol. 55 Issue 7, p552-558. 7p. 3 Diagrams, 5 Charts, 3 Graphs. |
| Subjects: | Isocyanates, Butanediol, Caprolactam, Catalysis, Curing, Bismuth compounds, Organometallic compounds, Molecular weights |
| Abstract: | Catalysis of cure reaction of ɛ-caprolactam-blocked polyisocyanate with 1,4-butane diol in the presence of DABCO - a tertiary amine, tin(II) 2-ethylhexanoate and non-tin organometallics like bismuth neodecanoate, calcium(II) 2-ethylhexanoate and zinc(II) 2-ethylhexanoate was investigated. The activity of these catalysts was studied by the determination of cure-time (gel-time) and analysis of absolute molecular weight of cured polymers. Cure-time results indicated that all the non-tin organometallics act as catalysts; they were more active than DABCO and except bismuth neodecanoate, other two non-tin compounds were also found to be equally active or more active than tin(II) 2-ethylhexanoate. Within the three organometallics studied, zinc (II) 2-ethylhexanoate showed highest catalytic activity, it reduced the cure-time more than 50% compared to the uncatalysed reaction. In the case of bismuth neodecanoate catalysed reaction, it was found that the viscosity was build-up to a certain limit and then decreased; this catalyst assisted chain degradation was confirmed by the analysis of molecular weight of polymers as a function of time. Catalytically active new species was formed when mixing the solution of DABCO to the solution of zinc (II) 2-ethylhexanoate and this formation was confirmed using FT-IR and UV-visible spectroscopy, but this species not showed synergism. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | Catalysis of cure reaction of ɛ-caprolactam-blocked polyisocyanate with 1,4-butane diol in the presence of DABCO - a tertiary amine, tin(II) 2-ethylhexanoate and non-tin organometallics like bismuth neodecanoate, calcium(II) 2-ethylhexanoate and zinc(II) 2-ethylhexanoate was investigated. The activity of these catalysts was studied by the determination of cure-time (gel-time) and analysis of absolute molecular weight of cured polymers. Cure-time results indicated that all the non-tin organometallics act as catalysts; they were more active than DABCO and except bismuth neodecanoate, other two non-tin compounds were also found to be equally active or more active than tin(II) 2-ethylhexanoate. Within the three organometallics studied, zinc (II) 2-ethylhexanoate showed highest catalytic activity, it reduced the cure-time more than 50% compared to the uncatalysed reaction. In the case of bismuth neodecanoate catalysed reaction, it was found that the viscosity was build-up to a certain limit and then decreased; this catalyst assisted chain degradation was confirmed by the analysis of molecular weight of polymers as a function of time. Catalytically active new species was formed when mixing the solution of DABCO to the solution of zinc (II) 2-ethylhexanoate and this formation was confirmed using FT-IR and UV-visible spectroscopy, but this species not showed synergism. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 10601325 |
| DOI: | 10.1080/10601325.2018.1481346 |
