Thermal Stabilizer

An antioxidant function that is stably expressed even in ultra-high temperature ranges

Nanodiamonds can be applied as antioxidizing agents that function even at high temperatures ranging from 260 to 400°C. The outermost surfaces of nanodiamonds contain many sp2 carbon and oxygen functional groups. This surface structure is similar to that of hindered phenol-based resin additives, which are widely used as antioxidizing agents in general, and oxygen function groups on the nanodiamond surface are considered to have a radical-scavenging function (oxidation prevention function).

Oxygen function groups in the nanodiamond core (diamond structure at the center) and on the nanodiamond surface have extremely high heat resistance, and it has been confirmed that they exist stably even in high-temperature environments exceeding 300°C. Thanks to this high thermal stability, nanodiamonds are expected to function as antioxidizing agents even for engineering plastics and super engineering plastics (such as PEEK, polyimide, and polyamidimide), which existing antioxidizing agents are incapable of doing.

Cross-section of a primary particle (4-6 nm). The diamond core (sp³) is in the center, surrounded by amorphous carbon (sp²). An explanatory diagram showing that oxygen-based functional groups are attached to the particle surface.

Chemical structure showing a surface structure similar to that of hindered phenols. Multiple hydroxyl groups (OH) and carbonyl groups (C=O) are attached to each site of the polycyclic aromatic structure.

Reinforcement of the performance of high heat-resistance thin-film coatings

In applications for functioning with a thin layer film coating with super engineering plastics like polyimide and polyamidimide, the heat resistance performance tends to drop compared with the bulk properties. Nanodiamonds can be used as a material to provide reinforcement against such a decrease in heat-resistance performance.

A table showing the results of thermogravimetric analysis of three types of resin: PEEK, polyimide, and polyamideimide, at different temperatures: 420°C, 450°C, and 400°C.

Strength retention in high temperature environments

In the case of resin products intended to be used in high-temperature environments, thermal degradation due to high temperatures can be suppressed by the addition of nanodiamonds. This is expected to suppress degradation caused not only by the temperature in the operating environment but also that caused by frictional heat generated by sliding parts, heat transmitted from other parts in contact, and other sources. With PEEK, the effect of improving the tensile strength retention rate is confirmed, as shown in the following graph.

A scatter graph showing the relationship between heat aging time (0 to 1500 hours) and tensile strength retention (%) for PEEK at 300°C. Two types of data are shown: PEEK alone and PEEK with 0.5 wt% nanodiamonds (NDs) added. The PEEK with NDs added shows a higher strength retention rate overall.

Learn more about nanodiamonds

About nanodiamond solutions

Our unique ultrasmall diamond generation technology will transform the future.

Ultra reduction using sunlight

Using nanodiamonds, CO_₂ is decomposed semi-permanently and continuously converted into raw materials through exposure to sunlight alone.

Cell vital sign sensing

Nanodiamonds with high biocompatibility assess the condition of the body at the cellular level.

MEMS/NEMS diamond sensor

Technology to precisely arrange each individual nanodiamond particle on a substrate surface.

Thermal stabilizer

Nanodiamonds express stable antioxidant and heat-resistance functions as well as strength retention even at temperatures exceeding 300°C.

Anti-wear agent for lubricating oil

Low viscosity, heavy loads, or low speeds. Nanodiamonds are functional even under harsh conditions.