Quantitative estimation of the degree of derivatization: an alternative methodology using 1‐D and 2‐D NMR experiments

Abstract

The precise estimation of the degree of derivatization of functional groups in polymers is important for determining their macroscopic properties. In this work, the quantitative estimation of the extent of esterification of novolac copolymers with di-tert-butyl dicarbonate was studied. Although the extent of esterification has been calculated previously by quantifying the signals from FT-IR and UV-Vis spectroscopy, these were restricted to monitoring the progress of the derivatization process. The 13C NMR signal intensities from the inverse-gated 1H-decoupled NMR spectrum have been used recently for the quantitative estimation of the degree of esterification of polymers. An alternative methodology has been suggested by us based on the fully relaxed 1H chemical shift intensities. However, since the proton signals of novolac resins are generally broad and overlapping, the proton decoupled 13C NMR spectrum was used to identify the 1H NMR signals using the 2-D HSQC technique. A TOCSY experiment was also performed to confirm further the 1H NMR signal assignments and, finally, the deconvoluted 1H NMR spectrum was used for the calculation of the extent of derivatization.

m/p‐Cresol–based t‐BOC protected alternating “high ortho” copolymer as a possible e‐beam resist: Characterization using multidimensional NMR spectroscopy

“…9 Wet development image formation using e-beam exposure has also been discussed t-BOC has been used as an esterifying agent because it increases the glass transition temperature T g and provides ''enhanced cleavage mechanism'' of the polymer. 10 In our earlier work, a m/p-cresol-based semialternating ''high ortho'' novolac copolymer 11 and CNSL/m-cresol based alternating ''high ortho'' novolac copolymer 12 were derivatized using di-tert-butyl dicarbonate. In this study, a m/p-cresol-based alternating ''high ortho'' copolymer has been esterified using di-tert-butyl dicarbonate, which makes it alkali insoluble.…”

“…In our earlier work, a m / p ‐cresol–based semialternating “high ortho” novolac copolymer11 and CNSL/ m ‐cresol based alternating “high ortho” novolac copolymer12 were derivatized using di‐ tert ‐butyl dicarbonate. In this study, a m / p ‐cresol–based alternating “high ortho” copolymer has been esterified using di‐ tert ‐butyl dicarbonate, which makes it alkali insoluble.…”

Cashew nut shell liquid based t‐BOC protected alternating “high ortho” copolymer as a possible e‐beam resist: Characterization using multi‐dimensional NMR spectroscopy

“…12 Wet development image formation using e-beam exposure has also been discussed t-BOC has been used as an esterifying agent because it increases the glass transition temperature T g and provides 'enhanced cleavage mechanism' of the polymer. 13 In our earlier work, 14 a m/p-cresol-based semialternating ''high ortho'' novolac copolymer was derivatized using di-t-butyl dicarbonate. In the present study, a cardanol/m-cresol-based alternating ''high ortho'' copolymer has been esterified using di-t-butyl dicarbonate, which makes it alkali insoluble.…”

“…In our earlier work,14 a m / p ‐cresol‐based semialternating “high ortho” novolac copolymer was derivatized using di‐ t ‐butyl dicarbonate. In the present study, a cardanol/ m ‐cresol‐based alternating “high ortho” copolymer has been esterified using di‐ t ‐butyl dicarbonate, which makes it alkali insoluble.…”