INVESTIGADORES
STRUMIA Miriam Cristina
artículos
Título:
Methylolation of melamine with incipient condensation. I. Synthesis and characterization
Autor/es:
VERÓNICA NICOLAU; MARISA MARTINELLI; MIRIAM STRUMIA; DIANA ESTENOZ; GREGORIO MEIRA
Revista:
JOURNAL OF APPLIED POLYMER SCIENCE
Editorial:
JOHN WILEY & SONS INC
Referencias:
Año: 2009 p. 1030 - 1041
ISSN:
0021-8995
Resumen:
This work investigates five reactions
between melamine (M) and formaldehyde (F) at pH ¼ 9.0,
and with initial F : M ratios of 2. The samples were analyzed
by size exclusion chromatography (SEC), volumetric
techniques, and (1H and 13C) NMR. Condensation was
quantified by the SEC measurements. In the experiments
at 38 and 48C, condensation was almost negligible, and
the reversibility of methylolation reactions determined that
equilibriums were reached in the ratios between primary,
secondary, and tertiary amines. In the experiments at 60,
70, and 90C, condensation was significant, but in all
cases, the mass fraction of single-ringed species was larger
than that of species with two or more rings per molecule.
The following were estimated by combining the SEC and
volumetric measurements: number-average molecular
weights, and average functionalities of reactive Hs, methylols,
methylene bridges, and ether bridges. The dissolution
of M in water was essentially instantaneous. The
measurements are employed in the next article of this series
for adjusting a novel mathematical model¼ 9.0,
and with initial F : M ratios of 2. The samples were analyzed
by size exclusion chromatography (SEC), volumetric
techniques, and (1H and 13C) NMR. Condensation was
quantified by the SEC measurements. In the experiments
at 38 and 48C, condensation was almost negligible, and
the reversibility of methylolation reactions determined that
equilibriums were reached in the ratios between primary,
secondary, and tertiary amines. In the experiments at 60,
70, and 90C, condensation was significant, but in all
cases, the mass fraction of single-ringed species was larger
than that of species with two or more rings per molecule.
The following were estimated by combining the SEC and
volumetric measurements: number-average molecular
weights, and average functionalities of reactive Hs, methylols,
methylene bridges, and ether bridges. The dissolution
of M in water was essentially instantaneous. The
measurements are employed in the next article of this series
for adjusting a novel mathematical model1H and 13C) NMR. Condensation was
quantified by the SEC measurements. In the experiments
at 38 and 48C, condensation was almost negligible, and
the reversibility of methylolation reactions determined that
equilibriums were reached in the ratios between primary,
secondary, and tertiary amines. In the experiments at 60,
70, and 90C, condensation was significant, but in all
cases, the mass fraction of single-ringed species was larger
than that of species with two or more rings per molecule.
The following were estimated by combining the SEC and
volumetric measurements: number-average molecular
weights, and average functionalities of reactive Hs, methylols,
methylene bridges, and ether bridges. The dissolution
of M in water was essentially instantaneous. The
measurements are employed in the next article of this series
for adjusting a novel mathematical modelC, condensation was almost negligible, and
the reversibility of methylolation reactions determined that
equilibriums were reached in the ratios between primary,
secondary, and tertiary amines. In the experiments at 60,
70, and 90C, condensation was significant, but in all
cases, the mass fraction of single-ringed species was larger
than that of species with two or more rings per molecule.
The following were estimated by combining the SEC and
volumetric measurements: number-average molecular
weights, and average functionalities of reactive Hs, methylols,
methylene bridges, and ether bridges. The dissolution
of M in water was essentially instantaneous. The
measurements are employed in the next article of this series
for adjusting a novel mathematical modelC, condensation was significant, but in all
cases, the mass fraction of single-ringed species was larger
than that of species with two or more rings per molecule.
The following were estimated by combining the SEC and
volumetric measurements: number-average molecular
weights, and average functionalities of reactive Hs, methylols,
methylene bridges, and ether bridges. The dissolution
of M in water was essentially instantaneous. The
measurements are employed in the next article of this series
for adjusting a novel mathematical model