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Soluble Fraction Analysis



Like the gravimetric analysis, the Soluble Fraction test is aimed at measuring the soluble/amorphous fraction of polypropylene and ethylene-propylene copolymers.
The quantity of amorphous fraction has a significant influence on the properties and performance of PP resins, so its analysis is fundamental for controlling the quality in polypropylene production.

The soluble fraction measurement is performed by CRYSTEX, which is an automated method based on the TREF crystallization technique.
The CRYSTEX method is included in the ISO 16152:2022 as an automated method for the determination of xylene-soluble matter in polypropylene, alternative and equivalent to the manual gravimetric method. ISO 16152 is equivalent to the ASTM D5492 and to ISO 6427, Annex B.

In addition to measuring the amorphous or soluble fraction percentage, CRYSTEX also quantifies the ethylene content and intrinsic viscosity in the original sample, and in the amorphous and crystalline fractions.

Soluble Fraction Detectors



An infrared detector is used to measure the quantity of soluble/amorphous fraction.
The infrared detector also has a composition sensor that can measure the ethylene content in the whole sample, in the crystalline fraction, and in the amorphous fraction.



The intrinsic viscosity value of the whole sample and of the amorphous and crystalline fractions can be obtained by using a viscometer detector incorporated into the CRYSTEX Instruments.

Soluble Fraction Analysis Fees

To calculate the final cost, please use the base amount (‘Soluble Fraction’ in this case) and then add the corresponding amount for any additional results or services that you want to include.

CRYSTEX QC/42 (Price/Sample)First SampleAdditional Samples
Soluble Fraction454€372€
Additional Results:
Ethylene Content176€143€
Intrinsic Viscosity216€181€
Calibration for Composition229€0€
Calibration for Intrinsic Viscosity134€0€
Additional Services:
Standard Data Re-processing109€109€
Minimum sample amount CRYSTEX QC>10 g
Minimum sample amount CRYSTEX 42>1 g

Terms & Conditions

Analytical Services Frequently Asked Questions

The fractionation service is available thanks to the Instruments PREP mc2 and PREP C20, capable of fractionating samples by molecular weight or by composition (TREF or CRYSTAF). Please visit the link Preparative Fractionation for more information.

The resulting fractions are later analyzed by the corresponding technique (GPC or TREF/CRYSTAF) to check the good performance of the fractionation process. Finally, the physical fractions are sent back to the customer by courier service as well as the analysis results of the fractions, so the customer can check the separation.

An Excel report with a summary of the results and averages is sent. The report contains the soluble fraction results and their equivalent in Xylene, but it also shows the C2 content and IV for the whole sample, and the soluble and crystalline fractions. If you have any question about the information sent, contact

Please send an email to and we will be pleased to help you.

To order any analytical service, please fill in the Analytical Service Request Form. Provide all the information available about the samples to be analyzed. Sent forms will be processed as formal orders for Polymer Char records. All the information provided is considered confidential information.

If a previous quotation is required, please do not hesitate to let us know by sending an email to

Samples should be shipped to:

Polymer Characterization S.A.
Valencia Technology Park
Gustave Eiffel 8
Paterna, Valencia
E-46980, Spain
Attn.: Analytical Services Department

We highly recommend to use courier service instead of post mail to ensure your samples arrive in good condition.

You will receive the results in less than a week. If you plan to send more than 10 samples, please check with our lab, as the response time may be longer in this case.
This time is approximate, and it depends on the service queue in the laboratory at the time of the order. Polymer Char will inform the customer if the turnaround time is expected to be longer.

Please refer to our Analytical Services Terms and in the first chapter, you will find the necessary amount for each technique.

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This Privacy Policy affects as well to the Customers’ Samples’ Analysis’ results. If a Privacy Agreement is required by the Customer, please contact us.

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