First off, latex is a form of poly-isoprene. The "isoprene" part here is the key chemical identity - the letter (so to speak) that repeats in the polymer. So latex is chemically quite distinct from polyurethane and polycarbonate.

Is polyurethane made of latex?

Polyurethane foam is made entirely synthetically.

There is no such thing as a natural PU mattress, in contrast to latex which can be 100% natural. There are three main grades of polyurethane foam. These are regular grade, high density, and high resiliency.

Can polyurethane cause allergies?

Isocyanates can cause “sensitization,” which means that some people may become allergic to isocyanates and could experience allergic reactions including: itching and watery eyes, skin rashes, asthma, and other breathing difficulties. Symptoms may also be delayed up to several hours after exposure.