OCSiAl, Daikin develop 'highly durable' graphene nanotube technology

LUXEMBOURG—Graphene nanotube supplier OCSiAl and fluorine technologies specialist Daikin Industries Ltd. have developed a graphene nanotube technology for "highly durable, electrically conductive fluoroelastomer (FKM) compounds with improved heat stability."

The new compound maintains chemical and high heat-resistance properties of FKM while improving its performance in terms of tear resistance and tensile strength, said OCSiAl in a Feb. 3 statement.

Furthermore, the new compound's improved electrically conductive properties will make it suitable for applications in electric vehicles components and various electrostatic discharge control areas.

"Standard conductive fillers bring a number of negative trade-offs to elastomers in terms of flexibility and elasticity, said Jupei Terada of Daikin's marketing department, chemicals division.

"This leads to hardening and a reduced life cycle of the final parts, which is critical in FKMs where the original hardness is already high," he said.

As part of the project, the partners introduced 0.3 percent of OCSiAl's Tuball-branded graphene nanotubes to FKM rubber to make the compounds anti-static with volume electrical resistivity below 10 Ω∙cm.

At the same time, the low working dosage allowed producers to avoid the negative trade-offs typical for other conductive additives in terms of hardness, extrusion rate, and degradation of mechanical strength and elastic behavior.

Tests at 200°C showed that FKM samples modified with nanotubes demonstrated improvement in tear strength of up to 61 percent, tensile strength of up to 92 percent, M50 of up to 71 percent, compared to reference material. The samples also showed better elastic properties, while also retaining hardness, said the OCSiAl statement.

In addition, assessment after heat ageing showed "significantly improved" mechanical property stability and retained elasticity compared to reference material.

The new compound showed a tear strength of almost 80 percent higher and modulus up to 54 percent higher compared to reference materials, while retained elastic properties were indicated after ageing at 230°C.

Nanotube-reinforced fluoroelastomers are currently being developed for applications in the automotive and equipment construction sectors, and can be used in seals, O-rings, hoses for hybrid vehicles, rubber jacketing materials, as well as rubber parts used in robotic factories.