Principal Component Analysis of Polyurethane Adhesive cured under Varying Environmental Conditions

Rotating three-dimensional Principal Component Analysis Plot, plotting the second, third and fourth Principal Components against each other. Mahalanobis distances calulated to encapsulate 95% of all measurement points.
Each dot represents one FTIR measurment with 36 measurements taken per sample. The samples consist of Polyurethane samples cured under varying environmental conditions. The conditions were 10°C, 23°C, 30°C and 40°C with the relative humidites set to 25%, 50% and 75% rH respectively. For the PCA the dirst derivative of the unprocessed spectra were used.