Process and device for characterizing a sample of a crosslinked plastic material by its gel fraction during its continuous manufacture.

摘要

Process for characterising, by a gel content, a gelled, crosslinked or vulcanised sample manufactured continuously and the device for implementing it. The sample travels along in a proton or fluorine nuclear magnetic resonance apparatus at a temperature which is constant and higher than its melting or glass transition temperature. The ratio of frequency to magnetic induction is substantially constant and equal to 42.5749 megahertz tesla<-><1> for the hydrogen resonance and equal to 40.0532 megahertz tesla<-><1> for that of fluorine. The sample is subjected to at least one sequence of at least two pulses and the intensity of the signal relating to at least one echo is picked up. The gel content of the sample is deduced from this by comparison with a calibration curve. Its gel content is thus checked and action is taken on the product manufacturing line so as to bring the gel content to the desired value. Application to the continuous monitoring of the manufacture of polymers. <IMAGE>