New bamboo-reinforced plastic absorbs electromagnetic waves while improving strength and toughness

With the proliferation of electronic devices, manufacturers are faced with the challenge of avoiding unwanted electromagnetic interference.Chinese researchers have developed a bamboo plastic composite with enhanced mechanical strength and electromagnetic wave absorption properties, which may offer a new route for protecting electronic devices.

The material was developed by Anhui Agricultural University in Hefei.They claim the composite could be useful for applications needing both durable materials and electromagnetic shielding, such as parts for smartphones, laptops and other electronic devices.

The research is published in Sustainable Carbon Materials.

Bamboo waste is used as the base

The scientists used bamboo biochar, a carbon-rich material that is made by burning bamboo in an oxygen-poor environment.This process, called pyrolysis, turns the bamboo into a material suitable to be added to a plastic composite.

Biochar, as a viable renewable alternative to traditional conductive fillers, can be restricted in performance by its relatively poor electrical conductivity and weak bonding with plastics.To get around these challenges, the team changed the biochar before putting it into the fresh material.

The first step was to prepare biochar by heating bamboo powder under nitrogen.They then used flash Joule heating (also known as ohmic or resistive heating) to change the carbon structure with a short burst of electrical energy.

Next, they applied APTES to the particles, a chemical that helps the biochar and plastic stick together. The modified particles were positioned between layers of two biodegradable plastics: polylactic acid (PLA) and polybutylene adipate-co-terephthalate (PBAT).

The outcome was a layered structure was created to create pathways that help absorb and weaken incoming electromagnetic waves.

Also Read: Archaeologists discover rare 4,000-year-old stone tomb ahead of industrial development in Norway

Strength and toughness are improved

Laboratory measurements showed that the optimized composite achieved a tensile strength of 25.5 megapascals (MPa), an 81% increase.It was 173% harder, to 2.68 megajoules per cubic meter.

It also became more capable of stretching out before breaking. Its elongation rose from 11.5% to 24.7%, more than doubling its earlier value.

These results suggest that modifying the bamboo-derived carbon and arranging it in layers can improve many material properties simultaneously.

Absorbing electromagnetic waves instead of reflecting them

The new composite takes a different approach by absorbing most of the incoming electromagnetic energy rather than depending mainly on reflection.

Tests featured that it provided average electromagnetic shielding of 36.7 decibels (dB) across frequencies from 8.2 to 12.4 gigahertz (GHz). By comparison, a nonlayered composite having the same amount of filler achieved 7.5 dB of shielding.

The researchers attributed most of the shielding performance to absorption, which accounted for 30.8 dB, while reflection contributed 5.9 dB.

Potential applications in electronic devices

The combination of mechanical durability, electrical conductivity and electromagnetic absorption could make the composite useful in components that require both structural strength and protection against interference.

Smartphones, laptops and other electronic devices are among the possible applications identified by the researchers. However, the reported findings concern the material's laboratory performance and do not establish that it is already being used in commercial electronics.

The research provides a possible route for turning bamboo-derived biochar into a functional component of stronger, more effective electromagnetic shielding materials.


Source: Interesting Engineering