ENGINEERING MATERIALS | PLASTICS
LIVING IN A MATERIALS WORLD
LD
Plastics play a practical role in our lives.
But, with the myriad available, as well as
the ecological repercussions, selecting
the right plastic for can be tricky.
Love it or hate it, live with it or
without it, plastic has come
a long way from the Bakelite
resin patented at the turn of
the 20th Century that revolutionised
how many consumer goods were
mass-manufactured. Lightweight,
durable and easy to work with,
like many resins today, it could be
moulded into an in nite number of
shapes.
So, how do you go about selecting
the best, most sustainable plastic
for your moulding venture today?
With more than 85,000 listed plastic
materials, and more than 45 polymer
families, Thomas Catinat, production
manager at Broanmain Plastics,
explains some of the common
compositions and characteristics of
materials that start in pellet form and
why, for the sake of ecology,
we should learn to respect
its purpose and consider
innovative ways to upcycle,
recycle and keep plastic out of
the waste stream.
BACK TO BASICS
Plastics are essentially atoms that are
grouped together to form molecules
called monomers. These monomers
link together to create polymers.
That’s why ‘poly’ features in so many
plastic materials names.
Polymers all offer varying degrees
of strength, resistance, elasticity and
even special features such as antibacterial
or UV protection. The choice
will depend on the application, for
example if it needs to withstand high
or extremely cold temperatures.
Narrowing the choices down
can feel daunting. Although most
customers know what they want,
an experienced moulder can make
recommendations based upon
the environment the component is
being used in, and help customers to
consider other usability factors, such
as slide action.
MAINSTAY MATERIALS
Polypropylene (PP) is generally
deemed the most versatile and
popular material for most applications.
It has a fairly high melting point, can
withstand daily wear and tear and
is resistant to cracking and stress,
even when exed. For this reason, it’s
often used in packaging applications,
such as snap on lids, bottle caps, or
medical tubing.
When replacing metal components
with plastic, PP can be used to reduce
weight providing the component won’t
be put under a high level of stress.
When high mechanical resistance is
needed, a stronger polymer, such as
nylon or a glass bre lling might be
used.
Another good feature of PP is, like
other thermoplastics, it can be melted
down to create new products. For
example, car parts, storage boxes,
plastic pallets and even garden
furniture.
Acrylonitrile Butadiene Styrene
(ABS) is also relatively inexpensive
and has good impact and chemical
Thomas Catinat,
production manager at
Broanmain Plastics
32 WWW.EUREKAMAGAZINE.CO.UK | JANUARY 2020
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