Journal ArticleDOI
The kinetics of dissociation of blocked 2,4‐diisocyanatotoluene (tdi) in amines
Prathima Kamath,M. Srinivasan +1 more
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TLDR
In this paper, the second-order rate constants for the dissociation of blocked diisocyanates were derived from Fourier Transform IR (FTIR) spectral data. And the relative effects of various blocking agents, basicity of the amines and temperature on the dissociability of blocked TDI have been determined.Abstract:
The kinetics of dissociation of blocked diisocyanates based on commercial diisocyanatotoluene (TDI) (80/20 mixture of 2,4- and 2,6- isomers) in the presence of amino compounds was studied by a volumetric method and Fourier Transform IR (FTIR) spectral data. Second-order rate constants for the dissociation of TDI adducts (with phenol, thiophenol and p-chlorophenol) in the presence of amines (dibenzyl, benzyl, cyclohexyl, n-hexyl and di-n-butyl) in cyclohexanone solvent are reported. The relative effects of various blocking agents, basicity of the amines and temperature on the dissociation of blocked TDI have been determined. An FTIR spectroscopic method was used to study the dissociation of blocked TDI (with blocking agents such as phenol, thiophenol, p-chlorophenol,p-nitrophenol,p-cresol, α-naphthol and resorcinol) in the presence of excess triethylamine and in cyclohexanone solvent. Pseudo-first-order rate constants were calculated from NCO concentrations as determined from FTIR spectra.read more
Citations
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Journal ArticleDOI
Blocked isocyanates: from analytical and experimental considerations to non-polyurethane applications
TL;DR: In this paper, the authors provide an introductory guide to blocked isocyanates, through discussion on different examples of blocking groups, along with experimental considerations for their application, and highlight the importance of matching the analytical technique to the application of the blocked Isocyanate, with differences in material state and experimental parameters having a great impact on the deblocking temperature reported.
Journal ArticleDOI
Dynamic mechanical and underwater acoustic properties of the polyurethane/epoxy resin blend elastomers filled with macroporous poly(vinyl acetate-co-triallyl isocyanurate) resin beads
Weihong Sun,Xin Yan,Xi Zhu +2 more
TL;DR: In this article, the influence of the beads on the dynamic mechanical and underwater acoustic properties of the intercrosslinked elastomer matrices was investigated, and the results showed that the beads with smaller diameters had a better enhancing effect on the acoustic properties than those with larger diameters.
Journal ArticleDOI
Successful synthesis of blocked polyisocyanates, using easily cleavable phenols as blocking agents, and their deblocking and cure studies
TL;DR: In this article, a series of blocked polyisocyanates were prepared using phenol, 2,4-dichlorophenol and 2-chloro-4-nitrophenol; their blocking and deblocking kinetics, deblocking temperatures, equilibrium temperatures, and cure-times were studied using a hot-stage FT-IR spectrophotometer.
Journal ArticleDOI
In Situ FT-IR Study on the Blocking Reaction of Isocyanate with Naphthol
TL;DR: In this paper, the authors investigated the blocking reaction of phenyl isocyanate with 1-naphthol and 2 naphthols with in situ FT-IR and found that there was a remarkable induction period in the reaction.
References
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Journal ArticleDOI
The Kinetics of the Triethylamine-catalyzed Reaction of Diisocyanates with 1-Butanol in Toluene
John Burkus,C. F. Eckert +1 more
Journal ArticleDOI
The Thermal Dissociation of Blocked Toluene Diisocyanates
G. R. Griffin,L. J. Willwerth +1 more
TL;DR: In this paper, an 80/20 mixlure of toluene-2,4-diisocyanate and 2,6-diiscyanate was used to determine the blocking temperatures for some blocked diisociyanates.
Journal ArticleDOI
On the Thermal Dissociation of Organic Compounds. X. The Effects of the Solvents (Amines and Fatty Acids) on the Thermal Dissociation of Urethans
Teruaki Mukaiyama,Yoichi Hoshino +1 more
Journal ArticleDOI
Curing kinetics of polyurethane reactions
TL;DR: In this article, the authors developed a kinetic model based on elementary reaction mechanisms to describe the phenomenon of limiting extent of reaction in polyurethane resins and applied it to experimental data available in the literature.
Journal ArticleDOI
On the Thermal Dissociation of Organic Compounds. XIV. The Effects of the Solvents and of the Substituents on the Thermal Dissociation of Urethans in Amines
TL;DR: The effects of amines, solvents and substituents on the dissociation of urethans in amines were studied and the kinetics of the dissociations were of the first order with respect to carbamates and of the second order withrespect to base.
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