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Method of regulating polypropylene crystallization behavior and crystal structure

A crystalline structure, polypropylene technology, applied in the direction of temperature control using electric methods, auxiliary controllers with auxiliary heating devices, instruments, etc., can solve the problem of not being able to meet the needs of self-nucleation to regulate crystallization behavior, and unable to self-nucleate temperature Precise control, low temperature control precision and other problems, to achieve the effect of simple operation, high control precision and precise control

Active Publication Date: 2012-04-11
FUDAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the use of DSC can only process milligram-level samples, and the regulated samples are difficult to test or further research on mechanical properties.
[0003] Large-sized samples can be prepared by using industrial production equipment, such as molding machines, injection machines, etc., but the temperature control accuracy of such equipment is low, and it is impossible to control the self-nucleation temperature more accurately, and cannot satisfy the self-nucleation regulation crystallization behavior needs

Method used

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  • Method of regulating polypropylene crystallization behavior and crystal structure
  • Method of regulating polypropylene crystallization behavior and crystal structure
  • Method of regulating polypropylene crystallization behavior and crystal structure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Isotactic polypropylene discs with a diameter of 25 mm were pressed in a hot press. The grade F401 homopolypropylene (manufactured by Yangzi Petrochemical Company) was heated to 200°C in the ARES rheometer and melted for 5 minutes, the distance between the plates was adjusted to 0.5mm, and the heating was stopped, so that the sample was naturally cooled to 50°C in the furnace. Then, slowly raise the temperature to 169.5° C., ensuring that the temperature will not overshoot during the heating process. Keep the temperature at 169.5°C for about 2 minutes, then execute the dynamic small-amplitude dynamic mode, cool the sample to 130°C for isothermal crystallization, and record the change of the storage modulus of the sample. The change curve of the isothermal crystallization modulus is as follows: figure 1 shown. As observed in the figure, the semi-crystallization time of isotactic polypropylene is about 300s. Using DSC to investigate the self-nucleating isotactic polypro...

Embodiment 2

[0018] Isotactic polypropylene discs with a diameter of 25 mm were pressed in a hot press. The isotactic polypropylene sample was heated to 200°C and melted for 5 minutes in the ARES rheometer, the distance between the plates was adjusted to 0.5 mm, the heating was stopped, and the sample was naturally cooled to 50°C in the furnace. Then, slowly raise the temperature to 171.0° C. to ensure that the temperature will not overshoot during the heating process. Keep the temperature at 171.0°C for about 2 minutes, then execute the dynamic small-amplitude dynamic mode, cool the sample to 130°C for isothermal crystallization, and record the change of the storage modulus of the sample. The change curve of the isothermal crystallization modulus is as follows: image 3 shown. As observed in the figure, the half-crystallization time of isotactic polypropylene is about 1400s. Using DSC to investigate the self-nucleating isotactic polypropylene sample at 171.0 °C, the crystallization temp...

Embodiment 3

[0020] Others are the same as in Example 1, but the clamp diameter of the parallel plate rheometer used is 50 mm. The obtained spherulite diameter is about 45 μm.

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Abstract

The invention belongs to the technical field of chemical control and detection, and particularly relates to a method of regulating isotactic polypropylene (iPP) crystallization behavior and crystal structure. The invention is characterized in that a parallel-plate rheometer is used as a tool, and the crystal structure of polypropylene is regulated by the spontaneous nucleation characteristic of semi-crystalline polymer. The spontaneous nucleation temperature is regulated by precise temperature control of the rheometer so as to obtain isotactic polypropylene with various crystal structures. The method can not only prepare samples for performance tests, but also monitor the crystallization process of isotactic polypropylene, and realize on-line observation of the spontaneous nucleation effect. The method has the advantages of simple operations, precise regulation, and the like, and has wide application prospects in the fields of fine chemical industry and the like.

Description

technical field [0001] The invention belongs to the technical field of chemical control and detection, and in particular relates to a method for regulating and controlling the crystallization behavior and crystallization structure of isotactic polypropylene (iPP). Background technique [0002] Isotactic polypropylene (iPP) is a polyolefin material widely used in industry. The regular chain structure makes iPP have a high crystallization tendency. At the same time, iPP is a typical homogeneous polycrystalline polymer, and its crystallinity, crystal composition and crystal morphology are important factors that determine the performance of the final product. Different geometric packing leads to different unit cell structures, and the three most common crystal forms in iPP are α, β, and γ crystal forms, respectively. In industrial production and theoretical research, in order to obtain a product with a specific performance, or to study the influence of other factors such as cry...

Claims

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Application Information

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IPC IPC(8): C08L23/12C08L23/14G01N11/00G05D23/30
Inventor 冯嘉春田野菲宋士杰赵义清
Owner FUDAN UNIV
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