Situ determination of DPC and BPA in polycarbonate by Raman spectroscopy
AssigneeGeneral Electric Company
InventorsRadislav Alexandrovich Potyrailo, Ronald Eugene Shaffer, Patrick Joseph McCloskey
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Abstract
The present invention provides a method for monitoring a reaction mixture using Raman spectroscopy. In a preferred embodiment, the invention provides a method for monitoring bulk and thin film melt polycarbonate polymerization reactions. In this method, the relative and absolute concentrations of the starting materials diphenylcarbonate (DPC) and bisphenol-A (BPA) are determined. Monitoring and maintenance of optimum stoichiometry in such a reaction is critical to ensuring desired polycarbonate product quality.
Claims70
A method for monitoring the process of polymer formation comprising:
- irradiating a polycarbonate or an intermediate thereof with a substantially monochromatic radiation;
- collecting a Raman spectrum corresponding to radiation scattered from the irradiated polycarbonate or intermediate thereof;
- monitoring at least one wavenumber of the Raman spectrum;
- correlating the monitored spectrum to at least one reaction component of interest;
- and
- applying a predetermined selection test to determine whether any one of a set of preselected reaction components needs to be adjusted.
A method for monitoring polycarbonate formation comprising:
- irradiating at least one polymer with substantially monochromatic radiation;
- collecting a Raman spectrum corresponding to radiation scattered from the irradiated polymer;
- measuring the intensity of at least two preselected Raman bands;
- correlating the intensity of at least two preselected Raman bands to the stoichiometry of sample diphenylcarbonate (DPC) and bisphenol-A (BPA);
- and
- applying a predetermined selection test to determine whether the input of DPC and BPA needs to be adjusted.
An apparatus for the nondestructive monitoring of polymer formation comprising:
- a light source, wherein said light source emits substantially monochromatic radiation to irradiate a sample of polycarbonate or intermediate thereof;
- a probe, wherein said probe transmits light from said light source to irradiate said sample of polycarbonate or intermediate thereof and collects radiation scattered from the irradiated sample corresponding to a Raman spectrum;
- and
- a detector, wherein said detector monitors at least one wavenumber of the collected Raman spectrum correlated to at least one reaction component of interest.
A method for monitoring polycarbonate formation comprising:
- irradiating at least one polymer, or an intermediate thereof, with substantially monochromatic radiation;
- collecting a Raman spectrum corresponding to radiation scattered from the irradiated polymer, or intermediate thereof;
- measuring the intensity of at least two preselected Raman bands;
- correlating the intensity of at least two preselected Raman bands to the stoichiometry of sample diphenylcarbonate (DPC) and bisphenol-A (BPA);
- and
- applying a predetermined selection test to determine whether the input of DPC and BPA needs to be adjusted.
Dependencies are inferred from the claim text.