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Method for measuring molecular weight distribution of linear polymer

A technology of molecular weight distribution and polymers, applied in measuring devices, analytical materials, instruments, etc., can solve problems such as ill-posed, unsatisfactory results, and limited application range

Inactive Publication Date: 2012-01-11
ZHEJIANG UNIV
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Problems solved by technology

[0005] However, due to the ill-posed problem in the inversion process, the results given are not satisfactory
In the publication "W.H..Tuminello, Molecular weight and molecular weight distribution from dynamic measurements of polymer melts. Polymer Eng. and Sci, 1986, 26(19), P: 1339-1347", Tuminello proposed a method for calculating the molecular weight distribution of linear polymers. model, but due to the limitations of its calibration method, its application range is limited

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  • Method for measuring molecular weight distribution of linear polymer
  • Method for measuring molecular weight distribution of linear polymer
  • Method for measuring molecular weight distribution of linear polymer

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Embodiment Construction

[0034] Examples are given below to further illustrate the present invention.

[0035] Take the determination of the molecular weight distribution of polytetrafluoroethylene hexafluoropropylene copolymer (FEP) as an example:

[0036] Use ARES (Advanced Rheological Expansion System) to scan the sample dynamically at 275°C and 300°C, and the measured data will translate to 300°C when the temperature passes through. Get the relationship between complex viscosity and frequency (such as figure 1 ) And dynamic storage modulus G′(ω) and dynamic loss modulus G″(ω) (e.g. figure 2 ).

[0037] In this example, within the test range of the instrument, the dynamic loss modulus G″(ω) does not show a peak value. The Maxwell-wiechcert model is used to fit the modulus (such as figure 2 ), get the first platform modulus G of FEP N 0 For: 1.41×10 6 Pa. :

[0038] The first platform modulus G N 0 Substituting formula (5) and formula (6), the FEP relative molecular weight integral weight distribution f...

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Abstract

The invention relates to a method for measuring molecular weight distribution of a linear polymer. Rheological behavior of the polymer is measured by a dynamic rheological test, and a dynamic storage modulus curve is converted into a weight integral distribution curve of the molecular weight according to a mathematical model, and the integral distribution curve is differentiated to obtain the molecular weight distribution of the linear polymer. The method is based on the rheology, does not need dissolution of the polymer, overcomes the limit that the molecular weight of insolubles or indissolubles can not be or is difficult to be measured by the traditional measurement method without dissolution of the polymer based on the rheology, and help cheaply, rapidly and reliably measure the molecular weight distribution of linear polymers with environmental protection. The method can be programmed and embedded in rheological test software to expand the application range of a rheometer.

Description

Technical field [0001] The present invention relates to a method for measuring the molecular weight distribution of a polymer, especially a method for measuring the molecular weight distribution of a linear polymer. Background technique [0002] The mechanical properties of polymer materials are not only related to the molecular weight, but also closely related to the molecular weight distribution. Therefore, characterizing the molecular weight and distribution of polymers is of great significance to the processing of materials and the improvement of mechanical properties. There are many methods to measure the molecular weight distribution of polymers, such as light scattering method, ultracentrifugal sedimentation velocity method, electron microscope method, volume exclusion method, etc. These methods all require finding a suitable solvent for the polymer, but it is difficult to find a suitable solvent for fluorine-containing polymers, so it is difficult to measure the molecular...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N33/00G01N11/00
Inventor 沈烈李新军
Owner ZHEJIANG UNIV
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