A. Murase et al., DISTRIBUTION ANALYSIS OF CARBOXYL GROUPS IN POLYMER BY A DERIVATIZATION ELECTRON PROBE X-RAY-MICROANALYSIS/, Bunseki Kagaku, 46(1), 1997, pp. 37-43
In order to determine the distribution of a small amount of carboxyl g
roups formed by the oxidation of polymers with micron-level lateral re
solution using an analytic method, referred to as ''derivatization-ele
ctron probe X-ray microanalysis (EPMA)'', the suitable condition of th
e derivatization reaction with carboxyl groups in polymers was investi
gated. It was found that carboxyl groups in polymer were derivatized s
electively using gas-phase esterification with 2,2,2-tribromoethanol (
TEE). Pyridine was used as a catalyst, and dicyclohexylcarbodiimide (D
CC) was used as a dehydration agent. The most suitable amounts of TBE,
pyridine, and DCC in a 50 ml reaction vessel were 70 mg, 70 mu g, and
50 mg, respectively. After setting a sample in the vessel without dir
ectly contacting the reagents, by heating the reagents and the sample
at ll0 degrees C for 2 hours, the highest reaction yield and selectivi
ty were obtained. By derivatization-EPMA using this derivatization con
dition, an analysis of the distributions of a small amount of carboxyl
groups in polymers with 3 mu m lateral resolution has become feasible
. For example, in the case of degraded polyethylene (PE), 0.6 units of
carboxyl groups per 10,000 ethylene units can be detected. The actual
applications to the depth analysis of degraded PE and Nylon-6 have pr
oved that this method is useful for the studies on polymer degradation
.