Features of High Temperature SEC Column

The GPC UT-800 columns have been developed to prevent shear degradation in the high molecular weight range. The existence of shear degradation can be confirmed using a multi angle laser light scattering(MALS) detector, which has high sensitivity in the high molecular weight range and can measure absolute molecular weight. This shows the comparison of results of analysis of high density polyethylene(HDPE) using conventional columns and UT-806M columns. Detection was performed using MALS and RI detectors. With conventional columns, the highest molecular weight portion detected was around 5,000,000. On the contrary, with UT-806M, the highest molecular weight portion was around 20,000,000 and the results show that high molecular weight portions which cannot be measured using conventional columns exist. Regarding weighted mean molecular weight values(Mw) obtained from GPC calibration curves, Mw using UT-806M columns is higher than tat using conventional columns. From the above results, it can be concluded that shear degradation in the high molecular weight range occurred with conventional columns, but, not with UT-806M columns.

Product name	Particle size (microm)	Mw of HDP
		A	B
GPC UT-806M	30	1,000,000	468,000
Conventional column	12	712,000	333,000
(A) Mw(PS) : obtained from calibration curve (B) Mw(PE) : Mw(PE)=A x 0.468

Sample : 0.3% HDPE-A, High density polyethylene, 500micro-L

Columns      : Shodex GPC UT-806M (8.0mmID*300mm) x 2
Eluent       : 0.1% BHT*/ODCB
Flow rate    : 1.0mL/min
Detector     : RI, MALS(Multi angle laser light scattering)
Column temp. : 145deg-C

*BHT: Butylhydroxytoluene