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Detection method for rapid determination of melt index and molecular weight of fiber-type polypropylene special-purpose material

A melting index and detection method technology, applied in the chemical industry, can solve the problems of waste liquid, such as great environmental impact, high operation requirements, and non-representation, and achieve the effects of low sample uniformity requirements, fast method, and low cost

Inactive Publication Date: 2016-06-15
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When measuring molecular weight by high-temperature gel permeation chromatography, 1,2,4-trichlorobenzene is used as a solvent for fiber-type polypropylene special material samples, and 2,6-di-tert-butyl-4-methylphenol is used as an anti- Oxygen agent, 1,2,4-trichlorobenzene is a highly toxic chemical, which is very toxic to the respiratory tract, skin and mucous membrane tissue of the test operator, and the waste liquid after use has a great impact on the environment; the standard The operation steps in the method are complicated, and it is often necessary to configure polystyrene solutions of different concentrations to generate a standard calibration curve, which requires high operation requirements; in addition, it takes at least 3-6 hours to dissolve the sample with a solvent in this method, making the entire test cycle relatively long. In addition, due to the small amount of fiber-type polypropylene sample used in this test, about 20mg, which is collected locally in the sample, higher requirements are placed on the uniformity of the sample itself, otherwise the measured value cannot represent the characteristics of the entire sample

Method used

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  • Detection method for rapid determination of melt index and molecular weight of fiber-type polypropylene special-purpose material
  • Detection method for rapid determination of melt index and molecular weight of fiber-type polypropylene special-purpose material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Use a mold to place a granular sample of fiber-type polypropylene special material with known weight-average molecular weight and melt index on a hot press, melt it at 180°C for 3 minutes, then apply a pressure of 4Mpa and continue hot pressing for 1 minute, and press to obtain Use the test sample; place the sample on a flat fixture with a diameter of 20mm in a strain-controlled rheometer. The applied detection frequency range is 10 -7 -628rad / s, set the temperature to 180°C, apply 5% strain, set the detection frequency range to 0.01-100rad / s, take 3 data points for each order of magnitude in logarithmic mode, set the integration time to 1 cycle, and measure Get the exponential scaling relationship between the zero-shear viscosity characteristic value and the melt index (MI) of fiber-type polypropylene special material, see figure 1 , the calculated pre-exponential factor is 5.75×10 4 , the exponent is -1.16, namely: η 0 =5.75×10 4 MI -1.16 ; Zero-shear viscosity a...

Embodiment 2

[0049] Use a mold to place a granular sample of fiber-type polypropylene special material with known weight-average molecular weight and melt index on a hot press, melt it at 180°C for 2 minutes, then apply a pressure of 3Mpa and continue hot pressing for 1 minute, and press to obtain Use the test sample; place the sample on a flat fixture with a diameter of 15mm in a strain-controlled rheometer. The applied detection frequency range is 10 -7 -628rad / s, set the temperature to 180°C, apply a strain of 1%, set the detection frequency range to 0.001-100rad / s, take 3 data points for each order of magnitude in logarithmic mode, set the integration time to 1 cycle, and measure The exponential scaling relationship between the zero-shear viscosity characteristic value and the melt index (MI) of fiber-type polypropylene special material is: η 0 =7.55×10 4 MI -1.21 ; Zero-shear viscosity and fiber-type polypropylene special material weight average molecular weight (M w ) The exponen...

Embodiment 3

[0052] Use a mold to place a granular sample of fiber-type polypropylene special material with known weight-average molecular weight and melt index on a hot press, melt it at 190°C for 3 minutes, then apply a pressure of 5Mpa and continue hot pressing for 2 minutes, and press to obtain Use a test piece; place the piece on a flat fixture of a strain-controlled rheometer with a diameter of 25mm. The applied detection frequency range is 10 -7 -628rad / s, set the temperature to 200°C, apply 8% strain, set the detection frequency range to 0.01-600rad / s, take 5 data points for each order of magnitude in logarithmic mode, set the integration time to 2 cycles, and measure The exponential scaling relationship between the zero-shear viscosity characteristic value and the melt index (MI) of fiber-type polypropylene special material is: η 0 =6.97×10 4 MI -1.23 ; Zero-shear viscosity and fiber-type polypropylene special material weight average molecular weight (M w ) has an exponential ...

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Abstract

A detection method for quickly determining the melt index and weight-average molecular weight of fiber-type polypropylene special materials: first, the known and to-be-measured fiber-type polypropylene special materials with melt index and weight-average molecular weight are made into test samples; then the known The test samples of melt index and weight average molecular weight are respectively placed on the fixture of the strain-controlled rheometer, and the zero-shear viscosity η of the fiber-type polypropylene special material with known melt index and weight average molecular weight is measured 0 , so as to determine the scale relationship between the melt index and weight-average molecular weight of the fiber-type polypropylene special material and the zero-shear viscosity; The zero-shear viscosity η of the fiber-type polypropylene special material whose melt index and weight-average molecular weight are to be measured 0 ; Finally, through the fiber-type polypropylene special material melt index and weight average molecular weight and zero-shear viscosity η 0 The scale relation calculated its melt index and weight average molecular weight.

Description

technical field [0001] The invention relates to a detection method in the field of chemical industry, in particular to a detection method for quickly determining the melt index and weight average molecular weight of fiber-type polypropylene special materials by using the linear viscoelastic characteristics of polymers. Background technique [0002] Fiber-type polypropylene special materials are widely used in non-woven fabrics, carpets, artificial turf, decorative fabrics and other industries, and the domestic market demand is very large. Several large petrochemical companies in China have successively launched fiber-type polypropylene special materials with a melt index in the range of 10-50g / 10min, but they still cannot meet the current domestic market demand. The melt index and molecular weight of fiber-type polypropylene special materials have a crucial influence on its spinning performance. Fiber-type polypropylene special materials with high melt index are close to Ne...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N11/00G01N1/28
Inventor 娄立娟陈商涛黄强黄伟欢吴林美王艳芳姜凯张凤波
Owner PETROCHINA CO LTD
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