Method for preparing nano-pore structured polyethylene terephthalate (PET) foams by foaming through supercritical CO2

A CO2, supercritical technology, applied in the field of preparing PET foaming materials with nanoporous structure, can solve the problems of poor signal-to-noise ratio, affecting gas diffusion properties, reducing equilibrium solubility, etc.

Inactive Publication Date: 2012-07-18
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the relatively slow crystallization rate of PET and the high pressure CO 2 Due to the poor signal noise ratio of the DSC curve in the environment, high-voltage DSC cannot be applied to CO 2 Study on Induced Crystallization Kinetics of PET
In fact, due to CO 2 Diffusion and CO 2 Induced crystallization exists at the same time and affects each other, that is, the existence of coupling between the two, CO 2 The study of inducing PET crystallization at room temperature is far more complicated than people imagined. On the one hand, CO 2 Dissolution in the PET matrix can induce polymer swelling, stress relaxation, and crystallization, and accelerate its crystallization rate; on the other hand, the increase of PET crystallinity will affect the gas diffusion properties and affect the final equilibrium solubility.

Method used

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  • Method for preparing nano-pore structured polyethylene terephthalate (PET) foams by foaming through supercritical CO2
  • Method for preparing nano-pore structured polyethylene terephthalate (PET) foams by foaming through supercritical CO2
  • Method for preparing nano-pore structured polyethylene terephthalate (PET) foams by foaming through supercritical CO2

Examples

Experimental program
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Effect test

Embodiment 1

[0031] Firstly, the above-prepared amorphous PET sheet is placed in an autoclave, and after the autoclave is sealed, it is first purged with low-pressure carbon dioxide gas three to four times to remove air, and then filled with supercritical carbon dioxide gas. Then the autoclave was immersed in a constant temperature water bath with CO 2 Diffused slowly into the PET matrix. After 10 days, the CO 2 The gas is vented, the autoclave is quickly opened, the PET sheet is taken out and quickly immersed in a high temperature silicone oil bath. Due to the rapid increase in the temperature of the PET matrix, the CO 2 In which the solubility decreases rapidly, CO 2 It is precipitated in the form of gas, and at the same time, the molecular chain of PET already has strong movement ability at this temperature, and the two together induce the nucleation and growth of bubbles. After 10 seconds, the PET samples were immersed in an ice-water bath to fix the cell morphology. The sample wa...

Embodiment 2

[0033] Firstly, the above-prepared amorphous PET sheet is placed in an autoclave, and after the autoclave is sealed, it is first purged with low-pressure carbon dioxide gas three to four times to remove air, and then filled with supercritical carbon dioxide gas. Then the autoclave was immersed in a constant temperature water bath with CO 2 Diffused slowly into the PET matrix. After 15 days, the CO 2 The gas is vented, the autoclave is quickly opened, the PET sheet is taken out and quickly immersed in a high temperature silicone oil bath. Due to the rapid increase in the temperature of the PET matrix, the CO 2 In which the solubility decreases rapidly, CO 2 It is precipitated in the form of gas, and at the same time, the molecular chain of PET already has strong movement ability at this temperature, and the two together induce the nucleation and growth of bubbles. After 10 seconds, the PET samples were immersed in an ice-water bath to fix the cell morphology. The sample wa...

Embodiment 3

[0035] Firstly, the above-prepared amorphous PET sheet is placed in an autoclave, and after the autoclave is sealed, it is first purged with low-pressure carbon dioxide gas three to four times to remove air, and then filled with supercritical carbon dioxide gas. Then the autoclave was immersed in a constant temperature water bath with CO 2 Diffused slowly into the PET matrix. After 20 days, the CO 2 The gas is vented, the autoclave is quickly opened, the PET sheet is taken out and quickly immersed in a high temperature silicone oil bath. Due to the rapid increase in the temperature of the PET matrix, the CO 2 In which the solubility decreases rapidly, CO 2 It is precipitated in the form of gas, and at the same time, the molecular chain of PET already has strong movement ability at this temperature, and the two together induce the nucleation and growth of bubbles. After 10 seconds, the PET samples were immersed in an ice-water bath to fix the cell morphology. The sample wa...

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Abstract

The invention aims to provide a method for preparing a polyethylene terephthalate (PET) nano-pore foaming material by inducing crystallization of PET through supercritical CO2, and aims to overcome the defect in the prior art and meet the development requirements of related fields. The PET is swelled and permeated by the supercritical CO2 at appropriate temperature, so that a large amount of CO2 can be dissolved in a PET substrate, and the crystallization of the PET can be induced when the concentration of the CO2 reaches a certain specific value; and therefore, a special crystal form and crystallinity distribution of the PET substrate are induced after the PET is swelled for appropriate time, temperature is quickly raised under the condition to make the CO2 in the PET substrate be supersaturated, and the foaming PET material with nano-aperture is obtained by nucleating and foaming.

Description

technical field [0001] This patent relates to a method for preparing polymer foam materials, in particular to a method using supercritical CO 2 A method for preparing a PET foam material with a nanoporous structure by combining the swelling and infiltration method with its induced crystallization. Background technique [0002] Polyethylene terephthalate (poly(ethylene terephthalate), PET) is a relatively cheap crystalline thermoplastic engineering plastic. Because of its high elastic modulus, high glass transition temperature (about 65-70°C) and good resistance to organic solvents and weathering, it is widely used in fiber textiles, films, container manufacturing and other fields. In some cases, it is even used as a substitute for commodity metals such as steel and aluminum. However, since PET is a semi-crystalline polymer with a linear molecular chain structure, the melt strength of the PET melt is low during processing in the molten state, and the merging and rupture of ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/12C08L67/02
Inventor 赵玲李大超刘涛
Owner EAST CHINA UNIV OF SCI & TECH
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