Polycarbonate is a 'thermoplastic' ...it is not a composite material....
Composite material is a combination of different materials ie. polyester resin and glass or carbon rovings etc.
Everything that you didn't want to know.....
"Polycarbonates received their name because they are polymers having functional groups linked together by carbonate groups (-O-(C=O)-O-) in a long molecular chain. Also carbon monoxide was used as a C1-synthon on an industrial scale to produce diphenyl carbonate, being later trans-esterified with a diphenolic derivative affording poly (aromatic carbonate)s.
Taking into consideration the C1-synthon polycarbonates can be divided into poly(aromatic carbonate)s and poly(aliphatic carbonate)s. The latter are a product of the reaction of carbon dioxide with epoxides, which owing to the kinetic stability of carbon dioxide requires the use of a catalyst. The working systems are based on porphyrins, alkoxides, carboxylates, salens and beta-diiminates as organic, chelating ligands and aluminium, zinc, cobalt and chromium as the metal centres. Poly(aliphatic carbonate)s display promising characteristics, have a better biodegradability than the aromatic ones and could be employed to develop other specialty polymers.[citation needed]
The most common type of polycarbonate plastic is made from bisphenol A (BPA).[2] This polycarbonate is a very durable material, and can be laminated to make bullet-proof "glass", though “bullet-resistant” would be more accurate. Although polycarbonate has high impact-resistance, it has low scratch-resistance and so a hard coating is applied to polycarbonate eyewear lenses and polycarbonate exterior automotive components. The characteristics of polycarbonate are quite like those of polymethyl methacrylate (PMMA; acrylic), but polycarbonate is stronger, usable in a larger temperature range and more expensive. This polymer is highly transparent to visible light and has better light transmission characteristics than many kinds of glass. CR-39 is a specific polycarbonate material — although it is usually referred to as CR-39 plastic — with good optical and mechanical properties, frequently used for eyeglass lenses."
As can be figured out from the above information, polycarbonate would not make very good engine covers as it has limited abrasion resistance which gets worse as the materials temperature rises....the reason I would never consider a PC helmet..puncture resistance after scraping down the road for even a few seconds.....zip.
BTW. chopping boards are generally polyethylene or polypropelyne....
Why am I such a fountain of useless knowledge......over 10 years in the plastics injection moulding industry.

the poly car bonnet...
