FRP vs Plastic – Which one is better?

Fibre Reinforced Polymer (FRP) sounds more exotic than plastic. Plastic still suffers from the image of cheap imitation. However, it’s anything but, when used correctly.

These days, plastic parts are integral to everyday life, and are literally life saving. Without plastic, electrical appliances would be dangerous, planes, trains and automobiles would be heavier, noisier, uncomfortable and less safe. Equipment would break down more often. If you’re reading this in an office, note the screen, keyboard, printer, phone, router and calculator are largely plastic.

Engineering plastics have better abrasion resistance than metal, and naturally replace metal in many wear pads. FRP has no advantage over plastic in these applications.

So, why bother with Fibre Reinforced Polymers (FRP)?

Take modern car panels. Holden ute tailgates use FRP. They look like metal, but they do the same job and are lighter in weight. Overseas car manufacturers are making bonnets in FRP. Some modern military aircraft save weight with FRP panels. Power boats use FRP. But why not plastic?

FRP is stiffer and stronger. At high speeds, air and water impact and turbulence cause high stress and vibration on panels. FRP has a higher stiffness, strength and resistance to fatigue. It resists rippling or fracture. FRP is often laminated to metal for increased impact resistance e.g. wide body aircraft.

Plastic is perfect for items which are likely to suffer less dynamic stress, like appliance casings. Of course, there are exceptions, like Polycarbonate bullet-proof glass. FRP might work better in this application, except that FRP is opaque.

As a general rule, FRP is better for higher stress applications, while plastic is better for less demanding ones.