Taking the silk road to tougher fabric

RP scientists' supersilk can be used in bulletproof vests, airplane parts
Grace Chua Straits Times 28 Apr 12;

IN THE past two years, materials scientist Willy Tan has gone from farming silkworms to weaving their silk into fabric, all in the name of science.

Now, he aims to turn the fruit of that labour into a $66 million-a-year business, putting enhanced silkworm silk into materials for bulletproof vests, lightweight airplane body parts and automotive parts.

Defence engineering firm ST Kinetics reckons such high-tech materials are worth that much to it, so it has chipped in $3 million to set up a new laboratory at Republic Polytechnic (RP), where Dr Tan is a senior academic staff member in the School of Applied Science.

The new lab, called the Advanced Composite Engineering Lab, opened earlier this month. It will offer RP students an avenue for their final-year research studies and host three to five interns a year.

Dr Tan got involved with the silkworm project in 2008 when the school was casting about for a project to commercialise. Then, it worked with National University of Singapore researchers who had filed a patent for a method to make silkworm silk stronger.

That is done by exposing the worm to an electric field before it spins its silk cocoon, causing the crystals in silk proteins to line up in a way that strengthens the strand.

In 2010, Dr Tan set up a laboratory at RP that now produces 20,000 cocoons at a time. A typical commercial silkworm farm produces about 100,000 cocoons at a go.

In the past two years, he and his colleagues have run tests on the 'supersilk', which is up to 40 per cent stronger than ordinary silk and needs two to three times the force before it breaks.

The enhanced silk also stretches 12 times as much and is lighter than current synthetic materials such as Kevlar, making it ideal for reinforced vests and helmets, for instance.

The team even visited silk farms and textile factories in Taiwan and China, and bought equipment like a state-of-the-art weaving machine for prototypes.

Woven different ways, the silk fabric also has different properties, which Dr Tan and his colleagues are now testing.

Currently, the supersilk costs $150 per kg to produce in the lab, but the cost will fall to about $80 at commercial scale.

That is cheaper than synthetic Kevlar, the material used in vests and helmets, which costs about $160 per kg.

Besides the ST Kinetics funding, the project has been supported by $2 million worth of research grants from the Ministry of Education and National Research Foundation, among others.

The RP scientists are not the only ones with an eye on silkworms. Last year, researchers from the Agency for Science, Technology and Research produced coloured and luminescent silk by feeding their silkworms various dyes.

Next, Dr Tan wants to add spider silk to the fabric to make it even stronger.

Spider silk is notoriously difficult to mass produce, but he has gone round to parks to harvest spider-web samples and work out how to make spiders produce their sticky webs on demand.

'I'm not a biologist,' Dr Tan said. 'There are so many new things that we've had to learn.'