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The
possibility of using the NMR-MOUSE®
for non-destructive on-line monitoring of adhesive
curing for front window panes of cars has been
investigated. The samples studied were heat-curing as
well as moisture-curing polyurethane rubber. The
adhesives were positioned in between sheets of 6 mm
thick glass and 0.8 mm thick iron. The T2-measurements
took place at a depth of 7 - 9 mm using a CPMG sequence.
Cured and uncured PUR differed in T2 by a factor 2.
Measurements at temperatures in between 10 °C and 45 °C
showed that T2 depends on temperature. Four different
rubber types could be distinguished by T2 measurements.
All these measurements showed the possibility of
detecting the change of molecular mobility following the
curing process.
For the moisture cured and the 2K PUR samples the
complete curing processes were followed in time. A
striking result was, that curing of moisture-curing PUR
takes much longer than expected. Furthermore, defects in
moisture cured samples could be detected by the
NMR-MOUSE®
by changes in the signal amplitudes. |
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Fig. 1: CPMG
data of cured
and uncured PUR |
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