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Method for preparing polytetrafluoroethylene with high intensity and creep deformation resistance

A technology of polytetrafluoroethylene and tetrafluoroethylene, which is applied in the field of preparation of high-strength creep-resistant polytetrafluoroethylene

Inactive Publication Date: 2012-08-01
SHANGHAI 3F NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] In addition, the modified polytetrafluoroethylene prepared by the prior art still has room for improvement in terms of properties (such as tensile strength and elongation at break)

Method used

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  • Method for preparing polytetrafluoroethylene with high intensity and creep deformation resistance
  • Method for preparing polytetrafluoroethylene with high intensity and creep deformation resistance
  • Method for preparing polytetrafluoroethylene with high intensity and creep deformation resistance

Examples

Experimental program
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Effect test

preparation example Construction

[0021] The invention provides a suspension preparation method of modified polytetrafluoroethylene, which does not use fluorine-containing surfactants (such as perfluorosurfactants). The method of the present invention comprises the step of adding all or part of the perfluoroalkyl vinyl ether and / or perfluorodioxole comonomer into a vacuumized reaction vessel filled with water.

[0022] The present invention uses water as the reaction medium for suspension polymerization. In the method of the present invention, water is first injected into the reaction vessel. The amount of water added is not particularly limited, and it can be a conventional amount used in the art, for example, it can account for 1 / 3 to 2 / 3 of the volume of the reaction vessel. In one example of the present invention, the volume of added water accounts for 3 / 5±10% of the volume of the reaction vessel.

[0023] To prevent oxygen from interfering with the polymerization reaction, the reaction vessel containing...

Embodiment

[0051] testing method

[0052] 1. Determination of the content of monomer units derived from perfluoropropyl vinyl ether in the copolymer

[0053] The amount of monomer units derived from perfluoropropyl vinyl ether in the samples was determined by infrared spectroscopy. The specific method is: press the sample particles to be tested into a transparent film, then put the film on the Fourier infrared spectrometer for analysis, and calculate the wave number from the obtained infrared spectrum to be 2365cm -1 and 994cm -1 The absorption peak intensity A, calculates the mass percentage content that is derived from the monomer unit of perfluoropropyl vinyl ether (PPVE) according to the following formula:

[0054] PPVE% (mass percentage) = (A994 / A2365) × 0.95

[0055] Among them, A994 is at 994cm -1 The intensity of the absorption peak at

[0056] A2365 is at 2365cm -1 The intensity of the absorption peak at .

[0057] 2. Determination of the content of monomer units de...

Embodiment 1

[0070] Inject 30 liters of deionized water into the 50-liter reactor, use high-purity nitrogen with a purity of 99.99% to repeatedly replace the air in the reactor for at least 3 times, and then check the oxygen content in the reactor until the oxygen content is lower than 30ppm, and the oxygen content is qualified Vacuumize the reactor to a vacuum degree of 0.06MPa and heat up to 75°C, vacuum inhale 40 grams of perfluoropropyl vinyl ether, add 5ml of ammonia water and 2 grams of potassium persulfate, and raise the pressure of the tetrafluoroethylene monomer in the kettle to To 1.2MPa, start stirring to start the reaction.

[0071] Control the ratio of the amount of tetrafluoroethylene monomer to the amount of deionized water to 280kg / m 3 , Keep the reaction temperature fluctuating within the range of 75±5°C during the reaction. After the reaction is finished, unreacted tetrafluoroethylene monomer is recovered, and the pressure inside the kettle is released to obtain fibrous ...

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Abstract

The invention discloses a suspension method for preparing modified polytetrafluoroethylene. The method comprises the following steps of: (1) adding all or part of perfluoroalkyl vinyl ether and / or a perfluor dioxole comonomer into a vacuumized reactor with water, wherein the vacuum degree of the reactor is high enough to enable the perfluoroalkyl vinyl ether and / or the perfluor dioxole comonomer to be gasified in the reactor, and the alkyl of the perfluoroalkyl vinyl ether contains 1-5 carbon atoms; (2) adding a tetrafluoroethylene monomer; and (3) triggering polymerization reaction: when only part of the perfluoroalkyl vinyl ether and / or the perfluor dioxole comonomer is added in the step (1), continuously adding the residual perfluoroalkyl vinyl ether and / or perfluor dioxole comonomer during polymerization reaction, wherein according to the method, a fluorine-containing surface active agent is not used.

Description

technical field [0001] The invention relates to a preparation method of high-strength creep-resistant polytetrafluoroethylene. technical background [0002] Polytetrafluoroethylene (PTFE), commonly known as the king of plastics, is known for its unparalleled resistance to chemical media, excellent electrical insulation properties, low dielectric constant, extremely low coefficient of friction and long-term use in the temperature range of -180 to 260 ° C, etc. It has become an indispensable and important material in the fields of military and civilian use. [0003] There are two main preparation methods for polytetrafluoroethylene (PTFE): emulsion polymerization and suspension polymerization. The products prepared by the two methods have different properties, processing methods and application fields. [0004] The particles obtained by emulsion polymerization are easy to form fibers, and the paste extrusion process is mainly used. Products include various pipes, raw materi...

Claims

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Application Information

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IPC IPC(8): C08F214/26C08F216/14C08F234/02C08F2/18
Inventor 纪云刘越鹏
Owner SHANGHAI 3F NEW MATERIAL
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