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CRYSTEX® 42 Frequently Asked Questions

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 the most relevant questions about CRYSTEX® 42.


Questions


Answers

What is the purpose of CRYSTEX 42 and CRYSTEX QC?
These two instruments automate the technique of the Xylene Solubles test. They are intended to measure the amorphous fraction of polypropylene and ethylene-propylene copolymers. The accuracy and precision of the Xylene Solubles test are very important to the process and product specifications of the resultant materials.

Traditionally, this test has been done using the gravimetric method, which requires manual operation along the whole process. As a result, the precision is poor and the procedure is time consuming and not safe.

Polymer Char’s CRYSTEX 42 and CRYSTEX QC instruments automate this technique obtaining high precision and accuracy in the results as well as avoiding manual solvents handling.

While CRYSTEX® QC was designed to be installed in each production plant to monitor in real time the process or the grade changes analyzing a significant amount of powder sample (up to 4 grams), CRYSTEX® 42, thanks to the incorporation of a high temperature autosampler with 42 positions, becomes a perfect complement to be used in a central lab, where large batches of pelletized more homogeneous samples need to be analyzed.

Are CRYSTEX 42 and CRYSTEX QC compatible with the ISO 6427 App. B?
Yes, they are.

Do CRYSTEX 42 or CRYSTEX QC provide the physical fractions in temperature?
CRYSTEX 42 and CRYSTEX QC are analytical instruments designed to measure the Soluble Fraction percentage in a fully automated way, but they don't provide any physical fraction. For this purpose, please read about PREP mc2 or PREP C20.

How many samples can be run at a time and how long will it take by CRYSTEX 42?
Up to 42 samples can be run by the CRYSTEX 42 autosampler, and each one takes approximately 90 minutes for analysis including dissolution.

How many samples can be run at a time and how long will it take by CRYSTEX QC?
One sample is performed in each run and complete process, including dissolution is carried out in about 2 hours.

How many grams of sample do I need for a CRYSTEX 42 analysis? And for CRYSTEX QC?
The standard amount used in CRYSTEX 42 analysis is around 200mg per sample and in CRYSTEX QC is 4g.

Due to the fact that the exact concentration is measured by the infrared detector during the analysis, there is no need of using the balance at all. Up to half a gram can be used for overcoming sample heterogeneity issues.

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.

Do CRYSTEX 42 and CRYSTEX QC obtain the Soluble Fraction percentage in PP without using Xylene?
Yes, it does. It has been shown that there is a good correlation between soluble measured in Xylene or in other solvents. Therefore, by applying the proper calibration, results obtained in other solvent can be translated to Xylene.

What kind of sample preparation is required by the user? How is the sample prepared?
No samples preparation is required by the user but putting the dry samples inside the vials in case of CRYSTEX 42 and in the bottle in case of the CRYSTEX QC (weighing doesn’t need to be precise). The rest of the steps are performed by the instrument automatically: vials filling, dissolution, crystallization, 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, the instrument is in charge of all the needed steps: vials filling, dissolution, crystallization, final cleaning, etc.

Which kind of samples can be analyzed?
This instrument is specially designed for the determination of the Soluble Fraction in polypropylene resins. With proper calibration it could be used to measure the amorphous fraction in any polyolefin.

Which is the detector used for the concentration measurement?
CRYSTEX 42 and CRYSTEX QC incorporate an infrared detector to measure the concentration of the solution both at high temperature when the sample is 100% dissolved and also at room temperature, to measure the percentage of the sample which remains in the solution after the crystallization cycle (rubber content). This detector is Polymer Char’s IR4 in its OEM version and therefore a composition sensor could be incorporated as well, to measure the methyls or carbonyls content on the whole sample and on the amorphous fraction.

Can I couple additional detectors to CRYSTEX 42 or to CRYSTEX QC?
A capillary viscometer and/or a composition sensor can be coupled to CRYSTEX 42 or CRYSTEX QC without adding complexity to the process. Therefore, additional information about the intrinsic viscosity and/or ethylene content on the whole sample and on the rubber content can be obtained with a similar analysis time.

How can I access and review my results?
Calculations can be accessed through the instrument database, storing all the samples previously analyzed. Results will provide directly the XS% per sample as well as the concentration measured by the infrared detector, as a result, there is no need of an accurate sample weighing before the process.

When additional detectors are incorporated to the instrument equipment, intrinsic viscosity results and methyls content will be shown per sample as well, both from the whole sample and also from the rubber content percentage.

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