Page 62 - Plastics News November 2017

TECHNOLOGY

Mussel-inspired plastic may lead to self-repairing body armour

cientists Megan Valentine at the University of is without them, they said. Valentine says the material
SCalifornia, Santa Barbara, and her colleagues created could also find an application in the joints of robotic arms
a plastic with these same properties by mimicking the that need to bear heavy weights but still move around.
chemistry the mussels use. Molecular bonds between Someday, she says, it could even be used to repair the
iron and an organic compound called catechol make the tendons in our joints.
material difficult to break or tear, while still allowing it
to remain stretchy.
Three partner institutes
from Aachen present latest

advancements in injection
moulding

he Institute of Plastics Processing (IKV) in Industry
Tand the Skilled Crafts at RWTH Aachen University
together with the Fraunhofer Institutes for Production
Technology (IPT) and for Laser Technology (ILT)
presented the latest developments in the injection
moulding of optical components at Fakuma 2017.
The team have developed a new mussels inspired plastic Together the three partner institutes presented
that can stretch without snapping and repair its own the “Plastic optical components from Aachen”
molecular bonds, paving the way for self- repairing body Today, plastics have proved to be the material of the
armour. The material could also find an application in the future for optical devices such as lenses with varied
joints of robotic arms that need to bear heavy weights technological applications, which enable economical
but still move around, researchers said. Mussels and
some other molluscs hang onto solid surfaces using an
adhesive protein and tough, plastic like fibres, which are
extremely strong and can repair themselves when a few
molecular bonds within them are broken, they said. The
study, published in the journal Science, found that for a
mussel, these stretchy yet strong fibres come in handy
when a wave hits. The iron-catechol bonds dissipate
energy from something hitting or stretching the material.
These "sacrificial bonds" break, but the overall structure
stays intact. "It is like a bike helmet: if you are in a
bike accident, the foam inside the helmet crushes and
dissipates some of the energy. All that energy that would
have gone into a skull fracture, instead goes into the production as well. The highlight of the presentation
was on the production of micro-structured lenses of
helmet," Megan Valentine from University of California liquid silicone rubber (LSR). Thanks to its temperature
said. "In our case, instead of foam we have this sacrificial and UV stability, LSR is interesting for LEDs. Its
bonding that protects the underlying polymer system," flexibility and elasticity also open up innovative design
Valentine added. By sacrificing the iron-catechol bonds, concepts. Other areas include the automotive industry,
the material can stretch by 50 per cent. Then, once the like primary optics and diffuser lenses, and also in
stress is taken away, the bonds reform, making it reusable, mobile phone cameras, displays and lifestyle products.
researchers said. Adding these bonds results in the plastic The advancements in these areas concentrate on the
being 770 times stretchier and 58 times stronger than it design of optical systems.

Plastics News N ovember 2017 62