Graphene material helium transmittance test methods and instruments

Abstract:The barrier performance of graphene to gas is one of the directions of
its application research.

In this paper, helium is used as the permeable gas, and the differential pressure gas permeation instrument is used to test the barrier performance of graphene samples to helium, and introduces the test principle, equipment parameters and scope of application, test process, etc.
, to provide a reference
for the study and testing of graphene or other materials on oxygen, nitrogen, carbon dioxide, sulfur hexafluoride, helium and other gases.

Keywords: helium permeability, differential pressure gas permeability, graphene, gas permeability, barrier performance 1, significance graphene as a hot emerging material in recent years, with excellent optical, electrical, mechanical properties, in electronics, optics, magnetism, biomedicine, catalysis, energy storage and sensors and other aspects have broad application prospects
.

The dense internal structure determines that graphene has excellent barrier properties, how to use or change the barrier properties is an important research direction of graphene, such as graphene gas barrier film, high permeability graphene filtration membrane, etc
.

Helium is an inert gas with the smallest molecular diameter, which is widely used in aerospace, medical, optoelectronic products production and other industries, and is also used in the preparation of graphene products and the
study of gas permeability.

In this paper, the test process of helium transmittance of graphene is used as an example to introduce an effective graphene gas barrier performance detection technology
.

2.
Test samplesThis paper takes the graphene film provided by a research institute as the test sample
.

3, the test method of thin film material gas permeability test method is mainly divided into two kinds of differential pressure method principle and isobaric method, differential pressure method can test more types of gases, isobaric method can only be used for oxygen transmittance test, therefore, this test reference using differential pressure method for testing, the test is based on GB/T 1038-2000 "plastic film and sheet gas permeability test method differential pressure method"
.

4.
Test equipmentThis paper adopts VAC-V2 differential pressure gas osmometer for test equipment to test the helium transmittance of samples, which is independently developed and produced
by Jinan Languang Electromechanical Technology Co.
, Ltd.

4.
1 Test principle The principle of differential pressure method is to obtain the gas permeability
of the material by monitoring the change of gas pressure in the low pressure chamber of the equipment by the pressure sensor.

The clamped specimen divides the test chamber of the equipment into two test chambers, the upper cavity is filled with test gas, in this case helium, and the lower chamber forms a low-pressure environment
by vacuuming.

At the beginning of infiltration, the helium in the upper cavity under the action of the pressure difference, from the upper cavity through the specimen into the lower cavity, causing a change in the gas pressure in the lower cavity, the pressure sensor in the lower cavity real-time monitoring of the lower cavity pressure with the osmosis time, and based on this to obtain the helium permeability
of the specimen.

4.
2 Scope of application (1) This equipment is professionally used for the test
of gas transmittance, permeability coefficient, solubility coefficient and diffusion coefficient of a variety of thin films and sheet specimens at various temperatures.

l Film: such as a variety of plastic films, paper-plastic composite films, co-extrusion films, aluminized films, aluminum foil, aluminum foil composite films and other film-like materials
.

l Sheet: such as a variety of engineering plastics, rubber, building materials and other sheet materials, such as PP sheet, PVC sheet, PVDC sheet
.

(2) This equipment can also be extended to aerospace materials, paper and cardboard, paint film, glass fiber cloth, glass fiber paper, cosmetic hose sheet, various rubber sheets and other materials for air permeability test
.

(3) This equipment is suitable for transmission rate testing of a variety of gases, such as oxygen, carbon dioxide, nitrogen, helium, air, etc
.

(4) The equipment can meet a number of national and international standards, such as ISO 15105-1, ISO 2556, GB/T 1038, ASTM D1434, JIS K7126-1, YBB00082003 and so on
.

4.
3 The test range of the equipment parameters is 0.
05 ~ 50,000 cm3/(m2·24h·0.
1MPa), and the vacuum resolution can reach 0.
1 Pa; The temperature control range is 5°C ~ 95°C, and the temperature control accuracy is ±0.
1°C; The humidity control range is 0%RH, 2%RH ~ 98.
5%RH, 100% RH, and the humidity control accuracy is ±1%RH, which can meet the testing needs of customers under different test conditions; There are three completely independent test chambers that allow three identical or different specimens to be tested simultaneously; Data fitting at any temperature can be carried out to easily obtain test results under special test conditions; After restructuring, it can also support the testing of toxic gases and flammable and explosive gases; Provide standard membranes for quick calibration to ensure the accuracy and versatility of test data; Support LystemTM laboratory data sharing system for unified management of test results and test reports
.

5.
Test process (1) Sample Cut 3 specimens with a diameter of 97 mm from the surface of the graphene film sample
.

(2) Loading Spray a layer of vacuum grease around the three test chambers, and then place a piece of filter paper with a diameter of 65 mm in the test area in the middle of each test chamber to support the specimen and prevent contamination
of the low pressure chamber.

Finally, paste the specimen flat on the test chamber, close the chamber and tighten it
.

(3) Test equipment connected to helium, set the specimen name, thickness, test temperature, test humidity and other parameter information on the control software, click the test start option, open the vacuum pump, and the test starts
.

(4) The end of the test The equipment automatically completes the upper cavity inflation - lower cavity vacuuming - upper and lower chamber vacuuming - upper cavity inflation - test penetration process in accordance with the set parameters, and after the test is completed, the equipment displays the test results
.

6.
Test resultsThe test results of the three specimens tested in this test are 1.
0113 cm3/(m2·24h·0.
1MPa), 1.
1848 cm3/(m2·24h·0.
1MPa), 1.
2007 cm3/(m2·24h·0.
1MPa), and the helium transmittance of graphene samples is the average of the three specimen test results 1.
1323 cm3/(m2·24h·0.
1MPa).

。
7.
Conclusion This paper introduces the detection technology
of testing the gas barrier performance of graphene materials by using the principle of differential pressure method.

The equipment is simple to operate, high degree of intelligence, reducing the process of human operation; The test results have high precision and good accuracy, which can truly reflect the barrier performance
of the tested graphene samples against helium.

Labthink Languang is a professional production and development of packaging testing equipment, providing efficient and reliable packaging testing services technology enterprises, over the years for the global customers to provide tens of thousands of times oxygen barrier testing equipment and services
.

To understand the relevant testing equipment and services, you can log on to the website of Jinan Languang Company to view specific information or call for consultation
.

Labthink Languang looks forward to enhancing technical exchanges and cooperation
with enterprises in the industry.