Presented at the 6th International Conference on Polyolefin Characterization (ICPC), 2016. Shanghai, China.
Juan Sancho-Tello, Esther López, Pilar del Hierro, Alberto Ortín, Benjamín Monrabal. Polymer Char, Spain.
Wallace W. Yau. Polyolefin Characterization Consultant, USA.
GPC-QC is a simplified and compact high-temperature GPC instrument, developed for measuring the Molar Mass Distribution (MMD) in a manufacturing plant laboratory. It has been demonstrated that the total cycle time, including the sample dissolution step, could be reduced to around 30 min, well in line with the process control requirements. In order to achieve such high throughput a fast GPC column is used, and resolution is compromised.
In order to enhance the molar mass and intrinsic viscosity distributions generated by the GPC-QC with dual detector (IR + online viscometer) and provide molar mass averages consistent with research-grade HT-GPC instruments, band broadening correction must be implemented. A theoretically sound, and at the same time convenient and reliable, algorithm has been developed in the past and here it has been adapted for implementation in GPC-QC data treatment software. It is based on estimation of an Effective Volume Offset (EVO) between IR and viscometer, and derivation of broadening correction variance and correction factors for each detector and distribution.
The calibration procedures here presented allow extracting complete and consistent information from the GPC-QC analysis while helping to keep the system in control, ensuring long-term reproducibility.