Page 62 - Plastics News June 2017

TECHNOLOGY

University of Bath scientists make biodegradable microbeads

from cellulose

cientists and engineers from the University of sewage treatment works, or even in the environment in
SBath, UK, have developed biodegradable a short period of time.
cellulosemicrobeads from a sustainable source that could
potentially replace harmful plastic ones that contribute The researchers anticipate they could use cellulose from a
to ocean pollution. range of ‘waste’ sources, including from the paper making
industry as a renewable source of raw material.

Dr Janet Scott, reader in the department of chemistry
and part of the CSCT, said, “Microbeadsused in
the cosmetics industry are often made of polyethylene
or polypropylene, which are cheap and easy to make.
However these polymers are derived from oil and they
take hundreds of years to break down in the environment.
We have developed a way of makingmicrobeads from
cellulose, which is not only from a renewable source,
but also biodegrades into harmless sugars. We hope in
the future these could be used as a direct replacement
forplastic microbeads.”
Microbeads are little spheres of plastic less than 0.5
mm in size that are added to personal care and cleaning Davide Mattia, professor of Chemical Engineering and
products including cosmetics, sunscreens and fillers to give part of the CSCT, said, “Our goal was to develop a
them a smooth texture. However they are too small to continuous process that could be scaled for manufacturing.
be removed by sewage filtration systems and so end up in We achieved this by working together from the start,
rivers and oceans, where they are ingested by birds, fish integrating process design and chemistry optimisation,
and other marine life. It is estimated that a single shower showing the strength of the multi-disciplinary approach
can result in 100,000 plastic particles entering the ocean, we have in the CSCT.” The beads are made using a
contributing to the eight million tonnes of plastic that solution of cellulose which is forced through tiny holes
enters the ocean every year. It is feared that the particles in a tubular membrane, creating spherical droplets of
could enter the food chain, harming wildlife but also the solution which are washed away from the membrane
potentially ending up in our food. using vegetable oil. The beads are then collected, set and
separated from the oil before use.
As a result of recent campaigning by environmental groups,
the UK Government has pledged to ban plasticmicrobeads in The physical properties of the beads can be tweaked
2017. Now a research team, from the University’s Centre by changing the structure of the cellulose, for example
for Sustainable Chemical Technologies (CSCT), has making the beads harder. A team, led by Dr Scott and
developed a way of producing a biodegradable renewable including Professor Davide Mattia (chemical engineering)
alternative to plastic microbeadsin a scalable, continuous and Professor Karen Edler (chemistry) has also just been
manufacturing process. awarded funding of just over £ 1 million by the Engineering
& Physical Sciences Research Council to develop porous
The beads are made from cellulose, which is the material
that forms the tough fibres found in wood and plants. In beads, capsules and microsponges.
this process our scientists dissolve the cellulose to reform They will work with industrial partners, to develop
it into tiny beads by forming droplets that are then ‘set’. materials that could be used in cosmeticsand personal
These microbeads are robust enough to remain stable in care products, or impregnated with agrichemicals for use
a bodywash, but can be broken down by organisms at the in, for example, slow release fertilisers.

Plastics News | June 2017 62