The effects of nanoconfinement on the reaction kinetics and properties of a monocyanate ester and the resulting cyanurate trimer are studied using differential scanning calorimetry (DSC). On the basis of both dynamic heating scans and isothermal reaction studies, the reaction rate is found to increase with decreasing nanopore size without a change in reaction mechanism. Both the monocyanate ester reactant and cyanurate product show reduced glass transition temperatures (T(g)s) as compared to the bulk; the T(g) depression increases with conversion and is more pronounced for the fully reacted product, suggesting that molecular stiffness influences the magnitude of nanoconfinement effects. Our results are consistent with the accelerated reaction and the T(g) depression found previously for the nanoconfined difunctional cyanate ester, supporting the supposition that intracyclization is not the origin of these effects.
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http://dx.doi.org/10.1021/jp912235c | DOI Listing |
Molecules
January 2019
Kazan Federal University, 18 Kremlevskaya Street, 420008, Kazan, Russia.
We described a synthetic approach to bisphenol-based monocyanate esters based on mono--methylation of parental bisphenols followed by cyanation of the residual phenolic hydroxyl. Structures of the synthesized compounds were determined by the application of IR, NMR ¹H and C spectroscopies, EI and MALDI mass spectrometry, and purity of the final product was controlled by HPLC. We showed that stability of the cyanate esters depends on the nature of the bridging group.
View Article and Find Full Text PDFJ Phys Chem B
February 2011
Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, USA.
A kinetic study of the trimerization of monocyanate ester both in the bulk and in the nanoconfinement of controlled pore glass is performed using differential scanning calorimetry. Both isothermal and dynamic experiments are analyzed. Although the activation energy for the reaction is the same within experimental error for the bulk and nanoconfined samples (approximately 21-23 kcal/mol), the reaction is accelerated under nanoconfinement by approximately 50 times in 13 nm pores compared with bulk.
View Article and Find Full Text PDFJ Phys Chem B
June 2010
Department of Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, USA.
The effects of nanoconfinement on the reaction kinetics and properties of a monocyanate ester and the resulting cyanurate trimer are studied using differential scanning calorimetry (DSC). On the basis of both dynamic heating scans and isothermal reaction studies, the reaction rate is found to increase with decreasing nanopore size without a change in reaction mechanism. Both the monocyanate ester reactant and cyanurate product show reduced glass transition temperatures (T(g)s) as compared to the bulk; the T(g) depression increases with conversion and is more pronounced for the fully reacted product, suggesting that molecular stiffness influences the magnitude of nanoconfinement effects.
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