On-line measurement and control of polymer properties by raman spectroscopy

A process for determining polymer properties in a fluidized-bed reactor system, the process comprising:

• (a) obtaining a locally weighted regression model for determining a polymer property selected from density, melt flow rate, molecular weight, molecular weight distribution, and functions thereof, the locally weighted regression model including principal component loadings and principal component scores;
• (b) acquiring a Raman spectrum of a sample comprising polyolefin particles;
• (c) calculating a new principal component score from at least a portion of the Raman spectrum and the principal component loadings;
• and
• (d) calculating the polymer property by applying the new principal component score to the locally weighted regression model.

A process for controlling polymer properties in a polymerization reactor system, the process comprising:

• (a) obtaining a regression model for determining a polymer property, the regression model including principal component loadings and principal component scores;
• (b) acquiring a Raman spectrum of a sample comprising polyolefin;
• (c) calculating a new principal component score from at least a portion of the Raman spectrum and the principal component loadings;
• (d) calculating the polymer property by applying the new principal component score to the regression model;
• and
• (e) adjusting at least one polymerization parameter based on the calculated polymer property.

A process for controlling polymer properties in a fluidized reactor system, the process comprising:

• (a) obtaining a locally weighted regression model for determining a polymer property selected from density, melt flow rate, molecular weight, molecular weight distribution, and functions thereof, the locally weighted regression model including principal component loadings and principal component scores;
• (b) acquiring a Raman spectrum of a sample comprising polyolefin particles;
• (c) calculating a new principal component score from at least a portion of the Raman spectrum and the principal component loadings;
• (d) calculating the polymer property by applying the new principal component score to the locally weighted regression model;
• and
• (e) adjusting at least one polymerization parameter based on the calculated polymer property.