Method for measuring molecular weight distribution of linear polymer

A technology of molecular weight distribution and polymer, applied in the direction of measuring devices, analytical materials, instruments, etc., can solve problems such as ill-fitting, calibration method limitations, and limited application range

Inactive Publication Date: 2009-06-17
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

Examples

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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] At 275°C and 300°C, ARES (Advanced Rheological Extension System) was used to perform dynamic frequency scanning on the sample, and the measured data was equivalently translated to 300°C by time and temperature. Get the relationship between complex viscosity and frequency (such as figure 1 ) and dynamic storage modulus G′(ω) and dynamic loss modulus G″(ω) (such as figure 2 ).

[0037] In this example, within the instrument test range, the dynamic loss modulus G″ (ω) does not have a peak value, and the modulus is fitted with the Maxwell-wiechcert model (such as figure 2 ), get the first plateau modulus of FEP For: 1.41×10 6 Pa. :

[0038] The modulus of the first plateau Substitute into formula (5), formula (6), obtain FEP relative molecu...

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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 determining the molecular weight distribution of polymers, in particular a method for measuring the molecular weight distribution of linear polymers. 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, it is of great significance to characterize the molecular weight and distribution of polymers for the processing of materials and the improvement of mechanical properties. There are many methods for measuring the molecular weight distribution of polymers, such as light scattering method, ultracentrifugation sedimentation velocity method, electron microscopy 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 the fluorine-containing polymer, so it is difficult to...

Claims

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Application Information

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