Bicycles

Self-curing resin finds use in a tougher bicycle helmet

Self-curing resin finds use in...
Once commercially available, the helmet should "offer the same protection of current top-tier helmets, but potentially at the price of mid-tier helmets"
Once commercially available, the helmet should "offer the same protection of current top-tier helmets, but potentially at the price of mid-tier helmets"
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From left to right: Research associate Goram Gohel, Assoc. Prof. Leong Kah Fai and research fellow Dr. Bhudolia Somen Kumar, with some of their helmets
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From left to right: Research associate Goram Gohel, Assoc. Prof. Leong Kah Fai and research fellow Dr. Bhudolia Somen Kumar, with some of their helmets

Once commercially available, the helmet should "offer the same protection of current top-tier helmets, but potentially at the price of mid-tier helmets"
2/2
Once commercially available, the helmet should "offer the same protection of current top-tier helmets, but potentially at the price of mid-tier helmets"

Bike helmets work by absorbing impact energy that would otherwise be passed through to the wearer's head. An experimental new helmet is claimed to do so better than conventional models, thanks to a special resin.

With a few notable exceptions, bicycle helmets typically consist of an outer plastic shell that dissipates impact energy by cracking, along with an underlying expanded polystyrene foam liner that compresses to absorb impact energy, further reducing the amount that reaches the rider's head.

Led by Assoc. Prof. Leong Kah Fai, scientists at Singapore's Nanyang Technological University (NTU) are developing a helmet in which the shell is instead made of carbon fiber impregnated with a thermoplastic resin known as Elium.

Made by French materials company Arkema, Elium gradually hardens into a solid at room temperature, unlike other resins that have to be heated in order to cure. This quality, along with its low viscosity, reportedly allows it to more thoroughly impregnate the carbon fibers, boosting the toughness of the resulting composite.

From left to right: Research associate Goram Gohel, Assoc. Prof. Leong Kah Fai and research fellow Dr. Bhudolia Somen Kumar, with some of their helmets
From left to right: Research associate Goram Gohel, Assoc. Prof. Leong Kah Fai and research fellow Dr. Bhudolia Somen Kumar, with some of their helmets

According to NTU, the Elium-infused shell of its prototype helmet is tougher, stiffer and less brittle than a traditional polycarbonate shell, allowing it to absorb more impact energy over a longer period of time (in other words, over a larger number of milliseconds per impact).

As a result, lab tests indicate that whereas the foam liner of a polycarbonate-shelled helmet has to absorb about 75 percent of the total impact energy, the liner of the Elium-shelled helmet only has to absorb about 35 percent. Additionally, the composite shell should be cheaper to manufacture than those made of traditional thermoplastics, which have to be molded at high temperatures.

It should be noted that the present prototype helmet is about 20 percent heavier than its conventional counterparts. The researchers hope to address this shortcoming by replacing the carbon fiber with lighter-weight polypropylene fabric.

Source: Nanyang Technological University

5 comments
5 comments
Martin Hone
So this is a more traditional resin-infused carbonfibre helmet. Traditional resins such as polyester, vinyl-ester and epoxy set at room temperature, so I don't see anything new here. Plastic helmets usually transfer the impact to the liner, whereas fibreglass delaminates thereby absorbing some of the impact and spreads the load before it is absorbed by the liner.
Bob Stuart
System Three "Phase Two" epoxy resin sets at room temperature and has a branching fracture pattern that absorbs great amounts of energy. Carbon fiber's great virtue is stiffness, which is not appropriate for crash protection. I'm glad they are replacing it. Spectra fiber, made from linear polyethylene, is very tough, beating Aramid which is also far tougher than 'glass or carbon.
Bricorn
As it is it's nothing revolutionary. What they need to do is to make cheaper units that could be used in bike dealers to customise the helmet to the rider's head shape. That I'd buy.
neon-yellow
Eliminating need for wasting all that heat energy represents an appealing manufacture process which may be considered revolutionary for its energy savings.
Worzel
While bike helmets may protect the rider from a cracked skull, they wont protect from a broken neck! The impact to a helmet, is eventually transmitted to the neck, so dont risk accidents under false illusions.