TOSOH
CUSTOMER MAGAZINE
Engineering plastics, such as ultra-high molecular weight polyolefins
or polyphenylene sulfides, excel other materials by their mechanical
strength and their resistance to chemical and physical degradation.
These properties turn into hurdles when it comes to characterization
of the polymers. They are crystalline and require elevated tempera-
tures or special solvents for complete dissolution. The GPC analysis
of engineering plastics at high temperatures requires specialized in-
struments and columns as high temperature is required throughout
the whole experiment to avoid re-crystallization and to ensure that
the sample remains in solution. The EcoSEC-HT GPC/SEC system pro-
vides stable thermostatization up to 220 °C. Integrated in a compact
design it offers autoinjector, pumps, oven, and an extremely stable
dual-flow refractive index (RI) detector with an independent tempera-
ture control.
The first step in high temperature polymer analysis is an efficient dis-
solution and filtration of samples prior to analysis. As the polymer
chain is stressed by heat and shaking sample preparation needs to
be very gentle. The best way to dissolve these polymers is moving
the sample carefully and applying an individual temperature program
until full dissolution has occurred. The optional DF-8321 sample pro-
cessing unit can process up to 24 samples at temperature programs
ranging from 40 to 220 °C. In addition samples can be filtered automa-
tically to avoid clogging of the GPC column.
Refractive index (RI) detection is the standard detection for GPC/SEC
applications. The new HT-GPC system offers a unique dual-flow RI
detector. The combination of a high performance heating system and
the dual flow RI detector speeds up equilibration time and reduces the
baseline noise in a very effective way. Figure 1 shows the equilibrati-
on of column temperature and detector signal at a flow rate of 1 mL/
min and a target temperature of 145 °C.
For optimum performance the GPC column should be carefully se-
lected to ideally fit the temperature and solvent conditions. The TS-
Kgel family offers a wide range of GPC/SEC columns with individual
pore sizes but also mixed-bed and multi-pore columns exhibiting line-
ar mass calibrations. The TSKgel GMH
HR
-HT2 series was developed
to complement the new high temperature GPC system when using
the maximum temperature range up to 220 °C. Figure 2 shows a GPC
analysis with RI-detection at 220°C.
The combination of HLC-8321GPC/HT and TSKgel GMH
HR
HT2 is a
powerful tool for GPC measurement of engineering plastics. An ac-
curate sample preparation is just as important as a stable RI detector
baseline. A stable RI detector baseline is required for successful ex-
periments in particular for repeatable and reproducible molar mass
average calculations.
HOT STUFF: HIGH TEMPERATURE GPC SYSTEM
A NEW COMPACT HIGH TEMPERATURE (HT) SYSTEM FOR GPC ANALYSIS AND CORRESPONDING GPC COLUMNS ARE THE LATEST
ADDITION TO TOSOH’S POLYMER ANALYSIS PLATFORM. EcoSEC-HT, THE ALL-IN-ONE GPC/SEC SYSTEM FOR THE ANALYSIS OF ENGINEE-
RING PLASTICS, PROVIDES STABLE THERMOSTATIZATION UP TO 220° C. THE TSKgel GMH
HR
-HT2 GPC COLUMNS WERE DEVELOPED TO
IDEALLY COMPLEMENT THE EcoSEC-HT.
06
WHAT’S NEW
GPC
6
8 10 12 14 16 18 20 22 24 26
Retention time (min)
0
20
40
60
80
100
-20
RI [mV]
0
50
100
150
200
Time (min)
200
100
-100
-300
-400
-500
-600
0
RI (mV)
Column Temp. (C)
RI
Column Temp.
-200
160
140
100
60
40
20
120
80
FIGURE 1: SYSTEM START-UP
Equilibration of temperature & RI signal
Figure 2: GPC ANALYSIS AT High Temperature
Polyphenylenesulfide (PPS) @ 220 °C, mobile phase: 1-chloronaphtalene; column:
TSKgel GMH
HR
-H(S)HT2 x 2
