Bengaluru, Sep 26
Here is good news for car
owners. A team of scientists from Germany and Finland has developed a
new type of rubber that can heal itself after a puncture -- a discovery
that means one may not have to call a mechanic after a flat tire.
The
development of this new material has been reported by Amit Das -- the
lead author -- and his colleagues in the latest issue of "Applied
Materials & Interfaces", a journal of the American Chemical Society.
Rubber
is made of long strands of molecules. When the tire is punctured, these
strands break. Traditionally, manufacturers add sulphur to ensure that
rubber is durable and elastic - a process known a vulcanisation. But
once the tire is pierced by a piece of glass or any sharp object, it
can't be patched for long-term use.
Now, for the first time, scientists have made tire-grade rubber using a new simple process that avoids vulcanization altogether.
"Here,
we describe a simple approach to converting commercially available and
widely used rubber into a highly elastic material with extraordinary
self-healing properties without using conventional cross-linking or
vulcanising agents," Das and colleagues report.
Testing -- by
different mechanical analysis and scanning electron microscopy -- showed
that a cut in the material healed at room temperature, a property that
could allow a tire to mend itself while parked.
They also found
that the process did not diminish the rubber's durability. The
researchers say their product could be further strengthened by adding
conventional fillers agents such as silica or carbon black.
Das
and his colleagues say their research was motivated by the pioneering
work of French scientists led by Ludwik Leibler who in 2008 created a
self-healing rubber-like material that could stretch to several times
its normal length when pulled.
However these prototypes were not stable over time, necessitating newer approach.
The
new research published by Das and colleagues in the ACS journal
outlines how the addition of carbon and nitrogen help broken chemical
bonds in rubber reform of their own accord.
"Modification of
commercially available butyl rubber into a self-healing product by
simple ionic transformation has not been reported before," the
scientists claim.
"Moreover, the cross-linked character of the
modified rubber without using any conventional curatives is first time
reported here."
According to the report, the ease of processing
and absence of non-toxic vulcanizing chemicals to synthesize such novel
self-healing rubbers "opens a new horizon in rubber technology and may
significantly increase interest in both commercial application and
academic research."
(K.S. Jayaraman can be contacted at [email protected])
