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CFC Frequently Asked Questions

We are aware that acquiring a lab instrument is an important decision, furthermore if Polyolefins’ research is related with your core business.

Although you can ask directly to our consultants whenever you want, you may prefer to know first the answers to the most typical questions about our instruments. Here are packed the most relevant questions about CFC.


Questions


Answers

Which is the purpose of CFC instrument?
CFC instrument is a fully automated analytical scale instrument to obtain the bivariate distribution of polyolefins in composition and molar mass. Three dimensional distribution relating molar mass and composition variables is often required for comprehensive characterization of complex materials, and complete cross-fractionation is the only technique which determines it with no loss of information.

This compact automated instrument fractionates the polymer according to crystallinity, following a TREF process (Temperature Rising Elution Fractionation), meanwhile the resulting fractions are continuously injected towards online GPC columns where a second fractionation, this time according to molar mass, is performed.

Polymer Char’s analytical CFC technology overcomes the difficulties of preparative fractionation methods which are tedious and time consuming. The full bivariate distribution is now measured in hours instead of days, with limited solvent consumption and no manual intervention, in an intrinsically safe setup.

Does CFC provide the physical fractions from the temperature steps?
CFC is an analytical instrument designed to obtain the bivariate distribution in a three dimensional plot as well as recovered GPC and TREF profiles in a fully automated way, but it doesn’t provide any physical fraction. It might be possible to collect the TREF fractions as they elute from the columns, however the instrument is not optimized for this and the process is not automated. Please refer to the PREP mc2 for an automated fractionation instrument.

How many samples can be run at a time and how long will they take?
Up to 42 samples can be run with no supervision required, in about 12 hours per sample under good resolution conditions (>20 temperature fractions).

How many grams of sample do I need for a CFC analysis?
The standard amount used in CFC analysis is around 100mg per sample.

Which solvents can be used?
1.2.4-Trichlorobenzene (TCB) and Orto-Dichlorobenzene (oDCB) are the most used solvents. Perchloroethylene could be used too. To use other solvents please consult Polymer Char first.

What kind of sample preparation is required by the user?
No samples preparation is required by the user but weighing the dry samples and putting them inside of the vials in the autosampler tray. The rest of the steps are performed by the instrument automatically: filling, dissolution, TREF column loading, crystallization, elution, GPC columns injection, final cleaning, etc. Therefore, when a run is finished, another one can be started immediately.

Do I need to handle solvents?
Solvents don’t need to be handled at any time; the whole process is fully automated and the instrument is in charge of all the needed steps: filling, dissolution, TREF column loading, crystallization, elution, GPC columns injection, final cleaning, etc.

Which kind of samples can be analyzed?
LLDPE, LDPE, HDPE, PP, E-P copolymers, multicatalyst reactor resins, and any semicrystalline polymer soluble in TCB or oDCB, giving response to C-H absorption.

Which is the detector used for concentration in CFC?
CFC incorporates an infrared detector to measure the concentration of each fraction going out of the TREF column and then being injected into the GPC columns. This detector is Polymer Char’s IR4 in its OEM version and therefore a composition sensor can be incorporated as well to obtain methyls or carbonyls content information. However, the use of IR5 detector instead is Polymer Char's recommendation for this instrument thanks to its outstanding sensitivity both in concentration and in composition.

Where are the columns located?
CFC instrument incorporates a TREF column, which is located in the main oven where the temperature ramps can be performed. GPC columns connection will be done in the instrument top oven, always kept at a constant high temperature for its optimum preservation.

How can I access and review my results?
After each sample analysis, data can already be accessed and calculated through the CFC software database. A powerful calculations package is included, capable of obtaining directly the 3 dimensional plot for the study of the interdependence of the Molecular Weight and the Chemical Composition Distribution of each sample. In addition to the 3D plot, the GPC and TREF recovered profiles are calculated too.

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