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Testing method of beta-form crystal content in non-planar polypropylene material

A polypropylene material and testing method technology, applied in the analysis of materials, using wave/particle radiation for material analysis, measuring devices, etc., can solve the problems that affect the content of β crystals, cannot truly reflect the content of β crystals, and large system errors, etc. To achieve the effect of accurate content determination

Inactive Publication Date: 2019-02-15
FUZHOU UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Although method 2 can evaluate the β-crystal content of the sample before pretreatment, different heating rates (that is, different test conditions) will affect the β-crystal content
Due to the many factors involved in the separation or fitting of the two peaks during the analysis process, the reproducibility of the calculation results is poor, and they are only estimates
At the same time, the β crystal is a thermodynamically metastable structure, and phase transition or recrystallization will inevitably occur during the heating process, which will bring large system errors
[0009] Method 3 prepares additional samples, which cannot truly reflect the content of β crystals in the product

Method used

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  • Testing method of beta-form crystal content in non-planar polypropylene material
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  • Testing method of beta-form crystal content in non-planar polypropylene material

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Experimental program
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Effect test

Embodiment 1

[0028] A test method for beta crystal content in non-planar polypropylene material, comprising the following steps:

[0029] Sample preparation method: from d n Cut a 2cm pipe section from a 25mm S2.5 β crystal form PP-RCT pipe fitting, use a slicer to cut out a relatively flat plane, and then polish it sequentially with a 300-mesh, 500-mesh, and 1000-mesh whetstone (not suitable for direct grinding, and the number of times of grinding is limited) Too much heat will cause crystal phase transformation), and a 1cm×1cm plane is produced.

[0030] Through the above method, the β→α transformation in the preparation process is minimized. The prepared sample adopts 4° / min scanning speed to measure the XRD spectrum of the sample, as figure 1 shown.

[0031] Use MDI Jade software to subtract the background (reduce the influence of thermal slow scattering, air scattering, fluorescence and electronic noise, etc.), smooth the line (reduce the influence of accidental factors), divide th...

Embodiment 2

[0037] A test method for beta crystal content in non-planar polypropylene material, comprising the following steps:

[0038] Sample preparation method: from d n Cut a 2cm pipe section from a 25mm S2.5 β crystal form PP-RCT pipe fitting, and grind it for 40 minutes with a liquid nitrogen freezing grinder at a temperature of -35°C, and sieve it to control the particle size of the ground powder to about 20 μm.

[0039] Through the above method, the β→α transformation in the preparation process is minimized. The prepared sample adopts 4° / min scanning speed to measure the XRD spectrum of the sample, as image 3 shown.

[0040] Use MDI Jade software to subtract the background (reduce the influence of thermal slow scattering, air scattering, fluorescence and electronic noise, etc.), smooth the line (reduce the influence of accidental factors), divide the peaks and refine the fitting, such as Figure 4 shown.

[0041] According to the data obtained by the peak splitting process, t...

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Abstract

The invention discloses a testing method of beta-form crystal content in a non-planar polypropylene material. The method comprises the following steps: preparing a plane conforming to test requirements by cutting a relatively flat plane with a microtome and then grinding sequentially with sharpening stones which are have different meshes; or, preparing a plane by grinding and sieving with a liquidnitrogen freezer mill at a temperature which is maintained at a polypropylene brittle temperature; and then measuring the X-ray diffraction pattern of the sample, and calculating the beta-form crystal content by a Turner-Jones formula. Compared with a conventional testing method, the testing method of Beta-form crystal content in the non-planar polypropylene material can more accurately reflect the actual beta-form crystal content of the product.

Description

technical field [0001] The invention belongs to the technical field of polypropylene material detection, in particular to a method for testing the beta crystal content of non-planar polypropylene materials. Background technique [0002] Polypropylene (PP) is a semi-crystalline polymer, and its crystallinity, crystal form, crystal content and crystal structure have a great influence on the macroscopic properties. Under different crystallization conditions, polypropylene can produce a variety of crystal structures, mainly monoclinic (α), hexagonal (β), triclinic (γ), smectic (δ) and pseudohexagonal crystals. The α crystal form is the most stable and the most common crystal form in commercial polypropylene. However, due to its low impact strength and heat distortion temperature, the use of polypropylene is limited to a certain extent. The β crystal form is thermodynamically metastable and kinetically unfavorable to the crystal form formed. High-content β-crystalline polyprop...

Claims

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Application Information

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IPC IPC(8): G01N23/2005G01N23/207
CPCG01N23/2005G01N23/207G01N2223/056G01N2223/1016
Inventor 郑玉婴肖潇赵波
Owner FUZHOU UNIVERSITY